Use usize, simplify is_eof

.cargo/config.toml

@@ -1,14 +1,3 @@
 [alias]
 dev = "run --package ruff_dev --bin ruff_dev"
 benchmark = "bench -p ruff_benchmark --bench linter --bench formatter --"
-
-# statically link the C runtime so the executable does not depend on
-# that shared/dynamic library.
-#
-# See: https://github.com/astral-sh/ruff/issues/11503
-[target.'cfg(all(target_env="msvc", target_os = "windows"))']
-rustflags = ["-C", "target-feature=+crt-static"]
-
-[target.'wasm32-unknown-unknown']
-# See https://docs.rs/getrandom/latest/getrandom/#webassembly-support
-rustflags = ["--cfg", 'getrandom_backend="wasm_js"']

.config/nextest.toml

@@ -6,10 +6,3 @@ failure-output = "immediate-final"
 fail-fast = false
 
 status-level = "skip"
-
-# Mark tests that take longer than 1s as slow.
-# Terminate after 60s as a stop-gap measure to terminate on deadlock.
-slow-timeout =  { period = "1s", terminate-after = 60 }
-
-# Show slow jobs in the final summary
-final-status-level = "slow"

.devcontainer/devcontainer.json

@@ -20,7 +20,7 @@
 			"extensions": [
 				"ms-python.python",
 				"rust-lang.rust-analyzer",
-				"fill-labs.dependi",
+				"serayuzgur.crates",
 				"tamasfe.even-better-toml",
 				"Swellaby.vscode-rust-test-adapter",
 				"charliermarsh.ruff"

.editorconfig

@@ -17,7 +17,4 @@ indent_size = 4
 trim_trailing_whitespace = false
 
 [*.md]
-max_line_length = 100
-
-[*.toml]
-indent_size = 4
+max_line_length = 100

.gitattributes

@@ -8,20 +8,7 @@ crates/ruff_linter/resources/test/fixtures/pycodestyle/W391_3.py text eol=crlf
 crates/ruff_python_formatter/resources/test/fixtures/ruff/docstring_code_examples_crlf.py text eol=crlf
 crates/ruff_python_formatter/tests/snapshots/format@docstring_code_examples_crlf.py.snap text eol=crlf
 
-crates/ruff_python_parser/resources/invalid/re_lexing/line_continuation_windows_eol.py text eol=crlf
-crates/ruff_python_parser/resources/invalid/re_lex_logical_token_windows_eol.py text eol=crlf
-crates/ruff_python_parser/resources/invalid/re_lex_logical_token_mac_eol.py text eol=cr
-
-crates/ruff_linter/resources/test/fixtures/ruff/RUF046_CR.py text eol=cr
-crates/ruff_linter/resources/test/fixtures/ruff/RUF046_LF.py text eol=lf
-
-crates/ruff_linter/resources/test/fixtures/pyupgrade/UP018_CR.py text eol=cr
-crates/ruff_linter/resources/test/fixtures/pyupgrade/UP018_LF.py text eol=lf
-
 crates/ruff_python_parser/resources/inline linguist-generated=true
 
-ruff.schema.json -diff linguist-generated=true text=auto eol=lf
-ty.schema.json -diff linguist-generated=true text=auto eol=lf
-crates/ruff_python_ast/src/generated.rs -diff linguist-generated=true text=auto eol=lf
-crates/ruff_python_formatter/src/generated.rs -diff linguist-generated=true text=auto eol=lf
+ruff.schema.json linguist-generated=true text=auto eol=lf
 *.md.snap linguist-language=Markdown

.github/CODEOWNERS

@@ -9,16 +9,9 @@
 /crates/ruff_formatter/ @MichaReiser
 /crates/ruff_python_formatter/ @MichaReiser
 /crates/ruff_python_parser/ @MichaReiser @dhruvmanila
-/crates/ruff_annotate_snippets/ @BurntSushi
 
 # flake8-pyi
 /crates/ruff_linter/src/rules/flake8_pyi/ @AlexWaygood
 
-# Script for fuzzing the parser/ty etc.
-/python/py-fuzzer/ @AlexWaygood
-
-# ty
-/crates/ty* @carljm @MichaReiser @AlexWaygood @sharkdp @dcreager
-/crates/ruff_db/ @carljm @MichaReiser @AlexWaygood @sharkdp @dcreager
-/scripts/ty_benchmark/ @carljm @MichaReiser @AlexWaygood @sharkdp @dcreager
-/crates/ty_python_semantic @carljm @AlexWaygood @sharkdp @dcreager
+# Script for fuzzing the parser
+/scripts/fuzz-parser/ @AlexWaygood

.github/ISSUE_TEMPLATE.md

@@ -0,0 +1,12 @@
+<!--
+Thank you for taking the time to report an issue! We're glad to have you involved with Ruff.
+
+If you're filing a bug report, please consider including the following information:
+
+* List of keywords you searched for before creating this issue. Write them down here so that others can find this issue more easily and help provide feedback.
+  e.g. "RUF001", "unused variable", "Jupyter notebook"
+* A minimal code snippet that reproduces the bug.
+* The command you invoked (e.g., `ruff /path/to/file.py --fix`), ideally including the `--isolated` flag.
+* The current Ruff settings (any relevant sections from your `pyproject.toml`).
+* The current Ruff version (`ruff --version`).
+-->

.github/ISSUE_TEMPLATE/1_bug_report.yaml

@@ -1,31 +0,0 @@
-name: Bug report
-description: Report an error or unexpected behavior
-body:
-  - type: markdown
-    attributes:
-      value: |
-        Thank you for taking the time to report an issue! We're glad to have you involved with Ruff.
-
-        **Before reporting, please make sure to search through [existing issues](https://github.com/astral-sh/ruff/issues?q=is:issue+is:open+label:bug) (including [closed](https://github.com/astral-sh/ruff/issues?q=is:issue%20state:closed%20label:bug)).**
-
-  - type: textarea
-    attributes:
-      label: Summary
-      description: |
-        A clear and concise description of the bug, including a minimal reproducible example.
-
-        Be sure to include the command you invoked (e.g., `ruff check /path/to/file.py --fix`), ideally including the `--isolated` flag and
-        the current Ruff settings (e.g., relevant sections from your `pyproject.toml`).
-
-        If possible, try to include the [playground](https://play.ruff.rs) link that reproduces this issue.
-
-    validations:
-      required: true
-
-  - type: input
-    attributes:
-      label: Version
-      description: What version of ruff are you using? (see `ruff version`)
-      placeholder: e.g., ruff 0.9.3 (90589372d 2025-01-23)
-    validations:
-      required: false

.github/ISSUE_TEMPLATE/2_rule_request.yaml

@@ -1,10 +0,0 @@
-name: Rule request
-description: Anything related to lint rules (proposing new rules, changes to existing rules, auto-fixes, etc.)
-body:
-  - type: textarea
-    attributes:
-      label: Summary
-      description: |
-        A clear and concise description of the relevant request. If applicable, please describe the current behavior as well.
-    validations:
-      required: true

.github/ISSUE_TEMPLATE/3_question.yaml

@@ -1,18 +0,0 @@
-name: Question
-description: Ask a question about Ruff
-labels: ["question"]
-body:
-  - type: textarea
-    attributes:
-      label: Question
-      description: Describe your question in detail.
-    validations:
-      required: true
-
-  - type: input
-    attributes:
-      label: Version
-      description: What version of ruff are you using? (see `ruff version`)
-      placeholder: e.g., ruff 0.9.3 (90589372d 2025-01-23)
-    validations:
-      required: false

.github/ISSUE_TEMPLATE/config.yml

@@ -1,11 +0,0 @@
-blank_issues_enabled: true
-contact_links:
-  - name: Report an issue with ty
-    url: https://github.com/astral-sh/ty/issues/new/choose
-    about: Please report issues for our type checker ty in the ty repository.
-  - name: Documentation
-    url: https://docs.astral.sh/ruff
-    about: Please consult the documentation before creating an issue.
-  - name: Community
-    url: https://discord.com/invite/astral-sh
-    about: Join our Discord community to ask questions and collaborate.

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,9 +1,8 @@
 <!--
-Thank you for contributing to Ruff/ty! To help us out with reviewing, please consider the following:
+Thank you for contributing to Ruff! To help us out with reviewing, please consider the following:
 
 - Does this pull request include a summary of the change? (See below.)
-- Does this pull request include a descriptive title? (Please prefix with `[ty]` for ty pull
-  requests.)
+- Does this pull request include a descriptive title?
 - Does this pull request include references to any relevant issues?
 -->
 

.github/actionlint.yaml

@@ -1,11 +0,0 @@
-# Configuration for the actionlint tool, which we run via pre-commit
-# to verify the correctness of the syntax in our GitHub Actions workflows.
-
-self-hosted-runner:
-  # Various runners we use that aren't recognized out-of-the-box by actionlint:
-  labels:
-    - depot-ubuntu-latest-8
-    - depot-ubuntu-22.04-16
-    - depot-ubuntu-22.04-32
-    - github-windows-2025-x86_64-8
-    - github-windows-2025-x86_64-16

.github/mypy-primer-ty.toml

@@ -1,8 +0,0 @@
-#:schema ../ty.schema.json
-# Configuration overrides for the mypy primer run
-
-# Enable off-by-default rules.
-[rules]
-possibly-unresolved-reference = "warn"
-unused-ignore-comment = "warn"
-division-by-zero = "warn"

.github/renovate.json5

@@ -8,82 +8,28 @@
   semanticCommits: "disabled",
   separateMajorMinor: false,
   prHourlyLimit: 10,
-  enabledManagers: ["github-actions", "pre-commit", "cargo", "pep621", "pip_requirements", "npm"],
+  enabledManagers: ["github-actions", "pre-commit", "cargo", "pep621", "npm"],
   cargo: {
     // See https://docs.renovatebot.com/configuration-options/#rangestrategy
     rangeStrategy: "update-lockfile",
   },
   pep621: {
-    // The default for this package manager is to only search for `pyproject.toml` files
-    // found at the repository root: https://docs.renovatebot.com/modules/manager/pep621/#file-matching
     fileMatch: ["^(python|scripts)/.*pyproject\\.toml$"],
   },
-  pip_requirements: {
-    // The default for this package manager is to run on all requirements.txt files:
-    // https://docs.renovatebot.com/modules/manager/pip_requirements/#file-matching
-    // `fileMatch` doesn't work for excluding files; to exclude `requirements.txt` files
-    // outside the `doc/` directory, we instead have to use `ignorePaths`. Unlike `fileMatch`,
-    // which takes a regex string, `ignorePaths` takes a glob string, so we have to use
-    // a "negative glob pattern".
-    // See:
-    // - https://docs.renovatebot.com/modules/manager/#ignoring-files-that-match-the-default-filematch
-    // - https://docs.renovatebot.com/configuration-options/#ignorepaths
-    // - https://docs.renovatebot.com/string-pattern-matching/#negative-matching
-    ignorePaths: ["!docs/requirements*.txt"]
-  },
   npm: {
-    // The default for this package manager is to only search for `package.json` files
-    // found at the repository root: https://docs.renovatebot.com/modules/manager/npm/#file-matching
     fileMatch: ["^playground/.*package\\.json$"],
   },
   "pre-commit": {
     enabled: true,
   },
   packageRules: [
-    // Pin GitHub Actions to immutable SHAs.
-    {
-      matchDepTypes: ["action"],
-      pinDigests: true,
-    },
-    // Annotate GitHub Actions SHAs with a SemVer version.
-    {
-      extends: ["helpers:pinGitHubActionDigests"],
-      extractVersion: "^(?<version>v?\\d+\\.\\d+\\.\\d+)$",
-      versioning: "regex:^v?(?<major>\\d+)(\\.(?<minor>\\d+)\\.(?<patch>\\d+))?$",
-    },
     {
       // Group upload/download artifact updates, the versions are dependent
       groupName: "Artifact GitHub Actions dependencies",
       matchManagers: ["github-actions"],
-      matchDatasources: ["gitea-tags", "github-tags"],
-      matchPackageNames: ["actions/.*-artifact"],
+      matchPackagePatterns: ["actions/.*-artifact"],
       description: "Weekly update of artifact-related GitHub Actions dependencies",
     },
-    {
-      // This package rule disables updates for GitHub runners:
-      // we'd only pin them to a specific version
-      // if there was a deliberate reason to do so
-      groupName: "GitHub runners",
-      matchManagers: ["github-actions"],
-      matchDatasources: ["github-runners"],
-      description: "Disable PRs updating GitHub runners (e.g. 'runs-on: macos-14')",
-      enabled: false,
-    },
-    {
-      // Disable updates of `zip-rs`; intentionally pinned for now due to ownership change
-      // See: https://github.com/astral-sh/uv/issues/3642
-      matchPackageNames: ["zip"],
-      matchManagers: ["cargo"],
-      enabled: false,
-    },
-    {
-      // `mkdocs-material` requires a manual update to keep the version in sync
-      // with `mkdocs-material-insider`.
-      // See: https://squidfunk.github.io/mkdocs-material/insiders/upgrade/
-      matchManagers: ["pip_requirements"],
-      matchPackageNames: ["mkdocs-material"],
-      enabled: false,
-    },
     {
       groupName: "pre-commit dependencies",
       matchManagers: ["pre-commit"],
@@ -98,15 +44,22 @@
     {
       groupName: "Monaco",
       matchManagers: ["npm"],
-      matchPackageNames: ["monaco"],
+      matchPackagePatterns: ["monaco"],
       description: "Weekly update of the Monaco editor",
     },
     {
       groupName: "strum",
       matchManagers: ["cargo"],
-      matchPackageNames: ["strum"],
+      matchPackagePatterns: ["strum"],
       description: "Weekly update of strum dependencies",
-    }
+    },
+    {
+      groupName: "ESLint",
+      matchManagers: ["npm"],
+      matchPackageNames: ["eslint"],
+      allowedVersions: "<9",
+      description: "Constraint ESLint to version 8 until TypeScript-eslint supports ESLint 9", // https://github.com/typescript-eslint/typescript-eslint/issues/8211
+    },
   ],
   vulnerabilityAlerts: {
     commitMessageSuffix: "",

.github/workflows/build-binaries.yml

@@ -1,480 +0,0 @@
-# Build ruff on all platforms.
-#
-# Generates both wheels (for PyPI) and archived binaries (for GitHub releases).
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a local
-# artifacts job within `cargo-dist`.
-name: "Build binaries"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-  pull_request:
-    paths:
-      # When we change pyproject.toml, we want to ensure that the maturin builds still work.
-      - pyproject.toml
-      # And when we change this workflow itself...
-      - .github/workflows/build-binaries.yml
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref }}
-  cancel-in-progress: true
-
-permissions: {}
-
-env:
-  PACKAGE_NAME: ruff
-  MODULE_NAME: ruff
-  PYTHON_VERSION: "3.13"
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-
-jobs:
-  sdist:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build sdist"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          command: sdist
-          args: --out dist
-      - name: "Test sdist"
-        run: |
-          pip install dist/"${PACKAGE_NAME}"-*.tar.gz --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
-      - name: "Upload sdist"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-sdist
-          path: dist
-
-  macos-x86_64:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: macos-14
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-          architecture: x64
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels - x86_64"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: x86_64
-          args: --release --locked --out dist
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-macos-x86_64
-          path: dist
-      - name: "Archive binary"
-        run: |
-          TARGET=x86_64-apple-darwin
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
-          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-macos-x86_64
-          path: |
-            *.tar.gz
-            *.sha256
-
-  macos-aarch64:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: macos-14
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-          architecture: arm64
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels - aarch64"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: aarch64
-          args: --release --locked --out dist
-      - name: "Test wheel - aarch64"
-        run: |
-          pip install dist/"${PACKAGE_NAME}"-*.whl --force-reinstall
-          ruff --help
-          python -m ruff --help
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-aarch64-apple-darwin
-          path: dist
-      - name: "Archive binary"
-        run: |
-          TARGET=aarch64-apple-darwin
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
-          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-aarch64-apple-darwin
-          path: |
-            *.tar.gz
-            *.sha256
-
-  windows:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: windows-latest
-    strategy:
-      matrix:
-        platform:
-          - target: x86_64-pc-windows-msvc
-            arch: x64
-          - target: i686-pc-windows-msvc
-            arch: x86
-          - target: aarch64-pc-windows-msvc
-            arch: x64
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-          architecture: ${{ matrix.platform.arch }}
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: ${{ matrix.platform.target }}
-          args: --release --locked --out dist
-        env:
-          # aarch64 build fails, see https://github.com/PyO3/maturin/issues/2110
-          XWIN_VERSION: 16
-      - name: "Test wheel"
-        if: ${{ !startsWith(matrix.platform.target, 'aarch64') }}
-        shell: bash
-        run: |
-          python -m pip install dist/"${PACKAGE_NAME}"-*.whl --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-${{ matrix.platform.target }}
-          path: dist
-      - name: "Archive binary"
-        shell: bash
-        run: |
-          ARCHIVE_FILE=ruff-${{ matrix.platform.target }}.zip
-          7z a $ARCHIVE_FILE ./target/${{ matrix.platform.target }}/release/ruff.exe
-          sha256sum $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-${{ matrix.platform.target }}
-          path: |
-            *.zip
-            *.sha256
-
-  linux:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        target:
-          - x86_64-unknown-linux-gnu
-          - i686-unknown-linux-gnu
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-          architecture: x64
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: ${{ matrix.target }}
-          manylinux: auto
-          args: --release --locked --out dist
-      - name: "Test wheel"
-        if: ${{ startsWith(matrix.target, 'x86_64') }}
-        run: |
-          pip install dist/"${PACKAGE_NAME}"-*.whl --force-reinstall
-          "${MODULE_NAME}" --help
-          python -m "${MODULE_NAME}" --help
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-${{ matrix.target }}
-          path: dist
-      - name: "Archive binary"
-        shell: bash
-        run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
-          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-${{ matrix.target }}
-          path: |
-            *.tar.gz
-            *.sha256
-
-  linux-cross:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        platform:
-          - target: aarch64-unknown-linux-gnu
-            arch: aarch64
-            # see https://github.com/astral-sh/ruff/issues/3791
-            # and https://github.com/gnzlbg/jemallocator/issues/170#issuecomment-1503228963
-            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
-          - target: armv7-unknown-linux-gnueabihf
-            arch: armv7
-          - target: s390x-unknown-linux-gnu
-            arch: s390x
-          - target: powerpc64le-unknown-linux-gnu
-            arch: ppc64le
-            # see https://github.com/astral-sh/ruff/issues/10073
-            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
-          - target: powerpc64-unknown-linux-gnu
-            arch: ppc64
-            # see https://github.com/astral-sh/ruff/issues/10073
-            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
-          - target: arm-unknown-linux-musleabihf
-            arch: arm
-
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: ${{ matrix.platform.target }}
-          manylinux: auto
-          docker-options: ${{ matrix.platform.maturin_docker_options }}
-          args: --release --locked --out dist
-      - uses: uraimo/run-on-arch-action@d94c13912ea685de38fccc1109385b83fd79427d # v3.0.1
-        if: ${{ matrix.platform.arch != 'ppc64' && matrix.platform.arch != 'ppc64le'}}
-        name: Test wheel
-        with:
-          arch: ${{ matrix.platform.arch == 'arm' && 'armv6' || matrix.platform.arch }}
-          distro: ${{ matrix.platform.arch == 'arm' && 'bullseye' || 'ubuntu20.04' }}
-          githubToken: ${{ github.token }}
-          install: |
-            apt-get update
-            apt-get install -y --no-install-recommends python3 python3-pip
-            pip3 install -U pip
-          run: |
-            pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
-            ruff --help
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-${{ matrix.platform.target }}
-          path: dist
-      - name: "Archive binary"
-        shell: bash
-        run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.platform.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
-          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-${{ matrix.platform.target }}
-          path: |
-            *.tar.gz
-            *.sha256
-
-  musllinux:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        target:
-          - x86_64-unknown-linux-musl
-          - i686-unknown-linux-musl
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-          architecture: x64
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: ${{ matrix.target }}
-          manylinux: musllinux_1_2
-          args: --release --locked --out dist
-      - name: "Test wheel"
-        if: matrix.target == 'x86_64-unknown-linux-musl'
-        uses: addnab/docker-run-action@4f65fabd2431ebc8d299f8e5a018d79a769ae185 # v3
-        with:
-          image: alpine:latest
-          options: -v ${{ github.workspace }}:/io -w /io
-          run: |
-            apk add python3
-            python -m venv .venv
-            .venv/bin/pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
-            .venv/bin/${{ env.MODULE_NAME }} --help
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-${{ matrix.target }}
-          path: dist
-      - name: "Archive binary"
-        shell: bash
-        run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
-          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-${{ matrix.target }}
-          path: |
-            *.tar.gz
-            *.sha256
-
-  musllinux-cross:
-    if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-build') }}
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        platform:
-          - target: aarch64-unknown-linux-musl
-            arch: aarch64
-            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
-          - target: armv7-unknown-linux-musleabihf
-            arch: armv7
-
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: ${{ env.PYTHON_VERSION }}
-      - name: "Prep README.md"
-        run: python scripts/transform_readme.py --target pypi
-      - name: "Build wheels"
-        uses: PyO3/maturin-action@aef21716ff3dcae8a1c301d23ec3e4446972a6e3 # v1.49.1
-        with:
-          target: ${{ matrix.platform.target }}
-          manylinux: musllinux_1_2
-          args: --release --locked --out dist
-          docker-options: ${{ matrix.platform.maturin_docker_options }}
-      - uses: uraimo/run-on-arch-action@d94c13912ea685de38fccc1109385b83fd79427d # v3.0.1
-        name: Test wheel
-        with:
-          arch: ${{ matrix.platform.arch }}
-          distro: alpine_latest
-          githubToken: ${{ github.token }}
-          install: |
-            apk add python3
-          run: |
-            python -m venv .venv
-            .venv/bin/pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
-            .venv/bin/${{ env.MODULE_NAME }} --help
-      - name: "Upload wheels"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: wheels-${{ matrix.platform.target }}
-          path: dist
-      - name: "Archive binary"
-        shell: bash
-        run: |
-          set -euo pipefail
-
-          TARGET=${{ matrix.platform.target }}
-          ARCHIVE_NAME=ruff-$TARGET
-          ARCHIVE_FILE=$ARCHIVE_NAME.tar.gz
-
-          mkdir -p $ARCHIVE_NAME
-          cp target/$TARGET/release/ruff $ARCHIVE_NAME/ruff
-          tar czvf $ARCHIVE_FILE $ARCHIVE_NAME
-          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
-      - name: "Upload binary"
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: artifacts-${{ matrix.platform.target }}
-          path: |
-            *.tar.gz
-            *.sha256

.github/workflows/build-docker.yml

@@ -1,299 +0,0 @@
-# Build and publish a Docker image.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a local
-# artifacts job within `cargo-dist`.
-#
-# TODO(charlie): Ideally, the publish step would happen as a publish job within `cargo-dist`, but
-# sharing the built image as an artifact between jobs is challenging.
-name: "[ruff] Build Docker image"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-  pull_request:
-    paths:
-      - .github/workflows/build-docker.yml
-
-env:
-  RUFF_BASE_IMG: ghcr.io/${{ github.repository_owner }}/ruff
-
-jobs:
-  docker-build:
-    name: Build Docker image (ghcr.io/astral-sh/ruff) for ${{ matrix.platform }}
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    strategy:
-      fail-fast: false
-      matrix:
-        platform:
-          - linux/amd64
-          - linux/arm64
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          submodules: recursive
-          persist-credentials: false
-
-      - uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0
-
-      - uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Check tag consistency
-        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-        env:
-          TAG: ${{ inputs.plan != '' && fromJson(inputs.plan).announcement_tag || 'dry-run' }}
-        run: |
-          version=$(grep -m 1 "^version = " pyproject.toml | sed -e 's/version = "\(.*\)"/\1/g')
-          if [ "${TAG}" != "${version}" ]; then
-            echo "The input tag does not match the version from pyproject.toml:" >&2
-            echo "${TAG}" >&2
-            echo "${version}" >&2
-            exit 1
-          else
-            echo "Releasing ${version}"
-          fi
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@902fa8ec7d6ecbf8d84d538b9b233a880e428804 # v5.7.0
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          # Defining this makes sure the org.opencontainers.image.version OCI label becomes the actual release version and not the branch name
-          tags: |
-            type=raw,value=dry-run,enable=${{ inputs.plan == '' || fromJson(inputs.plan).announcement_tag_is_implicit }}
-            type=pep440,pattern={{ version }},value=${{ inputs.plan != '' && fromJson(inputs.plan).announcement_tag || 'dry-run' }},enable=${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-
-      - name: Normalize Platform Pair (replace / with -)
-        run: |
-          platform=${{ matrix.platform }}
-          echo "PLATFORM_TUPLE=${platform//\//-}" >> "$GITHUB_ENV"
-
-      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
-      - name: Build and push by digest
-        id: build
-        uses: docker/build-push-action@1dc73863535b631f98b2378be8619f83b136f4a0 # v6.17.0
-        with:
-          context: .
-          platforms: ${{ matrix.platform }}
-          cache-from: type=gha,scope=ruff-${{ env.PLATFORM_TUPLE }}
-          cache-to: type=gha,mode=min,scope=ruff-${{ env.PLATFORM_TUPLE }}
-          labels: ${{ steps.meta.outputs.labels }}
-          outputs: type=image,name=${{ env.RUFF_BASE_IMG }},push-by-digest=true,name-canonical=true,push=${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-
-      - name: Export digests
-        env:
-          digest: ${{ steps.build.outputs.digest }}
-        run: |
-          mkdir -p /tmp/digests
-          touch "/tmp/digests/${digest#sha256:}"
-
-      - name: Upload digests
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: digests-${{ env.PLATFORM_TUPLE }}
-          path: /tmp/digests/*
-          if-no-files-found: error
-          retention-days: 1
-
-  docker-publish:
-    name: Publish Docker image (ghcr.io/astral-sh/ruff)
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    needs:
-      - docker-build
-    if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-    steps:
-      - name: Download digests
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
-        with:
-          path: /tmp/digests
-          pattern: digests-*
-          merge-multiple: true
-
-      - uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@902fa8ec7d6ecbf8d84d538b9b233a880e428804 # v5.7.0
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          # Order is on purpose such that the label org.opencontainers.image.version has the first pattern with the full version
-          tags: |
-            type=pep440,pattern={{ version }},value=${{ fromJson(inputs.plan).announcement_tag }}
-            type=pep440,pattern={{ major }}.{{ minor }},value=${{ fromJson(inputs.plan).announcement_tag }}
-
-      - uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
-      - name: Create manifest list and push
-        working-directory: /tmp/digests
-        # The jq command expands the docker/metadata json "tags" array entry to `-t tag1 -t tag2 ...` for each tag in the array
-        # The printf will expand the base image with the `<RUFF_BASE_IMG>@sha256:<sha256> ...` for each sha256 in the directory
-        # The final command becomes `docker buildx imagetools create -t tag1 -t tag2 ... <RUFF_BASE_IMG>@sha256:<sha256_1> <RUFF_BASE_IMG>@sha256:<sha256_2> ...`
-        run: |
-          # shellcheck disable=SC2046
-          docker buildx imagetools create \
-            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf "${RUFF_BASE_IMG}@sha256:%s " *)
-
-  docker-publish-extra:
-    name: Publish additional Docker image based on ${{ matrix.image-mapping }}
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    needs:
-      - docker-publish
-    if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-    strategy:
-      fail-fast: false
-      matrix:
-        # Mapping of base image followed by a comma followed by one or more base tags (comma separated)
-        # Note, org.opencontainers.image.version label will use the first base tag (use the most specific tag first)
-        image-mapping:
-          - alpine:3.21,alpine3.21,alpine
-          - debian:bookworm-slim,bookworm-slim,debian-slim
-          - buildpack-deps:bookworm,bookworm,debian
-    steps:
-      - uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0
-
-      - uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Generate Dynamic Dockerfile Tags
-        shell: bash
-        env:
-          TAG_VALUE: ${{ fromJson(inputs.plan).announcement_tag }}
-        run: |
-          set -euo pipefail
-
-          # Extract the image and tags from the matrix variable
-          IFS=',' read -r BASE_IMAGE BASE_TAGS <<< "${{ matrix.image-mapping }}"
-
-          # Generate Dockerfile content
-          cat <<EOF > Dockerfile
-          FROM ${BASE_IMAGE}
-          COPY --from=${RUFF_BASE_IMG}:latest /ruff /usr/local/bin/ruff
-          ENTRYPOINT []
-          CMD ["/usr/local/bin/ruff"]
-          EOF
-
-          # Initialize a variable to store all tag docker metadata patterns
-          TAG_PATTERNS=""
-
-          # Loop through all base tags and append its docker metadata pattern to the list
-          # Order is on purpose such that the label org.opencontainers.image.version has the first pattern with the full version
-          IFS=','; for TAG in ${BASE_TAGS}; do
-            TAG_PATTERNS="${TAG_PATTERNS}type=pep440,pattern={{ version }},suffix=-${TAG},value=${TAG_VALUE}\n"
-            TAG_PATTERNS="${TAG_PATTERNS}type=pep440,pattern={{ major }}.{{ minor }},suffix=-${TAG},value=${TAG_VALUE}\n"
-            TAG_PATTERNS="${TAG_PATTERNS}type=raw,value=${TAG}\n"
-          done
-
-          # Remove the trailing newline from the pattern list
-          TAG_PATTERNS="${TAG_PATTERNS%\\n}"
-
-          # Export image cache name
-          echo "IMAGE_REF=${BASE_IMAGE//:/-}" >> "$GITHUB_ENV"
-
-          # Export tag patterns using the multiline env var syntax
-          {
-            echo "TAG_PATTERNS<<EOF"
-            echo -e "${TAG_PATTERNS}"
-            echo EOF
-          } >> "$GITHUB_ENV"
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@902fa8ec7d6ecbf8d84d538b9b233a880e428804 # v5.7.0
-        # ghcr.io prefers index level annotations
-        env:
-          DOCKER_METADATA_ANNOTATIONS_LEVELS: index
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          flavor: |
-            latest=false
-          tags: |
-            ${{ env.TAG_PATTERNS }}
-
-      - name: Build and push
-        uses: docker/build-push-action@1dc73863535b631f98b2378be8619f83b136f4a0 # v6.17.0
-        with:
-          context: .
-          platforms: linux/amd64,linux/arm64
-          # We do not really need to cache here as the Dockerfile is tiny
-          #cache-from: type=gha,scope=ruff-${{ env.IMAGE_REF }}
-          #cache-to: type=gha,mode=min,scope=ruff-${{ env.IMAGE_REF }}
-          push: true
-          tags: ${{ steps.meta.outputs.tags }}
-          labels: ${{ steps.meta.outputs.labels }}
-          annotations: ${{ steps.meta.outputs.annotations }}
-
-  # This is effectively a duplicate of `docker-publish` to make https://github.com/astral-sh/ruff/pkgs/container/ruff
-  # show the ruff base image first since GitHub always shows the last updated image digests
-  # This works by annotating the original digests (previously non-annotated) which triggers an update to ghcr.io
-  docker-republish:
-    name: Annotate Docker image (ghcr.io/astral-sh/ruff)
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    needs:
-      - docker-publish-extra
-    if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-    steps:
-      - name: Download digests
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
-        with:
-          path: /tmp/digests
-          pattern: digests-*
-          merge-multiple: true
-
-      - uses: docker/setup-buildx-action@b5ca514318bd6ebac0fb2aedd5d36ec1b5c232a2 # v3.10.0
-
-      - name: Extract metadata (tags, labels) for Docker
-        id: meta
-        uses: docker/metadata-action@902fa8ec7d6ecbf8d84d538b9b233a880e428804 # v5.7.0
-        env:
-          DOCKER_METADATA_ANNOTATIONS_LEVELS: index
-        with:
-          images: ${{ env.RUFF_BASE_IMG }}
-          # Order is on purpose such that the label org.opencontainers.image.version has the first pattern with the full version
-          tags: |
-            type=pep440,pattern={{ version }},value=${{ fromJson(inputs.plan).announcement_tag }}
-            type=pep440,pattern={{ major }}.{{ minor }},value=${{ fromJson(inputs.plan).announcement_tag }}
-
-      - uses: docker/login-action@74a5d142397b4f367a81961eba4e8cd7edddf772 # v3.4.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.repository_owner }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      # Adapted from https://docs.docker.com/build/ci/github-actions/multi-platform/
-      - name: Create manifest list and push
-        working-directory: /tmp/digests
-        # The readarray part is used to make sure the quoting and special characters are preserved on expansion (e.g. spaces)
-        # The jq command expands the docker/metadata json "tags" array entry to `-t tag1 -t tag2 ...` for each tag in the array
-        # The printf will expand the base image with the `<RUFF_BASE_IMG>@sha256:<sha256> ...` for each sha256 in the directory
-        # The final command becomes `docker buildx imagetools create -t tag1 -t tag2 ... <RUFF_BASE_IMG>@sha256:<sha256_1> <RUFF_BASE_IMG>@sha256:<sha256_2> ...`
-        run: |
-          readarray -t lines <<< "$DOCKER_METADATA_OUTPUT_ANNOTATIONS"; annotations=(); for line in "${lines[@]}"; do annotations+=(--annotation "$line"); done
-
-          # shellcheck disable=SC2046
-          docker buildx imagetools create \
-            "${annotations[@]}" \
-            $(jq -cr '.tags | map("-t " + .) | join(" ")' <<< "$DOCKER_METADATA_OUTPUT_JSON") \
-            $(printf "${RUFF_BASE_IMG}@sha256:%s " *)

.github/workflows/daily_fuzz.yaml

@@ -31,31 +31,25 @@ jobs:
     # Don't run the cron job on forks:
     if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
     steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v5
         with:
-          persist-credentials: false
-      - uses: astral-sh/setup-uv@f0ec1fc3b38f5e7cd731bb6ce540c5af426746bb # v6.1.0
+          python-version: "3.12"
+      - name: Install uv
+        run: curl -LsSf https://astral.sh/uv/install.sh | sh
+      - name: Install Python requirements
+        run: uv pip install -r scripts/fuzz-parser/requirements.txt --system
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@67424c1b3680e35255d95971cbd5de0047bf31c3 # v1
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
+        uses: rui314/setup-mold@v1
+      - uses: Swatinem/rust-cache@v2
       - name: Build ruff
         # A debug build means the script runs slower once it gets started,
         # but this is outweighed by the fact that a release build takes *much* longer to compile in CI
         run: cargo build --locked
       - name: Fuzz
-        run: |
-          # shellcheck disable=SC2046
-          (
-            uvx \
-            --python=3.12 \
-            --from=./python/py-fuzzer \
-            fuzz \
-            --test-executable=target/debug/ruff \
-            --bin=ruff \
-            $(shuf -i 0-9999999999999999999 -n 1000)
-          )
+        run: python scripts/fuzz-parser/fuzz.py $(shuf -i 0-9999999999999999999 -n 1000) --test-executable target/debug/ruff
 
   create-issue-on-failure:
     name: Create an issue if the daily fuzz surfaced any bugs
@@ -65,7 +59,7 @@ jobs:
     permissions:
       issues: write
     steps:
-      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
+      - uses: actions/github-script@v7
         with:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           script: |
@@ -73,6 +67,6 @@ jobs:
               owner: "astral-sh",
               repo: "ruff",
               title: `Daily parser fuzz failed on ${new Date().toDateString()}`,
-              body: "Run listed here: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
+              body: "Runs listed here: https://github.com/astral-sh/ruff/actions/workflows/daily_fuzz.yml",
               labels: ["bug", "parser", "fuzzer"],
             })

.github/workflows/docs.yaml

@@ -0,0 +1,55 @@
+name: mkdocs
+
+on:
+  workflow_dispatch:
+    inputs:
+      ref:
+        description: "The commit SHA, tag, or branch to publish. Uses the default branch if not specified."
+        default: ""
+        type: string
+  release:
+    types: [published]
+
+jobs:
+  mkdocs:
+    runs-on: ubuntu-latest
+    env:
+      CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
+      MKDOCS_INSIDERS_SSH_KEY_EXISTS: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY != '' }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.ref }}
+      - uses: actions/setup-python@v5
+      - name: "Add SSH key"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
+        uses: webfactory/ssh-agent@v0.9.0
+        with:
+          ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
+      - name: "Install Rust toolchain"
+        run: rustup show
+      - uses: Swatinem/rust-cache@v2
+      - name: "Install Insiders dependencies"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
+        run: pip install -r docs/requirements-insiders.txt
+      - name: "Install dependencies"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
+        run: pip install -r docs/requirements.txt
+      - name: "Copy README File"
+        run: |
+          python scripts/transform_readme.py --target mkdocs
+          python scripts/generate_mkdocs.py
+      - name: "Build Insiders docs"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
+        run: mkdocs build --strict -f mkdocs.insiders.yml
+      - name: "Build docs"
+        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
+        run: mkdocs build --strict -f mkdocs.public.yml
+      - name: "Deploy to Cloudflare Pages"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        uses: cloudflare/wrangler-action@v3.4.1
+        with:
+          apiToken: ${{ secrets.CF_API_TOKEN }}
+          accountId: ${{ secrets.CF_ACCOUNT_ID }}
+          # `github.head_ref` is only set during pull requests and for manual runs or tags we use `main` to deploy to production
+          command: pages deploy site --project-name=astral-docs --branch ${{ github.head_ref || 'main' }} --commit-hash ${GITHUB_SHA}

.github/workflows/mypy_primer.yaml

@@ -1,101 +0,0 @@
-name: Run mypy_primer
-
-permissions: {}
-
-on:
-  pull_request:
-    paths:
-      - "crates/ty*/**"
-      - "crates/ruff_db"
-      - "crates/ruff_python_ast"
-      - "crates/ruff_python_parser"
-      - ".github/workflows/mypy_primer.yaml"
-      - ".github/workflows/mypy_primer_comment.yaml"
-      - "Cargo.lock"
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref_name }}-${{ github.event.pull_request.number || github.sha }}
-  cancel-in-progress: true
-
-env:
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-  RUST_BACKTRACE: 1
-
-jobs:
-  mypy_primer:
-    name: Run mypy_primer
-    runs-on: depot-ubuntu-22.04-32
-    timeout-minutes: 20
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          path: ruff
-          fetch-depth: 0
-          persist-credentials: false
-
-      - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@f0ec1fc3b38f5e7cd731bb6ce540c5af426746bb # v6.1.0
-
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
-        with:
-          workspaces: "ruff"
-
-      - name: Install Rust toolchain
-        run: rustup show
-
-      - name: Run mypy_primer
-        shell: bash
-        run: |
-          cd ruff
-
-          echo "Enabling mypy primer specific configuration overloads (see .github/mypy-primer-ty.toml)"
-          mkdir -p ~/.config/ty
-          cp .github/mypy-primer-ty.toml ~/.config/ty/ty.toml
-
-          PRIMER_SELECTOR="$(paste -s -d'|' crates/ty_python_semantic/resources/primer/good.txt)"
-
-          echo "new commit"
-          git rev-list --format=%s --max-count=1 "$GITHUB_SHA"
-
-          MERGE_BASE="$(git merge-base "$GITHUB_SHA" "origin/$GITHUB_BASE_REF")"
-          git checkout -b base_commit "$MERGE_BASE"
-          echo "base commit"
-          git rev-list --format=%s --max-count=1 base_commit
-
-          cd ..
-
-          echo "Project selector: $PRIMER_SELECTOR"
-          # Allow the exit code to be 0 or 1, only fail for actual mypy_primer crashes/bugs
-          uvx \
-            --from="git+https://github.com/hauntsaninja/mypy_primer@01a7ca325f674433c58e02416a867178d1571128" \
-            mypy_primer \
-            --repo ruff \
-            --type-checker ty \
-            --old base_commit \
-            --new "$GITHUB_SHA" \
-            --project-selector "/($PRIMER_SELECTOR)\$" \
-            --output concise \
-            --debug > mypy_primer.diff || [ $? -eq 1 ]
-
-          # Output diff with ANSI color codes
-          cat mypy_primer.diff
-
-          # Remove ANSI color codes before uploading
-          sed -ie 's/\x1b\[[0-9;]*m//g' mypy_primer.diff
-
-          echo ${{ github.event.number }} > pr-number
-
-      - name: Upload diff
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: mypy_primer_diff
-          path: mypy_primer.diff
-
-      - name: Upload pr-number
-        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
-        with:
-          name: pr-number
-          path: pr-number

.github/workflows/mypy_primer_comment.yaml

@@ -1,97 +0,0 @@
-name: PR comment (mypy_primer)
-
-on: # zizmor: ignore[dangerous-triggers]
-  workflow_run:
-    workflows: [Run mypy_primer]
-    types: [completed]
-  workflow_dispatch:
-    inputs:
-      workflow_run_id:
-        description: The mypy_primer workflow that triggers the workflow run
-        required: true
-
-jobs:
-  comment:
-    runs-on: ubuntu-24.04
-    permissions:
-      pull-requests: write
-    steps:
-      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
-        name: Download PR number
-        with:
-          name: pr-number
-          run_id: ${{ github.event.workflow_run.id ||  github.event.inputs.workflow_run_id }}
-          if_no_artifact_found: ignore
-          allow_forks: true
-
-      - name: Parse pull request number
-        id: pr-number
-        run: |
-          if [[ -f pr-number ]]
-          then
-            echo "pr-number=$(<pr-number)" >> "$GITHUB_OUTPUT"
-          fi
-
-      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
-        name: "Download mypy_primer results"
-        id: download-mypy_primer_diff
-        if: steps.pr-number.outputs.pr-number
-        with:
-          name: mypy_primer_diff
-          workflow: mypy_primer.yaml
-          pr: ${{ steps.pr-number.outputs.pr-number }}
-          path: pr/mypy_primer_diff
-          workflow_conclusion: completed
-          if_no_artifact_found: ignore
-          allow_forks: true
-
-      - name: Generate comment content
-        id: generate-comment
-        if: steps.download-mypy_primer_diff.outputs.found_artifact == 'true'
-        run: |
-          # Guard against malicious mypy_primer results that symlink to a secret
-          # file on this runner
-          if [[ -L pr/mypy_primer_diff/mypy_primer.diff ]]
-          then
-              echo "Error: mypy_primer.diff cannot be a symlink"
-              exit 1
-          fi
-
-          # Note this identifier is used to find the comment to update on
-          # subsequent runs
-          echo '<!-- generated-comment mypy_primer -->' >> comment.txt
-
-          echo '## `mypy_primer` results' >> comment.txt
-          if [ -s "pr/mypy_primer_diff/mypy_primer.diff" ]; then
-            echo '<details>' >> comment.txt
-            echo '<summary>Changes were detected when running on open source projects</summary>' >> comment.txt
-            echo '' >> comment.txt
-            echo '```diff' >> comment.txt
-            cat pr/mypy_primer_diff/mypy_primer.diff >> comment.txt
-            echo '```' >> comment.txt
-            echo '</details>' >> comment.txt
-          else
-            echo 'No ecosystem changes detected ✅' >> comment.txt
-          fi
-
-          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
-          cat comment.txt >> "$GITHUB_OUTPUT"
-          echo 'EOF' >> "$GITHUB_OUTPUT"
-
-      - name: Find existing comment
-        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
-        if: steps.generate-comment.outcome == 'success'
-        id: find-comment
-        with:
-          issue-number: ${{ steps.pr-number.outputs.pr-number }}
-          comment-author: "github-actions[bot]"
-          body-includes: "<!-- generated-comment mypy_primer -->"
-
-      - name: Create or update comment
-        if: steps.find-comment.outcome == 'success'
-        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4
-        with:
-          comment-id: ${{ steps.find-comment.outputs.comment-id }}
-          issue-number: ${{ steps.pr-number.outputs.pr-number }}
-          body-path: comment.txt
-          edit-mode: replace

.github/workflows/notify-dependents.yml

@@ -1,29 +0,0 @@
-# Notify downstream repositories of a new release.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a post-announce
-# job within `cargo-dist`.
-name: "[ruff] Notify dependents"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-jobs:
-  update-dependents:
-    name: Notify dependents
-    runs-on: ubuntu-latest
-    steps:
-      - name: "Update pre-commit mirror"
-        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
-        with:
-          github-token: ${{ secrets.RUFF_PRE_COMMIT_PAT }}
-          script: |
-            github.rest.actions.createWorkflowDispatch({
-              owner: 'astral-sh',
-              repo: 'ruff-pre-commit',
-              workflow_id: 'main.yml',
-              ref: 'main',
-            })

.github/workflows/playground.yaml

@@ -0,0 +1,48 @@
+name: "[Playground] Release"
+
+on:
+  workflow_dispatch:
+  release:
+    types: [published]
+
+env:
+  CARGO_INCREMENTAL: 0
+  CARGO_NET_RETRY: 10
+  CARGO_TERM_COLOR: always
+  RUSTUP_MAX_RETRIES: 10
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    env:
+      CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
+    steps:
+      - uses: actions/checkout@v4
+      - name: "Install Rust toolchain"
+        run: rustup target add wasm32-unknown-unknown
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 18
+          cache: "npm"
+          cache-dependency-path: playground/package-lock.json
+      - uses: jetli/wasm-pack-action@v0.4.0
+      - uses: jetli/wasm-bindgen-action@v0.2.0
+      - name: "Run wasm-pack"
+        run: wasm-pack build --target web --out-dir ../../playground/src/pkg crates/ruff_wasm
+      - name: "Install Node dependencies"
+        run: npm ci
+        working-directory: playground
+      - name: "Run TypeScript checks"
+        run: npm run check
+        working-directory: playground
+      - name: "Build JavaScript bundle"
+        run: npm run build
+        working-directory: playground
+      - name: "Deploy to Cloudflare Pages"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        uses: cloudflare/wrangler-action@v3.4.1
+        with:
+          apiToken: ${{ secrets.CF_API_TOKEN }}
+          accountId: ${{ secrets.CF_ACCOUNT_ID }}
+          # `github.head_ref` is only set during pull requests and for manual runs or tags we use `main` to deploy to production
+          command: pages deploy playground/dist --project-name=ruff-playground --branch ${{ github.head_ref || 'main' }} --commit-hash ${GITHUB_SHA}

.github/workflows/pr-comment.yaml

@@ -10,29 +10,29 @@ on:
         description: The ecosystem workflow that triggers the workflow run
         required: true
 
+permissions:
+  pull-requests: write
+
 jobs:
   comment:
     runs-on: ubuntu-latest
-    permissions:
-      pull-requests: write
     steps:
-      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+      - uses: dawidd6/action-download-artifact@v3
         name: Download pull request number
         with:
           name: pr-number
           run_id: ${{ github.event.workflow_run.id ||  github.event.inputs.workflow_run_id }}
           if_no_artifact_found: ignore
-          allow_forks: true
 
       - name: Parse pull request number
         id: pr-number
         run: |
           if [[ -f pr-number ]]
           then
-            echo "pr-number=$(<pr-number)" >> "$GITHUB_OUTPUT"
+            echo "pr-number=$(<pr-number)" >> $GITHUB_OUTPUT
           fi
 
-      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+      - uses: dawidd6/action-download-artifact@v3
         name: "Download ecosystem results"
         id: download-ecosystem-result
         if: steps.pr-number.outputs.pr-number
@@ -43,20 +43,11 @@ jobs:
           path: pr/ecosystem
           workflow_conclusion: completed
           if_no_artifact_found: ignore
-          allow_forks: true
 
       - name: Generate comment content
         id: generate-comment
         if: steps.download-ecosystem-result.outputs.found_artifact == 'true'
         run: |
-          # Guard against malicious ecosystem results that symlink to a secret
-          # file on this runner
-          if [[ -L pr/ecosystem/ecosystem-result ]]
-          then
-              echo "Error: ecosystem-result cannot be a symlink"
-              exit 1
-          fi
-
           # Note this identifier is used to find the comment to update on
           # subsequent runs
           echo '<!-- generated-comment ecosystem -->' >> comment.txt
@@ -65,12 +56,12 @@ jobs:
           cat pr/ecosystem/ecosystem-result >> comment.txt
           echo "" >> comment.txt
 
-          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
-          cat comment.txt >> "$GITHUB_OUTPUT"
-          echo 'EOF' >> "$GITHUB_OUTPUT"
+          echo 'comment<<EOF' >> $GITHUB_OUTPUT
+          cat comment.txt >> $GITHUB_OUTPUT
+          echo 'EOF' >> $GITHUB_OUTPUT
 
       - name: Find existing comment
-        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
+        uses: peter-evans/find-comment@v3
         if: steps.generate-comment.outcome == 'success'
         id: find-comment
         with:
@@ -80,7 +71,7 @@ jobs:
 
       - name: Create or update comment
         if: steps.find-comment.outcome == 'success'
-        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4
+        uses: peter-evans/create-or-update-comment@v4
         with:
           comment-id: ${{ steps.find-comment.outputs.comment-id }}
           issue-number: ${{ steps.pr-number.outputs.pr-number }}

.github/workflows/publish-docs.yml

@@ -1,144 +0,0 @@
-# Publish the Ruff documentation.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a post-announce
-# job within `cargo-dist`.
-name: mkdocs
-
-on:
-  workflow_dispatch:
-    inputs:
-      ref:
-        description: "The commit SHA, tag, or branch to publish. Uses the default branch if not specified."
-        default: ""
-        type: string
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-jobs:
-  mkdocs:
-    runs-on: ubuntu-latest
-    env:
-      MKDOCS_INSIDERS_SSH_KEY_EXISTS: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY != '' }}
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          ref: ${{ inputs.ref }}
-          persist-credentials: true
-
-      - uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
-        with:
-          python-version: 3.12
-
-      - name: "Set docs version"
-        env:
-          version: ${{ (inputs.plan != '' && fromJson(inputs.plan).announcement_tag) || inputs.ref }}
-        run: |
-          # if version is missing, use 'latest'
-          if [ -z "$version" ]; then
-            echo "Using 'latest' as version"
-            version="latest"
-          fi
-
-          # Use version as display name for now
-          display_name="$version"
-
-          echo "version=$version" >> "$GITHUB_ENV"
-          echo "display_name=$display_name" >> "$GITHUB_ENV"
-
-      - name: "Set branch name"
-        run: |
-          timestamp="$(date +%s)"
-
-          # create branch_display_name from display_name by replacing all
-          # characters disallowed in git branch names with hyphens
-          branch_display_name="$(echo "${display_name}" | tr -c '[:alnum:]._' '-' | tr -s '-')"
-
-          echo "branch_name=update-docs-$branch_display_name-$timestamp" >> "$GITHUB_ENV"
-          echo "timestamp=$timestamp" >> "$GITHUB_ENV"
-
-      - name: "Add SSH key"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        uses: webfactory/ssh-agent@a6f90b1f127823b31d4d4a8d96047790581349bd # v0.9.1
-        with:
-          ssh-private-key: ${{ secrets.MKDOCS_INSIDERS_SSH_KEY }}
-
-      - name: "Install Rust toolchain"
-        run: rustup show
-
-      - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
-
-      - name: "Install Insiders dependencies"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        run: pip install -r docs/requirements-insiders.txt
-
-      - name: "Install dependencies"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
-        run: pip install -r docs/requirements.txt
-
-      - name: "Copy README File"
-        run: |
-          python scripts/transform_readme.py --target mkdocs
-          python scripts/generate_mkdocs.py
-
-      - name: "Build Insiders docs"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
-        run: mkdocs build --strict -f mkdocs.insiders.yml
-
-      - name: "Build docs"
-        if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS != 'true' }}
-        run: mkdocs build --strict -f mkdocs.public.yml
-
-      - name: "Clone docs repo"
-        run: git clone https://${{ secrets.ASTRAL_DOCS_PAT }}@github.com/astral-sh/docs.git astral-docs
-
-      - name: "Copy docs"
-        run: rm -rf astral-docs/site/ruff && mkdir -p astral-docs/site && cp -r site/ruff astral-docs/site/
-
-      - name: "Commit docs"
-        working-directory: astral-docs
-        run: |
-          git config user.name "astral-docs-bot"
-          git config user.email "176161322+astral-docs-bot@users.noreply.github.com"
-
-          git checkout -b "${branch_name}"
-          git add site/ruff
-          git commit -m "Update ruff documentation for $version"
-
-      - name: "Create Pull Request"
-        working-directory: astral-docs
-        env:
-          GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
-        run: |
-          # set the PR title
-          pull_request_title="Update ruff documentation for ${display_name}"
-
-          # Delete any existing pull requests that are open for this version
-          # by checking against pull_request_title because the new PR will
-          # supersede the old one.
-          gh pr list --state open --json title --jq '.[] | select(.title == "$pull_request_title") | .number' | \
-            xargs -I {} gh pr close {}
-
-          # push the branch to GitHub
-          git push origin "${branch_name}"
-
-          # create the PR
-          gh pr create \
-            --base=main \
-            --head="${branch_name}" \
-            --title="${pull_request_title}" \
-            --body="Automated documentation update for ${display_name}" \
-            --label="documentation"
-
-      - name: "Merge Pull Request"
-        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-        working-directory: astral-docs
-        env:
-          GITHUB_TOKEN: ${{ secrets.ASTRAL_DOCS_PAT }}
-        run: |
-          # auto-merge the PR if the build was triggered by a release. Manual builds should be reviewed by a human.
-          # give the PR a few seconds to be created before trying to auto-merge it
-          sleep 10
-          gh pr merge --squash "${branch_name}"

.github/workflows/publish-playground.yml

@@ -1,54 +0,0 @@
-# Publish the Ruff playground.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a post-announce
-# job within `cargo-dist`.
-name: "[Playground] Release"
-
-on:
-  workflow_dispatch:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-env:
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-
-jobs:
-  publish:
-    runs-on: ubuntu-latest
-    env:
-      CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          persist-credentials: false
-      - name: "Install Rust toolchain"
-        run: rustup target add wasm32-unknown-unknown
-      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version: 22
-          cache: "npm"
-          cache-dependency-path: playground/package-lock.json
-      - uses: jetli/wasm-bindgen-action@20b33e20595891ab1a0ed73145d8a21fc96e7c29 # v0.2.0
-      - name: "Install Node dependencies"
-        run: npm ci
-        working-directory: playground
-      - name: "Run TypeScript checks"
-        run: npm run check
-        working-directory: playground
-      - name: "Build Ruff playground"
-        run: npm run build --workspace ruff-playground
-        working-directory: playground
-      - name: "Deploy to Cloudflare Pages"
-        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
-        uses: cloudflare/wrangler-action@da0e0dfe58b7a431659754fdf3f186c529afbe65 # v3.14.1
-        with:
-          apiToken: ${{ secrets.CF_API_TOKEN }}
-          accountId: ${{ secrets.CF_ACCOUNT_ID }}
-          # `github.head_ref` is only set during pull requests and for manual runs or tags we use `main` to deploy to production
-          command: pages deploy playground/ruff/dist --project-name=ruff-playground --branch ${{ github.head_ref || 'main' }} --commit-hash ${GITHUB_SHA}

.github/workflows/publish-pypi.yml

@@ -1,32 +0,0 @@
-# Publish a release to PyPI.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a publish job
-# within `cargo-dist`.
-name: "[ruff] Publish to PyPI"
-
-on:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-jobs:
-  pypi-publish:
-    name: Upload to PyPI
-    runs-on: ubuntu-latest
-    environment:
-      name: release
-    permissions:
-      # For PyPI's trusted publishing.
-      id-token: write
-    steps:
-      - name: "Install uv"
-        uses: astral-sh/setup-uv@f0ec1fc3b38f5e7cd731bb6ce540c5af426746bb # v6.1.0
-      - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
-        with:
-          pattern: wheels-*
-          path: wheels
-          merge-multiple: true
-      - name: Publish to PyPi
-        run: uv publish -v wheels/*

.github/workflows/publish-ty-playground.yml

@@ -1,58 +0,0 @@
-# Publish the ty playground.
-name: "[ty Playground] Release"
-
-permissions: {}
-
-on:
-  push:
-    branches: [main]
-    paths:
-      - "crates/ty*/**"
-      - "crates/ruff_db/**"
-      - "crates/ruff_python_ast/**"
-      - "crates/ruff_python_parser/**"
-      - "playground/**"
-      - ".github/workflows/publish-ty-playground.yml"
-
-concurrency:
-  group: ${{ github.workflow }}-${{ github.ref_name }}
-  cancel-in-progress: true
-
-env:
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-
-jobs:
-  publish:
-    runs-on: ubuntu-latest
-    env:
-      CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          persist-credentials: false
-      - name: "Install Rust toolchain"
-        run: rustup target add wasm32-unknown-unknown
-      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version: 22
-      - uses: jetli/wasm-bindgen-action@20b33e20595891ab1a0ed73145d8a21fc96e7c29 # v0.2.0
-      - name: "Install Node dependencies"
-        run: npm ci
-        working-directory: playground
-      - name: "Run TypeScript checks"
-        run: npm run check
-        working-directory: playground
-      - name: "Build ty playground"
-        run: npm run build --workspace ty-playground
-        working-directory: playground
-      - name: "Deploy to Cloudflare Pages"
-        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
-        uses: cloudflare/wrangler-action@da0e0dfe58b7a431659754fdf3f186c529afbe65 # v3.14.1
-        with:
-          apiToken: ${{ secrets.CF_API_TOKEN }}
-          accountId: ${{ secrets.CF_ACCOUNT_ID }}
-          # `github.head_ref` is only set during pull requests and for manual runs or tags we use `main` to deploy to production
-          command: pages deploy playground/ty/dist --project-name=ty-playground --branch ${{ github.head_ref || 'main' }} --commit-hash ${GITHUB_SHA}

.github/workflows/publish-wasm.yml

@@ -1,59 +0,0 @@
-# Build and publish ruff-api for wasm.
-#
-# Assumed to run as a subworkflow of .github/workflows/release.yml; specifically, as a publish
-# job within `cargo-dist`.
-name: "Build and publish wasm"
-
-on:
-  workflow_dispatch:
-  workflow_call:
-    inputs:
-      plan:
-        required: true
-        type: string
-
-env:
-  CARGO_INCREMENTAL: 0
-  CARGO_NET_RETRY: 10
-  CARGO_TERM_COLOR: always
-  RUSTUP_MAX_RETRIES: 10
-
-jobs:
-  ruff_wasm:
-    runs-on: ubuntu-latest
-    permissions:
-      contents: read
-      id-token: write
-    strategy:
-      matrix:
-        target: [web, bundler, nodejs]
-      fail-fast: false
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          persist-credentials: false
-      - name: "Install Rust toolchain"
-        run: rustup target add wasm32-unknown-unknown
-      - uses: jetli/wasm-pack-action@0d096b08b4e5a7de8c28de67e11e945404e9eefa # v0.4.0
-        with:
-          version: v0.13.1
-      - uses: jetli/wasm-bindgen-action@20b33e20595891ab1a0ed73145d8a21fc96e7c29 # v0.2.0
-      - name: "Run wasm-pack build"
-        run: wasm-pack build --target ${{ matrix.target }} crates/ruff_wasm
-      - name: "Rename generated package"
-        run: | # Replace the package name w/ jq
-          jq '.name="@astral-sh/ruff-wasm-${{ matrix.target }}"' crates/ruff_wasm/pkg/package.json > /tmp/package.json
-          mv /tmp/package.json crates/ruff_wasm/pkg
-      - run: cp LICENSE crates/ruff_wasm/pkg # wasm-pack does not put the LICENSE file in the pkg
-      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version: 20
-          registry-url: "https://registry.npmjs.org"
-      - name: "Publish (dry-run)"
-        if: ${{ inputs.plan == '' || fromJson(inputs.plan).announcement_tag_is_implicit }}
-        run: npm publish --dry-run crates/ruff_wasm/pkg
-      - name: "Publish"
-        if: ${{ inputs.plan != '' && !fromJson(inputs.plan).announcement_tag_is_implicit }}
-        run: npm publish --provenance --access public crates/ruff_wasm/pkg
-        env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}

.github/workflows/release.yaml

@@ -0,0 +1,600 @@
+name: "[ruff] Release"
+
+on:
+  workflow_dispatch:
+    inputs:
+      tag:
+        description: "The version to tag, without the leading 'v'. If omitted, will initiate a dry run (no uploads)."
+        type: string
+      sha:
+        description: "The full sha of the commit to be released. If omitted, the latest commit on the default branch will be used."
+        default: ""
+        type: string
+  pull_request:
+    paths:
+      # When we change pyproject.toml, we want to ensure that the maturin builds still work
+      - pyproject.toml
+      # And when we change this workflow itself...
+      - .github/workflows/release.yaml
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PACKAGE_NAME: ruff
+  PYTHON_VERSION: "3.11"
+  CARGO_INCREMENTAL: 0
+  CARGO_NET_RETRY: 10
+  CARGO_TERM_COLOR: always
+  RUSTUP_MAX_RETRIES: 10
+
+jobs:
+  sdist:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build sdist"
+        uses: PyO3/maturin-action@v1
+        with:
+          command: sdist
+          args: --out dist
+      - name: "Test sdist"
+        run: |
+          pip install dist/${{ env.PACKAGE_NAME }}-*.tar.gz --force-reinstall
+          ruff --help
+          python -m ruff --help
+      - name: "Upload sdist"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-sdist
+          path: dist
+
+  macos-x86_64:
+    runs-on: macos-12
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels - x86_64"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: x86_64
+          args: --release --locked --out dist
+      - name: "Test wheel - x86_64"
+        run: |
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ruff --help
+          python -m ruff --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-macos-x86_64
+          path: dist
+      - name: "Archive binary"
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-x86_64-apple-darwin.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/x86_64-apple-darwin/release ruff
+          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-macos-x86_64
+          path: |
+            *.tar.gz
+            *.sha256
+
+  macos-aarch64:
+    runs-on: macos-14
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: arm64
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels - aarch64"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: aarch64
+          args: --release --locked --out dist
+      - name: "Test wheel - aarch64"
+        run: |
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ruff --help
+          python -m ruff --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-aarch64-apple-darwin
+          path: dist
+      - name: "Archive binary"
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-aarch64-apple-darwin.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/aarch64-apple-darwin/release ruff
+          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-aarch64-apple-darwin
+          path: |
+            *.tar.gz
+            *.sha256
+
+  windows:
+    runs-on: windows-latest
+    strategy:
+      matrix:
+        platform:
+          - target: x86_64-pc-windows-msvc
+            arch: x64
+          - target: i686-pc-windows-msvc
+            arch: x86
+          - target: aarch64-pc-windows-msvc
+            arch: x64
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: ${{ matrix.platform.arch }}
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: ${{ matrix.platform.target }}
+          args: --release --locked --out dist
+      - name: "Test wheel"
+        if: ${{ !startsWith(matrix.platform.target, 'aarch64') }}
+        shell: bash
+        run: |
+          python -m pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ruff --help
+          python -m ruff --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-${{ matrix.platform.target }}
+          path: dist
+      - name: "Archive binary"
+        shell: bash
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.platform.target }}.zip
+          7z a $ARCHIVE_FILE ./target/${{ matrix.platform.target }}/release/ruff.exe
+          sha256sum $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-${{ matrix.platform.target }}
+          path: |
+            *.zip
+            *.sha256
+
+  linux:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target:
+          - x86_64-unknown-linux-gnu
+          - i686-unknown-linux-gnu
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: ${{ matrix.target }}
+          manylinux: auto
+          args: --release --locked --out dist
+      - name: "Test wheel"
+        if: ${{ startsWith(matrix.target, 'x86_64') }}
+        run: |
+          pip install dist/${{ env.PACKAGE_NAME }}-*.whl --force-reinstall
+          ruff --help
+          python -m ruff --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-${{ matrix.target }}
+          path: dist
+      - name: "Archive binary"
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.target }}/release ruff
+          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-${{ matrix.target }}
+          path: |
+            *.tar.gz
+            *.sha256
+
+  linux-cross:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform:
+          - target: aarch64-unknown-linux-gnu
+            arch: aarch64
+            # see https://github.com/astral-sh/ruff/issues/3791
+            # and https://github.com/gnzlbg/jemallocator/issues/170#issuecomment-1503228963
+            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
+          - target: armv7-unknown-linux-gnueabihf
+            arch: armv7
+          - target: s390x-unknown-linux-gnu
+            arch: s390x
+          - target: powerpc64le-unknown-linux-gnu
+            arch: ppc64le
+            # see https://github.com/astral-sh/ruff/issues/10073
+            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
+          - target: powerpc64-unknown-linux-gnu
+            arch: ppc64
+            # see https://github.com/astral-sh/ruff/issues/10073
+            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: ${{ matrix.platform.target }}
+          manylinux: auto
+          docker-options: ${{ matrix.platform.maturin_docker_options }}
+          args: --release --locked --out dist
+      - uses: uraimo/run-on-arch-action@v2
+        if: matrix.platform.arch != 'ppc64'
+        name: Test wheel
+        with:
+          arch: ${{ matrix.platform.arch }}
+          distro: ubuntu20.04
+          githubToken: ${{ github.token }}
+          install: |
+            apt-get update
+            apt-get install -y --no-install-recommends python3 python3-pip
+            pip3 install -U pip
+          run: |
+            pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
+            ruff --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-${{ matrix.platform.target }}
+          path: dist
+      - name: "Archive binary"
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.platform.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.platform.target }}/release ruff
+          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-${{ matrix.platform.target }}
+          path: |
+            *.tar.gz
+            *.sha256
+
+  musllinux:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target:
+          - x86_64-unknown-linux-musl
+          - i686-unknown-linux-musl
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: ${{ matrix.target }}
+          manylinux: musllinux_1_2
+          args: --release --locked --out dist
+      - name: "Test wheel"
+        if: matrix.target == 'x86_64-unknown-linux-musl'
+        uses: addnab/docker-run-action@v3
+        with:
+          image: alpine:latest
+          options: -v ${{ github.workspace }}:/io -w /io
+          run: |
+            apk add python3
+            python -m venv .venv
+            .venv/bin/pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
+            .venv/bin/ruff check --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-${{ matrix.target }}
+          path: dist
+      - name: "Archive binary"
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.target }}/release ruff
+          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-${{ matrix.target }}
+          path: |
+            *.tar.gz
+            *.sha256
+
+  musllinux-cross:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform:
+          - target: aarch64-unknown-linux-musl
+            arch: aarch64
+            maturin_docker_options: -e JEMALLOC_SYS_WITH_LG_PAGE=16
+          - target: armv7-unknown-linux-musleabihf
+            arch: armv7
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - uses: actions/setup-python@v5
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+      - name: "Prep README.md"
+        run: python scripts/transform_readme.py --target pypi
+      - name: "Build wheels"
+        uses: PyO3/maturin-action@v1
+        with:
+          target: ${{ matrix.platform.target }}
+          manylinux: musllinux_1_2
+          args: --release --locked --out dist
+          docker-options: ${{ matrix.platform.maturin_docker_options }}
+      - uses: uraimo/run-on-arch-action@v2
+        name: Test wheel
+        with:
+          arch: ${{ matrix.platform.arch }}
+          distro: alpine_latest
+          githubToken: ${{ github.token }}
+          install: |
+            apk add python3
+          run: |
+            python -m venv .venv
+            .venv/bin/pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
+            .venv/bin/ruff check --help
+      - name: "Upload wheels"
+        uses: actions/upload-artifact@v4
+        with:
+          name: wheels-${{ matrix.platform.target }}
+          path: dist
+      - name: "Archive binary"
+        run: |
+          ARCHIVE_FILE=ruff-${{ inputs.tag }}-${{ matrix.platform.target }}.tar.gz
+          tar czvf $ARCHIVE_FILE -C target/${{ matrix.platform.target }}/release ruff
+          shasum -a 256 $ARCHIVE_FILE > $ARCHIVE_FILE.sha256
+      - name: "Upload binary"
+        uses: actions/upload-artifact@v4
+        with:
+          name: binaries-${{ matrix.platform.target }}
+          path: |
+            *.tar.gz
+            *.sha256
+
+  validate-tag:
+    name: Validate tag
+    runs-on: ubuntu-latest
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: main # We checkout the main branch to check for the commit
+      - name: Check main branch
+        if: ${{ inputs.sha }}
+        run: |
+          # Fetch the main branch since a shallow checkout is used by default
+          git fetch origin main --unshallow
+          if ! git branch --contains ${{ inputs.sha }} | grep -E '(^|\s)main$'; then
+            echo "The specified sha is not on the main branch" >&2
+            exit 1
+          fi
+      - name: Check tag consistency
+        run: |
+          # Switch to the commit we want to release
+          git checkout ${{ inputs.sha }}
+          version=$(grep "version = " pyproject.toml | sed -e 's/version = "\(.*\)"/\1/g')
+          if [ "${{ inputs.tag }}" != "${version}" ]; then
+            echo "The input tag does not match the version from pyproject.toml:" >&2
+            echo "${{ inputs.tag }}" >&2
+            echo "${version}" >&2
+            exit 1
+          else
+            echo "Releasing ${version}"
+          fi
+
+  upload-release:
+    name: Upload to PyPI
+    runs-on: ubuntu-latest
+    needs:
+      - macos-aarch64
+      - macos-x86_64
+      - windows
+      - linux
+      - linux-cross
+      - musllinux
+      - musllinux-cross
+      - validate-tag
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    environment:
+      name: release
+    permissions:
+      # For pypi trusted publishing
+      id-token: write
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: wheels-*
+          path: wheels
+          merge-multiple: true
+      - name: Publish to PyPi
+        uses: pypa/gh-action-pypi-publish@release/v1
+        with:
+          skip-existing: true
+          packages-dir: wheels
+          verbose: true
+
+  tag-release:
+    name: Tag release
+    runs-on: ubuntu-latest
+    needs: upload-release
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    permissions:
+      # For git tag
+      contents: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+      - name: git tag
+        run: |
+          git config user.email "hey@astral.sh"
+          git config user.name "Ruff Release CI"
+          git tag -m "v${{ inputs.tag }}" "v${{ inputs.tag }}"
+          # If there is duplicate tag, this will fail. The publish to pypi action will have been a noop (due to skip
+          # existing), so we make a non-destructive exit here
+          git push --tags
+
+  publish-release:
+    name: Publish to GitHub
+    runs-on: ubuntu-latest
+    needs: tag-release
+    # If you don't set an input tag, it's a dry run (no uploads).
+    if: ${{ inputs.tag }}
+    permissions:
+      # For GitHub release publishing
+      contents: write
+    steps:
+      - uses: actions/download-artifact@v4
+        with:
+          pattern: binaries-*
+          path: binaries
+          merge-multiple: true
+      - name: "Publish to GitHub"
+        uses: softprops/action-gh-release@v2
+        with:
+          draft: true
+          files: binaries/*
+          tag_name: v${{ inputs.tag }}
+
+  docker-publish:
+    # This action doesn't need to wait on any other task, it's easy to re-tag if something failed and we're validating
+    # the tag here also
+    name: Push Docker image ghcr.io/astral-sh/ruff
+    runs-on: ubuntu-latest
+    environment:
+      name: release
+    permissions:
+      # For the docker push
+      packages: write
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          ref: ${{ inputs.sha }}
+
+      - uses: docker/setup-buildx-action@v3
+
+      - uses: docker/login-action@v3
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels) for Docker
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ghcr.io/astral-sh/ruff
+
+      - name: Check tag consistency
+        # Unlike validate-tag we don't check if the commit is on the main branch, but it seems good enough since we can
+        # change docker tags
+        if: ${{ inputs.tag }}
+        run: |
+          version=$(grep "version = " pyproject.toml | sed -e 's/version = "\(.*\)"/\1/g')
+          if [ "${{ inputs.tag }}" != "${version}" ]; then
+            echo "The input tag does not match the version from pyproject.toml:" >&2
+            echo "${{ inputs.tag }}" >&2
+            echo "${version}" >&2
+            exit 1
+          else
+            echo "Releasing ${version}"
+          fi
+
+      - name: "Build and push Docker image"
+        uses: docker/build-push-action@v5
+        with:
+          context: .
+          platforms: linux/amd64,linux/arm64
+          # Reuse the builder
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+          push: ${{ inputs.tag != '' }}
+          tags: ghcr.io/astral-sh/ruff:latest,ghcr.io/astral-sh/ruff:${{ inputs.tag || 'dry-run' }}
+          labels: ${{ steps.meta.outputs.labels }}
+
+  # After the release has been published, we update downstream repositories
+  # This is separate because if this fails the release is still fine, we just need to do some manual workflow triggers
+  update-dependents:
+    name: Update dependents
+    runs-on: ubuntu-latest
+    needs: publish-release
+    steps:
+      - name: "Update pre-commit mirror"
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.RUFF_PRE_COMMIT_PAT }}
+          script: |
+            github.rest.actions.createWorkflowDispatch({
+              owner: 'astral-sh',
+              repo: 'ruff-pre-commit',
+              workflow_id: 'main.yml',
+              ref: 'main',
+            })

.github/workflows/release.yml

@@ -1,306 +0,0 @@
-# This file was autogenerated by dist: https://github.com/astral-sh/cargo-dist
-#
-# Copyright 2022-2024, axodotdev
-# Copyright 2025 Astral Software Inc.
-# SPDX-License-Identifier: MIT or Apache-2.0
-#
-# CI that:
-#
-# * checks for a Git Tag that looks like a release
-# * builds artifacts with dist (archives, installers, hashes)
-# * uploads those artifacts to temporary workflow zip
-# * on success, uploads the artifacts to a GitHub Release
-#
-# Note that the GitHub Release will be created with a generated
-# title/body based on your changelogs.
-
-name: Release
-permissions:
-  "contents": "write"
-
-# This task will run whenever you workflow_dispatch with a tag that looks like a version
-# like "1.0.0", "v0.1.0-prerelease.1", "my-app/0.1.0", "releases/v1.0.0", etc.
-# Various formats will be parsed into a VERSION and an optional PACKAGE_NAME, where
-# PACKAGE_NAME must be the name of a Cargo package in your workspace, and VERSION
-# must be a Cargo-style SemVer Version (must have at least major.minor.patch).
-#
-# If PACKAGE_NAME is specified, then the announcement will be for that
-# package (erroring out if it doesn't have the given version or isn't dist-able).
-#
-# If PACKAGE_NAME isn't specified, then the announcement will be for all
-# (dist-able) packages in the workspace with that version (this mode is
-# intended for workspaces with only one dist-able package, or with all dist-able
-# packages versioned/released in lockstep).
-#
-# If you push multiple tags at once, separate instances of this workflow will
-# spin up, creating an independent announcement for each one. However, GitHub
-# will hard limit this to 3 tags per commit, as it will assume more tags is a
-# mistake.
-#
-# If there's a prerelease-style suffix to the version, then the release(s)
-# will be marked as a prerelease.
-on:
-  pull_request:
-  workflow_dispatch:
-    inputs:
-      tag:
-        description: Release Tag
-        required: true
-        default: dry-run
-        type: string
-
-jobs:
-  # Run 'dist plan' (or host) to determine what tasks we need to do
-  plan:
-    runs-on: "depot-ubuntu-latest-4"
-    outputs:
-      val: ${{ steps.plan.outputs.manifest }}
-      tag: ${{ (inputs.tag != 'dry-run' && inputs.tag) || '' }}
-      tag-flag: ${{ inputs.tag && inputs.tag != 'dry-run' && format('--tag={0}', inputs.tag) || '' }}
-      publishing: ${{ inputs.tag && inputs.tag != 'dry-run' }}
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    steps:
-      - uses: actions/checkout@85e6279cec87321a52edac9c87bce653a07cf6c2
-        with:
-          persist-credentials: false
-          submodules: recursive
-      - name: Install dist
-        # we specify bash to get pipefail; it guards against the `curl` command
-        # failing. otherwise `sh` won't catch that `curl` returned non-0
-        shell: bash
-        run: "curl --proto '=https' --tlsv1.2 -LsSf https://github.com/astral-sh/cargo-dist/releases/download/v0.28.5-prerelease.1/cargo-dist-installer.sh | sh"
-      - name: Cache dist
-        uses: actions/upload-artifact@6027e3dd177782cd8ab9af838c04fd81a07f1d47
-        with:
-          name: cargo-dist-cache
-          path: ~/.cargo/bin/dist
-      # sure would be cool if github gave us proper conditionals...
-      # so here's a doubly-nested ternary-via-truthiness to try to provide the best possible
-      # functionality based on whether this is a pull_request, and whether it's from a fork.
-      # (PRs run on the *source* but secrets are usually on the *target* -- that's *good*
-      # but also really annoying to build CI around when it needs secrets to work right.)
-      - id: plan
-        run: |
-          dist ${{ (inputs.tag && inputs.tag != 'dry-run' && format('host --steps=create --tag={0}', inputs.tag)) || 'plan' }} --output-format=json > plan-dist-manifest.json
-          echo "dist ran successfully"
-          cat plan-dist-manifest.json
-          echo "manifest=$(jq -c "." plan-dist-manifest.json)" >> "$GITHUB_OUTPUT"
-      - name: "Upload dist-manifest.json"
-        uses: actions/upload-artifact@6027e3dd177782cd8ab9af838c04fd81a07f1d47
-        with:
-          name: artifacts-plan-dist-manifest
-          path: plan-dist-manifest.json
-
-  custom-build-binaries:
-    needs:
-      - plan
-    if: ${{ needs.plan.outputs.publishing == 'true' || fromJson(needs.plan.outputs.val).ci.github.pr_run_mode == 'upload' || inputs.tag == 'dry-run' }}
-    uses: ./.github/workflows/build-binaries.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-
-  custom-build-docker:
-    needs:
-      - plan
-    if: ${{ needs.plan.outputs.publishing == 'true' || fromJson(needs.plan.outputs.val).ci.github.pr_run_mode == 'upload' || inputs.tag == 'dry-run' }}
-    uses: ./.github/workflows/build-docker.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    permissions:
-      "contents": "read"
-      "packages": "write"
-
-  # Build and package all the platform-agnostic(ish) things
-  build-global-artifacts:
-    needs:
-      - plan
-      - custom-build-binaries
-      - custom-build-docker
-    runs-on: "depot-ubuntu-latest-4"
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-      BUILD_MANIFEST_NAME: target/distrib/global-dist-manifest.json
-    steps:
-      - uses: actions/checkout@85e6279cec87321a52edac9c87bce653a07cf6c2
-        with:
-          persist-credentials: false
-          submodules: recursive
-      - name: Install cached dist
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093
-        with:
-          name: cargo-dist-cache
-          path: ~/.cargo/bin/
-      - run: chmod +x ~/.cargo/bin/dist
-      # Get all the local artifacts for the global tasks to use (for e.g. checksums)
-      - name: Fetch local artifacts
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093
-        with:
-          pattern: artifacts-*
-          path: target/distrib/
-          merge-multiple: true
-      - id: cargo-dist
-        shell: bash
-        run: |
-          dist build ${{ needs.plan.outputs.tag-flag }} --output-format=json "--artifacts=global" > dist-manifest.json
-          echo "dist ran successfully"
-
-          # Parse out what we just built and upload it to scratch storage
-          echo "paths<<EOF" >> "$GITHUB_OUTPUT"
-          jq --raw-output ".upload_files[]" dist-manifest.json >> "$GITHUB_OUTPUT"
-          echo "EOF" >> "$GITHUB_OUTPUT"
-
-          cp dist-manifest.json "$BUILD_MANIFEST_NAME"
-      - name: "Upload artifacts"
-        uses: actions/upload-artifact@6027e3dd177782cd8ab9af838c04fd81a07f1d47
-        with:
-          name: artifacts-build-global
-          path: |
-            ${{ steps.cargo-dist.outputs.paths }}
-            ${{ env.BUILD_MANIFEST_NAME }}
-  # Determines if we should publish/announce
-  host:
-    needs:
-      - plan
-      - custom-build-binaries
-      - custom-build-docker
-      - build-global-artifacts
-    # Only run if we're "publishing", and only if local and global didn't fail (skipped is fine)
-    if: ${{ always() && needs.plan.outputs.publishing == 'true' && (needs.build-global-artifacts.result == 'skipped' || needs.build-global-artifacts.result == 'success') && (needs.custom-build-binaries.result == 'skipped' || needs.custom-build-binaries.result == 'success') && (needs.custom-build-docker.result == 'skipped' || needs.custom-build-docker.result == 'success') }}
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    runs-on: "depot-ubuntu-latest-4"
-    outputs:
-      val: ${{ steps.host.outputs.manifest }}
-    steps:
-      - uses: actions/checkout@85e6279cec87321a52edac9c87bce653a07cf6c2
-        with:
-          persist-credentials: false
-          submodules: recursive
-      - name: Install cached dist
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093
-        with:
-          name: cargo-dist-cache
-          path: ~/.cargo/bin/
-      - run: chmod +x ~/.cargo/bin/dist
-      # Fetch artifacts from scratch-storage
-      - name: Fetch artifacts
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093
-        with:
-          pattern: artifacts-*
-          path: target/distrib/
-          merge-multiple: true
-      # This is a harmless no-op for GitHub Releases, hosting for that happens in "announce"
-      - id: host
-        shell: bash
-        run: |
-          dist host ${{ needs.plan.outputs.tag-flag }} --steps=upload --steps=release --output-format=json > dist-manifest.json
-          echo "artifacts uploaded and released successfully"
-          cat dist-manifest.json
-          echo "manifest=$(jq -c "." dist-manifest.json)" >> "$GITHUB_OUTPUT"
-      - name: "Upload dist-manifest.json"
-        uses: actions/upload-artifact@6027e3dd177782cd8ab9af838c04fd81a07f1d47
-        with:
-          # Overwrite the previous copy
-          name: artifacts-dist-manifest
-          path: dist-manifest.json
-
-  custom-publish-pypi:
-    needs:
-      - plan
-      - host
-    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
-    uses: ./.github/workflows/publish-pypi.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    # publish jobs get escalated permissions
-    permissions:
-      "id-token": "write"
-      "packages": "write"
-
-  custom-publish-wasm:
-    needs:
-      - plan
-      - host
-    if: ${{ !fromJson(needs.plan.outputs.val).announcement_is_prerelease || fromJson(needs.plan.outputs.val).publish_prereleases }}
-    uses: ./.github/workflows/publish-wasm.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-    # publish jobs get escalated permissions
-    permissions:
-      "contents": "read"
-      "id-token": "write"
-      "packages": "write"
-
-  # Create a GitHub Release while uploading all files to it
-  announce:
-    needs:
-      - plan
-      - host
-      - custom-publish-pypi
-      - custom-publish-wasm
-    # use "always() && ..." to allow us to wait for all publish jobs while
-    # still allowing individual publish jobs to skip themselves (for prereleases).
-    # "host" however must run to completion, no skipping allowed!
-    if: ${{ always() && needs.host.result == 'success' && (needs.custom-publish-pypi.result == 'skipped' || needs.custom-publish-pypi.result == 'success') && (needs.custom-publish-wasm.result == 'skipped' || needs.custom-publish-wasm.result == 'success') }}
-    runs-on: "depot-ubuntu-latest-4"
-    env:
-      GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-    steps:
-      - uses: actions/checkout@85e6279cec87321a52edac9c87bce653a07cf6c2
-        with:
-          persist-credentials: false
-          submodules: recursive
-      # Create a GitHub Release while uploading all files to it
-      - name: "Download GitHub Artifacts"
-        uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093
-        with:
-          pattern: artifacts-*
-          path: artifacts
-          merge-multiple: true
-      - name: Cleanup
-        run: |
-          # Remove the granular manifests
-          rm -f artifacts/*-dist-manifest.json
-      - name: Create GitHub Release
-        env:
-          PRERELEASE_FLAG: "${{ fromJson(needs.host.outputs.val).announcement_is_prerelease && '--prerelease' || '' }}"
-          ANNOUNCEMENT_TITLE: "${{ fromJson(needs.host.outputs.val).announcement_title }}"
-          ANNOUNCEMENT_BODY: "${{ fromJson(needs.host.outputs.val).announcement_github_body }}"
-          RELEASE_COMMIT: "${{ github.sha }}"
-        run: |
-          # Write and read notes from a file to avoid quoting breaking things
-          echo "$ANNOUNCEMENT_BODY" > $RUNNER_TEMP/notes.txt
-
-          gh release create "${{ needs.plan.outputs.tag }}" --target "$RELEASE_COMMIT" $PRERELEASE_FLAG --title "$ANNOUNCEMENT_TITLE" --notes-file "$RUNNER_TEMP/notes.txt" artifacts/*
-
-  custom-notify-dependents:
-    needs:
-      - plan
-      - announce
-    uses: ./.github/workflows/notify-dependents.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-
-  custom-publish-docs:
-    needs:
-      - plan
-      - announce
-    uses: ./.github/workflows/publish-docs.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit
-
-  custom-publish-playground:
-    needs:
-      - plan
-      - announce
-    uses: ./.github/workflows/publish-playground.yml
-    with:
-      plan: ${{ needs.plan.outputs.val }}
-    secrets: inherit

.github/workflows/sync_typeshed.yaml

@@ -1,83 +0,0 @@
-name: Sync typeshed
-
-on:
-  workflow_dispatch:
-  schedule:
-    # Run on the 1st and the 15th of every month:
-    - cron: "0 0 1,15 * *"
-
-env:
-  FORCE_COLOR: 1
-  GH_TOKEN: ${{ github.token }}
-
-jobs:
-  sync:
-    name: Sync typeshed
-    runs-on: ubuntu-latest
-    timeout-minutes: 20
-    # Don't run the cron job on forks:
-    if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
-    permissions:
-      contents: write
-      pull-requests: write
-    steps:
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        name: Checkout Ruff
-        with:
-          path: ruff
-          persist-credentials: true
-      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        name: Checkout typeshed
-        with:
-          repository: python/typeshed
-          path: typeshed
-          persist-credentials: false
-      - name: Setup git
-        run: |
-          git config --global user.name typeshedbot
-          git config --global user.email '<>'
-      - name: Sync typeshed
-        id: sync
-        run: |
-          rm -rf ruff/crates/ty_vendored/vendor/typeshed
-          mkdir ruff/crates/ty_vendored/vendor/typeshed
-          cp typeshed/README.md ruff/crates/ty_vendored/vendor/typeshed
-          cp typeshed/LICENSE ruff/crates/ty_vendored/vendor/typeshed
-          cp -r typeshed/stdlib ruff/crates/ty_vendored/vendor/typeshed/stdlib
-          rm -rf ruff/crates/ty_vendored/vendor/typeshed/stdlib/@tests
-          git -C typeshed rev-parse HEAD > ruff/crates/ty_vendored/vendor/typeshed/source_commit.txt
-      - name: Commit the changes
-        id: commit
-        if: ${{ steps.sync.outcome == 'success' }}
-        run: |
-          cd ruff
-          git checkout -b typeshedbot/sync-typeshed
-          git add .
-          git diff --staged --quiet || git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)"
-      - name: Create a PR
-        if: ${{ steps.sync.outcome == 'success' && steps.commit.outcome == 'success' }}
-        run: |
-          cd ruff
-          git push --force origin typeshedbot/sync-typeshed
-          gh pr list --repo "$GITHUB_REPOSITORY" --head typeshedbot/sync-typeshed --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
-          gh pr create --title "Sync vendored typeshed stubs" --body "Close and reopen this PR to trigger CI" --label "internal"
-
-  create-issue-on-failure:
-    name: Create an issue if the typeshed sync failed
-    runs-on: ubuntu-latest
-    needs: [sync]
-    if: ${{ github.repository == 'astral-sh/ruff' && always() && github.event_name == 'schedule' && needs.sync.result == 'failure' }}
-    permissions:
-      issues: write
-    steps:
-      - uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
-        with:
-          github-token: ${{ secrets.GITHUB_TOKEN }}
-          script: |
-            await github.rest.issues.create({
-              owner: "astral-sh",
-              repo: "ruff",
-              title: `Automated typeshed sync failed on ${new Date().toDateString()}`,
-              body: "Run listed here: https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}",
-              labels: ["bug", "ty"],
-            })

.github/zizmor.yml

@@ -1,19 +0,0 @@
-# Configuration for the zizmor static analysis tool, run via pre-commit in CI
-# https://woodruffw.github.io/zizmor/configuration/
-#
-# TODO: can we remove the ignores here so that our workflows are more secure?
-rules:
-  dangerous-triggers:
-    ignore:
-      - pr-comment.yaml
-  cache-poisoning:
-    ignore:
-      - build-docker.yml
-      - publish-playground.yml
-  excessive-permissions:
-    # it's hard to test what the impact of removing these ignores would be
-    # without actually running the release workflow...
-    ignore:
-      - build-docker.yml
-      - publish-playground.yml
-      - publish-docs.yml

.gitignore

@@ -21,18 +21,6 @@ flamegraph.svg
 # `CARGO_TARGET_DIR=target-llvm-lines RUSTFLAGS="-Csymbol-mangling-version=v0" cargo llvm-lines -p ruff --lib`
 /target*
 
-# samply profiles
-profile.json
-
-# tracing-flame traces
-tracing.folded
-tracing-flamechart.svg
-tracing-flamegraph.svg
-
-# insta
-*.rs.pending-snap
-
-
 ###
 # Rust.gitignore
 ###

.ignore

@@ -1 +0,0 @@
-!/.github/

.markdownlint.yaml

@@ -14,22 +14,7 @@ MD041: false
 # MD013/line-length
 MD013: false
 
-# MD014/commands-show-output
-MD014: false
-
 # MD024/no-duplicate-heading
 MD024:
   # Allow when nested under different parents e.g. CHANGELOG.md
   siblings_only: true
-
-# MD046/code-block-style
-#
-# Ignore this because it conflicts with the code block style used in content
-# tabs of mkdocs-material which is to add a blank line after the content title.
-#
-# Ref: https://github.com/astral-sh/ruff/pull/15011#issuecomment-2544790854
-MD046: false
-
-# Link text should be descriptive
-# Disallows link text like *here* which is annoying.
-MD059: false

.pre-commit-config.yaml

@@ -1,16 +1,9 @@
-fail_fast: false
+fail_fast: true
 
 exclude: |
   (?x)^(
-    .github/workflows/release.yml|
-    crates/ty_vendored/vendor/.*|
-    crates/ty_project/resources/.*|
-    crates/ty/docs/(configuration|rules|cli).md|
-    crates/ruff_benchmark/resources/.*|
     crates/ruff_linter/resources/.*|
     crates/ruff_linter/src/rules/.*/snapshots/.*|
-    crates/ruff_notebook/resources/.*|
-    crates/ruff_server/resources/.*|
     crates/ruff/resources/.*|
     crates/ruff_python_formatter/resources/.*|
     crates/ruff_python_formatter/tests/snapshots/.*|
@@ -19,23 +12,18 @@ exclude: |
   )$
 
 repos:
-  - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v5.0.0
-    hooks:
-      - id: check-merge-conflict
-
   - repo: https://github.com/abravalheri/validate-pyproject
-    rev: v0.24.1
+    rev: v0.16
     hooks:
       - id: validate-pyproject
 
   - repo: https://github.com/executablebooks/mdformat
-    rev: 0.7.22
+    rev: 0.7.17
     hooks:
       - id: mdformat
         additional_dependencies:
-          - mdformat-mkdocs==4.0.0
-          - mdformat-footnote==0.1.1
+          - mdformat-mkdocs
+          - mdformat-admon
         exclude: |
           (?x)^(
             docs/formatter/black\.md
@@ -43,7 +31,7 @@ repos:
           )$
 
   - repo: https://github.com/igorshubovych/markdownlint-cli
-    rev: v0.45.0
+    rev: v0.39.0
     hooks:
       - id: markdownlint-fix
         exclude: |
@@ -52,21 +40,8 @@ repos:
             | docs/\w+\.md
           )$
 
-  - repo: https://github.com/adamchainz/blacken-docs
-    rev: 1.19.1
-    hooks:
-      - id: blacken-docs
-        args: ["--pyi", "--line-length", "130"]
-        files: '^crates/.*/resources/mdtest/.*\.md'
-        exclude: |
-          (?x)^(
-            .*?invalid(_.+)*_syntax\.md
-          )$
-        additional_dependencies:
-          - black==25.1.0
-
   - repo: https://github.com/crate-ci/typos
-    rev: v1.32.0
+    rev: v1.20.10
     hooks:
       - id: typos
 
@@ -80,52 +55,25 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.11.11
+    rev: v0.4.2
     hooks:
       - id: ruff-format
       - id: ruff
         args: [--fix, --exit-non-zero-on-fix]
         types_or: [python, pyi]
         require_serial: true
+        exclude: |
+          (?x)^(
+            crates/ruff_linter/resources/.*|
+            crates/ruff_python_formatter/resources/.*
+          )$
 
   # Prettier
-  - repo: https://github.com/rbubley/mirrors-prettier
-    rev: v3.5.3
+  - repo: https://github.com/pre-commit/mirrors-prettier
+    rev: v3.1.0
     hooks:
       - id: prettier
         types: [yaml]
 
-  # zizmor detects security vulnerabilities in GitHub Actions workflows.
-  # Additional configuration for the tool is found in `.github/zizmor.yml`
-  - repo: https://github.com/woodruffw/zizmor-pre-commit
-    rev: v1.8.0
-    hooks:
-      - id: zizmor
-
-  - repo: https://github.com/python-jsonschema/check-jsonschema
-    rev: 0.33.0
-    hooks:
-      - id: check-github-workflows
-
-  # `actionlint` hook, for verifying correct syntax in GitHub Actions workflows.
-  # Some additional configuration for `actionlint` can be found in `.github/actionlint.yaml`.
-  - repo: https://github.com/rhysd/actionlint
-    rev: v1.7.7
-    hooks:
-      - id: actionlint
-        stages:
-          # This hook is disabled by default, since it's quite slow.
-          # To run all hooks *including* this hook, use `uvx pre-commit run -a --hook-stage=manual`.
-          # To run *just* this hook, use `uvx pre-commit run -a actionlint --hook-stage=manual`.
-          - manual
-        args:
-          - "-ignore=SC2129" # ignorable stylistic lint from shellcheck
-          - "-ignore=SC2016" # another shellcheck lint: seems to have false positives?
-        additional_dependencies:
-          # actionlint has a shellcheck integration which extracts shell scripts in `run:` steps from GitHub Actions
-          # and checks these with shellcheck. This is arguably its most useful feature,
-          # but the integration only works if shellcheck is installed
-          - "github.com/wasilibs/go-shellcheck/cmd/shellcheck@v0.10.0"
-
 ci:
   skip: [cargo-fmt, dev-generate-all]

.prettierignore

@@ -1,2 +0,0 @@
-# Auto-generated by `cargo-dist`.
-.github/workflows/release.yml

.vscode/extensions.json

@@ -1,5 +0,0 @@
-{
-    "recommendations": [
-        "rust-lang.rust-analyzer"
-    ]
-}

.vscode/settings.json

@@ -1,6 +0,0 @@
-{
-    "rust-analyzer.check.extraArgs": [
-        "--all-features"
-    ],
-    "rust-analyzer.check.command": "clippy",
-}

BREAKING_CHANGES.md

@@ -1,142 +1,5 @@
 # Breaking Changes
 
-## 0.11.0
-
-This is a follow-up to release 0.10.0. Because of a mistake in the release process, the `requires-python` inference changes were not included in that release. Ruff 0.11.0 now includes this change as well as the stabilization of the preview behavior for `PGH004`.
-
-- **Changes to how the Python version is inferred when a `target-version` is not specified** ([#16319](https://github.com/astral-sh/ruff/pull/16319))
-
-    In previous versions of Ruff, you could specify your Python version with:
-
-    - The `target-version` option in a `ruff.toml` file or the `[tool.ruff]` section of a pyproject.toml file.
-    - The `project.requires-python` field in a `pyproject.toml` file with a `[tool.ruff]` section.
-
-    These options worked well in most cases, and are still recommended for fine control of the Python version. However, because of the way Ruff discovers config files, `pyproject.toml` files without a `[tool.ruff]` section would be ignored, including the `requires-python` setting. Ruff would then use the default Python version (3.9 as of this writing) instead, which is surprising when you've attempted to request another version.
-
-    In v0.10, config discovery has been updated to address this issue:
-
-    - If Ruff finds a `ruff.toml` file without a `target-version`, it will check
-        for a `pyproject.toml` file in the same directory and respect its
-        `requires-python` version, even if it does not contain a `[tool.ruff]`
-        section.
-    - If Ruff finds a user-level configuration, the `requires-python` field of the closest `pyproject.toml` in a parent directory will take precedence.
-    - If there is no config file (`ruff.toml`or `pyproject.toml` with a
-        `[tool.ruff]` section) in the directory of the file being checked, Ruff will
-        search for the closest `pyproject.toml` in the parent directories and use its
-        `requires-python` setting.
-
-## 0.10.0
-
-- **Changes to how the Python version is inferred when a `target-version` is not specified** ([#16319](https://github.com/astral-sh/ruff/pull/16319))
-
-    Because of a mistake in the release process, the `requires-python` inference changes are not included in this release and instead shipped as part of 0.11.0.
-    You can find a description of this change in the 0.11.0 section.
-
-- **Updated `TYPE_CHECKING` behavior** ([#16669](https://github.com/astral-sh/ruff/pull/16669))
-
-    Previously, Ruff only recognized typechecking blocks that tested the `typing.TYPE_CHECKING` symbol. Now, Ruff recognizes any local variable named `TYPE_CHECKING`. This release also removes support for the legacy `if 0:` and `if False:` typechecking checks. Use a local `TYPE_CHECKING` variable instead.
-
-- **More robust noqa parsing** ([#16483](https://github.com/astral-sh/ruff/pull/16483))
-
-    The syntax for both file-level and in-line suppression comments has been unified and made more robust to certain errors. In most cases, this will result in more suppression comments being read by Ruff, but there are a few instances where previously read comments will now log an error to the user instead. Please refer to the documentation on [_Error suppression_](https://docs.astral.sh/ruff/linter/#error-suppression) for the full specification.
-
-- **Avoid unnecessary parentheses around with statements with a single context manager and a trailing comment** ([#14005](https://github.com/astral-sh/ruff/pull/14005))
-
-    This change fixes a bug in the formatter where it introduced unnecessary parentheses around with statements with a single context manager and a trailing comment. This change may result in a change in formatting for some users.
-
-- **Bump alpine default tag to 3.21 for derived Docker images** ([#16456](https://github.com/astral-sh/ruff/pull/16456))
-
-    Alpine 3.21 was released in Dec 2024 and is used in the official Alpine-based Python images. Now the ruff:alpine image will use 3.21 instead of 3.20 and ruff:alpine3.20 will no longer be updated.
-
-- **\[`unsafe-markup-use`\]: `RUF035` has been recoded to `S704`** ([#15957](https://github.com/astral-sh/ruff/pull/15957))
-
-## 0.9.0
-
-Ruff now formats your code according to the 2025 style guide. As a result, your code might now get formatted differently. See the [changelog](./CHANGELOG.md#090) for a detailed list of changes.
-
-## 0.8.0
-
-- **Default to Python 3.9**
-
-    Ruff now defaults to Python 3.9 instead of 3.8 if no explicit Python version is configured using [`ruff.target-version`](https://docs.astral.sh/ruff/settings/#target-version) or [`project.requires-python`](https://packaging.python.org/en/latest/guides/writing-pyproject-toml/#python-requires) ([#13896](https://github.com/astral-sh/ruff/pull/13896))
-
-- **Changed location of `pydoclint` diagnostics**
-
-    [`pydoclint`](https://docs.astral.sh/ruff/rules/#pydoclint-doc) diagnostics now point to the first-line of the problematic docstring. Previously, this was not the case.
-
-    If you've opted into these preview rules but have them suppressed using
-    [`noqa`](https://docs.astral.sh/ruff/linter/#error-suppression) comments in
-    some places, this change may mean that you need to move the `noqa` suppression
-    comments. Most users should be unaffected by this change.
-
-- **Use XDG (i.e. `~/.local/bin`) instead of the Cargo home directory in the standalone installer**
-
-    Previously, Ruff's installer used `$CARGO_HOME` or `~/.cargo/bin` for its target install directory. Now, Ruff will be installed into `$XDG_BIN_HOME`, `$XDG_DATA_HOME/../bin`, or `~/.local/bin` (in that order).
-
-    This change is only relevant to users of the standalone Ruff installer (using the shell or PowerShell script). If you installed Ruff using uv or pip, you should be unaffected.
-
-- **Changes to the line width calculation**
-
-    Ruff now uses a new version of the [unicode-width](https://github.com/unicode-rs/unicode-width) Rust crate to calculate the line width. In very rare cases, this may lead to lines containing Unicode characters being reformatted, or being considered too long when they were not before ([`E501`](https://docs.astral.sh/ruff/rules/line-too-long/)).
-
-## 0.7.0
-
-- The pytest rules `PT001` and `PT023` now default to omitting the decorator parentheses when there are no arguments
-    ([#12838](https://github.com/astral-sh/ruff/pull/12838), [#13292](https://github.com/astral-sh/ruff/pull/13292)).
-    This was a change that we attempted to make in Ruff v0.6.0, but only partially made due to an error on our part.
-    See the [blog post](https://astral.sh/blog/ruff-v0.7.0) for more details.
-- The `useless-try-except` rule (in our `tryceratops` category) has been recoded from `TRY302` to
-    `TRY203` ([#13502](https://github.com/astral-sh/ruff/pull/13502)). This ensures Ruff's code is consistent with
-    the same rule in the [`tryceratops`](https://github.com/guilatrova/tryceratops) linter.
-- The `lint.allow-unused-imports` setting has been removed ([#13677](https://github.com/astral-sh/ruff/pull/13677)). Use
-    [`lint.pyflakes.allow-unused-imports`](https://docs.astral.sh/ruff/settings/#lint_pyflakes_allowed-unused-imports)
-    instead.
-
-## 0.6.0
-
-- Detect imports in `src` layouts by default for `isort` rules ([#12848](https://github.com/astral-sh/ruff/pull/12848))
-
-- The pytest rules `PT001` and `PT023` now default to omitting the decorator parentheses when there are no arguments ([#12838](https://github.com/astral-sh/ruff/pull/12838)).
-
-- Lint and format Jupyter Notebook by default ([#12878](https://github.com/astral-sh/ruff/pull/12878)).
-
-    You can disable specific rules for notebooks using [`per-file-ignores`](https://docs.astral.sh/ruff/settings/#lint_per-file-ignores):
-
-    ```toml
-    [tool.ruff.lint.per-file-ignores]
-    "*.ipynb" = ["E501"] # disable line-too-long in notebooks
-    ```
-
-    If you'd prefer to either only lint or only format Jupyter Notebook files, you can use the
-    section-specific `exclude` option to do so. For example, the following would only lint Jupyter
-    Notebook files and not format them:
-
-    ```toml
-    [tool.ruff.format]
-    exclude = ["*.ipynb"]
-    ```
-
-    And, conversely, the following would only format Jupyter Notebook files and not lint them:
-
-    ```toml
-    [tool.ruff.lint]
-    exclude = ["*.ipynb"]
-    ```
-
-    You can completely disable Jupyter Notebook support by updating the [`extend-exclude`](https://docs.astral.sh/ruff/settings/#extend-exclude) setting:
-
-    ```toml
-    [tool.ruff]
-    extend-exclude = ["*.ipynb"]
-    ```
-
-## 0.5.0
-
-- Follow the XDG specification to discover user-level configurations on macOS (same as on other Unix platforms)
-- Selecting `ALL` now excludes deprecated rules
-- The released archives now include an extra level of nesting, which can be removed with `--strip-components=1` when untarring.
-- The release artifact's file name no longer includes the version tag. This enables users to install via `/latest` URLs on GitHub.
-
 ## 0.3.0
 
 ### Ruff 2024.2 style
@@ -246,7 +109,7 @@ flag or `unsafe-fixes` configuration option can be used to enable unsafe fixes.
 
 See the [docs](https://docs.astral.sh/ruff/configuration/#fix-safety) for details.
 
-### Remove formatter-conflicting rules from the default rule set ([#7900](https://github.com/astral-sh/ruff/pull/7900))
+### Remove formatter-conflicting rules from the default rule set  ([#7900](https://github.com/astral-sh/ruff/pull/7900))
 
 Previously, Ruff enabled all implemented rules in Pycodestyle (`E`) by default. Ruff now only includes the
 Pycodestyle prefixes `E4`, `E7`, and `E9` to exclude rules that conflict with automatic formatters. Consequently,
@@ -259,8 +122,8 @@ This change only affects those using Ruff under its default rule set. Users that
 
 ### Remove support for emoji identifiers ([#7212](https://github.com/astral-sh/ruff/pull/7212))
 
-Previously, Ruff supported non-standards-compliant emoji identifiers such as `📦 = 1`.
-We decided to remove this non-standard language extension. Ruff now reports syntax errors for invalid emoji identifiers in your code, the same as CPython.
+Previously, Ruff supported the non-standard compliant emoji identifiers e.g. `📦 = 1`.
+We decided to remove this non-standard language extension, and Ruff now reports syntax errors for emoji identifiers in your code, the same as CPython.
 
 ### Improved GitLab fingerprints ([#7203](https://github.com/astral-sh/ruff/pull/7203))
 

CODE_OF_CONDUCT.md

@@ -71,7 +71,8 @@ representative at an online or offline event.
 ## Enforcement
 
 Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported to the community leaders responsible for enforcement at <hey@astral.sh>.
+reported to the community leaders responsible for enforcement at
+<charlie.r.marsh@gmail.com>.
 All complaints will be reviewed and investigated promptly and fairly.
 
 All community leaders are obligated to respect the privacy and security of the

CONTRIBUTING.md

@@ -2,10 +2,34 @@
 
 Welcome! We're happy to have you here. Thank you in advance for your contribution to Ruff.
 
-> [!NOTE]
->
-> This guide is for Ruff. If you're looking to contribute to ty, please see [the ty contributing
-> guide](https://github.com/astral-sh/ruff/blob/main/crates/ty/CONTRIBUTING.md).
+- [The Basics](#the-basics)
+    - [Prerequisites](#prerequisites)
+    - [Development](#development)
+    - [Project Structure](#project-structure)
+    - [Example: Adding a new lint rule](#example-adding-a-new-lint-rule)
+        - [Rule naming convention](#rule-naming-convention)
+        - [Rule testing: fixtures and snapshots](#rule-testing-fixtures-and-snapshots)
+    - [Example: Adding a new configuration option](#example-adding-a-new-configuration-option)
+- [MkDocs](#mkdocs)
+- [Release Process](#release-process)
+    - [Creating a new release](#creating-a-new-release)
+- [Ecosystem CI](#ecosystem-ci)
+- [Benchmarking and Profiling](#benchmarking-and-profiling)
+    - [CPython Benchmark](#cpython-benchmark)
+    - [Microbenchmarks](#microbenchmarks)
+        - [Benchmark-driven Development](#benchmark-driven-development)
+        - [PR Summary](#pr-summary)
+        - [Tips](#tips)
+    - [Profiling Projects](#profiling-projects)
+        - [Linux](#linux)
+        - [Mac](#mac)
+- [`cargo dev`](#cargo-dev)
+- [Subsystems](#subsystems)
+    - [Compilation Pipeline](#compilation-pipeline)
+    - [Import Categorization](#import-categorization)
+        - [Project root](#project-root)
+        - [Package root](#package-root)
+        - [Import categorization](#import-categorization-1)
 
 ## The Basics
 
@@ -34,14 +58,16 @@ You'll also need [Insta](https://insta.rs/docs/) to update snapshot tests:
 cargo install cargo-insta
 ```
 
-You'll need [uv](https://docs.astral.sh/uv/getting-started/installation/) (or `pipx` and `pip`) to
-run Python utility commands.
+And you'll need pre-commit to run some validation checks:
+
+```shell
+pipx install pre-commit  # or `pip install pre-commit` if you have a virtualenv
+```
 
 You can optionally install pre-commit hooks to automatically run the validation checks
 when making a commit:
 
 ```shell
-uv tool install pre-commit
 pre-commit install
 ```
 
@@ -69,14 +95,12 @@ and that it passes both the lint and test validation checks:
 ```shell
 cargo clippy --workspace --all-targets --all-features -- -D warnings  # Rust linting
 RUFF_UPDATE_SCHEMA=1 cargo test  # Rust testing and updating ruff.schema.json
-uvx pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
+pre-commit run --all-files --show-diff-on-failure  # Rust and Python formatting, Markdown and Python linting, etc.
 ```
 
 These checks will run on GitHub Actions when you open your pull request, but running them locally
 will save you time and expedite the merge process.
 
-If you're using VS Code, you can also install the recommended [rust-analyzer](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust-analyzer) extension to get these checks while editing.
-
 Note that many code changes also require updating the snapshot tests, which is done interactively
 after running `cargo test` like so:
 
@@ -144,7 +168,7 @@ At a high level, the steps involved in adding a new lint rule are as follows:
 1. Create a file for your rule (e.g., `crates/ruff_linter/src/rules/flake8_bugbear/rules/assert_false.rs`).
 
 1. In that file, define a violation struct (e.g., `pub struct AssertFalse`). You can grep for
-    `#[derive(ViolationMetadata)]` to see examples.
+    `#[violation]` to see examples.
 
 1. In that file, define a function that adds the violation to the diagnostic list as appropriate
     (e.g., `pub(crate) fn assert_false`) based on whatever inputs are required for the rule (e.g.,
@@ -254,7 +278,7 @@ These represent, respectively: the schema used to parse the `pyproject.toml` fil
 intermediate representation; and the final, internal representation used to power Ruff.
 
 To add a new configuration option, you'll likely want to modify these latter few files (along with
-`args.rs`, if appropriate). If you want to pattern-match against an existing example, grep for
+`arg.rs`, if appropriate). If you want to pattern-match against an existing example, grep for
 `dummy_variable_rgx`, which defines a regular expression to match against acceptable unused
 variables (e.g., `_`).
 
@@ -270,20 +294,26 @@ To preview any changes to the documentation locally:
 
 1. Install the [Rust toolchain](https://www.rust-lang.org/tools/install).
 
+1. Install MkDocs and Material for MkDocs with:
+
+    ```shell
+    pip install -r docs/requirements.txt
+    ```
+
 1. Generate the MkDocs site with:
 
     ```shell
-    uv run --no-project --isolated --with-requirements docs/requirements.txt scripts/generate_mkdocs.py
+    python scripts/generate_mkdocs.py
     ```
 
 1. Run the development server with:
 
     ```shell
     # For contributors.
-    uvx --with-requirements docs/requirements.txt -- mkdocs serve -f mkdocs.public.yml
+    mkdocs serve -f mkdocs.public.yml
 
     # For members of the Astral org, which has access to MkDocs Insiders via sponsorship.
-    uvx --with-requirements docs/requirements-insiders.txt -- mkdocs serve -f mkdocs.insiders.yml
+    mkdocs serve -f mkdocs.insiders.yml
     ```
 
 The documentation should then be available locally at
@@ -301,63 +331,41 @@ even patch releases may contain [non-backwards-compatible changes](https://semve
 ### Creating a new release
 
 1. Install `uv`: `curl -LsSf https://astral.sh/uv/install.sh | sh`
-
-1. Run `./scripts/release.sh`; this command will:
-
+1. Run `./scripts/release/bump.sh`; this command will:
     - Generate a temporary virtual environment with `rooster`
     - Generate a changelog entry in `CHANGELOG.md`
     - Update versions in `pyproject.toml` and `Cargo.toml`
     - Update references to versions in the `README.md` and documentation
     - Display contributors for the release
-
 1. The changelog should then be editorialized for consistency
-
     - Often labels will be missing from pull requests they will need to be manually organized into the proper section
     - Changes should be edited to be user-facing descriptions, avoiding internal details
-
 1. Highlight any breaking changes in `BREAKING_CHANGES.md`
-
 1. Run `cargo check`. This should update the lock file with new versions.
-
 1. Create a pull request with the changelog and version updates
-
 1. Merge the PR
-
-1. Run the [release workflow](https://github.com/astral-sh/ruff/actions/workflows/release.yml) with:
-
+1. Run the [release workflow](https://github.com/astral-sh/ruff/actions/workflows/release.yaml) with:
     - The new version number (without starting `v`)
-
+    - The commit hash of the merged release pull request on `main`
 1. The release workflow will do the following:
-
     1. Build all the assets. If this fails (even though we tested in step 4), we haven't tagged or
-        uploaded anything, you can restart after pushing a fix. If you just need to rerun the build,
-        make sure you're [re-running all the failed
-        jobs](https://docs.github.com/en/actions/managing-workflow-runs/re-running-workflows-and-jobs#re-running-failed-jobs-in-a-workflow) and not just a single failed job.
+        uploaded anything, you can restart after pushing a fix.
     1. Upload to PyPI.
     1. Create and push the Git tag (as extracted from `pyproject.toml`). We create the Git tag only
         after building the wheels and uploading to PyPI, since we can't delete or modify the tag ([#4468](https://github.com/astral-sh/ruff/issues/4468)).
     1. Attach artifacts to draft GitHub release
     1. Trigger downstream repositories. This can fail non-catastrophically, as we can run any
         downstream jobs manually if needed.
-
-1. Verify the GitHub release:
-
-    1. The Changelog should match the content of `CHANGELOG.md`
-    1. Append the contributors from the `scripts/release.sh` script
-
+1. Publish the GitHub release
+    1. Open the draft release in the GitHub release section
+    1. Copy the changelog for the release into the GitHub release
+        - See previous releases for formatting of section headers
+    1. Append the contributors from the `bump.sh` script
 1. If needed, [update the schemastore](https://github.com/astral-sh/ruff/blob/main/scripts/update_schemastore.py).
-
     1. One can determine if an update is needed when
         `git diff old-version-tag new-version-tag -- ruff.schema.json` returns a non-empty diff.
     1. Once run successfully, you should follow the link in the output to create a PR.
-
-1. If needed, update the [`ruff-lsp`](https://github.com/astral-sh/ruff-lsp) and
-    [`ruff-vscode`](https://github.com/astral-sh/ruff-vscode) repositories and follow
-    the release instructions in those repositories. `ruff-lsp` should always be updated
-    before `ruff-vscode`.
-
-    This step is generally not required for a patch release, but should always be done
-    for a minor release.
+1. If needed, update the `ruff-lsp` and `ruff-vscode` repositories.
 
 ## Ecosystem CI
 
@@ -365,21 +373,13 @@ GitHub Actions will run your changes against a number of real-world projects fro
 report on any linter or formatter differences. You can also run those checks locally via:
 
 ```shell
-uvx --from ./python/ruff-ecosystem ruff-ecosystem check ruff "./target/debug/ruff"
-uvx --from ./python/ruff-ecosystem ruff-ecosystem format ruff "./target/debug/ruff"
+pip install -e ./python/ruff-ecosystem
+ruff-ecosystem check ruff "./target/debug/ruff"
+ruff-ecosystem format ruff "./target/debug/ruff"
 ```
 
 See the [ruff-ecosystem package](https://github.com/astral-sh/ruff/tree/main/python/ruff-ecosystem) for more details.
 
-## Upgrading Rust
-
-1. Change the `channel` in `./rust-toolchain.toml` to the new Rust version (`<latest>`)
-1. Change the `rust-version` in the `./Cargo.toml` to `<latest> - 2` (e.g. 1.84 if the latest is 1.86)
-1. Run `cargo clippy --fix --allow-dirty --allow-staged` to fix new clippy warnings
-1. Create and merge the PR
-1. Bump the Rust version in Ruff's conda forge recipe. See [this PR](https://github.com/conda-forge/ruff-feedstock/pull/266) for an example.
-1. Enjoy the new Rust version!
-
 ## Benchmarking and Profiling
 
 We have several ways of benchmarking and profiling Ruff:
@@ -388,7 +388,7 @@ We have several ways of benchmarking and profiling Ruff:
 - Microbenchmarks which run the linter or the formatter on individual files. These run on pull requests.
 - Profiling the linter on either the microbenchmarks or entire projects
 
-> **Note**
+> \[!NOTE\]
 > When running benchmarks, ensure that your CPU is otherwise idle (e.g., close any background
 > applications, like web browsers). You may also want to switch your CPU to a "performance"
 > mode, if it exists, especially when benchmarking short-lived processes.
@@ -402,18 +402,12 @@ which makes it a good target for benchmarking.
 git clone --branch 3.10 https://github.com/python/cpython.git crates/ruff_linter/resources/test/cpython
 ```
 
-Install `hyperfine`:
-
-```shell
-cargo install hyperfine
-```
-
 To benchmark the release build:
 
 ```shell
-cargo build --release --bin ruff && hyperfine --warmup 10 \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache -e" \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ -e"
+cargo build --release && hyperfine --warmup 10 \
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache -e" \
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ -e"
 
 Benchmark 1: ./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache
   Time (mean ± σ):     293.8 ms ±   3.2 ms    [User: 2384.6 ms, System: 90.3 ms]
@@ -432,7 +426,7 @@ To benchmark against the ecosystem's existing tools:
 
 ```shell
 hyperfine --ignore-failure --warmup 5 \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache" \
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache" \
   "pyflakes crates/ruff_linter/resources/test/cpython" \
   "autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython" \
   "pycodestyle crates/ruff_linter/resources/test/cpython" \
@@ -478,10 +472,10 @@ To benchmark a subset of rules, e.g. `LineTooLong` and `DocLineTooLong`:
 
 ```shell
 cargo build --release && hyperfine --warmup 10 \
-  "./target/release/ruff check ./crates/ruff_linter/resources/test/cpython/ --no-cache -e --select W505,E501"
+  "./target/release/ruff ./crates/ruff_linter/resources/test/cpython/ --no-cache -e --select W505,E501"
 ```
 
-You can run `uv venv --project ./scripts/benchmarks`, activate the venv and then run `uv sync --project ./scripts/benchmarks` to create a working environment for the
+You can run `poetry install` from `./scripts/benchmarks` to create a working environment for the
 above. All reported benchmarks were computed using the versions specified by
 `./scripts/benchmarks/pyproject.toml` on Python 3.11.
 
@@ -535,12 +529,10 @@ You can run the benchmarks with
 cargo benchmark
 ```
 
-`cargo benchmark` is an alias for `cargo bench -p ruff_benchmark --bench linter --bench formatter --`
-
 #### Benchmark-driven Development
 
 Ruff uses [Criterion.rs](https://bheisler.github.io/criterion.rs/book/) for benchmarks. You can use
-`--save-baseline=<name>` to store an initial baseline benchmark (e.g., on `main`) and then use
+`--save-baseline=<name>` to store an initial baseline benchmark (e.g. on `main`) and then use
 `--benchmark=<name>` to compare against that benchmark. Criterion will print a message telling you
 if the benchmark improved/regressed compared to that baseline.
 
@@ -575,7 +567,7 @@ cargo install critcmp
 
 #### Tips
 
-- Use `cargo bench -p ruff_benchmark <filter>` to only run specific benchmarks. For example: `cargo bench -p ruff_benchmark lexer`
+- Use `cargo bench -p ruff_benchmark <filter>` to only run specific benchmarks. For example: `cargo benchmark lexer`
     to only run the lexer benchmarks.
 - Use `cargo bench -p ruff_benchmark -- --quiet` for a more cleaned up output (without statistical relevance)
 - Use `cargo bench -p ruff_benchmark -- --quick` to get faster results (more prone to noise)
@@ -610,7 +602,8 @@ Then convert the recorded profile
 perf script -F +pid > /tmp/test.perf
 ```
 
-You can now view the converted file with [firefox profiler](https://profiler.firefox.com/). To learn more about Firefox profiler, read the [Firefox profiler profiling-guide](https://profiler.firefox.com/docs/#/./guide-perf-profiling).
+You can now view the converted file with [firefox profiler](https://profiler.firefox.com/), with a
+more in-depth guide [here](https://profiler.firefox.com/docs/#/./guide-perf-profiling)
 
 An alternative is to convert the perf data to `flamegraph.svg` using
 [flamegraph](https://github.com/flamegraph-rs/flamegraph) (`cargo install flamegraph`):
@@ -644,11 +637,11 @@ Otherwise, follow the instructions from the linux section.
 `cargo dev` is a shortcut for `cargo run --package ruff_dev --bin ruff_dev`. You can run some useful
 utils with it:
 
-- `cargo dev print-ast <file>`: Print the AST of a python file using Ruff's
-    [Python parser](https://github.com/astral-sh/ruff/tree/main/crates/ruff_python_parser).
-    For `if True: pass # comment`, you can see the syntax tree, the byte offsets for start and
-    stop of each node and also how the `:` token, the comment and whitespace are not represented
-    anymore:
+- `cargo dev print-ast <file>`: Print the AST of a python file using the
+    [RustPython parser](https://github.com/astral-sh/ruff/tree/main/crates/ruff_python_parser) that is
+    mainly used in Ruff. For `if True: pass # comment`, you can see the syntax tree, the byte offsets
+    for start and stop of each node and also how the `:` token, the comment and whitespace are not
+    represented anymore:
 
 ```text
 [
@@ -691,9 +684,9 @@ utils with it:
 23 Newline 24
 ```
 
-- `cargo dev print-cst <file>`: Print the CST of a Python file using
+- `cargo dev print-cst <file>`: Print the CST of a python file using
     [LibCST](https://github.com/Instagram/LibCST), which is used in addition to the RustPython parser
-    in Ruff. For example, for `if True: pass # comment`, everything, including the whitespace, is represented:
+    in Ruff. E.g. for `if True: pass # comment` everything including the whitespace is represented:
 
 ```text
 Module {
@@ -876,7 +869,7 @@ each configuration file.
 
 The package root is used to determine a file's "module path". Consider, again, `baz.py`. In that
 case, `./my_project/src/foo` was identified as the package root, so the module path for `baz.py`
-would resolve to `foo.bar.baz` — as computed by taking the relative path from the package root
+would resolve to  `foo.bar.baz` — as computed by taking the relative path from the package root
 (inclusive of the root itself). The module path can be thought of as "the path you would use to
 import the module" (e.g., `import foo.bar.baz`).
 
@@ -911,11 +904,15 @@ There are three ways in which an import can be categorized as "first-party":
     package (e.g., `from foo import bar` or `import foo.bar`), they'll be classified as first-party
     automatically. This check is as simple as comparing the first segment of the current file's
     module path to the first segment of the import.
-1. **Source roots**: Ruff supports a [`src`](https://docs.astral.sh/ruff/settings/#src) setting, which
+1. **Source roots**: Ruff supports a `[src](https://docs.astral.sh/ruff/settings/#src)` setting, which
     sets the directories to scan when identifying first-party imports. The algorithm is
     straightforward: given an import, like `import foo`, iterate over the directories enumerated in
     the `src` setting and, for each directory, check for the existence of a subdirectory `foo` or a
     file `foo.py`.
 
-By default, `src` is set to the project root, along with `"src"` subdirectory in the project root.
-This ensures that Ruff supports both flat and "src" layouts out of the box.
+By default, `src` is set to the project root. In the above example, we'd want to set
+`src = ["./src"]` to ensure that we locate `./my_project/src/foo` and thus categorize `import foo`
+as first-party in `baz.py`. In practice, for this limited example, setting `src = ["./src"]` is
+unnecessary, as all imports within `./my_project/src/foo` would be categorized as first-party via
+the same-package heuristic; but if your project contains multiple packages, you'll want to set `src`
+explicitly.

Cargo.toml

@@ -3,9 +3,8 @@ members = ["crates/*"]
 resolver = "2"
 
 [workspace.package]
-# Please update rustfmt.toml when bumping the Rust edition
-edition = "2024"
-rust-version = "1.85"
+edition = "2021"
+rust-version = "1.71"
 homepage = "https://docs.astral.sh/ruff"
 documentation = "https://docs.astral.sh/ruff"
 repository = "https://github.com/astral-sh/ruff"
@@ -13,190 +12,118 @@ authors = ["Charlie Marsh <charlie.r.marsh@gmail.com>"]
 license = "MIT"
 
 [workspace.dependencies]
-ruff = { path = "crates/ruff" }
-ruff_annotate_snippets = { path = "crates/ruff_annotate_snippets" }
-ruff_cache = { path = "crates/ruff_cache" }
-ruff_db = { path = "crates/ruff_db", default-features = false }
-ruff_diagnostics = { path = "crates/ruff_diagnostics" }
-ruff_formatter = { path = "crates/ruff_formatter" }
-ruff_graph = { path = "crates/ruff_graph" }
-ruff_index = { path = "crates/ruff_index" }
-ruff_linter = { path = "crates/ruff_linter" }
-ruff_macros = { path = "crates/ruff_macros" }
-ruff_notebook = { path = "crates/ruff_notebook" }
-ruff_options_metadata = { path = "crates/ruff_options_metadata" }
-ruff_python_ast = { path = "crates/ruff_python_ast" }
-ruff_python_codegen = { path = "crates/ruff_python_codegen" }
-ruff_python_formatter = { path = "crates/ruff_python_formatter" }
-ruff_python_index = { path = "crates/ruff_python_index" }
-ruff_python_literal = { path = "crates/ruff_python_literal" }
-ruff_python_parser = { path = "crates/ruff_python_parser" }
-ruff_python_semantic = { path = "crates/ruff_python_semantic" }
-ruff_python_stdlib = { path = "crates/ruff_python_stdlib" }
-ruff_python_trivia = { path = "crates/ruff_python_trivia" }
-ruff_server = { path = "crates/ruff_server" }
-ruff_source_file = { path = "crates/ruff_source_file" }
-ruff_text_size = { path = "crates/ruff_text_size" }
-ruff_workspace = { path = "crates/ruff_workspace" }
-
-ty = { path = "crates/ty" }
-ty_ide = { path = "crates/ty_ide" }
-ty_project = { path = "crates/ty_project", default-features = false }
-ty_python_semantic = { path = "crates/ty_python_semantic" }
-ty_server = { path = "crates/ty_server" }
-ty_test = { path = "crates/ty_test" }
-ty_vendored = { path = "crates/ty_vendored" }
-
 aho-corasick = { version = "1.1.3" }
-anstream = { version = "0.6.18" }
-anstyle = { version = "1.0.10" }
+annotate-snippets = { version = "0.9.2", features = ["color"] }
 anyhow = { version = "1.0.80" }
-assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
-bincode = { version = "2.0.0" }
+bincode = { version = "1.3.3" }
 bitflags = { version = "2.5.0" }
 bstr = { version = "1.9.1" }
 cachedir = { version = "0.3.1" }
-camino = { version = "1.1.7" }
+chrono = { version = "0.4.35", default-features = false, features = ["clock"] }
 clap = { version = "4.5.3", features = ["derive"] }
-clap_complete_command = { version = "0.6.0" }
-clearscreen = { version = "4.0.0" }
+clap_complete_command = { version = "0.5.1" }
+clearscreen = { version = "3.0.0" }
 codspeed-criterion-compat = { version = "2.6.0", default-features = false }
-colored = { version = "3.0.0" }
+colored = { version = "2.1.0" }
 console_error_panic_hook = { version = "0.1.7" }
 console_log = { version = "1.0.0" }
 countme = { version = "3.0.1" }
-compact_str = "0.9.0"
-criterion = { version = "0.6.0", default-features = false }
-crossbeam = { version = "0.8.4" }
-dashmap = { version = "6.0.1" }
-dir-test = { version = "0.4.0" }
-dunce = { version = "1.0.5" }
+criterion = { version = "0.5.1", default-features = false }
+crossbeam-channel = { version = "0.5.12" }
+dashmap = { version = "5.5.3" }
+dirs = { version = "5.0.0" }
 drop_bomb = { version = "0.1.5" }
 env_logger = { version = "0.11.0" }
-etcetera = { version = "0.10.0" }
-fern = { version = "0.7.0" }
+fern = { version = "0.6.1" }
 filetime = { version = "0.2.23" }
-getrandom = { version = "0.3.1" }
+fs-err = { version = "2.11.0" }
 glob = { version = "0.3.1" }
 globset = { version = "0.4.14" }
-globwalk = { version = "0.9.1" }
-hashbrown = { version = "0.15.0", default-features = false, features = [
-    "raw-entry",
-    "equivalent",
-    "inline-more",
-] }
-heck = "0.5.0"
+hashbrown = "0.14.3"
+hexf-parse = { version = "0.2.1" }
 ignore = { version = "0.4.22" }
 imara-diff = { version = "0.1.5" }
 imperative = { version = "1.0.4" }
-indexmap = { version = "2.6.0" }
+indexmap = { version = "2.2.6" }
 indicatif = { version = "0.17.8" }
 indoc = { version = "2.0.4" }
-insta = { version = "1.35.1" }
+insta = { version = "1.35.1", feature = ["filters", "glob"] }
 insta-cmd = { version = "0.6.0" }
 is-macro = { version = "0.3.5" }
 is-wsl = { version = "0.4.0" }
-itertools = { version = "0.14.0" }
-jiff = { version = "0.2.0" }
+itertools = { version = "0.12.1" }
 js-sys = { version = "0.3.69" }
-jod-thread = { version = "1.0.0" }
+jod-thread = { version = "0.1.2" }
+lexical-parse-float = { version = "0.8.0", features = ["format"] }
 libc = { version = "0.2.153" }
 libcst = { version = "1.1.0", default-features = false }
 log = { version = "0.4.17" }
 lsp-server = { version = "0.7.6" }
-lsp-types = { git = "https://github.com/astral-sh/lsp-types.git", rev = "3512a9f", features = [
-    "proposed",
-] }
+lsp-types = { version = "0.95.0", features = ["proposed"] }
 matchit = { version = "0.8.1" }
 memchr = { version = "2.7.1" }
 mimalloc = { version = "0.1.39" }
 natord = { version = "1.0.9" }
-notify = { version = "8.0.0" }
-ordermap = { version = "0.5.0" }
+notify = { version = "6.1.1" }
+num_cpus = { version = "1.16.0" }
+once_cell = { version = "1.19.0" }
 path-absolutize = { version = "3.1.1" }
 path-slash = { version = "0.2.1" }
 pathdiff = { version = "0.2.1" }
-pep440_rs = { version = "0.7.1" }
+parking_lot = "0.12.1"
+pep440_rs = { version = "0.6.0", features = ["serde"] }
 pretty_assertions = "1.3.0"
 proc-macro2 = { version = "1.0.79" }
-pyproject-toml = { version = "0.13.4" }
-quick-junit = { version = "0.5.0" }
+pyproject-toml = { version = "0.9.0" }
+quick-junit = { version = "0.4.0" }
 quote = { version = "1.0.23" }
-rand = { version = "0.9.0" }
+rand = { version = "0.8.5" }
 rayon = { version = "1.10.0" }
 regex = { version = "1.10.2" }
-rustc-hash = { version = "2.0.0" }
-rustc-stable-hash = { version = "0.1.2" }
-# When updating salsa, make sure to also update the revision in `fuzz/Cargo.toml`
-salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "4818b15f3b7516555d39f5a41cb75970448bee4c" }
+result-like = { version = "0.5.0" }
+rustc-hash = { version = "1.1.0" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }
 serde-wasm-bindgen = { version = "0.6.4" }
 serde_json = { version = "1.0.113" }
 serde_test = { version = "1.0.152" }
-serde_with = { version = "3.6.0", default-features = false, features = [
-    "macros",
-] }
+serde_with = { version = "3.6.0", default-features = false, features = ["macros"] }
 shellexpand = { version = "3.0.0" }
+shlex = { version = "1.3.0" }
 similar = { version = "2.4.0", features = ["inline"] }
 smallvec = { version = "1.13.2" }
-snapbox = { version = "0.6.0", features = [
-    "diff",
-    "term-svg",
-    "cmd",
-    "examples",
-] }
 static_assertions = "1.1.0"
-strum = { version = "0.27.0", features = ["strum_macros"] }
-strum_macros = { version = "0.27.0" }
+strum = { version = "0.26.0", features = ["strum_macros"] }
+strum_macros = { version = "0.26.0" }
 syn = { version = "2.0.55" }
 tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
-thiserror = { version = "2.0.0" }
-tikv-jemallocator = { version = "0.6.0" }
+thiserror = { version = "1.0.58" }
+tikv-jemallocator = { version = "0.5.0" }
 toml = { version = "0.8.11" }
 tracing = { version = "0.1.40" }
-tracing-flame = { version = "0.2.0" }
 tracing-indicatif = { version = "0.3.6" }
-tracing-log = { version = "0.2.0" }
-tracing-subscriber = { version = "0.3.18", default-features = false, features = [
-    "env-filter",
-    "fmt",
-    "ansi",
-    "smallvec"
-] }
-tryfn = { version = "0.2.1" }
+tracing-subscriber = { version = "0.3.18", features = ["env-filter"] }
+tracing-tree = { version = "0.3.0" }
 typed-arena = { version = "2.0.2" }
 unic-ucd-category = { version = "0.9" }
 unicode-ident = { version = "1.0.12" }
-unicode-width = { version = "0.2.0" }
+unicode-width = { version = "0.1.11" }
 unicode_names2 = { version = "1.2.2" }
 unicode-normalization = { version = "0.1.23" }
+ureq = { version = "2.9.6" }
 url = { version = "2.5.0" }
-uuid = { version = "1.6.1", features = [
-    "v4",
-    "fast-rng",
-    "macro-diagnostics",
-] }
+uuid = { version = "1.6.1", features = ["v4", "fast-rng", "macro-diagnostics", "js"] }
 walkdir = { version = "2.3.2" }
 wasm-bindgen = { version = "0.2.92" }
 wasm-bindgen-test = { version = "0.3.42" }
 wild = { version = "2" }
-zip = { version = "0.6.6", default-features = false }
-
-[workspace.metadata.cargo-shear]
-ignored = ["getrandom", "ruff_options_metadata", "uuid"]
-
 
 [workspace.lints.rust]
 unsafe_code = "warn"
 unreachable_pub = "warn"
-unexpected_cfgs = { level = "warn", check-cfg = [
-    "cfg(fuzzing)",
-    "cfg(codspeed)",
-] }
 
 [workspace.lints.clippy]
 pedantic = { level = "warn", priority = -2 }
@@ -205,18 +132,14 @@ char_lit_as_u8 = "allow"
 collapsible_else_if = "allow"
 collapsible_if = "allow"
 implicit_hasher = "allow"
-map_unwrap_or = "allow"
 match_same_arms = "allow"
 missing_errors_doc = "allow"
 missing_panics_doc = "allow"
 module_name_repetitions = "allow"
 must_use_candidate = "allow"
 similar_names = "allow"
-single_match_else = "allow"
 too_many_lines = "allow"
-needless_continue = "allow"       # An explicit continue can be more readable, especially if the alternative is an empty block.
-unnecessary_debug_formatting = "allow"  # too many instances, the display also doesn't quote the path which is often desired in logs where we use them the most often.
-# Without the hashes we run into a `rustfmt` bug in some snapshot tests, see #13250
+# To allow `#[allow(clippy::all)]` in `crates/ruff_python_parser/src/python.rs`.
 needless_raw_string_hashes = "allow"
 # Disallowed restriction lints
 print_stdout = "warn"
@@ -229,13 +152,6 @@ get_unwrap = "warn"
 rc_buffer = "warn"
 rc_mutex = "warn"
 rest_pat_in_fully_bound_structs = "warn"
-# nursery rules
-redundant_clone = "warn"
-debug_assert_with_mut_call = "warn"
-unused_peekable = "warn"
-
-# Diagnostics are not actionable: Enable once https://github.com/rust-lang/rust-clippy/issues/13774 is resolved.
-large_stack_arrays = "allow"
 
 [profile.release]
 # Note that we set these explicitly, and these values
@@ -260,9 +176,6 @@ opt-level = 3
 [profile.dev.package.similar]
 opt-level = 3
 
-[profile.dev.package.salsa]
-opt-level = 3
-
 # Reduce complexity of a parser function that would trigger a locals limit in a wasm tool.
 # https://github.com/bytecodealliance/wasm-tools/blob/b5c3d98e40590512a3b12470ef358d5c7b983b15/crates/wasmparser/src/limits.rs#L29
 [profile.dev.package.ruff_python_parser]
@@ -273,7 +186,3 @@ opt-level = 1
 [profile.profiling]
 inherits = "release"
 debug = 1
-
-# The profile that 'cargo dist' will build with.
-[profile.dist]
-inherits = "release"

Dockerfile

@@ -1,4 +1,4 @@
-FROM --platform=$BUILDPLATFORM ubuntu AS build
+FROM --platform=$BUILDPLATFORM ubuntu as build
 ENV HOME="/root"
 WORKDIR $HOME
 

LICENSE

@@ -1371,28 +1371,3 @@ are:
     OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     SOFTWARE.
   """
-
-- pydoclint, licensed as follows:
-  """
-    MIT License
-
-    Copyright (c) 2023 jsh9
-
-    Permission is hereby granted, free of charge, to any person obtaining a copy
-    of this software and associated documentation files (the "Software"), to deal
-    in the Software without restriction, including without limitation the rights
-    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-    copies of the Software, and to permit persons to whom the Software is
-    furnished to do so, subject to the following conditions:
-
-    The above copyright notice and this permission notice shall be included in all
-    copies or substantial portions of the Software.
-
-    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-    SOFTWARE.
-  """

README.md

@@ -28,14 +28,15 @@ An extremely fast Python linter and code formatter, written in Rust.
 - ⚡️ 10-100x faster than existing linters (like Flake8) and formatters (like Black)
 - 🐍 Installable via `pip`
 - 🛠️ `pyproject.toml` support
-- 🤝 Python 3.13 compatibility
-- ⚖️ Drop-in parity with [Flake8](https://docs.astral.sh/ruff/faq/#how-does-ruffs-linter-compare-to-flake8), isort, and [Black](https://docs.astral.sh/ruff/faq/#how-does-ruffs-formatter-compare-to-black)
+- 🤝 Python 3.12 compatibility
+- ⚖️ Drop-in parity with [Flake8](https://docs.astral.sh/ruff/faq/#how-does-ruff-compare-to-flake8), isort, and Black
 - 📦 Built-in caching, to avoid re-analyzing unchanged files
 - 🔧 Fix support, for automatic error correction (e.g., automatically remove unused imports)
 - 📏 Over [800 built-in rules](https://docs.astral.sh/ruff/rules/), with native re-implementations
     of popular Flake8 plugins, like flake8-bugbear
-- ⌨️ First-party [editor integrations](https://docs.astral.sh/ruff/editors) for [VS Code](https://github.com/astral-sh/ruff-vscode) and [more](https://docs.astral.sh/ruff/editors/setup)
-- 🌎 Monorepo-friendly, with [hierarchical and cascading configuration](https://docs.astral.sh/ruff/configuration/#config-file-discovery)
+- ⌨️ First-party [editor integrations](https://docs.astral.sh/ruff/integrations/) for
+    [VS Code](https://github.com/astral-sh/ruff-vscode) and [more](https://github.com/astral-sh/ruff-lsp)
+- 🌎 Monorepo-friendly, with [hierarchical and cascading configuration](https://docs.astral.sh/ruff/configuration/#pyprojecttoml-discovery)
 
 Ruff aims to be orders of magnitude faster than alternative tools while integrating more
 functionality behind a single, common interface.
@@ -109,47 +110,16 @@ For more, see the [documentation](https://docs.astral.sh/ruff/).
 1. [Who's Using Ruff?](#whos-using-ruff)
 1. [License](#license)
 
-## Getting Started<a id="getting-started"></a>
+## Getting Started
 
 For more, see the [documentation](https://docs.astral.sh/ruff/).
 
 ### Installation
 
-Ruff is available as [`ruff`](https://pypi.org/project/ruff/) on PyPI.
-
-Invoke Ruff directly with [`uvx`](https://docs.astral.sh/uv/):
+Ruff is available as [`ruff`](https://pypi.org/project/ruff/) on PyPI:
 
 ```shell
-uvx ruff check   # Lint all files in the current directory.
-uvx ruff format  # Format all files in the current directory.
-```
-
-Or install Ruff with `uv` (recommended), `pip`, or `pipx`:
-
-```shell
-# With uv.
-uv tool install ruff@latest  # Install Ruff globally.
-uv add --dev ruff            # Or add Ruff to your project.
-
-# With pip.
 pip install ruff
-
-# With pipx.
-pipx install ruff
-```
-
-Starting with version `0.5.0`, Ruff can be installed with our standalone installers:
-
-```shell
-# On macOS and Linux.
-curl -LsSf https://astral.sh/ruff/install.sh | sh
-
-# On Windows.
-powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
-
-# For a specific version.
-curl -LsSf https://astral.sh/ruff/0.11.11/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.11.11/install.ps1 | iex"
 ```
 
 You can also install Ruff via [Homebrew](https://formulae.brew.sh/formula/ruff), [Conda](https://anaconda.org/conda-forge/ruff),
@@ -182,7 +152,7 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
 ```yaml
 - repo: https://github.com/astral-sh/ruff-pre-commit
   # Ruff version.
-  rev: v0.11.11
+  rev: v0.4.2
   hooks:
     # Run the linter.
     - id: ruff
@@ -191,10 +161,11 @@ Ruff can also be used as a [pre-commit](https://pre-commit.com/) hook via [`ruff
     - id: ruff-format
 ```
 
-Ruff can also be used as a [VS Code extension](https://github.com/astral-sh/ruff-vscode) or with [various other editors](https://docs.astral.sh/ruff/editors/setup).
+Ruff can also be used as a [VS Code extension](https://github.com/astral-sh/ruff-vscode) or
+alongside any other editor through the [Ruff LSP](https://github.com/astral-sh/ruff-lsp).
 
 Ruff can also be used as a [GitHub Action](https://github.com/features/actions) via
-[`ruff-action`](https://github.com/astral-sh/ruff-action):
+[`ruff-action`](https://github.com/chartboost/ruff-action):
 
 ```yaml
 name: Ruff
@@ -204,10 +175,10 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: astral-sh/ruff-action@v3
+      - uses: chartboost/ruff-action@v1
 ```
 
-### Configuration<a id="configuration"></a>
+### Configuration
 
 Ruff can be configured through a `pyproject.toml`, `ruff.toml`, or `.ruff.toml` file (see:
 [_Configuration_](https://docs.astral.sh/ruff/configuration/), or [_Settings_](https://docs.astral.sh/ruff/settings/)
@@ -250,11 +221,11 @@ exclude = [
 line-length = 88
 indent-width = 4
 
-# Assume Python 3.9
-target-version = "py39"
+# Assume Python 3.8
+target-version = "py38"
 
 [lint]
-# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`) codes by default.
+# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`)  codes by default.
 select = ["E4", "E7", "E9", "F"]
 ignore = []
 
@@ -295,15 +266,10 @@ The remaining configuration options can be provided through a catch-all `--confi
 ruff check --config "lint.per-file-ignores = {'some_file.py' = ['F841']}"
 ```
 
-To opt in to the latest lint rules, formatter style changes, interface updates, and more, enable
-[preview mode](https://docs.astral.sh/ruff/rules/) by setting `preview = true` in your configuration
-file or passing `--preview` on the command line. Preview mode enables a collection of unstable
-features that may change prior to stabilization.
-
 See `ruff help` for more on Ruff's top-level commands, or `ruff help check` and `ruff help format`
 for more on the linting and formatting commands, respectively.
 
-## Rules<a id="rules"></a>
+## Rules
 
 <!-- Begin section: Rules -->
 
@@ -363,6 +329,7 @@ quality tools, including:
 - [flake8-super](https://pypi.org/project/flake8-super/)
 - [flake8-tidy-imports](https://pypi.org/project/flake8-tidy-imports/)
 - [flake8-todos](https://pypi.org/project/flake8-todos/)
+- [flake8-trio](https://pypi.org/project/flake8-trio/)
 - [flake8-type-checking](https://pypi.org/project/flake8-type-checking/)
 - [flake8-use-pathlib](https://pypi.org/project/flake8-use-pathlib/)
 - [flynt](https://pypi.org/project/flynt/) ([#2102](https://github.com/astral-sh/ruff/issues/2102))
@@ -379,21 +346,21 @@ quality tools, including:
 
 For a complete enumeration of the supported rules, see [_Rules_](https://docs.astral.sh/ruff/rules/).
 
-## Contributing<a id="contributing"></a>
+## Contributing
 
 Contributions are welcome and highly appreciated. To get started, check out the
 [**contributing guidelines**](https://docs.astral.sh/ruff/contributing/).
 
 You can also join us on [**Discord**](https://discord.com/invite/astral-sh).
 
-## Support<a id="support"></a>
+## Support
 
 Having trouble? Check out the existing issues on [**GitHub**](https://github.com/astral-sh/ruff/issues),
 or feel free to [**open a new one**](https://github.com/astral-sh/ruff/issues/new).
 
 You can also ask for help on [**Discord**](https://discord.com/invite/astral-sh).
 
-## Acknowledgements<a id="acknowledgements"></a>
+## Acknowledgements
 
 Ruff's linter draws on both the APIs and implementation details of many other
 tools in the Python ecosystem, especially [Flake8](https://github.com/PyCQA/flake8), [Pyflakes](https://github.com/PyCQA/pyflakes),
@@ -417,7 +384,7 @@ Ruff is the beneficiary of a large number of [contributors](https://github.com/a
 
 Ruff is released under the MIT license.
 
-## Who's Using Ruff?<a id="whos-using-ruff"></a>
+## Who's Using Ruff?
 
 Ruff is used by a number of major open-source projects and companies, including:
 
@@ -429,16 +396,13 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Babel](https://github.com/python-babel/babel)
 - Benchling ([Refac](https://github.com/benchling/refac))
 - [Bokeh](https://github.com/bokeh/bokeh)
-- CrowdCent ([NumerBlox](https://github.com/crowdcent/numerblox)) <!-- typos: ignore -->
 - [Cryptography (PyCA)](https://github.com/pyca/cryptography)
 - CERN ([Indico](https://getindico.io/))
 - [DVC](https://github.com/iterative/dvc)
 - [Dagger](https://github.com/dagger/dagger)
 - [Dagster](https://github.com/dagster-io/dagster)
 - Databricks ([MLflow](https://github.com/mlflow/mlflow))
-- [Dify](https://github.com/langgenius/dify)
 - [FastAPI](https://github.com/tiangolo/fastapi)
-- [Godot](https://github.com/godotengine/godot)
 - [Gradio](https://github.com/gradio-app/gradio)
 - [Great Expectations](https://github.com/great-expectations/great_expectations)
 - [HTTPX](https://github.com/encode/httpx)
@@ -447,11 +411,9 @@ Ruff is used by a number of major open-source projects and companies, including:
 - Hugging Face ([Transformers](https://github.com/huggingface/transformers),
     [Datasets](https://github.com/huggingface/datasets),
     [Diffusers](https://github.com/huggingface/diffusers))
-- IBM ([Qiskit](https://github.com/Qiskit/qiskit))
 - ING Bank ([popmon](https://github.com/ing-bank/popmon), [probatus](https://github.com/ing-bank/probatus))
 - [Ibis](https://github.com/ibis-project/ibis)
 - [ivy](https://github.com/unifyai/ivy)
-- [JAX](https://github.com/jax-ml/jax)
 - [Jupyter](https://github.com/jupyter-server/jupyter_server)
 - [Kraken Tech](https://kraken.tech/)
 - [LangChain](https://github.com/hwchase17/langchain)
@@ -463,10 +425,9 @@ Ruff is used by a number of major open-source projects and companies, including:
 - Microsoft ([Semantic Kernel](https://github.com/microsoft/semantic-kernel),
     [ONNX Runtime](https://github.com/microsoft/onnxruntime),
     [LightGBM](https://github.com/microsoft/LightGBM))
-- Modern Treasury ([Python SDK](https://github.com/Modern-Treasury/modern-treasury-python))
+- Modern Treasury ([Python SDK](https://github.com/Modern-Treasury/modern-treasury-python-sdk))
 - Mozilla ([Firefox](https://github.com/mozilla/gecko-dev))
 - [Mypy](https://github.com/python/mypy)
-- [Nautobot](https://github.com/nautobot/nautobot)
 - Netflix ([Dispatch](https://github.com/Netflix/dispatch))
 - [Neon](https://github.com/neondatabase/neon)
 - [Nokia](https://nokia.com/)
@@ -474,7 +435,6 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [NumPyro](https://github.com/pyro-ppl/numpyro)
 - [ONNX](https://github.com/onnx/onnx)
 - [OpenBB](https://github.com/OpenBB-finance/OpenBBTerminal)
-- [Open Wine Components](https://github.com/Open-Wine-Components/umu-launcher)
 - [PDM](https://github.com/pdm-project/pdm)
 - [PaddlePaddle](https://github.com/PaddlePaddle/Paddle)
 - [Pandas](https://github.com/pandas-dev/pandas)
@@ -502,7 +462,6 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Sphinx](https://github.com/sphinx-doc/sphinx)
 - [Stable Baselines3](https://github.com/DLR-RM/stable-baselines3)
 - [Starlette](https://github.com/encode/starlette)
-- [Streamlit](https://github.com/streamlit/streamlit)
 - [The Algorithms](https://github.com/TheAlgorithms/Python)
 - [Vega-Altair](https://github.com/altair-viz/altair)
 - WordPress ([Openverse](https://github.com/WordPress/openverse))
@@ -538,7 +497,7 @@ If you're using Ruff, consider adding the Ruff badge to your project's `README.m
 <a href="https://github.com/astral-sh/ruff"><img src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json" alt="Ruff" style="max-width:100%;"></a>
 ```
 
-## License<a id="license"></a>
+## License
 
 This repository is licensed under the [MIT License](https://github.com/astral-sh/ruff/blob/main/LICENSE)
 

SECURITY.md

@@ -1,15 +0,0 @@
-# Security policy
-
-## Reporting a vulnerability
-
-If you have found a possible vulnerability, please email `security at astral dot sh`.
-
-## Bug bounties
-
-While we sincerely appreciate and encourage reports of suspected security problems, please note that
-Astral does not currently run any bug bounty programs.
-
-## Vulnerability disclosures
-
-Critical vulnerabilities will be disclosed via GitHub's
-[security advisory](https://github.com/astral-sh/ruff/security) system.

_typos.toml

@@ -1,10 +1,6 @@
 [files]
 # https://github.com/crate-ci/typos/issues/868
-extend-exclude = [
-    "crates/ty_vendored/vendor/**/*",
-    "**/resources/**/*",
-    "**/snapshots/**/*",
-]
+extend-exclude = ["**/resources/**/*", "**/snapshots/**/*"]
 
 [default.extend-words]
 "arange" = "arange"  # e.g. `numpy.arange`
@@ -12,22 +8,12 @@ hel = "hel"
 whos = "whos"
 spawnve = "spawnve"
 ned = "ned"
-pn = "pn"  # `import panel as pn` is a thing
+pn = "pn"  # `import panel as pd` is a thing
 poit = "poit"
 BA = "BA" # acronym for "Bad Allowed", used in testing.
-jod = "jod" # e.g., `jod-thread`
-Numer = "Numer" # Library name 'NumerBlox' in "Who's Using Ruff?"
 
 [default]
 extend-ignore-re = [
-    # Line ignore with trailing "spellchecker:disable-line"
-    "(?Rm)^.*#\\s*spellchecker:disable-line$",
-    "LICENSEs",
-    # Various third party dependencies uses `typ` as struct field names (e.g., lsp_types::LogMessageParams)
-    "typ",
-    # TODO: Remove this once the `TYP` redirects are removed from `rule_redirects.rs`
-    "TYP",
+  # Line ignore with trailing "spellchecker:disable-line"
+  "(?Rm)^.*#\\s*spellchecker:disable-line$"
 ]
-
-[default.extend-identifiers]
-"FrIeNdLy" = "FrIeNdLy"

clippy.toml

@@ -1,26 +1,7 @@
 doc-valid-idents = [
-    "..",
-    "CodeQL",
-    "CPython",
-    "FastAPI",
-    "IPython",
-    "LangChain",
-    "LibCST",
-    "McCabe",
-    "NumPy",
-    "SCREAMING_SNAKE_CASE",
-    "SQLAlchemy",
-    "StackOverflow",
-    "PyCharm",
-    "SNMPv1",
-    "SNMPv2",
-    "SNMPv3",
-    "PyFlakes",
-]
-
-ignore-interior-mutability = [
-    # Interned is read-only. The wrapped `Rc` never gets updated.
-    "ruff_formatter::format_element::Interned",
-    # The expression is read-only.
-    "ruff_python_ast::hashable::HashableExpr",
+  "StackOverflow",
+  "CodeQL",
+  "IPython",
+  "NumPy",
+  "..",
 ]

crates/red_knot/Cargo.toml

@@ -0,0 +1,45 @@
+[package]
+name = "red_knot"
+version = "0.1.0"
+edition.workspace = true
+rust-version.workspace = true
+homepage.workspace = true
+documentation.workspace = true
+repository.workspace = true
+authors.workspace = true
+license.workspace = true
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+ruff_python_parser = { path = "../ruff_python_parser" }
+ruff_python_ast = { path = "../ruff_python_ast" }
+ruff_python_trivia = { path = "../ruff_python_trivia" }
+ruff_text_size = { path = "../ruff_text_size" }
+ruff_index = { path = "../ruff_index" }
+ruff_notebook = { path = "../ruff_notebook" }
+
+anyhow = { workspace = true }
+bitflags = { workspace = true }
+ctrlc = "3.4.4"
+crossbeam-channel = { workspace = true }
+dashmap = { workspace = true }
+hashbrown = { workspace = true }
+indexmap = { workspace = true }
+log = { workspace = true }
+notify = { workspace = true }
+parking_lot = { workspace = true }
+rayon = { workspace = true }
+rustc-hash = { workspace = true }
+smallvec = { workspace = true }
+smol_str = "0.2.1"
+tracing = { workspace = true }
+tracing-subscriber = { workspace = true }
+tracing-tree = { workspace = true }
+
+[dev-dependencies]
+textwrap = "0.16.1"
+tempfile = { workspace = true }
+
+[lints]
+workspace = true

crates/red_knot/src/ast_ids.rs

@@ -0,0 +1,415 @@
+use std::any::type_name;
+use std::fmt::{Debug, Formatter};
+use std::hash::{Hash, Hasher};
+use std::marker::PhantomData;
+
+use rustc_hash::FxHashMap;
+
+use ruff_index::{Idx, IndexVec};
+use ruff_python_ast::visitor::preorder;
+use ruff_python_ast::visitor::preorder::{PreorderVisitor, TraversalSignal};
+use ruff_python_ast::{
+    AnyNodeRef, AstNode, ExceptHandler, ExceptHandlerExceptHandler, Expr, MatchCase, ModModule,
+    NodeKind, Parameter, Stmt, StmtAnnAssign, StmtAssign, StmtAugAssign, StmtClassDef,
+    StmtFunctionDef, StmtGlobal, StmtImport, StmtImportFrom, StmtNonlocal, StmtTypeAlias,
+    TypeParam, TypeParamParamSpec, TypeParamTypeVar, TypeParamTypeVarTuple, WithItem,
+};
+use ruff_text_size::{Ranged, TextRange};
+
+/// A type agnostic ID that uniquely identifies an AST node in a file.
+#[ruff_index::newtype_index]
+pub struct AstId;
+
+/// A typed ID that uniquely identifies an AST node in a file.
+///
+/// This is different from [`AstId`] in that it is a combination of ID and the type of the node the ID identifies.
+/// Typing the ID prevents mixing IDs of different node types and allows to restrict the API to only accept
+/// nodes for which an ID has been created (not all AST nodes get an ID).
+pub struct TypedAstId<N: HasAstId> {
+    erased: AstId,
+    _marker: PhantomData<fn() -> N>,
+}
+
+impl<N: HasAstId> TypedAstId<N> {
+    /// Upcasts this ID from a more specific node type to a more general node type.
+    pub fn upcast<M: HasAstId>(self) -> TypedAstId<M>
+    where
+        N: Into<M>,
+    {
+        TypedAstId {
+            erased: self.erased,
+            _marker: PhantomData,
+        }
+    }
+}
+
+impl<N: HasAstId> Copy for TypedAstId<N> {}
+impl<N: HasAstId> Clone for TypedAstId<N> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<N: HasAstId> PartialEq for TypedAstId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        self.erased == other.erased
+    }
+}
+
+impl<N: HasAstId> Eq for TypedAstId<N> {}
+impl<N: HasAstId> Hash for TypedAstId<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.erased.hash(state);
+    }
+}
+
+impl<N: HasAstId> Debug for TypedAstId<N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_tuple("TypedAstId")
+            .field(&self.erased)
+            .field(&type_name::<N>())
+            .finish()
+    }
+}
+
+pub struct AstIds {
+    ids: IndexVec<AstId, NodeKey>,
+    reverse: FxHashMap<NodeKey, AstId>,
+}
+
+impl AstIds {
+    // TODO rust analyzer doesn't allocate an ID for every node. It only allocates ids for
+    //  nodes with a corresponding HIR element, that is nodes that are definitions.
+    pub fn from_module(module: &ModModule) -> Self {
+        let mut visitor = AstIdsVisitor::default();
+
+        // TODO: visit_module?
+        // Make sure we visit the root
+        visitor.create_id(module);
+        visitor.visit_body(&module.body);
+
+        while let Some(deferred) = visitor.deferred.pop() {
+            match deferred {
+                DeferredNode::FunctionDefinition(def) => {
+                    def.visit_preorder(&mut visitor);
+                }
+                DeferredNode::ClassDefinition(def) => def.visit_preorder(&mut visitor),
+            }
+        }
+
+        AstIds {
+            ids: visitor.ids,
+            reverse: visitor.reverse,
+        }
+    }
+
+    /// Returns the ID to the root node.
+    pub fn root(&self) -> NodeKey {
+        self.ids[AstId::new(0)]
+    }
+
+    /// Returns the [`TypedAstId`] for a node.
+    pub fn ast_id<N: HasAstId>(&self, node: &N) -> TypedAstId<N> {
+        let key = node.syntax_node_key();
+        TypedAstId {
+            erased: self.reverse.get(&key).copied().unwrap(),
+            _marker: PhantomData,
+        }
+    }
+
+    /// Returns the [`TypedAstId`] for the node identified with the given [`TypedNodeKey`].
+    pub fn ast_id_for_key<N: HasAstId>(&self, node: &TypedNodeKey<N>) -> TypedAstId<N> {
+        let ast_id = self.ast_id_for_node_key(node.inner);
+
+        TypedAstId {
+            erased: ast_id,
+            _marker: PhantomData,
+        }
+    }
+
+    /// Returns the untyped [`AstId`] for the node identified by the given `node` key.
+    pub fn ast_id_for_node_key(&self, node: NodeKey) -> AstId {
+        self.reverse
+            .get(&node)
+            .copied()
+            .expect("Can't find node in AstIds map.")
+    }
+
+    /// Returns the [`TypedNodeKey`] for the node identified by the given [`TypedAstId`].
+    pub fn key<N: HasAstId>(&self, id: TypedAstId<N>) -> TypedNodeKey<N> {
+        let syntax_key = self.ids[id.erased];
+
+        TypedNodeKey::new(syntax_key).unwrap()
+    }
+
+    pub fn node_key<H: HasAstId>(&self, id: TypedAstId<H>) -> NodeKey {
+        self.ids[id.erased]
+    }
+}
+
+impl std::fmt::Debug for AstIds {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let mut map = f.debug_map();
+        for (key, value) in self.ids.iter_enumerated() {
+            map.entry(&key, &value);
+        }
+
+        map.finish()
+    }
+}
+
+impl PartialEq for AstIds {
+    fn eq(&self, other: &Self) -> bool {
+        self.ids == other.ids
+    }
+}
+
+impl Eq for AstIds {}
+
+#[derive(Default)]
+struct AstIdsVisitor<'a> {
+    ids: IndexVec<AstId, NodeKey>,
+    reverse: FxHashMap<NodeKey, AstId>,
+    deferred: Vec<DeferredNode<'a>>,
+}
+
+impl<'a> AstIdsVisitor<'a> {
+    fn create_id<A: HasAstId>(&mut self, node: &A) {
+        let node_key = node.syntax_node_key();
+
+        let id = self.ids.push(node_key);
+        self.reverse.insert(node_key, id);
+    }
+}
+
+impl<'a> PreorderVisitor<'a> for AstIdsVisitor<'a> {
+    fn visit_stmt(&mut self, stmt: &'a Stmt) {
+        match stmt {
+            Stmt::FunctionDef(def) => {
+                self.create_id(def);
+                self.deferred.push(DeferredNode::FunctionDefinition(def));
+                return;
+            }
+            // TODO defer visiting the assignment body, type alias parameters etc?
+            Stmt::ClassDef(def) => {
+                self.create_id(def);
+                self.deferred.push(DeferredNode::ClassDefinition(def));
+                return;
+            }
+            Stmt::Expr(_) => {
+                // Skip
+                return;
+            }
+            Stmt::Return(_) => {}
+            Stmt::Delete(_) => {}
+            Stmt::Assign(assignment) => self.create_id(assignment),
+            Stmt::AugAssign(assignment) => {
+                self.create_id(assignment);
+            }
+            Stmt::AnnAssign(assignment) => self.create_id(assignment),
+            Stmt::TypeAlias(assignment) => self.create_id(assignment),
+            Stmt::For(_) => {}
+            Stmt::While(_) => {}
+            Stmt::If(_) => {}
+            Stmt::With(_) => {}
+            Stmt::Match(_) => {}
+            Stmt::Raise(_) => {}
+            Stmt::Try(_) => {}
+            Stmt::Assert(_) => {}
+            Stmt::Import(import) => self.create_id(import),
+            Stmt::ImportFrom(import_from) => self.create_id(import_from),
+            Stmt::Global(global) => self.create_id(global),
+            Stmt::Nonlocal(non_local) => self.create_id(non_local),
+            Stmt::Pass(_) => {}
+            Stmt::Break(_) => {}
+            Stmt::Continue(_) => {}
+            Stmt::IpyEscapeCommand(_) => {}
+        }
+
+        preorder::walk_stmt(self, stmt);
+    }
+
+    fn visit_expr(&mut self, _expr: &'a Expr) {}
+
+    fn visit_parameter(&mut self, parameter: &'a Parameter) {
+        self.create_id(parameter);
+        preorder::walk_parameter(self, parameter);
+    }
+
+    fn visit_except_handler(&mut self, except_handler: &'a ExceptHandler) {
+        match except_handler {
+            ExceptHandler::ExceptHandler(except_handler) => {
+                self.create_id(except_handler);
+            }
+        }
+
+        preorder::walk_except_handler(self, except_handler);
+    }
+
+    fn visit_with_item(&mut self, with_item: &'a WithItem) {
+        self.create_id(with_item);
+        preorder::walk_with_item(self, with_item);
+    }
+
+    fn visit_match_case(&mut self, match_case: &'a MatchCase) {
+        self.create_id(match_case);
+        preorder::walk_match_case(self, match_case);
+    }
+
+    fn visit_type_param(&mut self, type_param: &'a TypeParam) {
+        self.create_id(type_param);
+    }
+}
+
+enum DeferredNode<'a> {
+    FunctionDefinition(&'a StmtFunctionDef),
+    ClassDefinition(&'a StmtClassDef),
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct TypedNodeKey<N: AstNode> {
+    /// The type erased node key.
+    inner: NodeKey,
+    _marker: PhantomData<fn() -> N>,
+}
+
+impl<N: AstNode> TypedNodeKey<N> {
+    pub fn from_node(node: &N) -> Self {
+        let inner = NodeKey {
+            kind: node.as_any_node_ref().kind(),
+            range: node.range(),
+        };
+        Self {
+            inner,
+            _marker: PhantomData,
+        }
+    }
+
+    pub fn new(node_key: NodeKey) -> Option<Self> {
+        N::can_cast(node_key.kind).then_some(TypedNodeKey {
+            inner: node_key,
+            _marker: PhantomData,
+        })
+    }
+
+    pub fn resolve<'a>(&self, root: AnyNodeRef<'a>) -> Option<N::Ref<'a>> {
+        let node_ref = self.inner.resolve(root)?;
+
+        Some(N::cast_ref(node_ref).unwrap())
+    }
+
+    pub fn resolve_unwrap<'a>(&self, root: AnyNodeRef<'a>) -> N::Ref<'a> {
+        self.resolve(root).expect("node should resolve")
+    }
+
+    pub fn erased(&self) -> &NodeKey {
+        &self.inner
+    }
+}
+
+struct FindNodeKeyVisitor<'a> {
+    key: NodeKey,
+    result: Option<AnyNodeRef<'a>>,
+}
+
+impl<'a> PreorderVisitor<'a> for FindNodeKeyVisitor<'a> {
+    fn enter_node(&mut self, node: AnyNodeRef<'a>) -> TraversalSignal {
+        if self.result.is_some() {
+            return TraversalSignal::Skip;
+        }
+
+        if node.range() == self.key.range && node.kind() == self.key.kind {
+            self.result = Some(node);
+            TraversalSignal::Skip
+        } else if node.range().contains_range(self.key.range) {
+            TraversalSignal::Traverse
+        } else {
+            TraversalSignal::Skip
+        }
+    }
+
+    fn visit_body(&mut self, body: &'a [Stmt]) {
+        // TODO it would be more efficient to use binary search instead of linear
+        for stmt in body {
+            if stmt.range().start() > self.key.range.end() {
+                break;
+            }
+
+            self.visit_stmt(stmt);
+        }
+    }
+}
+
+// TODO an alternative to this is to have a `NodeId` on each node (in increasing order depending on the position).
+//  This would allow to reduce the size of this to a u32.
+//  What would be nice if we could use an `Arc::weak_ref` here but that only works if we use
+//   `Arc` internally
+// TODO: Implement the logic to resolve a node, given a db (and the correct file).
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub struct NodeKey {
+    kind: NodeKind,
+    range: TextRange,
+}
+
+impl NodeKey {
+    pub fn resolve<'a>(&self, root: AnyNodeRef<'a>) -> Option<AnyNodeRef<'a>> {
+        // We need to do a binary search here. Only traverse into a node if the range is withint the node
+        let mut visitor = FindNodeKeyVisitor {
+            key: *self,
+            result: None,
+        };
+
+        if visitor.enter_node(root) == TraversalSignal::Traverse {
+            root.visit_preorder(&mut visitor);
+        }
+
+        visitor.result
+    }
+}
+
+/// Marker trait implemented by AST nodes for which we extract the `AstId`.
+pub trait HasAstId: AstNode {
+    fn node_key(&self) -> TypedNodeKey<Self>
+    where
+        Self: Sized,
+    {
+        TypedNodeKey {
+            inner: self.syntax_node_key(),
+            _marker: PhantomData,
+        }
+    }
+
+    fn syntax_node_key(&self) -> NodeKey {
+        NodeKey {
+            kind: self.as_any_node_ref().kind(),
+            range: self.range(),
+        }
+    }
+}
+
+impl HasAstId for StmtFunctionDef {}
+impl HasAstId for StmtClassDef {}
+impl HasAstId for StmtAnnAssign {}
+impl HasAstId for StmtAugAssign {}
+impl HasAstId for StmtAssign {}
+impl HasAstId for StmtTypeAlias {}
+
+impl HasAstId for ModModule {}
+
+impl HasAstId for StmtImport {}
+
+impl HasAstId for StmtImportFrom {}
+
+impl HasAstId for Parameter {}
+
+impl HasAstId for TypeParam {}
+impl HasAstId for Stmt {}
+impl HasAstId for TypeParamTypeVar {}
+impl HasAstId for TypeParamTypeVarTuple {}
+impl HasAstId for TypeParamParamSpec {}
+impl HasAstId for StmtGlobal {}
+impl HasAstId for StmtNonlocal {}
+
+impl HasAstId for ExceptHandlerExceptHandler {}
+impl HasAstId for WithItem {}
+impl HasAstId for MatchCase {}

crates/red_knot/src/cache.rs

@@ -0,0 +1,158 @@
+use std::fmt::Formatter;
+use std::hash::Hash;
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+use dashmap::mapref::entry::Entry;
+
+use crate::FxDashMap;
+
+/// Simple key value cache that locks on a per-key level.
+pub struct KeyValueCache<K, V> {
+    map: FxDashMap<K, V>,
+    statistics: CacheStatistics,
+}
+
+impl<K, V> KeyValueCache<K, V>
+where
+    K: Eq + Hash + Clone,
+    V: Clone,
+{
+    pub fn try_get(&self, key: &K) -> Option<V> {
+        if let Some(existing) = self.map.get(key) {
+            self.statistics.hit();
+            Some(existing.clone())
+        } else {
+            self.statistics.miss();
+            None
+        }
+    }
+
+    pub fn get<F>(&self, key: &K, compute: F) -> V
+    where
+        F: FnOnce(&K) -> V,
+    {
+        match self.map.entry(key.clone()) {
+            Entry::Occupied(cached) => {
+                self.statistics.hit();
+
+                cached.get().clone()
+            }
+            Entry::Vacant(vacant) => {
+                self.statistics.miss();
+
+                let value = compute(key);
+                vacant.insert(value.clone());
+                value
+            }
+        }
+    }
+
+    pub fn set(&mut self, key: K, value: V) {
+        self.map.insert(key, value);
+    }
+
+    pub fn remove(&mut self, key: &K) -> Option<V> {
+        self.map.remove(key).map(|(_, value)| value)
+    }
+
+    pub fn clear(&mut self) {
+        self.map.clear();
+        self.map.shrink_to_fit();
+    }
+
+    pub fn statistics(&self) -> Option<Statistics> {
+        self.statistics.to_statistics()
+    }
+}
+
+impl<K, V> Default for KeyValueCache<K, V>
+where
+    K: Eq + Hash,
+    V: Clone,
+{
+    fn default() -> Self {
+        Self {
+            map: FxDashMap::default(),
+            statistics: CacheStatistics::default(),
+        }
+    }
+}
+
+impl<K, V> std::fmt::Debug for KeyValueCache<K, V>
+where
+    K: std::fmt::Debug + Eq + Hash,
+    V: std::fmt::Debug,
+{
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let mut debug = f.debug_map();
+
+        for entry in &self.map {
+            debug.entry(&entry.value(), &entry.key());
+        }
+
+        debug.finish()
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Statistics {
+    pub hits: usize,
+    pub misses: usize,
+}
+
+impl Statistics {
+    #[allow(clippy::cast_precision_loss)]
+    pub fn hit_rate(&self) -> Option<f64> {
+        if self.hits + self.misses == 0 {
+            return None;
+        }
+
+        Some((self.hits as f64) / (self.hits + self.misses) as f64)
+    }
+}
+
+#[cfg(debug_assertions)]
+pub type CacheStatistics = DebugStatistics;
+
+#[cfg(not(debug_assertions))]
+pub type CacheStatistics = ReleaseStatistics;
+
+#[derive(Debug, Default)]
+pub struct DebugStatistics {
+    hits: AtomicUsize,
+    misses: AtomicUsize,
+}
+
+impl DebugStatistics {
+    // TODO figure out appropriate Ordering
+    pub fn hit(&self) {
+        self.hits.fetch_add(1, Ordering::SeqCst);
+    }
+
+    pub fn miss(&self) {
+        self.misses.fetch_add(1, Ordering::SeqCst);
+    }
+
+    pub fn to_statistics(&self) -> Option<Statistics> {
+        let hits = self.hits.load(Ordering::SeqCst);
+        let misses = self.misses.load(Ordering::SeqCst);
+
+        Some(Statistics { hits, misses })
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct ReleaseStatistics;
+
+impl ReleaseStatistics {
+    #[inline]
+    pub const fn hit(&self) {}
+
+    #[inline]
+    pub const fn miss(&self) {}
+
+    #[inline]
+    pub const fn to_statistics(&self) -> Option<Statistics> {
+        None
+    }
+}

crates/red_knot/src/cancellation.rs

@@ -0,0 +1,66 @@
+use std::sync::{Arc, Condvar, Mutex};
+
+#[derive(Debug, Default)]
+pub struct CancellationTokenSource {
+    signal: Arc<(Mutex<bool>, Condvar)>,
+}
+
+impl CancellationTokenSource {
+    pub fn new() -> Self {
+        Self {
+            signal: Arc::new((Mutex::new(false), Condvar::default())),
+        }
+    }
+
+    #[tracing::instrument(level = "trace", skip_all)]
+    pub fn cancel(&self) {
+        let (cancelled, condvar) = &*self.signal;
+
+        let mut cancelled = cancelled.lock().unwrap();
+
+        if *cancelled {
+            return;
+        }
+
+        *cancelled = true;
+        condvar.notify_all();
+    }
+
+    pub fn is_cancelled(&self) -> bool {
+        let (cancelled, _) = &*self.signal;
+
+        *cancelled.lock().unwrap()
+    }
+
+    pub fn token(&self) -> CancellationToken {
+        CancellationToken {
+            signal: self.signal.clone(),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+pub struct CancellationToken {
+    signal: Arc<(Mutex<bool>, Condvar)>,
+}
+
+impl CancellationToken {
+    /// Returns `true` if cancellation has been requested.
+    pub fn is_cancelled(&self) -> bool {
+        let (cancelled, _) = &*self.signal;
+
+        *cancelled.lock().unwrap()
+    }
+
+    pub fn wait(&self) {
+        let (bool, condvar) = &*self.signal;
+
+        let lock = condvar
+            .wait_while(bool.lock().unwrap(), |bool| !*bool)
+            .unwrap();
+
+        debug_assert!(*lock);
+
+        drop(lock);
+    }
+}

crates/red_knot/src/db.rs

@@ -0,0 +1,186 @@
+use std::path::Path;
+use std::sync::Arc;
+
+use crate::files::FileId;
+use crate::lint::{Diagnostics, LintSemanticStorage, LintSyntaxStorage};
+use crate::module::{Module, ModuleData, ModuleName, ModuleResolver, ModuleSearchPath};
+use crate::parse::{Parsed, ParsedStorage};
+use crate::source::{Source, SourceStorage};
+use crate::symbols::{SymbolId, SymbolTable, SymbolTablesStorage};
+use crate::types::{Type, TypeStore};
+
+pub trait SourceDb {
+    // queries
+    fn file_id(&self, path: &std::path::Path) -> FileId;
+
+    fn file_path(&self, file_id: FileId) -> Arc<std::path::Path>;
+
+    fn source(&self, file_id: FileId) -> Source;
+
+    fn parse(&self, file_id: FileId) -> Parsed;
+
+    fn lint_syntax(&self, file_id: FileId) -> Diagnostics;
+}
+
+pub trait SemanticDb: SourceDb {
+    // queries
+    fn resolve_module(&self, name: ModuleName) -> Option<Module>;
+
+    fn file_to_module(&self, file_id: FileId) -> Option<Module>;
+
+    fn path_to_module(&self, path: &Path) -> Option<Module>;
+
+    fn symbol_table(&self, file_id: FileId) -> Arc<SymbolTable>;
+
+    fn infer_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Type;
+
+    fn lint_semantic(&self, file_id: FileId) -> Diagnostics;
+
+    // mutations
+
+    fn add_module(&mut self, path: &Path) -> Option<(Module, Vec<Arc<ModuleData>>)>;
+
+    fn set_module_search_paths(&mut self, paths: Vec<ModuleSearchPath>);
+}
+
+pub trait Db: SemanticDb {}
+
+#[derive(Debug, Default)]
+pub struct SourceJar {
+    pub sources: SourceStorage,
+    pub parsed: ParsedStorage,
+    pub lint_syntax: LintSyntaxStorage,
+}
+
+#[derive(Debug, Default)]
+pub struct SemanticJar {
+    pub module_resolver: ModuleResolver,
+    pub symbol_tables: SymbolTablesStorage,
+    pub type_store: TypeStore,
+    pub lint_semantic: LintSemanticStorage,
+}
+
+/// Gives access to a specific jar in the database.
+///
+/// Nope, the terminology isn't borrowed from Java but from Salsa <https://salsa-rs.github.io/salsa/>,
+/// which is an analogy to storing the salsa in different jars.
+///
+/// The basic idea is that each crate can define its own jar and the jars can be combined to a single
+/// database in the top level crate. Each crate also defines its own `Database` trait. The combination of
+/// `Database` trait and the jar allows to write queries in isolation without having to know how they get composed at the upper levels.
+///
+/// Salsa further defines a `HasIngredient` trait which slices the jar to a specific storage (e.g. a specific cache).
+/// We don't need this just jet because we write our queries by hand. We may want a similar trait if we decide
+/// to use a macro to generate the queries.
+pub trait HasJar<T> {
+    /// Gives a read-only reference to the jar.
+    fn jar(&self) -> &T;
+
+    /// Gives a mutable reference to the jar.
+    fn jar_mut(&mut self) -> &mut T;
+}
+
+#[cfg(test)]
+pub(crate) mod tests {
+    use std::path::Path;
+    use std::sync::Arc;
+
+    use crate::db::{HasJar, SourceDb, SourceJar};
+    use crate::files::{FileId, Files};
+    use crate::lint::{lint_semantic, lint_syntax, Diagnostics};
+    use crate::module::{
+        add_module, file_to_module, path_to_module, resolve_module, set_module_search_paths,
+        Module, ModuleData, ModuleName, ModuleSearchPath,
+    };
+    use crate::parse::{parse, Parsed};
+    use crate::source::{source_text, Source};
+    use crate::symbols::{symbol_table, SymbolId, SymbolTable};
+    use crate::types::{infer_symbol_type, Type};
+
+    use super::{SemanticDb, SemanticJar};
+
+    // This can be a partial database used in a single crate for testing.
+    // It would hold fewer data than the full database.
+    #[derive(Debug, Default)]
+    pub(crate) struct TestDb {
+        files: Files,
+        source: SourceJar,
+        semantic: SemanticJar,
+    }
+
+    impl HasJar<SourceJar> for TestDb {
+        fn jar(&self) -> &SourceJar {
+            &self.source
+        }
+
+        fn jar_mut(&mut self) -> &mut SourceJar {
+            &mut self.source
+        }
+    }
+
+    impl HasJar<SemanticJar> for TestDb {
+        fn jar(&self) -> &SemanticJar {
+            &self.semantic
+        }
+
+        fn jar_mut(&mut self) -> &mut SemanticJar {
+            &mut self.semantic
+        }
+    }
+
+    impl SourceDb for TestDb {
+        fn file_id(&self, path: &Path) -> FileId {
+            self.files.intern(path)
+        }
+
+        fn file_path(&self, file_id: FileId) -> Arc<Path> {
+            self.files.path(file_id)
+        }
+
+        fn source(&self, file_id: FileId) -> Source {
+            source_text(self, file_id)
+        }
+
+        fn parse(&self, file_id: FileId) -> Parsed {
+            parse(self, file_id)
+        }
+
+        fn lint_syntax(&self, file_id: FileId) -> Diagnostics {
+            lint_syntax(self, file_id)
+        }
+    }
+
+    impl SemanticDb for TestDb {
+        fn resolve_module(&self, name: ModuleName) -> Option<Module> {
+            resolve_module(self, name)
+        }
+
+        fn file_to_module(&self, file_id: FileId) -> Option<Module> {
+            file_to_module(self, file_id)
+        }
+
+        fn path_to_module(&self, path: &Path) -> Option<Module> {
+            path_to_module(self, path)
+        }
+
+        fn symbol_table(&self, file_id: FileId) -> Arc<SymbolTable> {
+            symbol_table(self, file_id)
+        }
+
+        fn infer_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Type {
+            infer_symbol_type(self, file_id, symbol_id)
+        }
+
+        fn lint_semantic(&self, file_id: FileId) -> Diagnostics {
+            lint_semantic(self, file_id)
+        }
+
+        fn add_module(&mut self, path: &Path) -> Option<(Module, Vec<Arc<ModuleData>>)> {
+            add_module(self, path)
+        }
+
+        fn set_module_search_paths(&mut self, paths: Vec<ModuleSearchPath>) {
+            set_module_search_paths(self, paths);
+        }
+    }
+}

crates/red_knot/src/files.rs

@@ -0,0 +1,148 @@
+use std::fmt::{Debug, Formatter};
+use std::hash::{Hash, Hasher};
+use std::path::Path;
+use std::sync::Arc;
+
+use hashbrown::hash_map::RawEntryMut;
+use parking_lot::RwLock;
+use rustc_hash::FxHasher;
+
+use ruff_index::{newtype_index, IndexVec};
+
+type Map<K, V> = hashbrown::HashMap<K, V, ()>;
+
+#[newtype_index]
+pub struct FileId;
+
+// TODO we'll need a higher level virtual file system abstraction that allows testing if a file exists
+// or retrieving its content (ideally lazily and in a way that the memory can be retained later)
+// I suspect that we'll end up with a FileSystem trait and our own Path abstraction.
+#[derive(Clone, Default)]
+pub struct Files {
+    inner: Arc<RwLock<FilesInner>>,
+}
+
+impl Files {
+    #[tracing::instrument(level = "debug", skip(self))]
+    pub fn intern(&self, path: &Path) -> FileId {
+        self.inner.write().intern(path)
+    }
+
+    pub fn try_get(&self, path: &Path) -> Option<FileId> {
+        self.inner.read().try_get(path)
+    }
+
+    #[tracing::instrument(level = "debug", skip(self))]
+    pub fn path(&self, id: FileId) -> Arc<Path> {
+        self.inner.read().path(id)
+    }
+}
+
+impl Debug for Files {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        let files = self.inner.read();
+        let mut debug = f.debug_map();
+        for item in files.iter() {
+            debug.entry(&item.0, &item.1);
+        }
+
+        debug.finish()
+    }
+}
+
+impl PartialEq for Files {
+    fn eq(&self, other: &Self) -> bool {
+        self.inner.read().eq(&other.inner.read())
+    }
+}
+
+impl Eq for Files {}
+
+#[derive(Default)]
+struct FilesInner {
+    by_path: Map<FileId, ()>,
+    // TODO should we use a map here to reclaim the space for removed files?
+    // TODO I think we should use our own path abstraction here to avoid having to normalize paths
+    // and dealing with non-utf paths everywhere.
+    by_id: IndexVec<FileId, Arc<Path>>,
+}
+
+impl FilesInner {
+    /// Inserts the path and returns a new id for it or returns the id if it is an existing path.
+    // TODO should this accept Path or PathBuf?
+    pub(crate) fn intern(&mut self, path: &Path) -> FileId {
+        let mut hasher = FxHasher::default();
+        path.hash(&mut hasher);
+        let hash = hasher.finish();
+
+        let entry = self
+            .by_path
+            .raw_entry_mut()
+            .from_hash(hash, |existing_file| &*self.by_id[*existing_file] == path);
+
+        match entry {
+            RawEntryMut::Occupied(entry) => *entry.key(),
+            RawEntryMut::Vacant(entry) => {
+                let id = self.by_id.push(Arc::from(path));
+                entry.insert_with_hasher(hash, id, (), |_| hash);
+                id
+            }
+        }
+    }
+
+    pub(crate) fn try_get(&self, path: &Path) -> Option<FileId> {
+        let mut hasher = FxHasher::default();
+        path.hash(&mut hasher);
+        let hash = hasher.finish();
+
+        Some(
+            *self
+                .by_path
+                .raw_entry()
+                .from_hash(hash, |existing_file| &*self.by_id[*existing_file] == path)?
+                .0,
+        )
+    }
+
+    /// Returns the path for the file with the given id.
+    pub(crate) fn path(&self, id: FileId) -> Arc<Path> {
+        self.by_id[id].clone()
+    }
+
+    pub(crate) fn iter(&self) -> impl Iterator<Item = (FileId, Arc<Path>)> + '_ {
+        self.by_path.keys().map(|id| (*id, self.by_id[*id].clone()))
+    }
+}
+
+impl PartialEq for FilesInner {
+    fn eq(&self, other: &Self) -> bool {
+        self.by_id == other.by_id
+    }
+}
+
+impl Eq for FilesInner {}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::path::PathBuf;
+
+    #[test]
+    fn insert_path_twice_same_id() {
+        let files = Files::default();
+        let path = PathBuf::from("foo/bar");
+        let id1 = files.intern(&path);
+        let id2 = files.intern(&path);
+        assert_eq!(id1, id2);
+    }
+
+    #[test]
+    fn insert_different_paths_different_ids() {
+        let files = Files::default();
+        let path1 = PathBuf::from("foo/bar");
+        let path2 = PathBuf::from("foo/bar/baz");
+        let id1 = files.intern(&path1);
+        let id2 = files.intern(&path2);
+        assert_ne!(id1, id2);
+    }
+}

crates/red_knot/src/hir.rs

@@ -0,0 +1,67 @@
+//! Key observations
+//!
+//! The HIR avoids allocations to large extends by:
+//! * Using an arena per node type
+//! * using ids and id ranges to reference items.
+//!
+//! Using separate arena per node type has the advantage that the IDs are relatively stable, because
+//! they only change when a node of the same kind has been added or removed. (What's unclear is if that matters or if
+//! it still triggers a re-compute because the AST-id in the node has changed).
+//!
+//! The HIR does not store all details. It mainly stores the *public* interface. There's a reference
+//! back to the AST node to get more details.
+//!
+//!
+
+use crate::ast_ids::{HasAstId, TypedAstId};
+use crate::files::FileId;
+use std::fmt::Formatter;
+use std::hash::{Hash, Hasher};
+
+pub struct HirAstId<N: HasAstId> {
+    file_id: FileId,
+    node_id: TypedAstId<N>,
+}
+
+impl<N: HasAstId> Copy for HirAstId<N> {}
+impl<N: HasAstId> Clone for HirAstId<N> {
+    fn clone(&self) -> Self {
+        *self
+    }
+}
+
+impl<N: HasAstId> PartialEq for HirAstId<N> {
+    fn eq(&self, other: &Self) -> bool {
+        self.file_id == other.file_id && self.node_id == other.node_id
+    }
+}
+
+impl<N: HasAstId> Eq for HirAstId<N> {}
+
+impl<N: HasAstId> std::fmt::Debug for HirAstId<N> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("HirAstId")
+            .field("file_id", &self.file_id)
+            .field("node_id", &self.node_id)
+            .finish()
+    }
+}
+
+impl<N: HasAstId> Hash for HirAstId<N> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.file_id.hash(state);
+        self.node_id.hash(state);
+    }
+}
+
+impl<N: HasAstId> HirAstId<N> {
+    pub fn upcast<M: HasAstId>(self) -> HirAstId<M>
+    where
+        N: Into<M>,
+    {
+        HirAstId {
+            file_id: self.file_id,
+            node_id: self.node_id.upcast(),
+        }
+    }
+}

crates/red_knot/src/hir/definition.rs

@@ -0,0 +1,556 @@
+use std::ops::{Index, Range};
+
+use ruff_index::{newtype_index, IndexVec};
+use ruff_python_ast::visitor::preorder;
+use ruff_python_ast::visitor::preorder::PreorderVisitor;
+use ruff_python_ast::{
+    Decorator, ExceptHandler, ExceptHandlerExceptHandler, Expr, MatchCase, ModModule, Stmt,
+    StmtAnnAssign, StmtAssign, StmtClassDef, StmtFunctionDef, StmtGlobal, StmtImport,
+    StmtImportFrom, StmtNonlocal, StmtTypeAlias, TypeParam, TypeParamParamSpec, TypeParamTypeVar,
+    TypeParamTypeVarTuple, WithItem,
+};
+
+use crate::ast_ids::{AstIds, HasAstId};
+use crate::files::FileId;
+use crate::hir::HirAstId;
+use crate::Name;
+
+#[newtype_index]
+pub struct FunctionId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Function {
+    ast_id: HirAstId<StmtFunctionDef>,
+    name: Name,
+    parameters: Range<ParameterId>,
+    type_parameters: Range<TypeParameterId>, // TODO: type_parameters, return expression, decorators
+}
+
+#[newtype_index]
+pub struct ParameterId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Parameter {
+    kind: ParameterKind,
+    name: Name,
+    default: Option<()>, // TODO use expression HIR
+    ast_id: HirAstId<ruff_python_ast::Parameter>,
+}
+
+// TODO or should `Parameter` be an enum?
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub enum ParameterKind {
+    PositionalOnly,
+    Arguments,
+    Vararg,
+    KeywordOnly,
+    Kwarg,
+}
+
+#[newtype_index]
+pub struct ClassId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Class {
+    name: Name,
+    ast_id: HirAstId<StmtClassDef>,
+    // TODO type parameters, inheritance, decorators, members
+}
+
+#[newtype_index]
+pub struct AssignmentId;
+
+// This can have more than one name...
+// but that means we can't implement `name()` on `ModuleItem`.
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Assignment {
+    // TODO: Handle multiple names  / targets
+    name: Name,
+    ast_id: HirAstId<StmtAssign>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct AnnotatedAssignment {
+    name: Name,
+    ast_id: HirAstId<StmtAnnAssign>,
+}
+
+#[newtype_index]
+pub struct AnnotatedAssignmentId;
+
+#[newtype_index]
+pub struct TypeAliasId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeAlias {
+    name: Name,
+    ast_id: HirAstId<StmtTypeAlias>,
+    parameters: Range<TypeParameterId>,
+}
+
+#[newtype_index]
+pub struct TypeParameterId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub enum TypeParameter {
+    TypeVar(TypeParameterTypeVar),
+    ParamSpec(TypeParameterParamSpec),
+    TypeVarTuple(TypeParameterTypeVarTuple),
+}
+
+impl TypeParameter {
+    pub fn ast_id(&self) -> HirAstId<TypeParam> {
+        match self {
+            TypeParameter::TypeVar(type_var) => type_var.ast_id.upcast(),
+            TypeParameter::ParamSpec(param_spec) => param_spec.ast_id.upcast(),
+            TypeParameter::TypeVarTuple(type_var_tuple) => type_var_tuple.ast_id.upcast(),
+        }
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeParameterTypeVar {
+    name: Name,
+    ast_id: HirAstId<TypeParamTypeVar>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeParameterParamSpec {
+    name: Name,
+    ast_id: HirAstId<TypeParamParamSpec>,
+}
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct TypeParameterTypeVarTuple {
+    name: Name,
+    ast_id: HirAstId<TypeParamTypeVarTuple>,
+}
+
+#[newtype_index]
+pub struct GlobalId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct Global {
+    // TODO track names
+    ast_id: HirAstId<StmtGlobal>,
+}
+
+#[newtype_index]
+pub struct NonLocalId;
+
+#[derive(Debug, Clone, Eq, PartialEq)]
+pub struct NonLocal {
+    // TODO track names
+    ast_id: HirAstId<StmtNonlocal>,
+}
+
+pub enum DefinitionId {
+    Function(FunctionId),
+    Parameter(ParameterId),
+    Class(ClassId),
+    Assignment(AssignmentId),
+    AnnotatedAssignment(AnnotatedAssignmentId),
+    Global(GlobalId),
+    NonLocal(NonLocalId),
+    TypeParameter(TypeParameterId),
+    TypeAlias(TypeAlias),
+}
+
+pub enum DefinitionItem {
+    Function(Function),
+    Parameter(Parameter),
+    Class(Class),
+    Assignment(Assignment),
+    AnnotatedAssignment(AnnotatedAssignment),
+    Global(Global),
+    NonLocal(NonLocal),
+    TypeParameter(TypeParameter),
+    TypeAlias(TypeAlias),
+}
+
+// The closest is rust-analyzers item-tree. It only represents "Items" which make the public interface of a module
+// (it excludes any other statement or expressions). rust-analyzer uses it as the main input to the name resolution
+// algorithm
+// > It is the input to the name resolution algorithm, as well as to the queries defined in `adt.rs`,
+// > `data.rs`, and most things in `attr.rs`.
+//
+// > One important purpose of this layer is to provide an "invalidation barrier" for incremental
+// > computations: when typing inside an item body, the `ItemTree` of the modified file is typically
+// > unaffected, so we don't have to recompute name resolution results or item data (see `data.rs`).
+//
+// I haven't fully figured this out but I think that this composes the "public" interface of a module?
+// But maybe that's too optimistic.
+//
+//
+#[derive(Debug, Clone, Default, Eq, PartialEq)]
+pub struct Definitions {
+    functions: IndexVec<FunctionId, Function>,
+    parameters: IndexVec<ParameterId, Parameter>,
+    classes: IndexVec<ClassId, Class>,
+    assignments: IndexVec<AssignmentId, Assignment>,
+    annotated_assignments: IndexVec<AnnotatedAssignmentId, AnnotatedAssignment>,
+    type_aliases: IndexVec<TypeAliasId, TypeAlias>,
+    type_parameters: IndexVec<TypeParameterId, TypeParameter>,
+    globals: IndexVec<GlobalId, Global>,
+    non_locals: IndexVec<NonLocalId, NonLocal>,
+}
+
+impl Definitions {
+    pub fn from_module(module: &ModModule, ast_ids: &AstIds, file_id: FileId) -> Self {
+        let mut visitor = DefinitionsVisitor {
+            definitions: Definitions::default(),
+            ast_ids,
+            file_id,
+        };
+
+        visitor.visit_body(&module.body);
+
+        visitor.definitions
+    }
+}
+
+impl Index<FunctionId> for Definitions {
+    type Output = Function;
+
+    fn index(&self, index: FunctionId) -> &Self::Output {
+        &self.functions[index]
+    }
+}
+
+impl Index<ParameterId> for Definitions {
+    type Output = Parameter;
+
+    fn index(&self, index: ParameterId) -> &Self::Output {
+        &self.parameters[index]
+    }
+}
+
+impl Index<ClassId> for Definitions {
+    type Output = Class;
+
+    fn index(&self, index: ClassId) -> &Self::Output {
+        &self.classes[index]
+    }
+}
+
+impl Index<AssignmentId> for Definitions {
+    type Output = Assignment;
+
+    fn index(&self, index: AssignmentId) -> &Self::Output {
+        &self.assignments[index]
+    }
+}
+
+impl Index<AnnotatedAssignmentId> for Definitions {
+    type Output = AnnotatedAssignment;
+
+    fn index(&self, index: AnnotatedAssignmentId) -> &Self::Output {
+        &self.annotated_assignments[index]
+    }
+}
+
+impl Index<TypeAliasId> for Definitions {
+    type Output = TypeAlias;
+
+    fn index(&self, index: TypeAliasId) -> &Self::Output {
+        &self.type_aliases[index]
+    }
+}
+
+impl Index<GlobalId> for Definitions {
+    type Output = Global;
+
+    fn index(&self, index: GlobalId) -> &Self::Output {
+        &self.globals[index]
+    }
+}
+
+impl Index<NonLocalId> for Definitions {
+    type Output = NonLocal;
+
+    fn index(&self, index: NonLocalId) -> &Self::Output {
+        &self.non_locals[index]
+    }
+}
+
+impl Index<TypeParameterId> for Definitions {
+    type Output = TypeParameter;
+
+    fn index(&self, index: TypeParameterId) -> &Self::Output {
+        &self.type_parameters[index]
+    }
+}
+
+struct DefinitionsVisitor<'a> {
+    definitions: Definitions,
+    ast_ids: &'a AstIds,
+    file_id: FileId,
+}
+
+impl DefinitionsVisitor<'_> {
+    fn ast_id<N: HasAstId>(&self, node: &N) -> HirAstId<N> {
+        HirAstId {
+            file_id: self.file_id,
+            node_id: self.ast_ids.ast_id(node),
+        }
+    }
+
+    fn lower_function_def(&mut self, function: &StmtFunctionDef) -> FunctionId {
+        let name = Name::new(&function.name);
+
+        let first_type_parameter_id = self.definitions.type_parameters.next_index();
+        let mut last_type_parameter_id = first_type_parameter_id;
+
+        if let Some(type_params) = &function.type_params {
+            for parameter in &type_params.type_params {
+                let id = self.lower_type_parameter(parameter);
+                last_type_parameter_id = id;
+            }
+        }
+
+        let parameters = self.lower_parameters(&function.parameters);
+
+        self.definitions.functions.push(Function {
+            name,
+            ast_id: self.ast_id(function),
+            parameters,
+            type_parameters: first_type_parameter_id..last_type_parameter_id,
+        })
+    }
+
+    fn lower_parameters(&mut self, parameters: &ruff_python_ast::Parameters) -> Range<ParameterId> {
+        let first_parameter_id = self.definitions.parameters.next_index();
+        let mut last_parameter_id = first_parameter_id;
+
+        for parameter in &parameters.posonlyargs {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::PositionalOnly,
+                name: Name::new(&parameter.parameter.name),
+                default: None,
+                ast_id: self.ast_id(&parameter.parameter),
+            });
+        }
+
+        if let Some(vararg) = &parameters.vararg {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::Vararg,
+                name: Name::new(&vararg.name),
+                default: None,
+                ast_id: self.ast_id(vararg),
+            });
+        }
+
+        for parameter in &parameters.kwonlyargs {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::KeywordOnly,
+                name: Name::new(&parameter.parameter.name),
+                default: None,
+                ast_id: self.ast_id(&parameter.parameter),
+            });
+        }
+
+        if let Some(kwarg) = &parameters.kwarg {
+            last_parameter_id = self.definitions.parameters.push(Parameter {
+                kind: ParameterKind::KeywordOnly,
+                name: Name::new(&kwarg.name),
+                default: None,
+                ast_id: self.ast_id(kwarg),
+            });
+        }
+
+        first_parameter_id..last_parameter_id
+    }
+
+    fn lower_class_def(&mut self, class: &StmtClassDef) -> ClassId {
+        let name = Name::new(&class.name);
+
+        self.definitions.classes.push(Class {
+            name,
+            ast_id: self.ast_id(class),
+        })
+    }
+
+    fn lower_assignment(&mut self, assignment: &StmtAssign) {
+        // FIXME handle multiple names
+        if let Some(Expr::Name(name)) = assignment.targets.first() {
+            self.definitions.assignments.push(Assignment {
+                name: Name::new(&name.id),
+                ast_id: self.ast_id(assignment),
+            });
+        }
+    }
+
+    fn lower_annotated_assignment(&mut self, annotated_assignment: &StmtAnnAssign) {
+        if let Expr::Name(name) = &*annotated_assignment.target {
+            self.definitions
+                .annotated_assignments
+                .push(AnnotatedAssignment {
+                    name: Name::new(&name.id),
+                    ast_id: self.ast_id(annotated_assignment),
+                });
+        }
+    }
+
+    fn lower_type_alias(&mut self, type_alias: &StmtTypeAlias) {
+        if let Expr::Name(name) = &*type_alias.name {
+            let name = Name::new(&name.id);
+
+            let lower_parameters_id = self.definitions.type_parameters.next_index();
+            let mut last_parameter_id = lower_parameters_id;
+
+            if let Some(type_params) = &type_alias.type_params {
+                for type_parameter in &type_params.type_params {
+                    let id = self.lower_type_parameter(type_parameter);
+                    last_parameter_id = id;
+                }
+            }
+
+            self.definitions.type_aliases.push(TypeAlias {
+                name,
+                ast_id: self.ast_id(type_alias),
+                parameters: lower_parameters_id..last_parameter_id,
+            });
+        }
+    }
+
+    fn lower_type_parameter(&mut self, type_parameter: &TypeParam) -> TypeParameterId {
+        match type_parameter {
+            TypeParam::TypeVar(type_var) => {
+                self.definitions
+                    .type_parameters
+                    .push(TypeParameter::TypeVar(TypeParameterTypeVar {
+                        name: Name::new(&type_var.name),
+                        ast_id: self.ast_id(type_var),
+                    }))
+            }
+            TypeParam::ParamSpec(param_spec) => {
+                self.definitions
+                    .type_parameters
+                    .push(TypeParameter::ParamSpec(TypeParameterParamSpec {
+                        name: Name::new(&param_spec.name),
+                        ast_id: self.ast_id(param_spec),
+                    }))
+            }
+            TypeParam::TypeVarTuple(type_var_tuple) => {
+                self.definitions
+                    .type_parameters
+                    .push(TypeParameter::TypeVarTuple(TypeParameterTypeVarTuple {
+                        name: Name::new(&type_var_tuple.name),
+                        ast_id: self.ast_id(type_var_tuple),
+                    }))
+            }
+        }
+    }
+
+    fn lower_import(&mut self, _import: &StmtImport) {
+        // TODO
+    }
+
+    fn lower_import_from(&mut self, _import_from: &StmtImportFrom) {
+        // TODO
+    }
+
+    fn lower_global(&mut self, global: &StmtGlobal) -> GlobalId {
+        self.definitions.globals.push(Global {
+            ast_id: self.ast_id(global),
+        })
+    }
+
+    fn lower_non_local(&mut self, non_local: &StmtNonlocal) -> NonLocalId {
+        self.definitions.non_locals.push(NonLocal {
+            ast_id: self.ast_id(non_local),
+        })
+    }
+
+    fn lower_except_handler(&mut self, _except_handler: &ExceptHandlerExceptHandler) {
+        // TODO
+    }
+
+    fn lower_with_item(&mut self, _with_item: &WithItem) {
+        // TODO
+    }
+
+    fn lower_match_case(&mut self, _match_case: &MatchCase) {
+        // TODO
+    }
+}
+
+impl PreorderVisitor<'_> for DefinitionsVisitor<'_> {
+    fn visit_stmt(&mut self, stmt: &Stmt) {
+        match stmt {
+            // Definition statements
+            Stmt::FunctionDef(definition) => {
+                self.lower_function_def(definition);
+                self.visit_body(&definition.body);
+            }
+            Stmt::ClassDef(definition) => {
+                self.lower_class_def(definition);
+                self.visit_body(&definition.body);
+            }
+            Stmt::Assign(assignment) => {
+                self.lower_assignment(assignment);
+            }
+            Stmt::AnnAssign(annotated_assignment) => {
+                self.lower_annotated_assignment(annotated_assignment);
+            }
+            Stmt::TypeAlias(type_alias) => {
+                self.lower_type_alias(type_alias);
+            }
+
+            Stmt::Import(import) => self.lower_import(import),
+            Stmt::ImportFrom(import_from) => self.lower_import_from(import_from),
+            Stmt::Global(global) => {
+                self.lower_global(global);
+            }
+            Stmt::Nonlocal(non_local) => {
+                self.lower_non_local(non_local);
+            }
+
+            // Visit the compound statement bodies because they can contain other definitions.
+            Stmt::For(_)
+            | Stmt::While(_)
+            | Stmt::If(_)
+            | Stmt::With(_)
+            | Stmt::Match(_)
+            | Stmt::Try(_) => {
+                preorder::walk_stmt(self, stmt);
+            }
+
+            // Skip over simple statements because they can't contain any other definitions.
+            Stmt::Return(_)
+            | Stmt::Delete(_)
+            | Stmt::AugAssign(_)
+            | Stmt::Raise(_)
+            | Stmt::Assert(_)
+            | Stmt::Expr(_)
+            | Stmt::Pass(_)
+            | Stmt::Break(_)
+            | Stmt::Continue(_)
+            | Stmt::IpyEscapeCommand(_) => {
+                // No op
+            }
+        }
+    }
+
+    fn visit_expr(&mut self, _: &'_ Expr) {}
+
+    fn visit_decorator(&mut self, _decorator: &'_ Decorator) {}
+
+    fn visit_except_handler(&mut self, except_handler: &'_ ExceptHandler) {
+        match except_handler {
+            ExceptHandler::ExceptHandler(except_handler) => {
+                self.lower_except_handler(except_handler);
+            }
+        }
+    }
+
+    fn visit_with_item(&mut self, with_item: &'_ WithItem) {
+        self.lower_with_item(with_item);
+    }
+
+    fn visit_match_case(&mut self, match_case: &'_ MatchCase) {
+        self.lower_match_case(match_case);
+        self.visit_body(&match_case.body);
+    }
+}

crates/red_knot/src/lib.rs

@@ -0,0 +1,109 @@
+use std::fmt::Formatter;
+use std::hash::BuildHasherDefault;
+use std::ops::Deref;
+use std::path::{Path, PathBuf};
+
+use rustc_hash::{FxHashSet, FxHasher};
+
+use crate::files::FileId;
+
+pub mod ast_ids;
+pub mod cache;
+pub mod cancellation;
+pub mod db;
+pub mod files;
+pub mod hir;
+pub mod lint;
+pub mod module;
+mod parse;
+pub mod program;
+pub mod source;
+mod symbols;
+mod types;
+pub mod watch;
+
+pub(crate) type FxDashMap<K, V> = dashmap::DashMap<K, V, BuildHasherDefault<FxHasher>>;
+#[allow(unused)]
+pub(crate) type FxDashSet<V> = dashmap::DashSet<V, BuildHasherDefault<FxHasher>>;
+pub(crate) type FxIndexSet<V> = indexmap::set::IndexSet<V, BuildHasherDefault<FxHasher>>;
+
+#[derive(Debug)]
+pub struct Workspace {
+    /// TODO this should be a resolved path. We should probably use a newtype wrapper that guarantees that
+    /// PATH is a UTF-8 path and is normalized.
+    root: PathBuf,
+    /// The files that are open in the workspace.
+    ///
+    /// * Editor: The files that are actively being edited in the editor (the user has a tab open with the file).
+    /// * CLI: The resolved files passed as arguments to the CLI.
+    open_files: FxHashSet<FileId>,
+}
+
+impl Workspace {
+    pub fn new(root: PathBuf) -> Self {
+        Self {
+            root,
+            open_files: FxHashSet::default(),
+        }
+    }
+
+    pub fn root(&self) -> &Path {
+        self.root.as_path()
+    }
+
+    // TODO having the content in workspace feels wrong.
+    pub fn open_file(&mut self, file_id: FileId) {
+        self.open_files.insert(file_id);
+    }
+
+    pub fn close_file(&mut self, file_id: FileId) {
+        self.open_files.remove(&file_id);
+    }
+
+    // TODO introduce an `OpenFile` type instead of using an anonymous tuple.
+    pub fn open_files(&self) -> impl Iterator<Item = FileId> + '_ {
+        self.open_files.iter().copied()
+    }
+
+    pub fn is_file_open(&self, file_id: FileId) -> bool {
+        self.open_files.contains(&file_id)
+    }
+}
+
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct Name(smol_str::SmolStr);
+
+impl Name {
+    #[inline]
+    pub fn new(name: &str) -> Self {
+        Self(smol_str::SmolStr::new(name))
+    }
+
+    pub fn as_str(&self) -> &str {
+        self.0.as_str()
+    }
+}
+
+impl Deref for Name {
+    type Target = str;
+
+    #[inline]
+    fn deref(&self) -> &Self::Target {
+        self.as_str()
+    }
+}
+
+impl<T> From<T> for Name
+where
+    T: Into<smol_str::SmolStr>,
+{
+    fn from(value: T) -> Self {
+        Self(value.into())
+    }
+}
+
+impl std::fmt::Display for Name {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.write_str(self.as_str())
+    }
+}

crates/red_knot/src/lint.rs

@@ -0,0 +1,252 @@
+use std::cell::RefCell;
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use ruff_python_ast::visitor::Visitor;
+use ruff_python_ast::{ModModule, StringLiteral};
+
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SemanticDb, SemanticJar, SourceDb, SourceJar};
+use crate::files::FileId;
+use crate::parse::Parsed;
+use crate::source::Source;
+use crate::symbols::{Definition, SymbolId, SymbolTable};
+use crate::types::Type;
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn lint_syntax<Db>(db: &Db, file_id: FileId) -> Diagnostics
+where
+    Db: SourceDb + HasJar<SourceJar>,
+{
+    let storage = &db.jar().lint_syntax;
+
+    storage.get(&file_id, |file_id| {
+        let mut diagnostics = Vec::new();
+
+        let source = db.source(*file_id);
+        lint_lines(source.text(), &mut diagnostics);
+
+        let parsed = db.parse(*file_id);
+
+        if parsed.errors().is_empty() {
+            let ast = parsed.ast();
+
+            let mut visitor = SyntaxLintVisitor {
+                diagnostics,
+                source: source.text(),
+            };
+            visitor.visit_body(&ast.body);
+            diagnostics = visitor.diagnostics;
+        } else {
+            diagnostics.extend(parsed.errors().iter().map(std::string::ToString::to_string));
+        }
+
+        Diagnostics::from(diagnostics)
+    })
+}
+
+fn lint_lines(source: &str, diagnostics: &mut Vec<String>) {
+    for (line_number, line) in source.lines().enumerate() {
+        if line.len() < 88 {
+            continue;
+        }
+
+        let char_count = line.chars().count();
+        if char_count > 88 {
+            diagnostics.push(format!(
+                "Line {} is too long ({} characters)",
+                line_number + 1,
+                char_count
+            ));
+        }
+    }
+}
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn lint_semantic<Db>(db: &Db, file_id: FileId) -> Diagnostics
+where
+    Db: SemanticDb + HasJar<SemanticJar>,
+{
+    let storage = &db.jar().lint_semantic;
+
+    storage.get(&file_id, |file_id| {
+        let source = db.source(*file_id);
+        let parsed = db.parse(*file_id);
+        let symbols = db.symbol_table(*file_id);
+
+        let context = SemanticLintContext {
+            file_id: *file_id,
+            source,
+            parsed,
+            symbols,
+            db,
+            diagnostics: RefCell::new(Vec::new()),
+        };
+
+        lint_unresolved_imports(&context);
+
+        Diagnostics::from(context.diagnostics.take())
+    })
+}
+
+fn lint_unresolved_imports(context: &SemanticLintContext) {
+    // TODO: Consider iterating over the dependencies (imports) only instead of all definitions.
+    for (symbol, definition) in context.symbols().all_definitions() {
+        match definition {
+            Definition::Import(import) => {
+                let ty = context.eval_symbol(symbol);
+
+                if ty.is_unknown() {
+                    context.push_diagnostic(format!("Unresolved module {}", import.module));
+                }
+            }
+            Definition::ImportFrom(import) => {
+                let ty = context.eval_symbol(symbol);
+
+                if ty.is_unknown() {
+                    let module_name = import.module().map(Deref::deref).unwrap_or_default();
+                    let message = if import.level() > 0 {
+                        format!(
+                            "Unresolved relative import '{}' from {}{}",
+                            import.name(),
+                            ".".repeat(import.level() as usize),
+                            module_name
+                        )
+                    } else {
+                        format!(
+                            "Unresolved import '{}' from '{}'",
+                            import.name(),
+                            module_name
+                        )
+                    };
+
+                    context.push_diagnostic(message);
+                }
+            }
+            _ => {}
+        }
+    }
+}
+
+pub struct SemanticLintContext<'a> {
+    file_id: FileId,
+    source: Source,
+    parsed: Parsed,
+    symbols: Arc<SymbolTable>,
+    db: &'a dyn SemanticDb,
+    diagnostics: RefCell<Vec<String>>,
+}
+
+impl<'a> SemanticLintContext<'a> {
+    pub fn source_text(&self) -> &str {
+        self.source.text()
+    }
+
+    pub fn file_id(&self) -> FileId {
+        self.file_id
+    }
+
+    pub fn ast(&self) -> &ModModule {
+        self.parsed.ast()
+    }
+
+    pub fn symbols(&self) -> &SymbolTable {
+        &self.symbols
+    }
+
+    pub fn eval_symbol(&self, symbol_id: SymbolId) -> Type {
+        self.db.infer_symbol_type(self.file_id, symbol_id)
+    }
+
+    pub fn push_diagnostic(&self, diagnostic: String) {
+        self.diagnostics.borrow_mut().push(diagnostic);
+    }
+
+    pub fn extend_diagnostics(&mut self, diagnostics: impl IntoIterator<Item = String>) {
+        self.diagnostics.get_mut().extend(diagnostics);
+    }
+}
+
+#[derive(Debug)]
+struct SyntaxLintVisitor<'a> {
+    diagnostics: Vec<String>,
+    source: &'a str,
+}
+
+impl Visitor<'_> for SyntaxLintVisitor<'_> {
+    fn visit_string_literal(&mut self, string_literal: &'_ StringLiteral) {
+        // A very naive implementation of use double quotes
+        let text = &self.source[string_literal.range];
+
+        if text.starts_with('\'') {
+            self.diagnostics
+                .push("Use double quotes for strings".to_string());
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum Diagnostics {
+    Empty,
+    List(Arc<Vec<String>>),
+}
+
+impl Diagnostics {
+    pub fn as_slice(&self) -> &[String] {
+        match self {
+            Diagnostics::Empty => &[],
+            Diagnostics::List(list) => list.as_slice(),
+        }
+    }
+}
+
+impl Deref for Diagnostics {
+    type Target = [String];
+    fn deref(&self) -> &Self::Target {
+        self.as_slice()
+    }
+}
+
+impl From<Vec<String>> for Diagnostics {
+    fn from(value: Vec<String>) -> Self {
+        if value.is_empty() {
+            Diagnostics::Empty
+        } else {
+            Diagnostics::List(Arc::new(value))
+        }
+    }
+}
+
+#[derive(Default, Debug)]
+pub struct LintSyntaxStorage(KeyValueCache<FileId, Diagnostics>);
+
+impl Deref for LintSyntaxStorage {
+    type Target = KeyValueCache<FileId, Diagnostics>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for LintSyntaxStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+#[derive(Default, Debug)]
+pub struct LintSemanticStorage(KeyValueCache<FileId, Diagnostics>);
+
+impl Deref for LintSemanticStorage {
+    type Target = KeyValueCache<FileId, Diagnostics>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for LintSemanticStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}

crates/red_knot/src/main.rs

@@ -0,0 +1,469 @@
+#![allow(clippy::dbg_macro)]
+
+use std::collections::hash_map::Entry;
+use std::path::Path;
+use std::sync::Mutex;
+
+use rustc_hash::FxHashMap;
+use tracing::subscriber::Interest;
+use tracing::{Level, Metadata};
+use tracing_subscriber::filter::LevelFilter;
+use tracing_subscriber::layer::{Context, Filter, SubscriberExt};
+use tracing_subscriber::{Layer, Registry};
+use tracing_tree::time::Uptime;
+
+use red_knot::cancellation::CancellationTokenSource;
+use red_knot::db::{HasJar, SourceDb, SourceJar};
+use red_knot::files::FileId;
+use red_knot::module::{ModuleSearchPath, ModuleSearchPathKind};
+use red_knot::program::check::{CheckError, RayonCheckScheduler};
+use red_knot::program::{FileChange, FileChangeKind, Program};
+use red_knot::watch::FileWatcher;
+use red_knot::Workspace;
+
+#[allow(clippy::print_stdout, clippy::unnecessary_wraps, clippy::print_stderr)]
+fn main() -> anyhow::Result<()> {
+    setup_tracing();
+
+    let arguments: Vec<_> = std::env::args().collect();
+
+    if arguments.len() < 2 {
+        eprintln!("Usage: red_knot <path>");
+        return Err(anyhow::anyhow!("Invalid arguments"));
+    }
+
+    let entry_point = Path::new(&arguments[1]);
+
+    if !entry_point.exists() {
+        eprintln!("The entry point does not exist.");
+        return Err(anyhow::anyhow!("Invalid arguments"));
+    }
+
+    if !entry_point.is_file() {
+        eprintln!("The entry point is not a file.");
+        return Err(anyhow::anyhow!("Invalid arguments"));
+    }
+
+    let workspace_folder = entry_point.parent().unwrap();
+    let workspace = Workspace::new(workspace_folder.to_path_buf());
+
+    let workspace_search_path = ModuleSearchPath::new(
+        workspace.root().to_path_buf(),
+        ModuleSearchPathKind::FirstParty,
+    );
+    let mut program = Program::new(workspace, vec![workspace_search_path]);
+
+    let entry_id = program.file_id(entry_point);
+    program.workspace_mut().open_file(entry_id);
+
+    let (main_loop, main_loop_cancellation_token) = MainLoop::new();
+
+    // Listen to Ctrl+C and abort the watch mode.
+    let main_loop_cancellation_token = Mutex::new(Some(main_loop_cancellation_token));
+    ctrlc::set_handler(move || {
+        let mut lock = main_loop_cancellation_token.lock().unwrap();
+
+        if let Some(token) = lock.take() {
+            token.stop();
+        }
+    })?;
+
+    let file_changes_notifier = main_loop.file_changes_notifier();
+
+    // Watch for file changes and re-trigger the analysis.
+    let mut file_watcher = FileWatcher::new(
+        move |changes| {
+            file_changes_notifier.notify(changes);
+        },
+        program.files().clone(),
+    )?;
+
+    file_watcher.watch_folder(workspace_folder)?;
+
+    main_loop.run(&mut program);
+
+    let source_jar: &SourceJar = program.jar();
+
+    dbg!(source_jar.parsed.statistics());
+    dbg!(source_jar.sources.statistics());
+
+    Ok(())
+}
+
+struct MainLoop {
+    orchestrator_sender: crossbeam_channel::Sender<OrchestratorMessage>,
+    main_loop_receiver: crossbeam_channel::Receiver<MainLoopMessage>,
+}
+
+impl MainLoop {
+    fn new() -> (Self, MainLoopCancellationToken) {
+        let (orchestrator_sender, orchestrator_receiver) = crossbeam_channel::bounded(1);
+        let (main_loop_sender, main_loop_receiver) = crossbeam_channel::bounded(1);
+
+        let mut orchestrator = Orchestrator {
+            pending_analysis: None,
+            receiver: orchestrator_receiver,
+            sender: main_loop_sender.clone(),
+            aggregated_changes: AggregatedChanges::default(),
+        };
+
+        std::thread::spawn(move || {
+            orchestrator.run();
+        });
+
+        (
+            Self {
+                orchestrator_sender,
+                main_loop_receiver,
+            },
+            MainLoopCancellationToken {
+                sender: main_loop_sender,
+            },
+        )
+    }
+
+    fn file_changes_notifier(&self) -> FileChangesNotifier {
+        FileChangesNotifier {
+            sender: self.orchestrator_sender.clone(),
+        }
+    }
+
+    fn run(self, program: &mut Program) {
+        self.orchestrator_sender
+            .send(OrchestratorMessage::Run)
+            .unwrap();
+
+        for message in &self.main_loop_receiver {
+            tracing::trace!("Main Loop: Tick");
+
+            match message {
+                MainLoopMessage::CheckProgram => {
+                    // Remove mutability from program.
+                    let program = &*program;
+                    let run_cancellation_token_source = CancellationTokenSource::new();
+                    let run_cancellation_token = run_cancellation_token_source.token();
+                    let sender = &self.orchestrator_sender;
+
+                    sender
+                        .send(OrchestratorMessage::CheckProgramStarted {
+                            cancellation_token: run_cancellation_token_source,
+                        })
+                        .unwrap();
+
+                    rayon::in_place_scope(|scope| {
+                        let scheduler = RayonCheckScheduler::new(program, scope);
+
+                        let result = program.check(&scheduler, run_cancellation_token);
+                        match result {
+                            Ok(result) => sender
+                                .send(OrchestratorMessage::CheckProgramCompleted(result))
+                                .unwrap(),
+                            Err(CheckError::Cancelled) => sender
+                                .send(OrchestratorMessage::CheckProgramCancelled)
+                                .unwrap(),
+                        }
+                    });
+                }
+                MainLoopMessage::ApplyChanges(changes) => {
+                    program.apply_changes(changes.iter());
+                }
+                MainLoopMessage::CheckCompleted(diagnostics) => {
+                    dbg!(diagnostics);
+                }
+                MainLoopMessage::Exit => {
+                    return;
+                }
+            }
+        }
+    }
+}
+
+impl Drop for MainLoop {
+    fn drop(&mut self) {
+        self.orchestrator_sender
+            .send(OrchestratorMessage::Shutdown)
+            .unwrap();
+    }
+}
+
+#[derive(Debug, Clone)]
+struct FileChangesNotifier {
+    sender: crossbeam_channel::Sender<OrchestratorMessage>,
+}
+
+impl FileChangesNotifier {
+    fn notify(&self, changes: Vec<FileChange>) {
+        self.sender
+            .send(OrchestratorMessage::FileChanges(changes))
+            .unwrap();
+    }
+}
+
+#[derive(Debug)]
+struct MainLoopCancellationToken {
+    sender: crossbeam_channel::Sender<MainLoopMessage>,
+}
+
+impl MainLoopCancellationToken {
+    fn stop(self) {
+        self.sender.send(MainLoopMessage::Exit).unwrap();
+    }
+}
+
+struct Orchestrator {
+    aggregated_changes: AggregatedChanges,
+    pending_analysis: Option<PendingAnalysisState>,
+
+    /// Sends messages to the main loop.
+    sender: crossbeam_channel::Sender<MainLoopMessage>,
+    /// Receives messages from the main loop.
+    receiver: crossbeam_channel::Receiver<OrchestratorMessage>,
+}
+
+impl Orchestrator {
+    fn run(&mut self) {
+        while let Ok(message) = self.receiver.recv() {
+            match message {
+                OrchestratorMessage::Run => {
+                    self.pending_analysis = None;
+                    self.sender.send(MainLoopMessage::CheckProgram).unwrap();
+                }
+
+                OrchestratorMessage::CheckProgramStarted { cancellation_token } => {
+                    debug_assert!(self.pending_analysis.is_none());
+
+                    self.pending_analysis = Some(PendingAnalysisState { cancellation_token });
+                }
+
+                OrchestratorMessage::CheckProgramCompleted(diagnostics) => {
+                    self.pending_analysis
+                        .take()
+                        .expect("Expected a pending analysis.");
+
+                    self.sender
+                        .send(MainLoopMessage::CheckCompleted(diagnostics))
+                        .unwrap();
+                }
+
+                OrchestratorMessage::CheckProgramCancelled => {
+                    self.pending_analysis
+                        .take()
+                        .expect("Expected a pending analysis.");
+
+                    self.debounce_changes();
+                }
+
+                OrchestratorMessage::FileChanges(changes) => {
+                    // Request cancellation, but wait until all analysis tasks have completed to
+                    // avoid stale messages in the next main loop.
+                    let pending = if let Some(pending_state) = self.pending_analysis.as_ref() {
+                        pending_state.cancellation_token.cancel();
+                        true
+                    } else {
+                        false
+                    };
+
+                    self.aggregated_changes.extend(changes);
+
+                    // If there are no pending analysis tasks, apply the file changes. Otherwise
+                    // keep running until all file checks have completed.
+                    if !pending {
+                        self.debounce_changes();
+                    }
+                }
+                OrchestratorMessage::Shutdown => {
+                    return self.shutdown();
+                }
+            }
+        }
+    }
+
+    fn debounce_changes(&mut self) {
+        debug_assert!(self.pending_analysis.is_none());
+
+        loop {
+            // Consume possibly incoming file change messages before running a new analysis, but don't wait for more than 100ms.
+            crossbeam_channel::select! {
+                recv(self.receiver) -> message => {
+                    match message {
+                        Ok(OrchestratorMessage::Shutdown) => {
+                            return self.shutdown();
+                        }
+                        Ok(OrchestratorMessage::FileChanges(file_changes)) => {
+                            self.aggregated_changes.extend(file_changes);
+                        }
+
+                        Ok(OrchestratorMessage::CheckProgramStarted {..}| OrchestratorMessage::CheckProgramCompleted(_) | OrchestratorMessage::CheckProgramCancelled) => unreachable!("No program check should be running while debouncing changes."),
+                        Ok(OrchestratorMessage::Run) => unreachable!("The orchestrator is already running."),
+
+                        Err(_) => {
+                            // There are no more senders, no point in waiting for more messages
+                            return;
+                        }
+                    }
+                },
+                default(std::time::Duration::from_millis(100)) => {
+                    // No more file changes after 100 ms, send the changes and schedule a new analysis
+                    self.sender.send(MainLoopMessage::ApplyChanges(std::mem::take(&mut self.aggregated_changes))).unwrap();
+                    self.sender.send(MainLoopMessage::CheckProgram).unwrap();
+                    return;
+                }
+            }
+        }
+    }
+
+    #[allow(clippy::unused_self)]
+    fn shutdown(&self) {
+        tracing::trace!("Shutting down orchestrator.");
+    }
+}
+
+#[derive(Debug)]
+struct PendingAnalysisState {
+    cancellation_token: CancellationTokenSource,
+}
+
+/// Message sent from the orchestrator to the main loop.
+#[derive(Debug)]
+enum MainLoopMessage {
+    CheckProgram,
+    CheckCompleted(Vec<String>),
+    ApplyChanges(AggregatedChanges),
+    Exit,
+}
+
+#[derive(Debug)]
+enum OrchestratorMessage {
+    Run,
+    Shutdown,
+
+    CheckProgramStarted {
+        cancellation_token: CancellationTokenSource,
+    },
+    CheckProgramCompleted(Vec<String>),
+    CheckProgramCancelled,
+
+    FileChanges(Vec<FileChange>),
+}
+
+#[derive(Default, Debug)]
+struct AggregatedChanges {
+    changes: FxHashMap<FileId, FileChangeKind>,
+}
+
+impl AggregatedChanges {
+    fn add(&mut self, change: FileChange) {
+        match self.changes.entry(change.file_id()) {
+            Entry::Occupied(mut entry) => {
+                let merged = entry.get_mut();
+
+                match (merged, change.kind()) {
+                    (FileChangeKind::Created, FileChangeKind::Deleted) => {
+                        // Deletion after creations means that ruff never saw the file.
+                        entry.remove();
+                    }
+                    (FileChangeKind::Created, FileChangeKind::Modified) => {
+                        // No-op, for ruff, modifying a file that it doesn't yet know that it exists is still considered a creation.
+                    }
+
+                    (FileChangeKind::Modified, FileChangeKind::Created) => {
+                        // Uhh, that should probably not happen. Continue considering it a modification.
+                    }
+
+                    (FileChangeKind::Modified, FileChangeKind::Deleted) => {
+                        *entry.get_mut() = FileChangeKind::Deleted;
+                    }
+
+                    (FileChangeKind::Deleted, FileChangeKind::Created) => {
+                        *entry.get_mut() = FileChangeKind::Modified;
+                    }
+
+                    (FileChangeKind::Deleted, FileChangeKind::Modified) => {
+                        // That's weird, but let's consider it a modification.
+                        *entry.get_mut() = FileChangeKind::Modified;
+                    }
+
+                    (FileChangeKind::Created, FileChangeKind::Created)
+                    | (FileChangeKind::Modified, FileChangeKind::Modified)
+                    | (FileChangeKind::Deleted, FileChangeKind::Deleted) => {
+                        // No-op transitions. Some of them should be impossible but we handle them anyway.
+                    }
+                }
+            }
+            Entry::Vacant(entry) => {
+                entry.insert(change.kind());
+            }
+        }
+    }
+
+    fn extend<I>(&mut self, changes: I)
+    where
+        I: IntoIterator<Item = FileChange>,
+        I::IntoIter: ExactSizeIterator,
+    {
+        let iter = changes.into_iter();
+        self.changes.reserve(iter.len());
+
+        for change in iter {
+            self.add(change);
+        }
+    }
+
+    fn iter(&self) -> impl Iterator<Item = FileChange> + '_ {
+        self.changes
+            .iter()
+            .map(|(id, kind)| FileChange::new(*id, *kind))
+    }
+}
+
+fn setup_tracing() {
+    let subscriber = Registry::default().with(
+        tracing_tree::HierarchicalLayer::default()
+            .with_indent_lines(true)
+            .with_indent_amount(2)
+            .with_bracketed_fields(true)
+            .with_thread_ids(true)
+            .with_targets(true)
+            .with_writer(|| Box::new(std::io::stderr()))
+            .with_timer(Uptime::default())
+            .with_filter(LoggingFilter {
+                trace_level: Level::TRACE,
+            }),
+    );
+
+    tracing::subscriber::set_global_default(subscriber).unwrap();
+}
+
+struct LoggingFilter {
+    trace_level: Level,
+}
+
+impl LoggingFilter {
+    fn is_enabled(&self, meta: &Metadata<'_>) -> bool {
+        let filter = if meta.target().starts_with("red_knot") || meta.target().starts_with("ruff") {
+            self.trace_level
+        } else {
+            Level::INFO
+        };
+
+        meta.level() <= &filter
+    }
+}
+
+impl<S> Filter<S> for LoggingFilter {
+    fn enabled(&self, meta: &Metadata<'_>, _cx: &Context<'_, S>) -> bool {
+        self.is_enabled(meta)
+    }
+
+    fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest {
+        if self.is_enabled(meta) {
+            Interest::always()
+        } else {
+            Interest::never()
+        }
+    }
+
+    fn max_level_hint(&self) -> Option<LevelFilter> {
+        Some(LevelFilter::from_level(self.trace_level))
+    }
+}

crates/red_knot/src/parse.rs

@@ -0,0 +1,95 @@
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use ruff_python_ast as ast;
+use ruff_python_parser::{Mode, ParseError};
+use ruff_text_size::{Ranged, TextRange};
+
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SourceDb, SourceJar};
+use crate::files::FileId;
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Parsed {
+    inner: Arc<ParsedInner>,
+}
+
+#[derive(Debug, PartialEq)]
+struct ParsedInner {
+    ast: ast::ModModule,
+    errors: Vec<ParseError>,
+}
+
+impl Parsed {
+    fn new(ast: ast::ModModule, errors: Vec<ParseError>) -> Self {
+        Self {
+            inner: Arc::new(ParsedInner { ast, errors }),
+        }
+    }
+
+    pub(crate) fn from_text(text: &str) -> Self {
+        let result = ruff_python_parser::parse(text, Mode::Module);
+
+        let (module, errors) = match result {
+            Ok(ast::Mod::Module(module)) => (module, vec![]),
+            Ok(ast::Mod::Expression(expression)) => (
+                ast::ModModule {
+                    range: expression.range(),
+                    body: vec![ast::Stmt::Expr(ast::StmtExpr {
+                        range: expression.range(),
+                        value: expression.body,
+                    })],
+                },
+                vec![],
+            ),
+            Err(errors) => (
+                ast::ModModule {
+                    range: TextRange::default(),
+                    body: Vec::new(),
+                },
+                vec![errors],
+            ),
+        };
+
+        Parsed::new(module, errors)
+    }
+
+    pub fn ast(&self) -> &ast::ModModule {
+        &self.inner.ast
+    }
+
+    pub fn errors(&self) -> &[ParseError] {
+        &self.inner.errors
+    }
+}
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn parse<Db>(db: &Db, file_id: FileId) -> Parsed
+where
+    Db: SourceDb + HasJar<SourceJar>,
+{
+    let parsed = db.jar();
+
+    parsed.parsed.get(&file_id, |file_id| {
+        let source = db.source(*file_id);
+
+        Parsed::from_text(source.text())
+    })
+}
+
+#[derive(Debug, Default)]
+pub struct ParsedStorage(KeyValueCache<FileId, Parsed>);
+
+impl Deref for ParsedStorage {
+    type Target = KeyValueCache<FileId, Parsed>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for ParsedStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}

crates/red_knot/src/program/check.rs

@@ -0,0 +1,315 @@
+use std::num::NonZeroUsize;
+
+use rayon::max_num_threads;
+use rustc_hash::FxHashSet;
+
+use crate::cancellation::CancellationToken;
+use crate::db::{SemanticDb, SourceDb};
+use crate::files::FileId;
+use crate::lint::Diagnostics;
+use crate::program::Program;
+use crate::symbols::Dependency;
+
+impl Program {
+    /// Checks all open files in the workspace and its dependencies.
+    #[tracing::instrument(level = "debug", skip_all)]
+    pub fn check(
+        &self,
+        scheduler: &dyn CheckScheduler,
+        cancellation_token: CancellationToken,
+    ) -> Result<Vec<String>, CheckError> {
+        let check_loop = CheckFilesLoop::new(scheduler, cancellation_token);
+
+        check_loop.run(self.workspace().open_files.iter().copied())
+    }
+
+    /// Checks a single file and its dependencies.
+    #[tracing::instrument(level = "debug", skip(self, scheduler, cancellation_token))]
+    pub fn check_file(
+        &self,
+        file: FileId,
+        scheduler: &dyn CheckScheduler,
+        cancellation_token: CancellationToken,
+    ) -> Result<Vec<String>, CheckError> {
+        let check_loop = CheckFilesLoop::new(scheduler, cancellation_token);
+
+        check_loop.run([file].into_iter())
+    }
+
+    #[tracing::instrument(level = "debug", skip(self, context))]
+    fn do_check_file(
+        &self,
+        file: FileId,
+        context: &CheckContext,
+    ) -> Result<Diagnostics, CheckError> {
+        context.cancelled_ok()?;
+
+        let symbol_table = self.symbol_table(file);
+        let dependencies = symbol_table.dependencies();
+
+        if !dependencies.is_empty() {
+            let module = self.file_to_module(file);
+
+            // TODO scheduling all dependencies here is wasteful if we don't infer any types on them
+            //  but I think that's unlikely, so it is okay?
+            //  Anyway, we need to figure out a way to retrieve the dependencies of a module
+            //  from the persistent cache. So maybe it should be a separate query after all.
+            for dependency in dependencies {
+                let dependency_name = match dependency {
+                    Dependency::Module(name) => Some(name.clone()),
+                    Dependency::Relative { .. } => module
+                        .as_ref()
+                        .and_then(|module| module.resolve_dependency(self, dependency)),
+                };
+
+                if let Some(dependency_name) = dependency_name {
+                    // TODO We may want to have a different check functions for non-first-party
+                    //   files because we only need to index them and not check them.
+                    //   Supporting non-first-party code also requires supporting typing stubs.
+                    if let Some(dependency) = self.resolve_module(dependency_name) {
+                        if dependency.path(self).root().kind().is_first_party() {
+                            context.schedule_check_file(dependency.path(self).file());
+                        }
+                    }
+                }
+            }
+        }
+
+        let mut diagnostics = Vec::new();
+
+        if self.workspace().is_file_open(file) {
+            diagnostics.extend_from_slice(&self.lint_syntax(file));
+            diagnostics.extend_from_slice(&self.lint_semantic(file));
+        }
+
+        Ok(Diagnostics::from(diagnostics))
+    }
+}
+
+/// Schedules checks for files.
+pub trait CheckScheduler {
+    /// Schedules a check for a file.
+    ///
+    /// The check can either be run immediately on the current thread or the check can be queued
+    /// in a thread pool and ran asynchronously.
+    ///
+    /// The order in which scheduled checks are executed is not guaranteed.
+    ///
+    /// The implementation should call [`CheckFileTask::run`] to execute the check.
+    fn check_file(&self, file_task: CheckFileTask);
+
+    /// The maximum number of checks that can be run concurrently.
+    ///
+    /// Returns `None` if the checks run on the current thread (no concurrency).
+    fn max_concurrency(&self) -> Option<NonZeroUsize>;
+}
+
+/// Scheduler that runs checks on a rayon thread pool.
+pub struct RayonCheckScheduler<'program, 'scope_ref, 'scope> {
+    program: &'program Program,
+    scope: &'scope_ref rayon::Scope<'scope>,
+}
+
+impl<'program, 'scope_ref, 'scope> RayonCheckScheduler<'program, 'scope_ref, 'scope> {
+    pub fn new(program: &'program Program, scope: &'scope_ref rayon::Scope<'scope>) -> Self {
+        Self { program, scope }
+    }
+}
+
+impl<'program, 'scope_ref, 'scope> CheckScheduler
+    for RayonCheckScheduler<'program, 'scope_ref, 'scope>
+where
+    'program: 'scope,
+{
+    fn check_file(&self, check_file_task: CheckFileTask) {
+        let child_span =
+            tracing::trace_span!("check_file", file_id = check_file_task.file_id.as_u32());
+        let program = self.program;
+
+        self.scope
+            .spawn(move |_| child_span.in_scope(|| check_file_task.run(program)));
+    }
+
+    fn max_concurrency(&self) -> Option<NonZeroUsize> {
+        Some(NonZeroUsize::new(max_num_threads()).unwrap_or(NonZeroUsize::MIN))
+    }
+}
+
+/// Scheduler that runs all checks on the current thread.
+pub struct SameThreadCheckScheduler<'a> {
+    program: &'a Program,
+}
+
+impl<'a> SameThreadCheckScheduler<'a> {
+    pub fn new(program: &'a Program) -> Self {
+        Self { program }
+    }
+}
+
+impl CheckScheduler for SameThreadCheckScheduler<'_> {
+    fn check_file(&self, task: CheckFileTask) {
+        task.run(self.program);
+    }
+
+    fn max_concurrency(&self) -> Option<NonZeroUsize> {
+        None
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum CheckError {
+    Cancelled,
+}
+
+#[derive(Debug)]
+pub struct CheckFileTask {
+    file_id: FileId,
+    context: CheckContext,
+}
+
+impl CheckFileTask {
+    /// Runs the check and communicates the result to the orchestrator.
+    pub fn run(self, program: &Program) {
+        match program.do_check_file(self.file_id, &self.context) {
+            Ok(diagnostics) => self
+                .context
+                .sender
+                .send(CheckFileMessage::Completed(diagnostics))
+                .unwrap(),
+            Err(CheckError::Cancelled) => self
+                .context
+                .sender
+                .send(CheckFileMessage::Cancelled)
+                .unwrap(),
+        }
+    }
+}
+
+#[derive(Clone, Debug)]
+struct CheckContext {
+    cancellation_token: CancellationToken,
+    sender: crossbeam_channel::Sender<CheckFileMessage>,
+}
+
+impl CheckContext {
+    fn new(
+        cancellation_token: CancellationToken,
+        sender: crossbeam_channel::Sender<CheckFileMessage>,
+    ) -> Self {
+        Self {
+            cancellation_token,
+            sender,
+        }
+    }
+
+    /// Queues a new file for checking using the [`CheckScheduler`].
+    #[allow(unused)]
+    fn schedule_check_file(&self, file_id: FileId) {
+        self.sender.send(CheckFileMessage::Queue(file_id)).unwrap();
+    }
+
+    /// Returns `true` if the check has been cancelled.
+    fn is_cancelled(&self) -> bool {
+        self.cancellation_token.is_cancelled()
+    }
+
+    fn cancelled_ok(&self) -> Result<(), CheckError> {
+        if self.is_cancelled() {
+            Err(CheckError::Cancelled)
+        } else {
+            Ok(())
+        }
+    }
+}
+
+struct CheckFilesLoop<'a> {
+    scheduler: &'a dyn CheckScheduler,
+    cancellation_token: CancellationToken,
+    pending: usize,
+    queued_files: FxHashSet<FileId>,
+}
+
+impl<'a> CheckFilesLoop<'a> {
+    fn new(scheduler: &'a dyn CheckScheduler, cancellation_token: CancellationToken) -> Self {
+        Self {
+            scheduler,
+            cancellation_token,
+
+            queued_files: FxHashSet::default(),
+            pending: 0,
+        }
+    }
+
+    fn run(mut self, files: impl Iterator<Item = FileId>) -> Result<Vec<String>, CheckError> {
+        let (sender, receiver) = if let Some(max_concurrency) = self.scheduler.max_concurrency() {
+            crossbeam_channel::bounded(max_concurrency.get())
+        } else {
+            // The checks run on the current thread. That means it is necessary to store all messages
+            // or we risk deadlocking when the main loop never gets a chance to read the messages.
+            crossbeam_channel::unbounded()
+        };
+
+        let context = CheckContext::new(self.cancellation_token.clone(), sender.clone());
+
+        for file in files {
+            self.queue_file(file, context.clone())?;
+        }
+
+        self.run_impl(receiver, &context)
+    }
+
+    fn run_impl(
+        mut self,
+        receiver: crossbeam_channel::Receiver<CheckFileMessage>,
+        context: &CheckContext,
+    ) -> Result<Vec<String>, CheckError> {
+        if self.cancellation_token.is_cancelled() {
+            return Err(CheckError::Cancelled);
+        }
+
+        let mut result = Vec::default();
+
+        for message in receiver {
+            match message {
+                CheckFileMessage::Completed(diagnostics) => {
+                    result.extend_from_slice(&diagnostics);
+
+                    self.pending -= 1;
+
+                    if self.pending == 0 {
+                        break;
+                    }
+                }
+                CheckFileMessage::Queue(id) => {
+                    self.queue_file(id, context.clone())?;
+                }
+                CheckFileMessage::Cancelled => {
+                    return Err(CheckError::Cancelled);
+                }
+            }
+        }
+
+        Ok(result)
+    }
+
+    fn queue_file(&mut self, file_id: FileId, context: CheckContext) -> Result<(), CheckError> {
+        if context.is_cancelled() {
+            return Err(CheckError::Cancelled);
+        }
+
+        if self.queued_files.insert(file_id) {
+            self.pending += 1;
+
+            self.scheduler
+                .check_file(CheckFileTask { file_id, context });
+        }
+
+        Ok(())
+    }
+}
+
+enum CheckFileMessage {
+    Completed(Diagnostics),
+    Queue(FileId),
+    Cancelled,
+}

crates/red_knot/src/program/mod.rs

@@ -0,0 +1,183 @@
+pub mod check;
+
+use std::path::Path;
+use std::sync::Arc;
+
+use crate::db::{Db, HasJar, SemanticDb, SemanticJar, SourceDb, SourceJar};
+use crate::files::{FileId, Files};
+use crate::lint::{
+    lint_semantic, lint_syntax, Diagnostics, LintSemanticStorage, LintSyntaxStorage,
+};
+use crate::module::{
+    add_module, file_to_module, path_to_module, resolve_module, set_module_search_paths, Module,
+    ModuleData, ModuleName, ModuleResolver, ModuleSearchPath,
+};
+use crate::parse::{parse, Parsed, ParsedStorage};
+use crate::source::{source_text, Source, SourceStorage};
+use crate::symbols::{symbol_table, SymbolId, SymbolTable, SymbolTablesStorage};
+use crate::types::{infer_symbol_type, Type, TypeStore};
+use crate::Workspace;
+
+#[derive(Debug)]
+pub struct Program {
+    files: Files,
+    source: SourceJar,
+    semantic: SemanticJar,
+    workspace: Workspace,
+}
+
+impl Program {
+    pub fn new(workspace: Workspace, module_search_paths: Vec<ModuleSearchPath>) -> Self {
+        Self {
+            source: SourceJar {
+                sources: SourceStorage::default(),
+                parsed: ParsedStorage::default(),
+                lint_syntax: LintSyntaxStorage::default(),
+            },
+            semantic: SemanticJar {
+                module_resolver: ModuleResolver::new(module_search_paths),
+                symbol_tables: SymbolTablesStorage::default(),
+                type_store: TypeStore::default(),
+                lint_semantic: LintSemanticStorage::default(),
+            },
+            files: Files::default(),
+            workspace,
+        }
+    }
+
+    pub fn apply_changes<I>(&mut self, changes: I)
+    where
+        I: IntoIterator<Item = FileChange>,
+    {
+        for change in changes {
+            self.semantic
+                .module_resolver
+                .remove_module(&self.file_path(change.id));
+            self.semantic.symbol_tables.remove(&change.id);
+            self.source.sources.remove(&change.id);
+            self.source.parsed.remove(&change.id);
+            self.source.lint_syntax.remove(&change.id);
+            // TODO: remove all dependent modules as well
+            self.semantic.type_store.remove_module(change.id);
+            self.semantic.lint_semantic.remove(&change.id);
+        }
+    }
+
+    pub fn files(&self) -> &Files {
+        &self.files
+    }
+
+    pub fn workspace(&self) -> &Workspace {
+        &self.workspace
+    }
+
+    pub fn workspace_mut(&mut self) -> &mut Workspace {
+        &mut self.workspace
+    }
+}
+
+impl SourceDb for Program {
+    fn file_id(&self, path: &Path) -> FileId {
+        self.files.intern(path)
+    }
+
+    fn file_path(&self, file_id: FileId) -> Arc<Path> {
+        self.files.path(file_id)
+    }
+
+    fn source(&self, file_id: FileId) -> Source {
+        source_text(self, file_id)
+    }
+
+    fn parse(&self, file_id: FileId) -> Parsed {
+        parse(self, file_id)
+    }
+
+    fn lint_syntax(&self, file_id: FileId) -> Diagnostics {
+        lint_syntax(self, file_id)
+    }
+}
+
+impl SemanticDb for Program {
+    fn resolve_module(&self, name: ModuleName) -> Option<Module> {
+        resolve_module(self, name)
+    }
+
+    fn file_to_module(&self, file_id: FileId) -> Option<Module> {
+        file_to_module(self, file_id)
+    }
+
+    fn path_to_module(&self, path: &Path) -> Option<Module> {
+        path_to_module(self, path)
+    }
+
+    fn symbol_table(&self, file_id: FileId) -> Arc<SymbolTable> {
+        symbol_table(self, file_id)
+    }
+
+    fn infer_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Type {
+        infer_symbol_type(self, file_id, symbol_id)
+    }
+
+    fn lint_semantic(&self, file_id: FileId) -> Diagnostics {
+        lint_semantic(self, file_id)
+    }
+
+    // Mutations
+    fn add_module(&mut self, path: &Path) -> Option<(Module, Vec<Arc<ModuleData>>)> {
+        add_module(self, path)
+    }
+
+    fn set_module_search_paths(&mut self, paths: Vec<ModuleSearchPath>) {
+        set_module_search_paths(self, paths);
+    }
+}
+
+impl Db for Program {}
+
+impl HasJar<SourceJar> for Program {
+    fn jar(&self) -> &SourceJar {
+        &self.source
+    }
+
+    fn jar_mut(&mut self) -> &mut SourceJar {
+        &mut self.source
+    }
+}
+
+impl HasJar<SemanticJar> for Program {
+    fn jar(&self) -> &SemanticJar {
+        &self.semantic
+    }
+
+    fn jar_mut(&mut self) -> &mut SemanticJar {
+        &mut self.semantic
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+pub struct FileChange {
+    id: FileId,
+    kind: FileChangeKind,
+}
+
+impl FileChange {
+    pub fn new(file_id: FileId, kind: FileChangeKind) -> Self {
+        Self { id: file_id, kind }
+    }
+
+    pub fn file_id(&self) -> FileId {
+        self.id
+    }
+
+    pub fn kind(&self) -> FileChangeKind {
+        self.kind
+    }
+}
+
+#[derive(Copy, Clone, Debug, Eq, PartialEq)]
+pub enum FileChangeKind {
+    Created,
+    Modified,
+    Deleted,
+}

crates/red_knot/src/source.rs

@@ -0,0 +1,96 @@
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SourceDb, SourceJar};
+use ruff_notebook::Notebook;
+use ruff_python_ast::PySourceType;
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use crate::files::FileId;
+
+#[tracing::instrument(level = "debug", skip(db))]
+pub(crate) fn source_text<Db>(db: &Db, file_id: FileId) -> Source
+where
+    Db: SourceDb + HasJar<SourceJar>,
+{
+    let sources = &db.jar().sources;
+
+    sources.get(&file_id, |file_id| {
+        let path = db.file_path(*file_id);
+
+        let source_text = std::fs::read_to_string(&path).unwrap_or_else(|err| {
+            tracing::error!("Failed to read file '{path:?}: {err}'. Falling back to empty text");
+            String::new()
+        });
+
+        let python_ty = PySourceType::from(&path);
+
+        let kind = match python_ty {
+            PySourceType::Python => {
+                SourceKind::Python(Arc::from(source_text))
+            }
+            PySourceType::Stub => SourceKind::Stub(Arc::from(source_text)),
+            PySourceType::Ipynb => {
+                let notebook = Notebook::from_source_code(&source_text).unwrap_or_else(|err| {
+                    // TODO should this be changed to never fail?
+                    // or should we instead add a diagnostic somewhere? But what would we return in this case?
+                    tracing::error!(
+                        "Failed to parse notebook '{path:?}: {err}'. Falling back to an empty notebook"
+                    );
+                    Notebook::from_source_code("").unwrap()
+                });
+
+                SourceKind::IpyNotebook(Arc::new(notebook))
+            }
+        };
+
+        Source { kind }
+    })
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum SourceKind {
+    Python(Arc<str>),
+    Stub(Arc<str>),
+    IpyNotebook(Arc<Notebook>),
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub struct Source {
+    kind: SourceKind,
+}
+
+impl Source {
+    pub fn python<T: Into<Arc<str>>>(source: T) -> Self {
+        Self {
+            kind: SourceKind::Python(source.into()),
+        }
+    }
+    pub fn kind(&self) -> &SourceKind {
+        &self.kind
+    }
+
+    pub fn text(&self) -> &str {
+        match &self.kind {
+            SourceKind::Python(text) => text,
+            SourceKind::Stub(text) => text,
+            SourceKind::IpyNotebook(notebook) => notebook.source_code(),
+        }
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct SourceStorage(pub(crate) KeyValueCache<FileId, Source>);
+
+impl Deref for SourceStorage {
+    type Target = KeyValueCache<FileId, Source>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for SourceStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}

crates/red_knot/src/symbols.rs

@@ -0,0 +1,939 @@
+#![allow(dead_code)]
+
+use std::hash::{Hash, Hasher};
+use std::iter::{Copied, DoubleEndedIterator, FusedIterator};
+use std::num::NonZeroU32;
+use std::ops::{Deref, DerefMut};
+use std::sync::Arc;
+
+use bitflags::bitflags;
+use hashbrown::hash_map::{Keys, RawEntryMut};
+use rustc_hash::{FxHashMap, FxHasher};
+
+use ruff_index::{newtype_index, IndexVec};
+use ruff_python_ast as ast;
+use ruff_python_ast::visitor::preorder::PreorderVisitor;
+
+use crate::ast_ids::TypedNodeKey;
+use crate::cache::KeyValueCache;
+use crate::db::{HasJar, SemanticDb, SemanticJar};
+use crate::files::FileId;
+use crate::module::ModuleName;
+use crate::Name;
+
+#[allow(unreachable_pub)]
+#[tracing::instrument(level = "debug", skip(db))]
+pub fn symbol_table<Db>(db: &Db, file_id: FileId) -> Arc<SymbolTable>
+where
+    Db: SemanticDb + HasJar<SemanticJar>,
+{
+    let jar = db.jar();
+
+    jar.symbol_tables.get(&file_id, |_| {
+        let parsed = db.parse(file_id);
+        Arc::from(SymbolTable::from_ast(parsed.ast()))
+    })
+}
+
+type Map<K, V> = hashbrown::HashMap<K, V, ()>;
+
+#[newtype_index]
+pub(crate) struct ScopeId;
+
+impl ScopeId {
+    pub(crate) fn scope(self, table: &SymbolTable) -> &Scope {
+        &table.scopes_by_id[self]
+    }
+}
+
+#[newtype_index]
+pub struct SymbolId;
+
+impl SymbolId {
+    pub(crate) fn symbol(self, table: &SymbolTable) -> &Symbol {
+        &table.symbols_by_id[self]
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+pub(crate) enum ScopeKind {
+    Module,
+    Annotation,
+    Class,
+    Function,
+}
+
+#[derive(Debug)]
+pub(crate) struct Scope {
+    name: Name,
+    kind: ScopeKind,
+    child_scopes: Vec<ScopeId>,
+    // symbol IDs, hashed by symbol name
+    symbols_by_name: Map<SymbolId, ()>,
+}
+
+impl Scope {
+    pub(crate) fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    pub(crate) fn kind(&self) -> ScopeKind {
+        self.kind
+    }
+}
+
+#[derive(Debug)]
+pub(crate) enum Kind {
+    FreeVar,
+    CellVar,
+    CellVarAssigned,
+    ExplicitGlobal,
+    ImplicitGlobal,
+}
+
+bitflags! {
+    #[derive(Copy,Clone,Debug)]
+    pub(crate) struct SymbolFlags: u8 {
+        const IS_USED         = 1 << 0;
+        const IS_DEFINED      = 1 << 1;
+        /// TODO: This flag is not yet set by anything
+        const MARKED_GLOBAL   = 1 << 2;
+        /// TODO: This flag is not yet set by anything
+        const MARKED_NONLOCAL = 1 << 3;
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct Symbol {
+    name: Name,
+    flags: SymbolFlags,
+    // kind: Kind,
+}
+
+impl Symbol {
+    pub(crate) fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    /// Is the symbol used in its containing scope?
+    pub(crate) fn is_used(&self) -> bool {
+        self.flags.contains(SymbolFlags::IS_USED)
+    }
+
+    /// Is the symbol defined in its containing scope?
+    pub(crate) fn is_defined(&self) -> bool {
+        self.flags.contains(SymbolFlags::IS_DEFINED)
+    }
+
+    // TODO: implement Symbol.kind 2-pass analysis to categorize as: free-var, cell-var,
+    // explicit-global, implicit-global and implement Symbol.kind by modifying the preorder
+    // traversal code
+}
+
+// TODO storing TypedNodeKey for definitions means we have to search to find them again in the AST;
+// this is at best O(log n). If looking up definitions is a bottleneck we should look for
+// alternatives here.
+#[derive(Clone, Debug)]
+pub(crate) enum Definition {
+    // For the import cases, we don't need reference to any arbitrary AST subtrees (annotations,
+    // RHS), and referencing just the import statement node is imprecise (a single import statement
+    // can assign many symbols, we'd have to re-search for the one we care about), so we just copy
+    // the small amount of information we need from the AST.
+    Import(ImportDefinition),
+    ImportFrom(ImportFromDefinition),
+    ClassDef(TypedNodeKey<ast::StmtClassDef>),
+    FunctionDef(TypedNodeKey<ast::StmtFunctionDef>),
+    Assignment(TypedNodeKey<ast::StmtAssign>),
+    AnnotatedAssignment(TypedNodeKey<ast::StmtAnnAssign>),
+    // TODO with statements, except handlers, function args...
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct ImportDefinition {
+    pub(crate) module: ModuleName,
+}
+
+#[derive(Clone, Debug)]
+pub(crate) struct ImportFromDefinition {
+    pub(crate) module: Option<ModuleName>,
+    pub(crate) name: Name,
+    pub(crate) level: u32,
+}
+
+impl ImportFromDefinition {
+    pub(crate) fn module(&self) -> Option<&ModuleName> {
+        self.module.as_ref()
+    }
+
+    pub(crate) fn name(&self) -> &Name {
+        &self.name
+    }
+
+    pub(crate) fn level(&self) -> u32 {
+        self.level
+    }
+}
+
+#[derive(Debug, Clone)]
+pub enum Dependency {
+    Module(ModuleName),
+    Relative {
+        level: NonZeroU32,
+        module: Option<ModuleName>,
+    },
+}
+
+/// Table of all symbols in all scopes for a module.
+#[derive(Debug)]
+pub struct SymbolTable {
+    scopes_by_id: IndexVec<ScopeId, Scope>,
+    symbols_by_id: IndexVec<SymbolId, Symbol>,
+    defs: FxHashMap<SymbolId, Vec<Definition>>,
+    dependencies: Vec<Dependency>,
+}
+
+impl SymbolTable {
+    pub(crate) fn from_ast(module: &ast::ModModule) -> Self {
+        let root_scope_id = SymbolTable::root_scope_id();
+        let mut builder = SymbolTableBuilder {
+            table: SymbolTable::new(),
+            scopes: vec![root_scope_id],
+            current_definition: None,
+        };
+        builder.visit_body(&module.body);
+        builder.table
+    }
+
+    pub(crate) fn new() -> Self {
+        let mut table = SymbolTable {
+            scopes_by_id: IndexVec::new(),
+            symbols_by_id: IndexVec::new(),
+            defs: FxHashMap::default(),
+            dependencies: Vec::new(),
+        };
+        table.scopes_by_id.push(Scope {
+            name: Name::new("<module>"),
+            kind: ScopeKind::Module,
+            child_scopes: Vec::new(),
+            symbols_by_name: Map::default(),
+        });
+        table
+    }
+
+    pub(crate) fn dependencies(&self) -> &[Dependency] {
+        &self.dependencies
+    }
+
+    pub(crate) const fn root_scope_id() -> ScopeId {
+        ScopeId::from_usize(0)
+    }
+
+    pub(crate) fn root_scope(&self) -> &Scope {
+        &self.scopes_by_id[SymbolTable::root_scope_id()]
+    }
+
+    pub(crate) fn symbol_ids_for_scope(&self, scope_id: ScopeId) -> Copied<Keys<SymbolId, ()>> {
+        self.scopes_by_id[scope_id].symbols_by_name.keys().copied()
+    }
+
+    pub(crate) fn symbols_for_scope(
+        &self,
+        scope_id: ScopeId,
+    ) -> SymbolIterator<Copied<Keys<SymbolId, ()>>> {
+        SymbolIterator {
+            table: self,
+            ids: self.symbol_ids_for_scope(scope_id),
+        }
+    }
+
+    pub(crate) fn root_symbol_ids(&self) -> Copied<Keys<SymbolId, ()>> {
+        self.symbol_ids_for_scope(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn root_symbols(&self) -> SymbolIterator<Copied<Keys<SymbolId, ()>>> {
+        self.symbols_for_scope(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn child_scope_ids_of(&self, scope_id: ScopeId) -> &[ScopeId] {
+        &self.scopes_by_id[scope_id].child_scopes
+    }
+
+    pub(crate) fn child_scopes_of(&self, scope_id: ScopeId) -> ScopeIterator<&[ScopeId]> {
+        ScopeIterator {
+            table: self,
+            ids: self.child_scope_ids_of(scope_id),
+        }
+    }
+
+    pub(crate) fn root_child_scope_ids(&self) -> &[ScopeId] {
+        self.child_scope_ids_of(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn root_child_scopes(&self) -> ScopeIterator<&[ScopeId]> {
+        self.child_scopes_of(SymbolTable::root_scope_id())
+    }
+
+    pub(crate) fn symbol_id_by_name(&self, scope_id: ScopeId, name: &str) -> Option<SymbolId> {
+        let scope = &self.scopes_by_id[scope_id];
+        let hash = SymbolTable::hash_name(name);
+        let name = Name::new(name);
+        scope
+            .symbols_by_name
+            .raw_entry()
+            .from_hash(hash, |symid| self.symbols_by_id[*symid].name == name)
+            .map(|(symbol_id, ())| *symbol_id)
+    }
+
+    pub(crate) fn symbol_by_name(&self, scope_id: ScopeId, name: &str) -> Option<&Symbol> {
+        Some(&self.symbols_by_id[self.symbol_id_by_name(scope_id, name)?])
+    }
+
+    pub(crate) fn root_symbol_id_by_name(&self, name: &str) -> Option<SymbolId> {
+        self.symbol_id_by_name(SymbolTable::root_scope_id(), name)
+    }
+
+    pub(crate) fn root_symbol_by_name(&self, name: &str) -> Option<&Symbol> {
+        self.symbol_by_name(SymbolTable::root_scope_id(), name)
+    }
+
+    pub(crate) fn definitions(&self, symbol_id: SymbolId) -> &[Definition] {
+        self.defs
+            .get(&symbol_id)
+            .map(std::vec::Vec::as_slice)
+            .unwrap_or_default()
+    }
+
+    pub(crate) fn all_definitions(&self) -> impl Iterator<Item = (SymbolId, &Definition)> + '_ {
+        self.defs
+            .iter()
+            .flat_map(|(sym_id, defs)| defs.iter().map(move |def| (*sym_id, def)))
+    }
+
+    fn add_or_update_symbol(
+        &mut self,
+        scope_id: ScopeId,
+        name: &str,
+        flags: SymbolFlags,
+    ) -> SymbolId {
+        let hash = SymbolTable::hash_name(name);
+        let scope = &mut self.scopes_by_id[scope_id];
+        let name = Name::new(name);
+
+        let entry = scope
+            .symbols_by_name
+            .raw_entry_mut()
+            .from_hash(hash, |existing| self.symbols_by_id[*existing].name == name);
+
+        match entry {
+            RawEntryMut::Occupied(entry) => {
+                if let Some(symbol) = self.symbols_by_id.get_mut(*entry.key()) {
+                    symbol.flags.insert(flags);
+                };
+                *entry.key()
+            }
+            RawEntryMut::Vacant(entry) => {
+                let id = self.symbols_by_id.push(Symbol { name, flags });
+                entry.insert_with_hasher(hash, id, (), |_| hash);
+                id
+            }
+        }
+    }
+
+    fn add_child_scope(
+        &mut self,
+        parent_scope_id: ScopeId,
+        name: &str,
+        kind: ScopeKind,
+    ) -> ScopeId {
+        let new_scope_id = self.scopes_by_id.push(Scope {
+            name: Name::new(name),
+            kind,
+            child_scopes: Vec::new(),
+            symbols_by_name: Map::default(),
+        });
+        let parent_scope = &mut self.scopes_by_id[parent_scope_id];
+        parent_scope.child_scopes.push(new_scope_id);
+        new_scope_id
+    }
+
+    fn hash_name(name: &str) -> u64 {
+        let mut hasher = FxHasher::default();
+        name.hash(&mut hasher);
+        hasher.finish()
+    }
+}
+
+pub(crate) struct SymbolIterator<'a, I> {
+    table: &'a SymbolTable,
+    ids: I,
+}
+
+impl<'a, I> Iterator for SymbolIterator<'a, I>
+where
+    I: Iterator<Item = SymbolId>,
+{
+    type Item = &'a Symbol;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next()?;
+        Some(&self.table.symbols_by_id[id])
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.ids.size_hint()
+    }
+}
+
+impl<'a, I> FusedIterator for SymbolIterator<'a, I> where
+    I: Iterator<Item = SymbolId> + FusedIterator
+{
+}
+
+impl<'a, I> DoubleEndedIterator for SymbolIterator<'a, I>
+where
+    I: Iterator<Item = SymbolId> + DoubleEndedIterator,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next_back()?;
+        Some(&self.table.symbols_by_id[id])
+    }
+}
+
+pub(crate) struct ScopeIterator<'a, I> {
+    table: &'a SymbolTable,
+    ids: I,
+}
+
+impl<'a, I> Iterator for ScopeIterator<'a, I>
+where
+    I: Iterator<Item = ScopeId>,
+{
+    type Item = &'a Scope;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next()?;
+        Some(&self.table.scopes_by_id[id])
+    }
+
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.ids.size_hint()
+    }
+}
+
+impl<'a, I> FusedIterator for ScopeIterator<'a, I> where I: Iterator<Item = ScopeId> + FusedIterator {}
+
+impl<'a, I> DoubleEndedIterator for ScopeIterator<'a, I>
+where
+    I: Iterator<Item = ScopeId> + DoubleEndedIterator,
+{
+    fn next_back(&mut self) -> Option<Self::Item> {
+        let id = self.ids.next_back()?;
+        Some(&self.table.scopes_by_id[id])
+    }
+}
+
+struct SymbolTableBuilder {
+    table: SymbolTable,
+    scopes: Vec<ScopeId>,
+    /// the definition whose target(s) we are currently walking
+    current_definition: Option<Definition>,
+}
+
+impl SymbolTableBuilder {
+    fn add_or_update_symbol(&mut self, identifier: &str, flags: SymbolFlags) -> SymbolId {
+        self.table
+            .add_or_update_symbol(self.cur_scope(), identifier, flags)
+    }
+
+    fn add_or_update_symbol_with_def(
+        &mut self,
+        identifier: &str,
+        definition: Definition,
+    ) -> SymbolId {
+        let symbol_id = self.add_or_update_symbol(identifier, SymbolFlags::IS_DEFINED);
+        self.table
+            .defs
+            .entry(symbol_id)
+            .or_default()
+            .push(definition);
+        symbol_id
+    }
+
+    fn push_scope(&mut self, child_of: ScopeId, name: &str, kind: ScopeKind) -> ScopeId {
+        let scope_id = self.table.add_child_scope(child_of, name, kind);
+        self.scopes.push(scope_id);
+        scope_id
+    }
+
+    fn pop_scope(&mut self) -> ScopeId {
+        self.scopes
+            .pop()
+            .expect("Scope stack should never be empty")
+    }
+
+    fn cur_scope(&self) -> ScopeId {
+        *self
+            .scopes
+            .last()
+            .expect("Scope stack should never be empty")
+    }
+
+    fn with_type_params(
+        &mut self,
+        name: &str,
+        params: &Option<Box<ast::TypeParams>>,
+        nested: impl FnOnce(&mut Self),
+    ) {
+        if let Some(type_params) = params {
+            self.push_scope(self.cur_scope(), name, ScopeKind::Annotation);
+            for type_param in &type_params.type_params {
+                let name = match type_param {
+                    ast::TypeParam::TypeVar(ast::TypeParamTypeVar { name, .. }) => name,
+                    ast::TypeParam::ParamSpec(ast::TypeParamParamSpec { name, .. }) => name,
+                    ast::TypeParam::TypeVarTuple(ast::TypeParamTypeVarTuple { name, .. }) => name,
+                };
+                self.add_or_update_symbol(name, SymbolFlags::IS_DEFINED);
+            }
+        }
+        nested(self);
+        if params.is_some() {
+            self.pop_scope();
+        }
+    }
+}
+
+impl PreorderVisitor<'_> for SymbolTableBuilder {
+    fn visit_expr(&mut self, expr: &ast::Expr) {
+        if let ast::Expr::Name(ast::ExprName { id, ctx, .. }) = expr {
+            let flags = match ctx {
+                ast::ExprContext::Load => SymbolFlags::IS_USED,
+                ast::ExprContext::Store => SymbolFlags::IS_DEFINED,
+                ast::ExprContext::Del => SymbolFlags::IS_DEFINED,
+                ast::ExprContext::Invalid => SymbolFlags::empty(),
+            };
+            self.add_or_update_symbol(id, flags);
+            if flags.contains(SymbolFlags::IS_DEFINED) {
+                if let Some(curdef) = self.current_definition.clone() {
+                    self.add_or_update_symbol_with_def(id, curdef);
+                }
+            }
+        }
+        ast::visitor::preorder::walk_expr(self, expr);
+    }
+
+    fn visit_stmt(&mut self, stmt: &ast::Stmt) {
+        // TODO need to capture more definition statements here
+        match stmt {
+            ast::Stmt::ClassDef(node) => {
+                let def = Definition::ClassDef(TypedNodeKey::from_node(node));
+                self.add_or_update_symbol_with_def(&node.name, def);
+                self.with_type_params(&node.name, &node.type_params, |builder| {
+                    builder.push_scope(builder.cur_scope(), &node.name, ScopeKind::Class);
+                    ast::visitor::preorder::walk_stmt(builder, stmt);
+                    builder.pop_scope();
+                });
+            }
+            ast::Stmt::FunctionDef(node) => {
+                let def = Definition::FunctionDef(TypedNodeKey::from_node(node));
+                self.add_or_update_symbol_with_def(&node.name, def);
+                self.with_type_params(&node.name, &node.type_params, |builder| {
+                    builder.push_scope(builder.cur_scope(), &node.name, ScopeKind::Function);
+                    ast::visitor::preorder::walk_stmt(builder, stmt);
+                    builder.pop_scope();
+                });
+            }
+            ast::Stmt::Import(ast::StmtImport { names, .. }) => {
+                for alias in names {
+                    let symbol_name = if let Some(asname) = &alias.asname {
+                        asname.id.as_str()
+                    } else {
+                        alias.name.id.split('.').next().unwrap()
+                    };
+
+                    let module = ModuleName::new(&alias.name.id);
+
+                    let def = Definition::Import(ImportDefinition {
+                        module: module.clone(),
+                    });
+                    self.add_or_update_symbol_with_def(symbol_name, def);
+                    self.table.dependencies.push(Dependency::Module(module));
+                }
+            }
+            ast::Stmt::ImportFrom(ast::StmtImportFrom {
+                module,
+                names,
+                level,
+                ..
+            }) => {
+                let module = module.as_ref().map(|m| ModuleName::new(&m.id));
+
+                for alias in names {
+                    let symbol_name = if let Some(asname) = &alias.asname {
+                        asname.id.as_str()
+                    } else {
+                        alias.name.id.as_str()
+                    };
+                    let def = Definition::ImportFrom(ImportFromDefinition {
+                        module: module.clone(),
+                        name: Name::new(&alias.name.id),
+                        level: *level,
+                    });
+                    self.add_or_update_symbol_with_def(symbol_name, def);
+                }
+
+                let dependency = if let Some(module) = module {
+                    match NonZeroU32::new(*level) {
+                        Some(level) => Dependency::Relative {
+                            level,
+                            module: Some(module),
+                        },
+                        None => Dependency::Module(module),
+                    }
+                } else {
+                    Dependency::Relative {
+                        level: NonZeroU32::new(*level)
+                            .expect("Import without a module to have a level > 0"),
+                        module,
+                    }
+                };
+
+                self.table.dependencies.push(dependency);
+            }
+            ast::Stmt::Assign(node) => {
+                debug_assert!(self.current_definition.is_none());
+                self.current_definition =
+                    Some(Definition::Assignment(TypedNodeKey::from_node(node)));
+                ast::visitor::preorder::walk_stmt(self, stmt);
+                self.current_definition = None;
+            }
+            _ => {
+                ast::visitor::preorder::walk_stmt(self, stmt);
+            }
+        }
+    }
+}
+
+#[derive(Debug, Default)]
+pub struct SymbolTablesStorage(KeyValueCache<FileId, Arc<SymbolTable>>);
+
+impl Deref for SymbolTablesStorage {
+    type Target = KeyValueCache<FileId, Arc<SymbolTable>>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+impl DerefMut for SymbolTablesStorage {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.0
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use textwrap::dedent;
+
+    use crate::parse::Parsed;
+    use crate::symbols::ScopeKind;
+
+    use super::{SymbolFlags, SymbolId, SymbolIterator, SymbolTable};
+
+    mod from_ast {
+        use super::*;
+
+        fn parse(code: &str) -> Parsed {
+            Parsed::from_text(&dedent(code))
+        }
+
+        fn names<I>(it: SymbolIterator<I>) -> Vec<&str>
+        where
+            I: Iterator<Item = SymbolId>,
+        {
+            let mut symbols: Vec<_> = it.map(|sym| sym.name.as_str()).collect();
+            symbols.sort_unstable();
+            symbols
+        }
+
+        #[test]
+        fn empty() {
+            let parsed = parse("");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()).len(), 0);
+        }
+
+        #[test]
+        fn simple() {
+            let parsed = parse("x");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["x"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("x").unwrap())
+                    .len(),
+                0
+            );
+        }
+
+        #[test]
+        fn annotation_only() {
+            let parsed = parse("x: int");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["int", "x"]);
+            // TODO record definition
+        }
+
+        #[test]
+        fn import() {
+            let parsed = parse("import foo");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("foo").unwrap())
+                    .len(),
+                1
+            );
+        }
+
+        #[test]
+        fn import_sub() {
+            let parsed = parse("import foo.bar");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo"]);
+        }
+
+        #[test]
+        fn import_as() {
+            let parsed = parse("import foo.bar as baz");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["baz"]);
+        }
+
+        #[test]
+        fn import_from() {
+            let parsed = parse("from bar import foo");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("foo").unwrap())
+                    .len(),
+                1
+            );
+            assert!(
+                table.root_symbol_id_by_name("foo").is_some_and(|sid| {
+                    let s = sid.symbol(&table);
+                    s.is_defined() || !s.is_used()
+                }),
+                "symbols that are defined get the defined flag"
+            );
+        }
+
+        #[test]
+        fn assign() {
+            let parsed = parse("x = foo");
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["foo", "x"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("x").unwrap())
+                    .len(),
+                1
+            );
+            assert!(
+                table.root_symbol_id_by_name("foo").is_some_and(|sid| {
+                    let s = sid.symbol(&table);
+                    !s.is_defined() && s.is_used()
+                }),
+                "a symbol used but not defined in a scope should have only the used flag"
+            );
+        }
+
+        #[test]
+        fn class_scope() {
+            let parsed = parse(
+                "
+                class C:
+                    x = 1
+                y = 2
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["C", "y"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let c_scope = scopes[0].scope(&table);
+            assert_eq!(c_scope.kind(), ScopeKind::Class);
+            assert_eq!(c_scope.name(), "C");
+            assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("C").unwrap())
+                    .len(),
+                1
+            );
+        }
+
+        #[test]
+        fn func_scope() {
+            let parsed = parse(
+                "
+                def func():
+                    x = 1
+                y = 2
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["func", "y"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let func_scope = scopes[0].scope(&table);
+            assert_eq!(func_scope.kind(), ScopeKind::Function);
+            assert_eq!(func_scope.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("func").unwrap())
+                    .len(),
+                1
+            );
+        }
+
+        #[test]
+        fn dupes() {
+            let parsed = parse(
+                "
+                def func():
+                    x = 1
+                def func():
+                    y = 2
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["func"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 2);
+            let func_scope_1 = scopes[0].scope(&table);
+            let func_scope_2 = scopes[1].scope(&table);
+            assert_eq!(func_scope_1.kind(), ScopeKind::Function);
+            assert_eq!(func_scope_1.name(), "func");
+            assert_eq!(func_scope_2.kind(), ScopeKind::Function);
+            assert_eq!(func_scope_2.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(scopes[0])), vec!["x"]);
+            assert_eq!(names(table.symbols_for_scope(scopes[1])), vec!["y"]);
+            assert_eq!(
+                table
+                    .definitions(table.root_symbol_id_by_name("func").unwrap())
+                    .len(),
+                2
+            );
+        }
+
+        #[test]
+        fn generic_func() {
+            let parsed = parse(
+                "
+                def func[T]():
+                    x = 1
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["func"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let ann_scope_id = scopes[0];
+            let ann_scope = ann_scope_id.scope(&table);
+            assert_eq!(ann_scope.kind(), ScopeKind::Annotation);
+            assert_eq!(ann_scope.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(ann_scope_id)), vec!["T"]);
+            let scopes = table.child_scope_ids_of(ann_scope_id);
+            assert_eq!(scopes.len(), 1);
+            let func_scope_id = scopes[0];
+            let func_scope = func_scope_id.scope(&table);
+            assert_eq!(func_scope.kind(), ScopeKind::Function);
+            assert_eq!(func_scope.name(), "func");
+            assert_eq!(names(table.symbols_for_scope(func_scope_id)), vec!["x"]);
+        }
+
+        #[test]
+        fn generic_class() {
+            let parsed = parse(
+                "
+                class C[T]:
+                    x = 1
+                ",
+            );
+            let table = SymbolTable::from_ast(parsed.ast());
+            assert_eq!(names(table.root_symbols()), vec!["C"]);
+            let scopes = table.root_child_scope_ids();
+            assert_eq!(scopes.len(), 1);
+            let ann_scope_id = scopes[0];
+            let ann_scope = ann_scope_id.scope(&table);
+            assert_eq!(ann_scope.kind(), ScopeKind::Annotation);
+            assert_eq!(ann_scope.name(), "C");
+            assert_eq!(names(table.symbols_for_scope(ann_scope_id)), vec!["T"]);
+            assert!(
+                table
+                    .symbol_by_name(ann_scope_id, "T")
+                    .is_some_and(|s| s.is_defined() && !s.is_used()),
+                "type parameters are defined by the scope that introduces them"
+            );
+            let scopes = table.child_scope_ids_of(ann_scope_id);
+            assert_eq!(scopes.len(), 1);
+            let func_scope_id = scopes[0];
+            let func_scope = func_scope_id.scope(&table);
+            assert_eq!(func_scope.kind(), ScopeKind::Class);
+            assert_eq!(func_scope.name(), "C");
+            assert_eq!(names(table.symbols_for_scope(func_scope_id)), vec!["x"]);
+        }
+    }
+
+    #[test]
+    fn insert_same_name_symbol_twice() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let symbol_id_1 = table.add_or_update_symbol(root_scope_id, "foo", SymbolFlags::IS_DEFINED);
+        let symbol_id_2 = table.add_or_update_symbol(root_scope_id, "foo", SymbolFlags::IS_USED);
+        assert_eq!(symbol_id_1, symbol_id_2);
+        assert!(symbol_id_1.symbol(&table).is_used(), "flags must merge");
+        assert!(symbol_id_1.symbol(&table).is_defined(), "flags must merge");
+    }
+
+    #[test]
+    fn insert_different_named_symbols() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let symbol_id_1 = table.add_or_update_symbol(root_scope_id, "foo", SymbolFlags::empty());
+        let symbol_id_2 = table.add_or_update_symbol(root_scope_id, "bar", SymbolFlags::empty());
+        assert_ne!(symbol_id_1, symbol_id_2);
+    }
+
+    #[test]
+    fn add_child_scope_with_symbol() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let foo_symbol_top = table.add_or_update_symbol(root_scope_id, "foo", SymbolFlags::empty());
+        let c_scope = table.add_child_scope(root_scope_id, "C", ScopeKind::Class);
+        let foo_symbol_inner = table.add_or_update_symbol(c_scope, "foo", SymbolFlags::empty());
+        assert_ne!(foo_symbol_top, foo_symbol_inner);
+    }
+
+    #[test]
+    fn scope_from_id() {
+        let table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let scope = root_scope_id.scope(&table);
+        assert_eq!(scope.name.as_str(), "<module>");
+        assert_eq!(scope.kind, ScopeKind::Module);
+    }
+
+    #[test]
+    fn symbol_from_id() {
+        let mut table = SymbolTable::new();
+        let root_scope_id = SymbolTable::root_scope_id();
+        let foo_symbol_id = table.add_or_update_symbol(root_scope_id, "foo", SymbolFlags::empty());
+        let symbol = foo_symbol_id.symbol(&table);
+        assert_eq!(symbol.name.as_str(), "foo");
+    }
+}

crates/red_knot/src/types.rs

@@ -0,0 +1,560 @@
+#![allow(dead_code)]
+use crate::ast_ids::NodeKey;
+use crate::files::FileId;
+use crate::symbols::SymbolId;
+use crate::{FxDashMap, FxIndexSet, Name};
+use ruff_index::{newtype_index, IndexVec};
+use rustc_hash::FxHashMap;
+
+pub(crate) mod infer;
+
+pub(crate) use infer::infer_symbol_type;
+
+/// unique ID for a type
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
+pub enum Type {
+    /// the dynamic or gradual type: a statically-unknown set of values
+    Any,
+    /// the empty set of values
+    Never,
+    /// unknown type (no annotation)
+    /// equivalent to Any, or to object in strict mode
+    Unknown,
+    /// name is not bound to any value
+    Unbound,
+    /// a specific function object
+    Function(FunctionTypeId),
+    /// a specific class object
+    Class(ClassTypeId),
+    /// the set of Python objects with the given class in their __class__'s method resolution order
+    Instance(ClassTypeId),
+    Union(UnionTypeId),
+    Intersection(IntersectionTypeId),
+    // TODO protocols, callable types, overloads, generics, type vars
+}
+
+impl Type {
+    fn display<'a>(&'a self, store: &'a TypeStore) -> DisplayType<'a> {
+        DisplayType { ty: self, store }
+    }
+
+    pub const fn is_unbound(&self) -> bool {
+        matches!(self, Type::Unbound)
+    }
+
+    pub const fn is_unknown(&self) -> bool {
+        matches!(self, Type::Unknown)
+    }
+}
+
+impl From<FunctionTypeId> for Type {
+    fn from(id: FunctionTypeId) -> Self {
+        Type::Function(id)
+    }
+}
+
+impl From<UnionTypeId> for Type {
+    fn from(id: UnionTypeId) -> Self {
+        Type::Union(id)
+    }
+}
+
+impl From<IntersectionTypeId> for Type {
+    fn from(id: IntersectionTypeId) -> Self {
+        Type::Intersection(id)
+    }
+}
+
+// TODO: currently calling `get_function` et al and holding on to the `FunctionTypeRef` will lock a
+// shard of this dashmap, for as long as you hold the reference. This may be a problem. We could
+// switch to having all the arenas hold Arc, or we could see if we can split up ModuleTypeStore,
+// and/or give it inner mutability and finer-grained internal locking.
+#[derive(Debug, Default)]
+pub struct TypeStore {
+    modules: FxDashMap<FileId, ModuleTypeStore>,
+}
+
+impl TypeStore {
+    pub fn remove_module(&mut self, file_id: FileId) {
+        self.modules.remove(&file_id);
+    }
+
+    pub fn cache_symbol_type(&self, file_id: FileId, symbol_id: SymbolId, ty: Type) {
+        self.add_or_get_module(file_id)
+            .symbol_types
+            .insert(symbol_id, ty);
+    }
+
+    pub fn cache_node_type(&self, file_id: FileId, node_key: NodeKey, ty: Type) {
+        self.add_or_get_module(file_id)
+            .node_types
+            .insert(node_key, ty);
+    }
+
+    pub fn get_cached_symbol_type(&self, file_id: FileId, symbol_id: SymbolId) -> Option<Type> {
+        self.try_get_module(file_id)?
+            .symbol_types
+            .get(&symbol_id)
+            .copied()
+    }
+
+    pub fn get_cached_node_type(&self, file_id: FileId, node_key: &NodeKey) -> Option<Type> {
+        self.try_get_module(file_id)?
+            .node_types
+            .get(node_key)
+            .copied()
+    }
+
+    fn add_or_get_module(&self, file_id: FileId) -> ModuleStoreRefMut {
+        self.modules
+            .entry(file_id)
+            .or_insert_with(|| ModuleTypeStore::new(file_id))
+    }
+
+    fn get_module(&self, file_id: FileId) -> ModuleStoreRef {
+        self.try_get_module(file_id).expect("module should exist")
+    }
+
+    fn try_get_module(&self, file_id: FileId) -> Option<ModuleStoreRef> {
+        self.modules.get(&file_id)
+    }
+
+    fn add_function(&self, file_id: FileId, name: &str) -> FunctionTypeId {
+        self.add_or_get_module(file_id).add_function(name)
+    }
+
+    fn add_class(&self, file_id: FileId, name: &str, bases: Vec<Type>) -> ClassTypeId {
+        self.add_or_get_module(file_id).add_class(name, bases)
+    }
+
+    fn add_union(&mut self, file_id: FileId, elems: &[Type]) -> UnionTypeId {
+        self.add_or_get_module(file_id).add_union(elems)
+    }
+
+    fn add_intersection(
+        &mut self,
+        file_id: FileId,
+        positive: &[Type],
+        negative: &[Type],
+    ) -> IntersectionTypeId {
+        self.add_or_get_module(file_id)
+            .add_intersection(positive, negative)
+    }
+
+    fn get_function(&self, id: FunctionTypeId) -> FunctionTypeRef {
+        FunctionTypeRef {
+            module_store: self.get_module(id.file_id),
+            function_id: id.func_id,
+        }
+    }
+
+    fn get_class(&self, id: ClassTypeId) -> ClassTypeRef {
+        ClassTypeRef {
+            module_store: self.get_module(id.file_id),
+            class_id: id.class_id,
+        }
+    }
+
+    fn get_union(&self, id: UnionTypeId) -> UnionTypeRef {
+        UnionTypeRef {
+            module_store: self.get_module(id.file_id),
+            union_id: id.union_id,
+        }
+    }
+
+    fn get_intersection(&self, id: IntersectionTypeId) -> IntersectionTypeRef {
+        IntersectionTypeRef {
+            module_store: self.get_module(id.file_id),
+            intersection_id: id.intersection_id,
+        }
+    }
+}
+
+type ModuleStoreRef<'a> = dashmap::mapref::one::Ref<
+    'a,
+    FileId,
+    ModuleTypeStore,
+    std::hash::BuildHasherDefault<rustc_hash::FxHasher>,
+>;
+
+type ModuleStoreRefMut<'a> = dashmap::mapref::one::RefMut<
+    'a,
+    FileId,
+    ModuleTypeStore,
+    std::hash::BuildHasherDefault<rustc_hash::FxHasher>,
+>;
+
+#[derive(Debug)]
+pub(crate) struct FunctionTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    function_id: ModuleFunctionTypeId,
+}
+
+impl<'a> std::ops::Deref for FunctionTypeRef<'a> {
+    type Target = FunctionType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_function(self.function_id)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct ClassTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    class_id: ModuleClassTypeId,
+}
+
+impl<'a> std::ops::Deref for ClassTypeRef<'a> {
+    type Target = ClassType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_class(self.class_id)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct UnionTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    union_id: ModuleUnionTypeId,
+}
+
+impl<'a> std::ops::Deref for UnionTypeRef<'a> {
+    type Target = UnionType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_union(self.union_id)
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct IntersectionTypeRef<'a> {
+    module_store: ModuleStoreRef<'a>,
+    intersection_id: ModuleIntersectionTypeId,
+}
+
+impl<'a> std::ops::Deref for IntersectionTypeRef<'a> {
+    type Target = IntersectionType;
+
+    fn deref(&self) -> &Self::Target {
+        self.module_store.get_intersection(self.intersection_id)
+    }
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct FunctionTypeId {
+    file_id: FileId,
+    func_id: ModuleFunctionTypeId,
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct ClassTypeId {
+    file_id: FileId,
+    class_id: ModuleClassTypeId,
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct UnionTypeId {
+    file_id: FileId,
+    union_id: ModuleUnionTypeId,
+}
+
+#[derive(Copy, Clone, Debug, Hash, Eq, PartialEq)]
+pub struct IntersectionTypeId {
+    file_id: FileId,
+    intersection_id: ModuleIntersectionTypeId,
+}
+
+#[newtype_index]
+struct ModuleFunctionTypeId;
+
+#[newtype_index]
+struct ModuleClassTypeId;
+
+#[newtype_index]
+struct ModuleUnionTypeId;
+
+#[newtype_index]
+struct ModuleIntersectionTypeId;
+
+#[derive(Debug)]
+struct ModuleTypeStore {
+    file_id: FileId,
+    /// arena of all function types defined in this module
+    functions: IndexVec<ModuleFunctionTypeId, FunctionType>,
+    /// arena of all class types defined in this module
+    classes: IndexVec<ModuleClassTypeId, ClassType>,
+    /// arenda of all union types created in this module
+    unions: IndexVec<ModuleUnionTypeId, UnionType>,
+    /// arena of all intersection types created in this module
+    intersections: IndexVec<ModuleIntersectionTypeId, IntersectionType>,
+    /// cached types of symbols in this module
+    symbol_types: FxHashMap<SymbolId, Type>,
+    /// cached types of AST nodes in this module
+    node_types: FxHashMap<NodeKey, Type>,
+}
+
+impl ModuleTypeStore {
+    fn new(file_id: FileId) -> Self {
+        Self {
+            file_id,
+            functions: IndexVec::default(),
+            classes: IndexVec::default(),
+            unions: IndexVec::default(),
+            intersections: IndexVec::default(),
+            symbol_types: FxHashMap::default(),
+            node_types: FxHashMap::default(),
+        }
+    }
+
+    fn add_function(&mut self, name: &str) -> FunctionTypeId {
+        let func_id = self.functions.push(FunctionType {
+            name: Name::new(name),
+        });
+        FunctionTypeId {
+            file_id: self.file_id,
+            func_id,
+        }
+    }
+
+    fn add_class(&mut self, name: &str, bases: Vec<Type>) -> ClassTypeId {
+        let class_id = self.classes.push(ClassType {
+            name: Name::new(name),
+            // TODO: if no bases are given, that should imply [object]
+            bases,
+        });
+        ClassTypeId {
+            file_id: self.file_id,
+            class_id,
+        }
+    }
+
+    fn add_union(&mut self, elems: &[Type]) -> UnionTypeId {
+        let union_id = self.unions.push(UnionType {
+            elements: elems.iter().copied().collect(),
+        });
+        UnionTypeId {
+            file_id: self.file_id,
+            union_id,
+        }
+    }
+
+    fn add_intersection(&mut self, positive: &[Type], negative: &[Type]) -> IntersectionTypeId {
+        let intersection_id = self.intersections.push(IntersectionType {
+            positive: positive.iter().copied().collect(),
+            negative: negative.iter().copied().collect(),
+        });
+        IntersectionTypeId {
+            file_id: self.file_id,
+            intersection_id,
+        }
+    }
+
+    fn get_function(&self, func_id: ModuleFunctionTypeId) -> &FunctionType {
+        &self.functions[func_id]
+    }
+
+    fn get_class(&self, class_id: ModuleClassTypeId) -> &ClassType {
+        &self.classes[class_id]
+    }
+
+    fn get_union(&self, union_id: ModuleUnionTypeId) -> &UnionType {
+        &self.unions[union_id]
+    }
+
+    fn get_intersection(&self, intersection_id: ModuleIntersectionTypeId) -> &IntersectionType {
+        &self.intersections[intersection_id]
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+struct DisplayType<'a> {
+    ty: &'a Type,
+    store: &'a TypeStore,
+}
+
+impl std::fmt::Display for DisplayType<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self.ty {
+            Type::Any => f.write_str("Any"),
+            Type::Never => f.write_str("Never"),
+            Type::Unknown => f.write_str("Unknown"),
+            Type::Unbound => f.write_str("Unbound"),
+            // TODO functions and classes should display using a fully qualified name
+            Type::Class(class_id) => {
+                f.write_str("Literal[")?;
+                f.write_str(self.store.get_class(*class_id).name())?;
+                f.write_str("]")
+            }
+            Type::Instance(class_id) => f.write_str(self.store.get_class(*class_id).name()),
+            Type::Function(func_id) => f.write_str(self.store.get_function(*func_id).name()),
+            Type::Union(union_id) => self
+                .store
+                .get_module(union_id.file_id)
+                .get_union(union_id.union_id)
+                .display(f, self.store),
+            Type::Intersection(int_id) => self
+                .store
+                .get_module(int_id.file_id)
+                .get_intersection(int_id.intersection_id)
+                .display(f, self.store),
+        }
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct ClassType {
+    name: Name,
+    bases: Vec<Type>,
+}
+
+impl ClassType {
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+
+    fn bases(&self) -> &[Type] {
+        self.bases.as_slice()
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct FunctionType {
+    name: Name,
+}
+
+impl FunctionType {
+    fn name(&self) -> &str {
+        self.name.as_str()
+    }
+}
+
+#[derive(Debug)]
+pub(crate) struct UnionType {
+    // the union type includes values in any of these types
+    elements: FxIndexSet<Type>,
+}
+
+impl UnionType {
+    fn display(&self, f: &mut std::fmt::Formatter<'_>, store: &TypeStore) -> std::fmt::Result {
+        f.write_str("(")?;
+        let mut first = true;
+        for ty in &self.elements {
+            if !first {
+                f.write_str(" | ")?;
+            };
+            first = false;
+            write!(f, "{}", ty.display(store))?;
+        }
+        f.write_str(")")
+    }
+}
+
+// Negation types aren't expressible in annotations, and are most likely to arise from type
+// narrowing along with intersections (e.g. `if not isinstance(...)`), so we represent them
+// directly in intersections rather than as a separate type. This sacrifices some efficiency in the
+// case where a Not appears outside an intersection (unclear when that could even happen, but we'd
+// have to represent it as a single-element intersection if it did) in exchange for better
+// efficiency in the not-within-intersection case.
+#[derive(Debug)]
+pub(crate) struct IntersectionType {
+    // the intersection type includes only values in all of these types
+    positive: FxIndexSet<Type>,
+    // negated elements of the intersection, e.g.
+    negative: FxIndexSet<Type>,
+}
+
+impl IntersectionType {
+    fn display(&self, f: &mut std::fmt::Formatter<'_>, store: &TypeStore) -> std::fmt::Result {
+        f.write_str("(")?;
+        let mut first = true;
+        for (neg, ty) in self
+            .positive
+            .iter()
+            .map(|ty| (false, ty))
+            .chain(self.negative.iter().map(|ty| (true, ty)))
+        {
+            if !first {
+                f.write_str(" & ")?;
+            };
+            first = false;
+            if neg {
+                f.write_str("~")?;
+            };
+            write!(f, "{}", ty.display(store))?;
+        }
+        f.write_str(")")
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::files::Files;
+    use crate::types::{Type, TypeStore};
+    use crate::FxIndexSet;
+    use std::path::Path;
+
+    #[test]
+    fn add_class() {
+        let store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let id = store.add_class(file_id, "C", Vec::new());
+        assert_eq!(store.get_class(id).name(), "C");
+        let inst = Type::Instance(id);
+        assert_eq!(format!("{}", inst.display(&store)), "C");
+    }
+
+    #[test]
+    fn add_function() {
+        let store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let id = store.add_function(file_id, "func");
+        assert_eq!(store.get_function(id).name(), "func");
+        let func = Type::Function(id);
+        assert_eq!(format!("{}", func.display(&store)), "func");
+    }
+
+    #[test]
+    fn add_union() {
+        let mut store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let c1 = store.add_class(file_id, "C1", Vec::new());
+        let c2 = store.add_class(file_id, "C2", Vec::new());
+        let elems = vec![Type::Instance(c1), Type::Instance(c2)];
+        let id = store.add_union(file_id, &elems);
+        assert_eq!(
+            store.get_union(id).elements,
+            elems.into_iter().collect::<FxIndexSet<_>>()
+        );
+        let union = Type::Union(id);
+        assert_eq!(format!("{}", union.display(&store)), "(C1 | C2)");
+    }
+
+    #[test]
+    fn add_intersection() {
+        let mut store = TypeStore::default();
+        let files = Files::default();
+        let file_id = files.intern(Path::new("/foo"));
+        let c1 = store.add_class(file_id, "C1", Vec::new());
+        let c2 = store.add_class(file_id, "C2", Vec::new());
+        let c3 = store.add_class(file_id, "C3", Vec::new());
+        let pos = vec![Type::Instance(c1), Type::Instance(c2)];
+        let neg = vec![Type::Instance(c3)];
+        let id = store.add_intersection(file_id, &pos, &neg);
+        assert_eq!(
+            store.get_intersection(id).positive,
+            pos.into_iter().collect::<FxIndexSet<_>>()
+        );
+        assert_eq!(
+            store.get_intersection(id).negative,
+            neg.into_iter().collect::<FxIndexSet<_>>()
+        );
+        let intersection = Type::Intersection(id);
+        assert_eq!(
+            format!("{}", intersection.display(&store)),
+            "(C1 & C2 & ~C3)"
+        );
+    }
+}

crates/red_knot/src/types/infer.rs

@@ -0,0 +1,219 @@
+#![allow(dead_code)]
+
+use ruff_python_ast::AstNode;
+
+use crate::db::{HasJar, SemanticDb, SemanticJar};
+use crate::module::ModuleName;
+use crate::symbols::{Definition, ImportFromDefinition, SymbolId};
+use crate::types::Type;
+use crate::FileId;
+use ruff_python_ast as ast;
+
+// FIXME: Figure out proper dead-lock free synchronisation now that this takes `&db` instead of `&mut db`.
+#[tracing::instrument(level = "trace", skip(db))]
+pub fn infer_symbol_type<Db>(db: &Db, file_id: FileId, symbol_id: SymbolId) -> Type
+where
+    Db: SemanticDb + HasJar<SemanticJar>,
+{
+    let symbols = db.symbol_table(file_id);
+    let defs = symbols.definitions(symbol_id);
+
+    if let Some(ty) = db
+        .jar()
+        .type_store
+        .get_cached_symbol_type(file_id, symbol_id)
+    {
+        return ty;
+    }
+
+    // TODO handle multiple defs, conditional defs...
+    assert_eq!(defs.len(), 1);
+
+    let ty = match &defs[0] {
+        Definition::ImportFrom(ImportFromDefinition {
+            module,
+            name,
+            level,
+        }) => {
+            // TODO relative imports
+            assert!(matches!(level, 0));
+            let module_name = ModuleName::new(module.as_ref().expect("TODO relative imports"));
+            if let Some(module) = db.resolve_module(module_name) {
+                let remote_file_id = module.path(db).file();
+                let remote_symbols = db.symbol_table(remote_file_id);
+                if let Some(remote_symbol_id) = remote_symbols.root_symbol_id_by_name(name) {
+                    db.infer_symbol_type(remote_file_id, remote_symbol_id)
+                } else {
+                    Type::Unknown
+                }
+            } else {
+                Type::Unknown
+            }
+        }
+        Definition::ClassDef(node_key) => db
+            .jar()
+            .type_store
+            .get_cached_node_type(file_id, node_key.erased())
+            .unwrap_or_else(|| {
+                let parsed = db.parse(file_id);
+                let ast = parsed.ast();
+                let node = node_key.resolve_unwrap(ast.as_any_node_ref());
+
+                let bases: Vec<_> = node
+                    .bases()
+                    .iter()
+                    .map(|base_expr| infer_expr_type(db, file_id, base_expr))
+                    .collect();
+
+                let store = &db.jar().type_store;
+                let ty = Type::Class(store.add_class(file_id, &node.name.id, bases));
+                store.cache_node_type(file_id, *node_key.erased(), ty);
+                ty
+            }),
+        Definition::FunctionDef(node_key) => db
+            .jar()
+            .type_store
+            .get_cached_node_type(file_id, node_key.erased())
+            .unwrap_or_else(|| {
+                let parsed = db.parse(file_id);
+                let ast = parsed.ast();
+                let node = node_key
+                    .resolve(ast.as_any_node_ref())
+                    .expect("node key should resolve");
+
+                let store = &db.jar().type_store;
+                let ty = store.add_function(file_id, &node.name.id).into();
+                store.cache_node_type(file_id, *node_key.erased(), ty);
+                ty
+            }),
+        Definition::Assignment(node_key) => {
+            let parsed = db.parse(file_id);
+            let ast = parsed.ast();
+            let node = node_key.resolve_unwrap(ast.as_any_node_ref());
+            // TODO handle unpacking assignment correctly
+            infer_expr_type(db, file_id, &node.value)
+        }
+        _ => todo!("other kinds of definitions"),
+    };
+
+    db.jar()
+        .type_store
+        .cache_symbol_type(file_id, symbol_id, ty);
+    // TODO record dependencies
+    ty
+}
+
+fn infer_expr_type<Db>(db: &Db, file_id: FileId, expr: &ast::Expr) -> Type
+where
+    Db: SemanticDb + HasJar<SemanticJar>,
+{
+    // TODO cache the resolution of the type on the node
+    let symbols = db.symbol_table(file_id);
+    match expr {
+        ast::Expr::Name(name) => {
+            if let Some(symbol_id) = symbols.root_symbol_id_by_name(&name.id) {
+                db.infer_symbol_type(file_id, symbol_id)
+            } else {
+                Type::Unknown
+            }
+        }
+        _ => todo!("full expression type resolution"),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::db::tests::TestDb;
+    use crate::db::{HasJar, SemanticDb, SemanticJar};
+    use crate::module::{ModuleName, ModuleSearchPath, ModuleSearchPathKind};
+    use crate::types::Type;
+
+    // TODO with virtual filesystem we shouldn't have to write files to disk for these
+    // tests
+
+    struct TestCase {
+        temp_dir: tempfile::TempDir,
+        db: TestDb,
+
+        src: ModuleSearchPath,
+    }
+
+    fn create_test() -> std::io::Result<TestCase> {
+        let temp_dir = tempfile::tempdir()?;
+
+        let src = temp_dir.path().join("src");
+        std::fs::create_dir(&src)?;
+        let src = ModuleSearchPath::new(src.canonicalize()?, ModuleSearchPathKind::FirstParty);
+
+        let roots = vec![src.clone()];
+
+        let mut db = TestDb::default();
+        db.set_module_search_paths(roots);
+
+        Ok(TestCase { temp_dir, db, src })
+    }
+
+    #[test]
+    fn follow_import_to_class() -> std::io::Result<()> {
+        let case = create_test()?;
+        let db = &case.db;
+
+        let a_path = case.src.path().join("a.py");
+        let b_path = case.src.path().join("b.py");
+        std::fs::write(a_path, "from b import C as D; E = D")?;
+        std::fs::write(b_path, "class C: pass")?;
+        let a_file = db
+            .resolve_module(ModuleName::new("a"))
+            .expect("module should be found")
+            .path(db)
+            .file();
+        let a_syms = db.symbol_table(a_file);
+        let e_sym = a_syms
+            .root_symbol_id_by_name("E")
+            .expect("E symbol should be found");
+
+        let ty = db.infer_symbol_type(a_file, e_sym);
+
+        let jar = HasJar::<SemanticJar>::jar(db);
+        assert!(matches!(ty, Type::Class(_)));
+        assert_eq!(format!("{}", ty.display(&jar.type_store)), "Literal[C]");
+
+        Ok(())
+    }
+
+    #[test]
+    fn resolve_base_class_by_name() -> std::io::Result<()> {
+        let case = create_test()?;
+        let db = &case.db;
+
+        let path = case.src.path().join("mod.py");
+        std::fs::write(path, "class Base: pass\nclass Sub(Base): pass")?;
+        let file = db
+            .resolve_module(ModuleName::new("mod"))
+            .expect("module should be found")
+            .path(db)
+            .file();
+        let syms = db.symbol_table(file);
+        let sym = syms
+            .root_symbol_id_by_name("Sub")
+            .expect("Sub symbol should be found");
+
+        let ty = db.infer_symbol_type(file, sym);
+
+        let Type::Class(class_id) = ty else {
+            panic!("Sub is not a Class")
+        };
+        let jar = HasJar::<SemanticJar>::jar(db);
+        let base_names: Vec<_> = jar
+            .type_store
+            .get_class(class_id)
+            .bases()
+            .iter()
+            .map(|base_ty| format!("{}", base_ty.display(&jar.type_store)))
+            .collect();
+
+        assert_eq!(base_names, vec!["Literal[Base]"]);
+
+        Ok(())
+    }
+}

crates/red_knot/src/watch.rs

@@ -0,0 +1,78 @@
+use anyhow::Context;
+use std::path::Path;
+
+use crate::files::Files;
+use crate::program::{FileChange, FileChangeKind};
+use notify::event::{CreateKind, RemoveKind};
+use notify::{recommended_watcher, Event, EventKind, RecommendedWatcher, RecursiveMode, Watcher};
+
+pub struct FileWatcher {
+    watcher: RecommendedWatcher,
+}
+
+pub trait EventHandler: Send + 'static {
+    fn handle(&self, changes: Vec<FileChange>);
+}
+
+impl<F> EventHandler for F
+where
+    F: Fn(Vec<FileChange>) + Send + 'static,
+{
+    fn handle(&self, changes: Vec<FileChange>) {
+        let f = self;
+        f(changes);
+    }
+}
+
+impl FileWatcher {
+    pub fn new<E>(handler: E, files: Files) -> anyhow::Result<Self>
+    where
+        E: EventHandler,
+    {
+        Self::from_handler(Box::new(handler), files)
+    }
+
+    fn from_handler(handler: Box<dyn EventHandler>, files: Files) -> anyhow::Result<Self> {
+        let watcher = recommended_watcher(move |changes: notify::Result<Event>| {
+            match changes {
+                Ok(event) => {
+                    // TODO verify that this handles all events correctly
+                    let change_kind = match event.kind {
+                        EventKind::Create(CreateKind::File) => FileChangeKind::Created,
+                        EventKind::Modify(_) => FileChangeKind::Modified,
+                        EventKind::Remove(RemoveKind::File) => FileChangeKind::Deleted,
+                        _ => {
+                            return;
+                        }
+                    };
+
+                    let mut changes = Vec::new();
+
+                    for path in event.paths {
+                        if path.is_file() {
+                            let id = files.intern(&path);
+                            changes.push(FileChange::new(id, change_kind));
+                        }
+                    }
+
+                    if !changes.is_empty() {
+                        handler.handle(changes);
+                    }
+                }
+                // TODO proper error handling
+                Err(err) => {
+                    panic!("Error: {err}");
+                }
+            }
+        })
+        .context("Failed to create file watcher.")?;
+
+        Ok(Self { watcher })
+    }
+
+    pub fn watch_folder(&mut self, path: &Path) -> anyhow::Result<()> {
+        self.watcher.watch(path, RecursiveMode::Recursive)?;
+
+        Ok(())
+    }
+}

crates/ruff/Cargo.toml

@@ -1,7 +1,7 @@
 [package]
 name = "ruff"
-version = "0.11.11"
-publish = true
+version = "0.4.2"
+publish = false
 authors = { workspace = true }
 edition = { workspace = true }
 rust-version = { workspace = true }
@@ -13,39 +13,35 @@ readme = "../../README.md"
 default-run = "ruff"
 
 [dependencies]
-ruff_cache = { workspace = true }
-ruff_db = { workspace = true, default-features = false, features = ["os"] }
-ruff_diagnostics = { workspace = true }
-ruff_graph = { workspace = true, features = ["serde", "clap"] }
-ruff_linter = { workspace = true, features = ["clap"] }
-ruff_macros = { workspace = true }
-ruff_notebook = { workspace = true }
-ruff_options_metadata = { workspace = true, features = ["serde"] }
-ruff_python_ast = { workspace = true }
-ruff_python_formatter = { workspace = true }
-ruff_python_parser = { workspace = true }
-ruff_server = { workspace = true }
-ruff_source_file = { workspace = true }
-ruff_text_size = { workspace = true }
-ruff_workspace = { workspace = true }
+ruff_cache = { path = "../ruff_cache" }
+ruff_diagnostics = { path = "../ruff_diagnostics" }
+ruff_linter = { path = "../ruff_linter", features = ["clap"] }
+ruff_macros = { path = "../ruff_macros" }
+ruff_notebook = { path = "../ruff_notebook" }
+ruff_python_ast = { path = "../ruff_python_ast" }
+ruff_python_formatter = { path = "../ruff_python_formatter" }
+ruff_server = { path = "../ruff_server" }
+ruff_source_file = { path = "../ruff_source_file" }
+ruff_text_size = { path = "../ruff_text_size" }
+ruff_workspace = { path = "../ruff_workspace" }
 
 anyhow = { workspace = true }
 argfile = { workspace = true }
-bincode = { workspace = true, features = ["serde"] }
+bincode = { workspace = true }
 bitflags = { workspace = true }
 cachedir = { workspace = true }
+chrono = { workspace = true }
 clap = { workspace = true, features = ["derive", "env", "wrap_help"] }
 clap_complete_command = { workspace = true }
 clearscreen = { workspace = true }
 colored = { workspace = true }
 filetime = { workspace = true }
-globwalk = { workspace = true }
 ignore = { workspace = true }
 is-macro = { workspace = true }
 itertools = { workspace = true }
-jiff = { workspace = true }
 log = { workspace = true }
 notify = { workspace = true }
+num_cpus = { workspace = true }
 path-absolutize = { workspace = true, features = ["once_cell_cache"] }
 rayon = { workspace = true }
 regex = { workspace = true }
@@ -58,33 +54,25 @@ tempfile = { workspace = true }
 thiserror = { workspace = true }
 toml = { workspace = true }
 tracing = { workspace = true, features = ["log"] }
+tracing-subscriber = { workspace = true, features = ["registry"] }
+tracing-tree = { workspace = true }
 walkdir = { workspace = true }
 wild = { workspace = true }
 
 [dev-dependencies]
 # Enable test rules during development
-ruff_linter = { workspace = true, features = ["clap", "test-rules"] }
-
-assert_fs = { workspace = true }
+ruff_linter = { path = "../ruff_linter", features = ["clap", "test-rules"] }
 # Avoid writing colored snapshots when running tests from the terminal
 colored = { workspace = true, features = ["no-color"] }
-indoc = { workspace = true }
 insta = { workspace = true, features = ["filters", "json"] }
 insta-cmd = { workspace = true }
 tempfile = { workspace = true }
 test-case = { workspace = true }
 
-[package.metadata.cargo-shear]
-# Used via macro expansion.
-ignored = ["jiff"]
-
-[package.metadata.dist]
-dist = true
-
 [target.'cfg(target_os = "windows")'.dependencies]
 mimalloc = { workspace = true }
 
-[target.'cfg(all(not(target_os = "windows"), not(target_os = "openbsd"), not(target_os = "aix"), not(target_os = "android"), any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "powerpc64")))'.dependencies]
+[target.'cfg(all(not(target_os = "windows"), not(target_os = "openbsd"), any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "powerpc64")))'.dependencies]
 tikv-jemallocator = { workspace = true }
 
 [lints]

crates/ruff/build.rs

@@ -1,8 +1,4 @@
-use std::{
-    fs,
-    path::{Path, PathBuf},
-    process::Command,
-};
+use std::{fs, path::Path, process::Command};
 
 fn main() {
     // The workspace root directory is not available without walking up the tree
@@ -13,8 +9,9 @@ fn main() {
 
     commit_info(&workspace_root);
 
+    #[allow(clippy::disallowed_methods)]
     let target = std::env::var("TARGET").unwrap();
-    println!("cargo::rustc-env=RUST_HOST_TARGET={target}");
+    println!("cargo:rustc-env=RUST_HOST_TARGET={target}");
 }
 
 fn commit_info(workspace_root: &Path) {
@@ -24,22 +21,27 @@ fn commit_info(workspace_root: &Path) {
         return;
     }
 
-    if let Some(git_head_path) = git_head(&git_dir) {
-        println!("cargo:rerun-if-changed={}", git_head_path.display());
+    let git_head_path = git_dir.join("HEAD");
+    println!(
+        "cargo:rerun-if-changed={}",
+        git_head_path.as_path().display()
+    );
 
-        let git_head_contents = fs::read_to_string(git_head_path);
-        if let Ok(git_head_contents) = git_head_contents {
-            // The contents are either a commit or a reference in the following formats
-            // - "<commit>" when the head is detached
-            // - "ref <ref>" when working on a branch
-            // If a commit, checking if the HEAD file has changed is sufficient
-            // If a ref, we need to add the head file for that ref to rebuild on commit
-            let mut git_ref_parts = git_head_contents.split_whitespace();
-            git_ref_parts.next();
-            if let Some(git_ref) = git_ref_parts.next() {
-                let git_ref_path = git_dir.join(git_ref);
-                println!("cargo:rerun-if-changed={}", git_ref_path.display());
-            }
+    let git_head_contents = fs::read_to_string(git_head_path);
+    if let Ok(git_head_contents) = git_head_contents {
+        // The contents are either a commit or a reference in the following formats
+        // - "<commit>" when the head is detached
+        // - "ref <ref>" when working on a branch
+        // If a commit, checking if the HEAD file has changed is sufficient
+        // If a ref, we need to add the head file for that ref to rebuild on commit
+        let mut git_ref_parts = git_head_contents.split_whitespace();
+        git_ref_parts.next();
+        if let Some(git_ref) = git_ref_parts.next() {
+            let git_ref_path = git_dir.join(git_ref);
+            println!(
+                "cargo:rerun-if-changed={}",
+                git_ref_path.as_path().display()
+            );
         }
     }
 
@@ -48,7 +50,7 @@ fn commit_info(workspace_root: &Path) {
         .arg("-1")
         .arg("--date=short")
         .arg("--abbrev=9")
-        .arg("--format=%H %h %cd %(describe:tags)")
+        .arg("--format=%H %h %cd %(describe)")
         .output()
     {
         Ok(output) if output.status.success() => output,
@@ -57,49 +59,22 @@ fn commit_info(workspace_root: &Path) {
     let stdout = String::from_utf8(output.stdout).unwrap();
     let mut parts = stdout.split_whitespace();
     let mut next = || parts.next().unwrap();
-    println!("cargo::rustc-env=RUFF_COMMIT_HASH={}", next());
-    println!("cargo::rustc-env=RUFF_COMMIT_SHORT_HASH={}", next());
-    println!("cargo::rustc-env=RUFF_COMMIT_DATE={}", next());
+    println!("cargo:rustc-env=RUFF_COMMIT_HASH={}", next());
+    println!("cargo:rustc-env=RUFF_COMMIT_SHORT_HASH={}", next());
+    println!("cargo:rustc-env=RUFF_COMMIT_DATE={}", next());
 
     // Describe can fail for some commits
     // https://git-scm.com/docs/pretty-formats#Documentation/pretty-formats.txt-emdescribeoptionsem
     if let Some(describe) = parts.next() {
         let mut describe_parts = describe.split('-');
         println!(
-            "cargo::rustc-env=RUFF_LAST_TAG={}",
+            "cargo:rustc-env=RUFF_LAST_TAG={}",
             describe_parts.next().unwrap()
         );
         // If this is the tagged commit, this component will be missing
         println!(
-            "cargo::rustc-env=RUFF_LAST_TAG_DISTANCE={}",
+            "cargo:rustc-env=RUFF_LAST_TAG_DISTANCE={}",
             describe_parts.next().unwrap_or("0")
         );
     }
 }
-
-fn git_head(git_dir: &Path) -> Option<PathBuf> {
-    // The typical case is a standard git repository.
-    let git_head_path = git_dir.join("HEAD");
-    if git_head_path.exists() {
-        return Some(git_head_path);
-    }
-    if !git_dir.is_file() {
-        return None;
-    }
-    // If `.git/HEAD` doesn't exist and `.git` is actually a file,
-    // then let's try to attempt to read it as a worktree. If it's
-    // a worktree, then its contents will look like this, e.g.:
-    //
-    //     gitdir: /home/andrew/astral/uv/main/.git/worktrees/pr2
-    //
-    // And the HEAD file we want to watch will be at:
-    //
-    //     /home/andrew/astral/uv/main/.git/worktrees/pr2/HEAD
-    let contents = fs::read_to_string(git_dir).ok()?;
-    let (label, worktree_path) = contents.split_once(':')?;
-    if label != "gitdir" {
-        return None;
-    }
-    let worktree_path = worktree_path.trim();
-    Some(PathBuf::from(worktree_path))
-}

crates/ruff/src/args.rs

@@ -1,36 +1,32 @@
 use std::cmp::Ordering;
-use std::fmt::{Formatter, Write as _};
+use std::fmt::Formatter;
 use std::ops::Deref;
 use std::path::{Path, PathBuf};
 use std::str::FromStr;
 use std::sync::Arc;
 
-use crate::commands::completions::config::{OptionString, OptionStringParser};
 use anyhow::bail;
 use clap::builder::{TypedValueParser, ValueParserFactory};
-use clap::{Parser, Subcommand, command};
+use clap::{command, Parser};
 use colored::Colorize;
-use itertools::Itertools;
 use path_absolutize::path_dedot;
 use regex::Regex;
-use ruff_graph::Direction;
+use rustc_hash::FxHashMap;
+use toml;
+
 use ruff_linter::line_width::LineLength;
 use ruff_linter::logging::LogLevel;
 use ruff_linter::registry::Rule;
 use ruff_linter::settings::types::{
-    ExtensionPair, FilePattern, OutputFormat, PatternPrefixPair, PerFileIgnore, PreviewMode,
-    PythonVersion, UnsafeFixes,
+    ExtensionPair, FilePattern, PatternPrefixPair, PerFileIgnore, PreviewMode, PythonVersion,
+    SerializationFormat, UnsafeFixes,
 };
-use ruff_linter::{RuleParser, RuleSelector, RuleSelectorParser};
-use ruff_options_metadata::{OptionEntry, OptionsMetadata};
-use ruff_python_ast as ast;
-use ruff_source_file::{LineIndex, OneIndexed, PositionEncoding};
+use ruff_linter::{warn_user, RuleParser, RuleSelector, RuleSelectorParser};
+use ruff_source_file::{LineIndex, OneIndexed};
 use ruff_text_size::TextRange;
 use ruff_workspace::configuration::{Configuration, RuleSelection};
 use ruff_workspace::options::{Options, PycodestyleOptions};
 use ruff_workspace::resolver::ConfigurationTransformer;
-use rustc_hash::FxHashMap;
-use toml;
 
 /// All configuration options that can be passed "globally",
 /// i.e., can be passed to all subcommands
@@ -82,7 +78,7 @@ impl GlobalConfigArgs {
 #[command(
     author,
     name = "ruff",
-    about = "Ruff: An extremely fast Python linter and code formatter.",
+    about = "Ruff: An extremely fast Python linter.",
     after_help = "For help with a specific command, see: `ruff help <command>`."
 )]
 #[command(version)]
@@ -93,12 +89,13 @@ pub struct Args {
     pub(crate) global_options: GlobalConfigArgs,
 }
 
-#[expect(clippy::large_enum_variant)]
+#[allow(clippy::large_enum_variant)]
 #[derive(Debug, clap::Subcommand)]
 pub enum Command {
-    /// Run Ruff on the given files or directories.
+    /// Run Ruff on the given files or directories (default).
     Check(CheckCommand),
     /// Explain a rule (or all rules).
+    #[clap(alias = "--explain")]
     #[command(group = clap::ArgGroup::new("selector").multiple(false).required(true))]
     Rule {
         /// Rule to explain
@@ -114,17 +111,7 @@ pub enum Command {
         output_format: HelpFormat,
     },
     /// List or describe the available configuration options.
-    Config {
-        /// Config key to show
-        #[arg(
-            value_parser = OptionStringParser,
-            hide_possible_values = true
-        )]
-        option: Option<OptionString>,
-        /// Output format
-        #[arg(long, value_enum, default_value = "text")]
-        output_format: HelpFormat,
-    },
+    Config { option: Option<String> },
     /// List all supported upstream linters.
     Linter {
         /// Output format
@@ -132,17 +119,15 @@ pub enum Command {
         output_format: HelpFormat,
     },
     /// Clear any caches in the current directory and any subdirectories.
+    #[clap(alias = "--clean")]
     Clean,
     /// Generate shell completion.
-    #[clap(hide = true)]
+    #[clap(alias = "--generate-shell-completion", hide = true)]
     GenerateShellCompletion { shell: clap_complete_command::Shell },
     /// Run the Ruff formatter on the given files or directories.
     Format(FormatCommand),
     /// Run the language server.
     Server(ServerCommand),
-    /// Run analysis over Python source code.
-    #[clap(subcommand)]
-    Analyze(AnalyzeCommand),
     /// Display Ruff's version
     Version {
         #[arg(long, value_enum, default_value = "text")]
@@ -150,41 +135,9 @@ pub enum Command {
     },
 }
 
-#[derive(Debug, Subcommand)]
-pub enum AnalyzeCommand {
-    /// Generate a map of Python file dependencies or dependents.
-    Graph(AnalyzeGraphCommand),
-}
-
-#[derive(Clone, Debug, clap::Parser)]
-pub struct AnalyzeGraphCommand {
-    /// List of files or directories to include.
-    #[clap(help = "List of files or directories to include [default: .]")]
-    files: Vec<PathBuf>,
-    /// The direction of the import map. By default, generates a dependency map, i.e., a map from
-    /// file to files that it depends on. Use `--direction dependents` to generate a map from file
-    /// to files that depend on it.
-    #[clap(long, value_enum, default_value_t)]
-    direction: Direction,
-    /// Attempt to detect imports from string literals.
-    #[clap(long)]
-    detect_string_imports: bool,
-    /// Enable preview mode. Use `--no-preview` to disable.
-    #[arg(long, overrides_with("no_preview"))]
-    preview: bool,
-    #[clap(long, overrides_with("preview"), hide = true)]
-    no_preview: bool,
-    /// The minimum Python version that should be supported.
-    #[arg(long, value_enum)]
-    target_version: Option<PythonVersion>,
-    /// Path to a virtual environment to use for resolving additional dependencies
-    #[arg(long)]
-    python: Option<PathBuf>,
-}
-
 // The `Parser` derive is for ruff_dev, for ruff `Args` would be sufficient
 #[derive(Clone, Debug, clap::Parser)]
-#[expect(clippy::struct_excessive_bools)]
+#[allow(clippy::struct_excessive_bools)]
 pub struct CheckCommand {
     /// List of files or directories to check.
     #[clap(help = "List of files or directories to check [default: .]")]
@@ -201,20 +154,26 @@ pub struct CheckCommand {
     unsafe_fixes: bool,
     #[arg(long, overrides_with("unsafe_fixes"), hide = true)]
     no_unsafe_fixes: bool,
+    /// Show violations with source code.
+    /// Use `--no-show-source` to disable.
+    /// (Deprecated: use `--output-format=full` or `--output-format=concise` instead of `--show-source` and `--no-show-source`, respectively)
+    #[arg(long, overrides_with("no_show_source"))]
+    show_source: bool,
+    #[clap(long, overrides_with("show_source"), hide = true)]
+    no_show_source: bool,
     /// Show an enumeration of all fixed lint violations.
     /// Use `--no-show-fixes` to disable.
     #[arg(long, overrides_with("no_show_fixes"))]
     show_fixes: bool,
     #[clap(long, overrides_with("show_fixes"), hide = true)]
     no_show_fixes: bool,
-    /// Avoid writing any fixed files back; instead, output a diff for each changed file to stdout, and exit 0 if there are no diffs.
-    /// Implies `--fix-only`.
+    /// Avoid writing any fixed files back; instead, output a diff for each changed file to stdout. Implies `--fix-only`.
     #[arg(long, conflicts_with = "show_fixes")]
     pub diff: bool,
     /// Run in watch mode by re-running whenever files change.
     #[arg(short, long)]
     pub watch: bool,
-    /// Apply fixes to resolve lint violations, but don't report on, or exit non-zero for, leftover violations. Implies `--fix`.
+    /// Apply fixes to resolve lint violations, but don't report on leftover violations. Implies `--fix`.
     /// Use `--no-fix-only` to disable or `--unsafe-fixes` to include unsafe fixes.
     #[arg(long, overrides_with("no_fix_only"))]
     fix_only: bool,
@@ -225,9 +184,10 @@ pub struct CheckCommand {
     ignore_noqa: bool,
 
     /// Output serialization format for violations.
-    /// The default serialization format is "full".
+    /// The default serialization format is "concise".
+    /// In preview mode, the default serialization format is "full".
     #[arg(long, value_enum, env = "RUFF_OUTPUT_FORMAT")]
-    pub output_format: Option<OutputFormat>,
+    pub output_format: Option<SerializationFormat>,
 
     /// Specify file to write the linter output to (default: stdout).
     #[arg(short, long, env = "RUFF_OUTPUT_FILE")]
@@ -378,7 +338,7 @@ pub struct CheckCommand {
     /// The name of the file when passing it through stdin.
     #[arg(long, help_heading = "Miscellaneous")]
     pub stdin_filename: Option<PathBuf>,
-    /// List of mappings from file extension to language (one of `python`, `ipynb`, `pyi`). For
+    /// List of mappings from file extension to language (one of ["python", "ipynb", "pyi"]). For
     /// example, to treat `.ipy` files as IPython notebooks, use `--extension ipy:ipynb`.
     #[arg(long, value_delimiter = ',')]
     pub extension: Option<Vec<ExtensionPair>>,
@@ -398,6 +358,7 @@ pub struct CheckCommand {
         long,
         // Unsupported default-command arguments.
         conflicts_with = "diff",
+        conflicts_with = "show_source",
         conflicts_with = "watch",
     )]
     pub statistics: bool,
@@ -443,10 +404,13 @@ pub struct CheckCommand {
         conflicts_with = "watch",
     )]
     pub show_settings: bool,
+    /// Dev-only argument to show fixes
+    #[arg(long, hide = true)]
+    pub ecosystem_ci: bool,
 }
 
 #[derive(Clone, Debug, clap::Parser)]
-#[expect(clippy::struct_excessive_bools)]
+#[allow(clippy::struct_excessive_bools)]
 pub struct FormatCommand {
     /// List of files or directories to format.
     #[clap(help = "List of files or directories to format [default: .]")]
@@ -502,7 +466,7 @@ pub struct FormatCommand {
     /// The name of the file when passing it through stdin.
     #[arg(long, help_heading = "Miscellaneous")]
     pub stdin_filename: Option<PathBuf>,
-    /// List of mappings from file extension to language (one of `python`, `ipynb`, `pyi`). For
+    /// List of mappings from file extension to language (one of ["python", "ipynb", "pyi"]). For
     /// example, to treat `.ipy` files as IPython notebooks, use `--extension ipy:ipynb`.
     #[arg(long, value_delimiter = ',')]
     pub extension: Option<Vec<ExtensionPair>>,
@@ -530,28 +494,13 @@ pub struct FormatCommand {
     /// The option can only be used when formatting a single file. Range formatting of notebooks is unsupported.
     #[clap(long, help_heading = "Editor options", verbatim_doc_comment)]
     pub range: Option<FormatRange>,
-
-    /// Exit with a non-zero status code if any files were modified via format, even if all files were formatted successfully.
-    #[arg(long, help_heading = "Miscellaneous", alias = "exit-non-zero-on-fix")]
-    pub exit_non_zero_on_format: bool,
 }
 
 #[derive(Copy, Clone, Debug, clap::Parser)]
 pub struct ServerCommand {
-    /// Enable preview mode. Use `--no-preview` to disable.
-    ///
-    /// This enables unstable server features and turns on the preview mode for the linter
-    /// and the formatter.
-    #[arg(long, overrides_with("no_preview"))]
-    preview: bool,
-    #[clap(long, overrides_with("preview"), hide = true)]
-    no_preview: bool,
-}
-
-impl ServerCommand {
-    pub(crate) fn resolve_preview(self) -> Option<bool> {
-        resolve_bool_arg(self.preview, self.no_preview)
-    }
+    /// Enable preview mode; required for regular operation
+    #[arg(long)]
+    pub(crate) preview: bool,
 }
 
 #[derive(Debug, Clone, Copy, clap::ValueEnum)]
@@ -560,7 +509,7 @@ pub enum HelpFormat {
     Json,
 }
 
-#[expect(clippy::module_name_repetitions)]
+#[allow(clippy::module_name_repetitions)]
 #[derive(Debug, Default, Clone, clap::Args)]
 pub struct LogLevelArgs {
     /// Enable verbose logging.
@@ -706,6 +655,7 @@ impl CheckCommand {
         let check_arguments = CheckArguments {
             add_noqa: self.add_noqa,
             diff: self.diff,
+            ecosystem_ci: self.ecosystem_ci,
             exit_non_zero_on_fix: self.exit_non_zero_on_fix,
             exit_zero: self.exit_zero,
             files: self.files,
@@ -735,7 +685,7 @@ impl CheckCommand {
             preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
             respect_gitignore: resolve_bool_arg(self.respect_gitignore, self.no_respect_gitignore),
             select: self.select,
-            target_version: self.target_version.map(ast::PythonVersion::from),
+            target_version: self.target_version,
             unfixable: self.unfixable,
             // TODO(charlie): Included in `pyproject.toml`, but not inherited.
             cache_dir: self.cache_dir,
@@ -744,10 +694,13 @@ impl CheckCommand {
             unsafe_fixes: resolve_bool_arg(self.unsafe_fixes, self.no_unsafe_fixes)
                 .map(UnsafeFixes::from),
             force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
-            output_format: self.output_format,
+            output_format: resolve_output_format(
+                self.output_format,
+                resolve_bool_arg(self.show_source, self.no_show_source),
+                resolve_bool_arg(self.preview, self.no_preview).unwrap_or_default(),
+            ),
             show_fixes: resolve_bool_arg(self.show_fixes, self.no_show_fixes),
             extension: self.extension,
-            ..ExplicitConfigOverrides::default()
         };
 
         let config_args = ConfigArguments::from_cli_arguments(global_options, cli_overrides)?;
@@ -769,7 +722,6 @@ impl FormatCommand {
             no_cache: self.no_cache,
             stdin_filename: self.stdin_filename,
             range: self.range,
-            exit_non_zero_on_format: self.exit_non_zero_on_format,
         };
 
         let cli_overrides = ExplicitConfigOverrides {
@@ -778,38 +730,11 @@ impl FormatCommand {
             exclude: self.exclude,
             preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
             force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
-            target_version: self.target_version.map(ast::PythonVersion::from),
+            target_version: self.target_version,
             cache_dir: self.cache_dir,
             extension: self.extension,
-            ..ExplicitConfigOverrides::default()
-        };
 
-        let config_args = ConfigArguments::from_cli_arguments(global_options, cli_overrides)?;
-        Ok((format_arguments, config_args))
-    }
-}
-
-impl AnalyzeGraphCommand {
-    /// Partition the CLI into command-line arguments and configuration
-    /// overrides.
-    pub fn partition(
-        self,
-        global_options: GlobalConfigArgs,
-    ) -> anyhow::Result<(AnalyzeGraphArgs, ConfigArguments)> {
-        let format_arguments = AnalyzeGraphArgs {
-            files: self.files,
-            direction: self.direction,
-            python: self.python,
-        };
-
-        let cli_overrides = ExplicitConfigOverrides {
-            detect_string_imports: if self.detect_string_imports {
-                Some(true)
-            } else {
-                None
-            },
-            preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
-            target_version: self.target_version.map(ast::PythonVersion::from),
+            // Unsupported on the formatter CLI, but required on `Overrides`.
             ..ExplicitConfigOverrides::default()
         };
 
@@ -838,7 +763,7 @@ enum InvalidConfigFlagReason {
     ValidTomlButInvalidRuffSchema(toml::de::Error),
     /// It was a valid ruff config file, but the user tried to pass a
     /// value for `extend` as part of the config override.
-    /// `extend` is special, because it affects which config files we look at
+    // `extend` is special, because it affects which config files we look at
     /// in the first place. We currently only parse --config overrides *after*
     /// we've combined them with all the arguments from the various config files
     /// that we found, so trying to override `extend` as part of a --config
@@ -972,51 +897,23 @@ A `--config` flag must either be a path to a `.toml` configuration file
         // the user was trying to pass in a path to a configuration file
         // or some inline TOML.
         // We want to display the most helpful error to the user as possible.
-        if Path::new(value)
+        if std::path::Path::new(value)
             .extension()
-            .is_some_and(|ext| ext.eq_ignore_ascii_case("toml"))
+            .map_or(false, |ext| ext.eq_ignore_ascii_case("toml"))
         {
             if !value.contains('=') {
-                let _ = write!(
-                    &mut tip,
+                tip.push_str(&format!(
                     "
 
 It looks like you were trying to pass a path to a configuration file.
 The path `{value}` does not point to a configuration file"
-                );
-            }
-        } else if let Some((key, value)) = value.split_once('=') {
-            let key = key.trim_ascii();
-            let value = value.trim_ascii_start();
-
-            match Options::metadata().find(key) {
-                Some(OptionEntry::Set(set)) if !value.starts_with('{') => {
-                    let prefixed_subfields = set
-                        .collect_fields()
-                        .iter()
-                        .map(|(name, _)| format!("- `{key}.{name}`"))
-                        .join("\n");
-
-                    let _ = write!(
-                        &mut tip,
-                        "
-
-`{key}` is a table of configuration options.
-Did you want to override one of the table's subkeys?
-
-Possible choices:
-
-{prefixed_subfields}"
-                    );
-                }
-                _ => {
-                    let _ = write!(
-                        &mut tip,
-                        "\n\n{}:\n\n{underlying_error}",
-                        config_parse_error.description()
-                    );
-                }
+                ));
             }
+        } else if value.contains('=') {
+            tip.push_str(&format!(
+                "\n\n{}:\n\n{underlying_error}",
+                config_parse_error.description()
+            ));
         }
         let tip = tip.trim_end().to_owned().into();
 
@@ -1029,12 +926,50 @@ Possible choices:
     }
 }
 
+fn resolve_output_format(
+    output_format: Option<SerializationFormat>,
+    show_sources: Option<bool>,
+    preview: bool,
+) -> Option<SerializationFormat> {
+    Some(match (output_format, show_sources) {
+        (Some(o), None) => o,
+        (Some(SerializationFormat::Grouped), Some(true)) => {
+            warn_user!("`--show-source` with `--output-format=grouped` is deprecated, and will not show source files. Use `--output-format=full` to show source information.");
+            SerializationFormat::Grouped
+        }
+        (Some(fmt), Some(true)) => {
+            warn_user!("The `--show-source` argument is deprecated and has been ignored in favor of `--output-format={fmt}`.");
+            fmt
+        }
+        (Some(fmt), Some(false)) => {
+            warn_user!("The `--no-show-source` argument is deprecated and has been ignored in favor of `--output-format={fmt}`.");
+            fmt
+        }
+        (None, Some(true)) => {
+            warn_user!("The `--show-source` argument is deprecated. Use `--output-format=full` instead.");
+            SerializationFormat::Full
+        }
+        (None, Some(false)) => {
+            warn_user!("The `--no-show-source` argument is deprecated. Use `--output-format=concise` instead.");
+            SerializationFormat::Concise
+        }
+        (None, None) => return None
+    }).map(|format| match format {
+        SerializationFormat::Text => {
+            warn_user!("`--output-format=text` is deprecated. Use `--output-format=full` or `--output-format=concise` instead. `text` will be treated as `{}`.", SerializationFormat::default(preview));
+            SerializationFormat::default(preview)
+        },
+        other => other
+    })
+}
+
 /// CLI settings that are distinct from configuration (commands, lists of files,
 /// etc.).
-#[expect(clippy::struct_excessive_bools)]
+#[allow(clippy::struct_excessive_bools)]
 pub struct CheckArguments {
     pub add_noqa: bool,
     pub diff: bool,
+    pub ecosystem_ci: bool,
     pub exit_non_zero_on_fix: bool,
     pub exit_zero: bool,
     pub files: Vec<PathBuf>,
@@ -1050,7 +985,7 @@ pub struct CheckArguments {
 
 /// CLI settings that are distinct from configuration (commands, lists of files,
 /// etc.).
-#[expect(clippy::struct_excessive_bools)]
+#[allow(clippy::struct_excessive_bools)]
 pub struct FormatArguments {
     pub check: bool,
     pub no_cache: bool,
@@ -1058,7 +993,6 @@ pub struct FormatArguments {
     pub files: Vec<PathBuf>,
     pub stdin_filename: Option<PathBuf>,
     pub range: Option<FormatRange>,
-    pub exit_non_zero_on_format: bool,
 }
 
 /// A text range specified by line and column numbers.
@@ -1073,9 +1007,8 @@ impl FormatRange {
     ///
     /// Returns an empty range if the start range is past the end of `source`.
     pub(super) fn to_text_range(self, source: &str, line_index: &LineIndex) -> TextRange {
-        let start_byte_offset =
-            line_index.offset(self.start.into(), source, PositionEncoding::Utf32);
-        let end_byte_offset = line_index.offset(self.end.into(), source, PositionEncoding::Utf32);
+        let start_byte_offset = line_index.offset(self.start.line, self.start.column, source);
+        let end_byte_offset = line_index.offset(self.end.line, self.end.column, source);
 
         TextRange::new(start_byte_offset, end_byte_offset)
     }
@@ -1126,10 +1059,10 @@ impl std::fmt::Display for FormatRangeParseError {
                 write!(
                     f,
                     "the start position '{start_invalid}' is greater than the end position '{end_invalid}'.\n  {tip} Try switching start and end: '{end}-{start}'",
-                    start_invalid = start.to_string().bold().yellow(),
-                    end_invalid = end.to_string().bold().yellow(),
-                    start = start.to_string().green().bold(),
-                    end = end.to_string().green().bold()
+                    start_invalid=start.to_string().bold().yellow(),
+                    end_invalid=end.to_string().bold().yellow(),
+                    start=start.to_string().green().bold(),
+                    end=end.to_string().green().bold()
                 )
             }
             FormatRangeParseError::InvalidStart(inner) => inner.write(f, true),
@@ -1146,15 +1079,6 @@ pub struct LineColumn {
     pub column: OneIndexed,
 }
 
-impl From<LineColumn> for ruff_source_file::SourceLocation {
-    fn from(value: LineColumn) -> Self {
-        Self {
-            line: value.line,
-            character_offset: value.column,
-        }
-    }
-}
-
 impl std::fmt::Display for LineColumn {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         write!(f, "{line}:{column}", line = self.line, column = self.column)
@@ -1230,53 +1154,40 @@ impl LineColumnParseError {
 
         match self {
             LineColumnParseError::ColumnParseError(inner) => {
-                write!(
-                    f,
-                    "the {range}s column is not a valid number ({inner})'\n  {tip} The format is 'line:column'."
-                )
+                write!(f, "the {range}s column is not a valid number ({inner})'\n  {tip} The format is 'line:column'.")
             }
             LineColumnParseError::LineParseError(inner) => {
-                write!(
-                    f,
-                    "the {range} line is not a valid number ({inner})\n  {tip} The format is 'line:column'."
-                )
+                write!(f, "the {range} line is not a valid number ({inner})\n  {tip} The format is 'line:column'.")
             }
             LineColumnParseError::ZeroColumnIndex { line } => {
                 write!(
                     f,
                     "the {range} column is 0, but it should be 1 or greater.\n  {tip} The column numbers start at 1.\n  {tip} Try {suggestion} instead.",
-                    suggestion = format!("{line}:1").green().bold()
+                    suggestion=format!("{line}:1").green().bold()
                 )
             }
             LineColumnParseError::ZeroLineIndex { column } => {
                 write!(
                     f,
                     "the {range} line is 0, but it should be 1 or greater.\n  {tip} The line numbers start at 1.\n  {tip} Try {suggestion} instead.",
-                    suggestion = format!("1:{column}").green().bold()
+                    suggestion=format!("1:{column}").green().bold()
                 )
             }
             LineColumnParseError::ZeroLineAndColumnIndex => {
                 write!(
                     f,
                     "the {range} line and column are both 0, but they should be 1 or greater.\n  {tip} The line and column numbers start at 1.\n  {tip} Try {suggestion} instead.",
-                    suggestion = "1:1".to_string().green().bold()
+                    suggestion="1:1".to_string().green().bold()
                 )
             }
         }
     }
 }
 
-/// CLI settings that are distinct from configuration (commands, lists of files, etc.).
-#[derive(Clone, Debug)]
-pub struct AnalyzeGraphArgs {
-    pub files: Vec<PathBuf>,
-    pub direction: Direction,
-    pub python: Option<PathBuf>,
-}
-
 /// Configuration overrides provided via dedicated CLI flags:
 /// `--line-length`, `--respect-gitignore`, etc.
 #[derive(Clone, Default)]
+#[allow(clippy::struct_excessive_bools)]
 struct ExplicitConfigOverrides {
     dummy_variable_rgx: Option<Regex>,
     exclude: Option<Vec<FilePattern>>,
@@ -1293,7 +1204,7 @@ struct ExplicitConfigOverrides {
     preview: Option<PreviewMode>,
     respect_gitignore: Option<bool>,
     select: Option<Vec<RuleSelector>>,
-    target_version: Option<ast::PythonVersion>,
+    target_version: Option<PythonVersion>,
     unfixable: Option<Vec<RuleSelector>>,
     // TODO(charlie): Captured in pyproject.toml as a default, but not part of `Settings`.
     cache_dir: Option<PathBuf>,
@@ -1301,10 +1212,9 @@ struct ExplicitConfigOverrides {
     fix_only: Option<bool>,
     unsafe_fixes: Option<UnsafeFixes>,
     force_exclude: Option<bool>,
-    output_format: Option<OutputFormat>,
+    output_format: Option<SerializationFormat>,
     show_fixes: Option<bool>,
     extension: Option<Vec<ExtensionPair>>,
-    detect_string_imports: Option<bool>,
 }
 
 impl ConfigurationTransformer for ExplicitConfigOverrides {
@@ -1389,9 +1299,6 @@ impl ConfigurationTransformer for ExplicitConfigOverrides {
         if let Some(extension) = &self.extension {
             config.extension = Some(extension.iter().cloned().collect());
         }
-        if let Some(detect_string_imports) = &self.detect_string_imports {
-            config.analyze.detect_string_imports = Some(*detect_string_imports);
-        }
 
         config
     }

crates/ruff/src/cache.rs

@@ -3,8 +3,8 @@ use std::fs::{self, File};
 use std::hash::Hasher;
 use std::io::{self, BufReader, Write};
 use std::path::{Path, PathBuf};
-use std::sync::Mutex;
 use std::sync::atomic::{AtomicU64, Ordering};
+use std::sync::Mutex;
 use std::time::{Duration, SystemTime};
 
 use anyhow::{Context, Result};
@@ -13,21 +13,21 @@ use itertools::Itertools;
 use log::{debug, error};
 use rayon::iter::ParallelIterator;
 use rayon::iter::{IntoParallelIterator, ParallelBridge};
-use ruff_linter::codes::Rule;
 use rustc_hash::FxHashMap;
+use serde::{Deserialize, Serialize};
 use tempfile::NamedTempFile;
 
 use ruff_cache::{CacheKey, CacheKeyHasher};
-use ruff_diagnostics::Fix;
+use ruff_diagnostics::{DiagnosticKind, Fix};
 use ruff_linter::message::Message;
-use ruff_linter::package::PackageRoot;
-use ruff_linter::{VERSION, warn_user};
+use ruff_linter::{warn_user, VERSION};
 use ruff_macros::CacheKey;
 use ruff_notebook::NotebookIndex;
+use ruff_python_ast::imports::ImportMap;
 use ruff_source_file::SourceFileBuilder;
-use ruff_text_size::{Ranged, TextRange, TextSize};
-use ruff_workspace::Settings;
+use ruff_text_size::{TextRange, TextSize};
 use ruff_workspace::resolver::Resolver;
+use ruff_workspace::Settings;
 
 use crate::diagnostics::Diagnostics;
 
@@ -86,7 +86,7 @@ pub(crate) struct Cache {
     changes: Mutex<Vec<Change>>,
     /// The "current" timestamp used as cache for the updates of
     /// [`FileCache::last_seen`]
-    #[expect(clippy::struct_field_names)]
+    #[allow(clippy::struct_field_names)]
     last_seen_cache: u64,
 }
 
@@ -112,24 +112,23 @@ impl Cache {
                 return Cache::empty(path, package_root);
             }
             Err(err) => {
-                warn_user!("Failed to open cache file `{}`: {err}", path.display());
+                warn_user!("Failed to open cache file '{}': {err}", path.display());
                 return Cache::empty(path, package_root);
             }
         };
 
-        let mut package: PackageCache =
-            match bincode::decode_from_reader(BufReader::new(file), bincode::config::standard()) {
-                Ok(package) => package,
-                Err(err) => {
-                    warn_user!("Failed parse cache file `{}`: {err}", path.display());
-                    return Cache::empty(path, package_root);
-                }
-            };
+        let mut package: PackageCache = match bincode::deserialize_from(BufReader::new(file)) {
+            Ok(package) => package,
+            Err(err) => {
+                warn_user!("Failed parse cache file '{}': {err}", path.display());
+                return Cache::empty(path, package_root);
+            }
+        };
 
         // Sanity check.
         if package.package_root != package_root {
             warn_user!(
-                "Different package root in cache: expected `{}`, got `{}`",
+                "Different package root in cache: expected '{}', got '{}'",
                 package_root.display(),
                 package.package_root.display(),
             );
@@ -147,7 +146,7 @@ impl Cache {
         Cache::new(path, package)
     }
 
-    #[expect(clippy::cast_possible_truncation)]
+    #[allow(clippy::cast_possible_truncation)]
     fn new(path: PathBuf, package: PackageCache) -> Self {
         Cache {
             path,
@@ -176,36 +175,24 @@ impl Cache {
 
         // Serialize to in-memory buffer because hyperfine benchmark showed that it's faster than
         // using a `BufWriter` and our cache files are small enough that streaming isn't necessary.
-        let serialized = bincode::encode_to_vec(&self.package, bincode::config::standard())
-            .context("Failed to serialize cache data")?;
+        let serialized =
+            bincode::serialize(&self.package).context("Failed to serialize cache data")?;
         temp_file
             .write_all(&serialized)
             .context("Failed to write serialized cache to temporary file.")?;
 
-        if let Err(err) = temp_file.persist(&self.path) {
-            // On Windows, writing to the cache file can fail if the file is still open (e.g., if
-            // the user is running Ruff from multiple processes over the same directory).
-            if cfg!(windows) && err.error.kind() == io::ErrorKind::PermissionDenied {
-                warn_user!(
-                    "Failed to write cache file `{}`: {}",
-                    self.path.display(),
-                    err.error
-                );
-            } else {
-                return Err(err).with_context(|| {
-                    format!(
-                        "Failed to rename temporary cache file to {}",
-                        self.path.display()
-                    )
-                });
-            }
-        }
+        temp_file.persist(&self.path).with_context(|| {
+            format!(
+                "Failed to rename temporary cache file to {}",
+                self.path.display()
+            )
+        })?;
 
         Ok(())
     }
 
     /// Applies the pending changes without storing the cache to disk.
-    #[expect(clippy::cast_possible_truncation)]
+    #[allow(clippy::cast_possible_truncation)]
     pub(crate) fn save(&mut self) -> bool {
         /// Maximum duration for which we keep a file in cache that hasn't been seen.
         const MAX_LAST_SEEN: Duration = Duration::from_secs(30 * 24 * 60 * 60); // 30 days.
@@ -312,7 +299,7 @@ impl Cache {
 }
 
 /// On disk representation of a cache of a package.
-#[derive(bincode::Encode, Debug, bincode::Decode)]
+#[derive(Deserialize, Debug, Serialize)]
 struct PackageCache {
     /// Path to the root of the package.
     ///
@@ -324,7 +311,7 @@ struct PackageCache {
 }
 
 /// On disk representation of the cache per source file.
-#[derive(bincode::Decode, Debug, bincode::Encode)]
+#[derive(Deserialize, Debug, Serialize)]
 pub(crate) struct FileCache {
     /// Key that determines if the cached item is still valid.
     key: u64,
@@ -347,17 +334,12 @@ impl FileCache {
                 let file = SourceFileBuilder::new(path.to_string_lossy(), &*lint.source).finish();
                 lint.messages
                     .iter()
-                    .map(|msg| {
-                        Message::diagnostic(
-                            msg.rule.into(),
-                            msg.body.clone(),
-                            msg.suggestion.clone(),
-                            msg.range,
-                            msg.fix.clone(),
-                            msg.parent,
-                            file.clone(),
-                            msg.noqa_offset,
-                        )
+                    .map(|msg| Message {
+                        kind: msg.kind.clone(),
+                        range: msg.range,
+                        fix: msg.fix.clone(),
+                        file: file.clone(),
+                        noqa_offset: msg.noqa_offset,
                     })
                     .collect()
             };
@@ -366,12 +348,12 @@ impl FileCache {
             } else {
                 FxHashMap::default()
             };
-            Diagnostics::new(messages, notebook_indexes)
+            Diagnostics::new(messages, lint.imports.clone(), notebook_indexes)
         })
     }
 }
 
-#[derive(Debug, Default, bincode::Decode, bincode::Encode)]
+#[derive(Debug, Default, Deserialize, Serialize)]
 struct FileCacheData {
     lint: Option<LintCacheData>,
     formatted: bool,
@@ -409,10 +391,10 @@ pub(crate) fn init(path: &Path) -> Result<()> {
     Ok(())
 }
 
-#[derive(bincode::Decode, Debug, bincode::Encode, PartialEq)]
+#[derive(Deserialize, Debug, Serialize, PartialEq)]
 pub(crate) struct LintCacheData {
     /// Imports made.
-    // pub(super) imports: ImportMap,
+    pub(super) imports: ImportMap,
     /// Diagnostic messages.
     pub(super) messages: Vec<CacheMessage>,
     /// Source code of the file.
@@ -422,44 +404,41 @@ pub(crate) struct LintCacheData {
     /// This will be empty if `messages` is empty.
     pub(super) source: String,
     /// Notebook index if this file is a Jupyter Notebook.
-    #[bincode(with_serde)]
     pub(super) notebook_index: Option<NotebookIndex>,
 }
 
 impl LintCacheData {
     pub(crate) fn from_messages(
         messages: &[Message],
+        imports: ImportMap,
         notebook_index: Option<NotebookIndex>,
     ) -> Self {
         let source = if let Some(msg) = messages.first() {
-            msg.source_file().source_text().to_owned()
+            msg.file.source_text().to_owned()
         } else {
             String::new() // No messages, no need to keep the source!
         };
 
         let messages = messages
             .iter()
-            .filter_map(|msg| msg.to_rule().map(|rule| (rule, msg)))
-            .map(|(rule, msg)| {
+            .map(|msg| {
                 // Make sure that all message use the same source file.
                 assert_eq!(
-                    msg.source_file(),
-                    messages.first().unwrap().source_file(),
+                    msg.file,
+                    messages.first().unwrap().file,
                     "message uses a different source file"
                 );
                 CacheMessage {
-                    rule,
-                    body: msg.body().to_string(),
-                    suggestion: msg.suggestion().map(ToString::to_string),
-                    range: msg.range(),
-                    parent: msg.parent,
-                    fix: msg.fix().cloned(),
-                    noqa_offset: msg.noqa_offset(),
+                    kind: msg.kind.clone(),
+                    range: msg.range,
+                    fix: msg.fix.clone(),
+                    noqa_offset: msg.noqa_offset,
                 }
             })
             .collect();
 
         Self {
+            imports,
             messages,
             source,
             notebook_index,
@@ -468,24 +447,13 @@ impl LintCacheData {
 }
 
 /// On disk representation of a diagnostic message.
-#[derive(bincode::Decode, Debug, bincode::Encode, PartialEq)]
+#[derive(Deserialize, Debug, Serialize, PartialEq)]
 pub(super) struct CacheMessage {
-    /// The rule for the cached diagnostic.
-    #[bincode(with_serde)]
-    rule: Rule,
-    /// The message body to display to the user, to explain the diagnostic.
-    body: String,
-    /// The message to display to the user, to explain the suggested fix.
-    suggestion: Option<String>,
+    kind: DiagnosticKind,
     /// Range into the message's [`FileCache::source`].
-    #[bincode(with_serde)]
     range: TextRange,
-    #[bincode(with_serde)]
-    parent: Option<TextSize>,
-    #[bincode(with_serde)]
     fix: Option<Fix>,
-    #[bincode(with_serde)]
-    noqa_offset: Option<TextSize>,
+    noqa_offset: TextSize,
 }
 
 pub(crate) trait PackageCaches {
@@ -517,7 +485,7 @@ pub(crate) struct PackageCacheMap<'a>(FxHashMap<&'a Path, Cache>);
 
 impl<'a> PackageCacheMap<'a> {
     pub(crate) fn init(
-        package_roots: &FxHashMap<&'a Path, Option<PackageRoot<'a>>>,
+        package_roots: &FxHashMap<&'a Path, Option<&'a Path>>,
         resolver: &Resolver,
     ) -> Self {
         fn init_cache(path: &Path) {
@@ -533,9 +501,7 @@ impl<'a> PackageCacheMap<'a> {
         Self(
             package_roots
                 .iter()
-                .map(|(package, package_root)| {
-                    package_root.map(PackageRoot::path).unwrap_or(package)
-                })
+                .map(|(package, package_root)| package_root.unwrap_or(package))
                 .unique()
                 .par_bridge()
                 .map(|cache_root| {
@@ -603,23 +569,20 @@ mod tests {
     use std::time::SystemTime;
 
     use anyhow::Result;
-    use filetime::{FileTime, set_file_mtime};
+    use filetime::{set_file_mtime, FileTime};
     use itertools::Itertools;
-    use ruff_linter::settings::LinterSettings;
     use test_case::test_case;
 
     use ruff_cache::CACHE_DIR_NAME;
-    use ruff_linter::message::Message;
-    use ruff_linter::package::PackageRoot;
     use ruff_linter::settings::flags;
     use ruff_linter::settings::types::UnsafeFixes;
-    use ruff_python_ast::{PySourceType, PythonVersion};
+    use ruff_python_ast::PySourceType;
     use ruff_workspace::Settings;
 
     use crate::cache::{self, FileCache, FileCacheData, FileCacheKey};
     use crate::cache::{Cache, RelativePathBuf};
-    use crate::commands::format::{FormatCommandError, FormatMode, FormatResult, format_path};
-    use crate::diagnostics::{Diagnostics, lint_path};
+    use crate::commands::format::{format_path, FormatCommandError, FormatMode, FormatResult};
+    use crate::diagnostics::{lint_path, Diagnostics};
 
     #[test_case("../ruff_linter/resources/test/fixtures", "ruff_tests/cache_same_results_ruff_linter"; "ruff_linter_fixtures")]
     #[test_case("../ruff_notebook/resources/test/fixtures", "ruff_tests/cache_same_results_ruff_notebook"; "ruff_notebook_fixtures")]
@@ -631,10 +594,6 @@ mod tests {
 
         let settings = Settings {
             cache_dir,
-            linter: LinterSettings {
-                unresolved_target_version: PythonVersion::latest().into(),
-                ..Default::default()
-            },
             ..Settings::default()
         };
 
@@ -669,7 +628,7 @@ mod tests {
 
                 let diagnostics = lint_path(
                     &path,
-                    Some(PackageRoot::root(&package_root)),
+                    Some(&package_root),
                     &settings.linter,
                     Some(&cache),
                     flags::Noqa::Enabled,
@@ -677,7 +636,11 @@ mod tests {
                     UnsafeFixes::Enabled,
                 )
                 .unwrap();
-                if diagnostics.messages.iter().any(Message::is_syntax_error) {
+                if diagnostics
+                    .messages
+                    .iter()
+                    .any(|m| m.kind.name == "SyntaxError")
+                {
                     parse_errors.push(path.clone());
                 }
                 paths.push(path);
@@ -702,7 +665,7 @@ mod tests {
 
             assert!(
                 cache.package.files.contains_key(relative_path),
-                "missing file from cache: `{}`",
+                "missing file from cache: '{}'",
                 relative_path.display()
             );
         }
@@ -711,7 +674,7 @@ mod tests {
         for path in paths {
             got_diagnostics += lint_path(
                 &path,
-                Some(PackageRoot::root(&package_root)),
+                Some(&package_root),
                 &settings.linter,
                 Some(&cache),
                 flags::Noqa::Enabled,
@@ -721,10 +684,7 @@ mod tests {
             .unwrap();
         }
 
-        assert_eq!(
-            expected_diagnostics, got_diagnostics,
-            "left == {expected_diagnostics:#?}, right == {got_diagnostics:#?}",
-        );
+        assert_eq!(expected_diagnostics, got_diagnostics);
     }
 
     #[test]
@@ -850,6 +810,7 @@ mod tests {
         // Regression test for issue #3086.
 
         #[cfg(unix)]
+        #[allow(clippy::items_after_statements)]
         fn flip_execute_permission_bit(path: &Path) -> io::Result<()> {
             use std::os::unix::fs::PermissionsExt;
             let file = fs::OpenOptions::new().write(true).open(path)?;
@@ -858,6 +819,7 @@ mod tests {
         }
 
         #[cfg(windows)]
+        #[allow(clippy::items_after_statements)]
         fn flip_read_only_permission(path: &Path) -> io::Result<()> {
             let file = fs::OpenOptions::new().write(true).open(path)?;
             let mut perms = file.metadata()?.permissions();
@@ -1085,7 +1047,7 @@ mod tests {
         ) -> Result<Diagnostics, anyhow::Error> {
             lint_path(
                 &self.package_root.join(path),
-                Some(PackageRoot::root(&self.package_root)),
+                Some(&self.package_root),
                 &self.settings.linter,
                 Some(cache),
                 flags::Noqa::Enabled,

crates/ruff/src/commands/add_noqa.rs

@@ -10,9 +10,7 @@ use ruff_linter::linter::add_noqa_to_path;
 use ruff_linter::source_kind::SourceKind;
 use ruff_linter::warn_user_once;
 use ruff_python_ast::{PySourceType, SourceType};
-use ruff_workspace::resolver::{
-    PyprojectConfig, ResolvedFile, match_exclusion, python_files_in_path,
-};
+use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile};
 
 use crate::args::ConfigArguments;
 
@@ -26,7 +24,7 @@ pub(crate) fn add_noqa(
     let start = Instant::now();
     let (paths, resolver) = python_files_in_path(files, pyproject_config, config_arguments)?;
     let duration = start.elapsed();
-    debug!("Identified files to lint in: {duration:?}");
+    debug!("Identified files to lint in: {:?}", duration);
 
     if paths.is_empty() {
         warn_user_once!("No Python files found under the given path(s)");
@@ -59,15 +57,6 @@ pub(crate) fn add_noqa(
                 .and_then(|parent| package_roots.get(parent))
                 .and_then(|package| *package);
             let settings = resolver.resolve(path);
-            if (settings.file_resolver.force_exclude || !resolved_file.is_root())
-                && match_exclusion(
-                    resolved_file.path(),
-                    resolved_file.file_name(),
-                    &settings.linter.exclude,
-                )
-            {
-                return None;
-            }
             let source_kind = match SourceKind::from_path(path, source_type) {
                 Ok(Some(source_kind)) => source_kind,
                 Ok(None) => return None,
@@ -87,7 +76,7 @@ pub(crate) fn add_noqa(
         .sum();
 
     let duration = start.elapsed();
-    debug!("Added noqa to files in: {duration:?}");
+    debug!("Added noqa to files in: {:?}", duration);
 
     Ok(modifications)
 }

crates/ruff/src/commands/analyze_graph.rs

@@ -1,262 +0,0 @@
-use crate::args::{AnalyzeGraphArgs, ConfigArguments};
-use crate::resolve::resolve;
-use crate::{ExitStatus, resolve_default_files};
-use anyhow::Result;
-use log::{debug, warn};
-use path_absolutize::CWD;
-use ruff_db::system::{SystemPath, SystemPathBuf};
-use ruff_graph::{Direction, ImportMap, ModuleDb, ModuleImports};
-use ruff_linter::package::PackageRoot;
-use ruff_linter::{warn_user, warn_user_once};
-use ruff_python_ast::{PySourceType, SourceType};
-use ruff_workspace::resolver::{ResolvedFile, match_exclusion, python_files_in_path};
-use rustc_hash::FxHashMap;
-use std::io::Write;
-use std::path::{Path, PathBuf};
-use std::sync::{Arc, Mutex};
-
-/// Generate an import map.
-pub(crate) fn analyze_graph(
-    args: AnalyzeGraphArgs,
-    config_arguments: &ConfigArguments,
-) -> Result<ExitStatus> {
-    // Construct the "default" settings. These are used when no `pyproject.toml`
-    // files are present, or files are injected from outside the hierarchy.
-    let pyproject_config = resolve(config_arguments, None)?;
-    if pyproject_config.settings.analyze.preview.is_disabled() {
-        warn_user!("`ruff analyze graph` is experimental and may change without warning");
-    }
-
-    // Write all paths relative to the current working directory.
-    let root =
-        SystemPathBuf::from_path_buf(CWD.clone()).expect("Expected a UTF-8 working directory");
-
-    // Find all Python files.
-    let files = resolve_default_files(args.files, false);
-    let (paths, resolver) = python_files_in_path(&files, &pyproject_config, config_arguments)?;
-
-    if paths.is_empty() {
-        warn_user_once!("No Python files found under the given path(s)");
-        return Ok(ExitStatus::Success);
-    }
-
-    // Resolve all package roots.
-    let package_roots = resolver
-        .package_roots(
-            &paths
-                .iter()
-                .flatten()
-                .map(ResolvedFile::path)
-                .collect::<Vec<_>>(),
-        )
-        .into_iter()
-        .map(|(path, package)| {
-            (
-                path.to_path_buf(),
-                package.map(PackageRoot::path).map(Path::to_path_buf),
-            )
-        })
-        .collect::<FxHashMap<_, _>>();
-
-    // Create a database from the source roots.
-    let src_roots = package_roots
-        .values()
-        .filter_map(|package| package.as_deref())
-        .filter_map(|package| package.parent())
-        .map(Path::to_path_buf)
-        .filter_map(|path| SystemPathBuf::from_path_buf(path).ok())
-        .collect();
-
-    let db = ModuleDb::from_src_roots(
-        src_roots,
-        pyproject_config
-            .settings
-            .analyze
-            .target_version
-            .as_tuple()
-            .into(),
-        args.python
-            .and_then(|python| SystemPathBuf::from_path_buf(python).ok()),
-    )?;
-
-    let imports = {
-        // Create a cache for resolved globs.
-        let glob_resolver = Arc::new(Mutex::new(GlobResolver::default()));
-
-        // Collect and resolve the imports for each file.
-        let result = Arc::new(Mutex::new(Vec::new()));
-        let inner_result = Arc::clone(&result);
-        let db = db.clone();
-
-        rayon::scope(move |scope| {
-            for resolved_file in paths {
-                let Ok(resolved_file) = resolved_file else {
-                    continue;
-                };
-
-                let path = resolved_file.path();
-                let package = path
-                    .parent()
-                    .and_then(|parent| package_roots.get(parent))
-                    .and_then(Clone::clone);
-
-                // Resolve the per-file settings.
-                let settings = resolver.resolve(path);
-                let string_imports = settings.analyze.detect_string_imports;
-                let include_dependencies = settings.analyze.include_dependencies.get(path).cloned();
-
-                // Skip excluded files.
-                if (settings.file_resolver.force_exclude || !resolved_file.is_root())
-                    && match_exclusion(
-                        resolved_file.path(),
-                        resolved_file.file_name(),
-                        &settings.analyze.exclude,
-                    )
-                {
-                    continue;
-                }
-
-                // Ignore non-Python files.
-                let source_type = match settings.analyze.extension.get(path) {
-                    None => match SourceType::from(&path) {
-                        SourceType::Python(source_type) => source_type,
-                        SourceType::Toml(_) => {
-                            debug!("Ignoring TOML file: {}", path.display());
-                            continue;
-                        }
-                    },
-                    Some(language) => PySourceType::from(language),
-                };
-                if matches!(source_type, PySourceType::Ipynb) {
-                    debug!("Ignoring Jupyter notebook: {}", path.display());
-                    continue;
-                }
-
-                // Convert to system paths.
-                let Ok(package) = package.map(SystemPathBuf::from_path_buf).transpose() else {
-                    warn!("Failed to convert package to system path");
-                    continue;
-                };
-                let Ok(path) = SystemPathBuf::from_path_buf(resolved_file.into_path()) else {
-                    warn!("Failed to convert path to system path");
-                    continue;
-                };
-
-                let db = db.clone();
-                let glob_resolver = glob_resolver.clone();
-                let root = root.clone();
-                let result = inner_result.clone();
-                scope.spawn(move |_| {
-                    // Identify any imports via static analysis.
-                    let mut imports =
-                        ModuleImports::detect(&db, &path, package.as_deref(), string_imports)
-                            .unwrap_or_else(|err| {
-                                warn!("Failed to generate import map for {path}: {err}");
-                                ModuleImports::default()
-                            });
-
-                    debug!("Discovered {} imports for {}", imports.len(), path);
-
-                    // Append any imports that were statically defined in the configuration.
-                    if let Some((root, globs)) = include_dependencies {
-                        let mut glob_resolver = glob_resolver.lock().unwrap();
-                        imports.extend(glob_resolver.resolve(root, globs));
-                    }
-
-                    // Convert the path (and imports) to be relative to the working directory.
-                    let path = path
-                        .strip_prefix(&root)
-                        .map(SystemPath::to_path_buf)
-                        .unwrap_or(path);
-                    let imports = imports.relative_to(&root);
-
-                    result.lock().unwrap().push((path, imports));
-                });
-            }
-        });
-
-        // Collect the results.
-        Arc::into_inner(result).unwrap().into_inner()?
-    };
-
-    // Generate the import map.
-    let import_map = match args.direction {
-        Direction::Dependencies => ImportMap::dependencies(imports),
-        Direction::Dependents => ImportMap::dependents(imports),
-    };
-
-    // Print to JSON.
-    writeln!(
-        std::io::stdout(),
-        "{}",
-        serde_json::to_string_pretty(&import_map)?
-    )?;
-
-    std::mem::forget(db);
-
-    Ok(ExitStatus::Success)
-}
-
-/// A resolver for glob sets.
-#[derive(Default, Debug)]
-struct GlobResolver {
-    cache: GlobCache,
-}
-
-impl GlobResolver {
-    /// Resolve a set of globs, anchored at a given root.
-    fn resolve(&mut self, root: PathBuf, globs: Vec<String>) -> Vec<SystemPathBuf> {
-        if let Some(cached) = self.cache.get(&root, &globs) {
-            return cached.clone();
-        }
-
-        let walker = match globwalk::GlobWalkerBuilder::from_patterns(&root, &globs)
-            .file_type(globwalk::FileType::FILE)
-            .build()
-        {
-            Ok(walker) => walker,
-            Err(err) => {
-                warn!("Failed to read glob walker: {err}");
-                return Vec::new();
-            }
-        };
-
-        let mut paths = Vec::new();
-        for entry in walker {
-            let entry = match entry {
-                Ok(entry) => entry,
-                Err(err) => {
-                    warn!("Failed to read glob entry: {err}");
-                    continue;
-                }
-            };
-            let path = match SystemPathBuf::from_path_buf(entry.into_path()) {
-                Ok(path) => path,
-                Err(err) => {
-                    warn!("Failed to convert path to system path: {}", err.display());
-                    continue;
-                }
-            };
-            paths.push(path);
-        }
-
-        self.cache.insert(root, globs, paths.clone());
-        paths
-    }
-}
-
-/// A cache for resolved globs.
-#[derive(Default, Debug)]
-struct GlobCache(FxHashMap<PathBuf, FxHashMap<Vec<String>, Vec<SystemPathBuf>>>);
-
-impl GlobCache {
-    /// Insert a resolved glob.
-    fn insert(&mut self, root: PathBuf, globs: Vec<String>, paths: Vec<SystemPathBuf>) {
-        self.0.entry(root).or_default().insert(globs, paths);
-    }
-
-    /// Get a resolved glob.
-    fn get(&self, root: &Path, globs: &[String]) -> Option<&Vec<SystemPathBuf>> {
-        self.0.get(root).and_then(|map| map.get(globs))
-    }
-}

crates/ruff/src/commands/check.rs

@@ -11,25 +11,26 @@ use log::{debug, error, warn};
 use rayon::prelude::*;
 use rustc_hash::FxHashMap;
 
-use ruff_db::panic::catch_unwind;
 use ruff_diagnostics::Diagnostic;
 use ruff_linter::message::Message;
-use ruff_linter::package::PackageRoot;
 use ruff_linter::registry::Rule;
 use ruff_linter::settings::types::UnsafeFixes;
-use ruff_linter::settings::{LinterSettings, flags};
-use ruff_linter::{IOError, fs, warn_user_once};
+use ruff_linter::settings::{flags, LinterSettings};
+use ruff_linter::{fs, warn_user_once, IOError};
+use ruff_python_ast::imports::ImportMap;
 use ruff_source_file::SourceFileBuilder;
-use ruff_text_size::TextRange;
+use ruff_text_size::{TextRange, TextSize};
 use ruff_workspace::resolver::{
-    PyprojectConfig, ResolvedFile, match_exclusion, python_files_in_path,
+    match_exclusion, python_files_in_path, PyprojectConfig, ResolvedFile,
 };
 
 use crate::args::ConfigArguments;
 use crate::cache::{Cache, PackageCacheMap, PackageCaches};
 use crate::diagnostics::Diagnostics;
+use crate::panic::catch_unwind;
 
 /// Run the linter over a collection of files.
+#[allow(clippy::too_many_arguments)]
 pub(crate) fn check(
     files: &[PathBuf],
     pyproject_config: &PyprojectConfig,
@@ -59,7 +60,7 @@ pub(crate) fn check(
     );
 
     // Load the caches.
-    let caches = if cache.is_enabled() {
+    let caches = if bool::from(cache) {
         Some(PackageCacheMap::init(&package_roots, &resolver))
     } else {
         None
@@ -87,9 +88,7 @@ pub(crate) fn check(
                     return None;
                 }
 
-                let cache_root = package
-                    .map(PackageRoot::path)
-                    .unwrap_or_else(|| path.parent().unwrap_or(path));
+                let cache_root = package.unwrap_or_else(|| path.parent().unwrap_or(path));
                 let cache = caches.get(cache_root);
 
                 lint_path(
@@ -133,8 +132,9 @@ pub(crate) fn check(
                         vec![Message::from_diagnostic(
                             Diagnostic::new(IOError { message }, TextRange::default()),
                             dummy,
-                            None,
+                            TextSize::default(),
                         )],
+                        ImportMap::default(),
                         FxHashMap::default(),
                     )
                 } else {
@@ -173,16 +173,17 @@ pub(crate) fn check(
     caches.persist()?;
 
     let duration = start.elapsed();
-    debug!("Checked {checked_files:?} files in: {duration:?}");
+    debug!("Checked {:?} files in: {:?}", checked_files, duration);
 
     Ok(all_diagnostics)
 }
 
 /// Wraps [`lint_path`](crate::diagnostics::lint_path) in a [`catch_unwind`](std::panic::catch_unwind) and emits
 /// a diagnostic if the linting the file panics.
+#[allow(clippy::too_many_arguments)]
 fn lint_path(
     path: &Path,
-    package: Option<PackageRoot<'_>>,
+    package: Option<&Path>,
     settings: &LinterSettings,
     cache: Option<&Cache>,
     noqa: flags::Noqa,
@@ -228,9 +229,9 @@ mod test {
     use ruff_linter::message::{Emitter, EmitterContext, TextEmitter};
     use ruff_linter::registry::Rule;
     use ruff_linter::settings::types::UnsafeFixes;
-    use ruff_linter::settings::{LinterSettings, flags};
-    use ruff_workspace::Settings;
+    use ruff_linter::settings::{flags, LinterSettings};
     use ruff_workspace::resolver::{PyprojectConfig, PyprojectDiscoveryStrategy};
+    use ruff_workspace::Settings;
 
     use crate::args::ConfigArguments;
 
@@ -269,7 +270,8 @@ mod test {
 
         // Run
         let diagnostics = check(
-            &[tempdir.path().to_path_buf()],
+            // Notebooks are not included by default
+            &[tempdir.path().to_path_buf(), notebook],
             &pyproject_config,
             &ConfigArguments::default(),
             flags::Cache::Disabled,

crates/ruff/src/commands/check_stdin.rs

@@ -1,13 +1,13 @@
 use std::path::Path;
 
 use anyhow::Result;
-use ruff_linter::package::PackageRoot;
+
 use ruff_linter::packaging;
 use ruff_linter::settings::flags;
-use ruff_workspace::resolver::{PyprojectConfig, Resolver, match_exclusion, python_file_at_path};
+use ruff_workspace::resolver::{match_exclusion, python_file_at_path, PyprojectConfig, Resolver};
 
 use crate::args::ConfigArguments;
-use crate::diagnostics::{Diagnostics, lint_stdin};
+use crate::diagnostics::{lint_stdin, Diagnostics};
 use crate::stdin::{parrot_stdin, read_from_stdin};
 
 /// Run the linter over a single file, read from `stdin`.
@@ -42,7 +42,6 @@ pub(crate) fn check_stdin(
     let stdin = read_from_stdin()?;
     let package_root = filename.and_then(Path::parent).and_then(|path| {
         packaging::detect_package_root(path, &resolver.base_settings().linter.namespace_packages)
-            .map(PackageRoot::root)
     });
     let mut diagnostics = lint_stdin(
         filename,

crates/ruff/src/commands/completions/config.rs

@@ -1,156 +0,0 @@
-use clap::builder::{PossibleValue, TypedValueParser, ValueParserFactory};
-use itertools::Itertools;
-use std::str::FromStr;
-
-use ruff_options_metadata::{OptionField, OptionSet, OptionsMetadata, Visit};
-use ruff_workspace::options::Options;
-
-#[derive(Default)]
-struct CollectOptionsVisitor {
-    values: Vec<(String, String)>,
-    parents: Vec<String>,
-}
-
-impl IntoIterator for CollectOptionsVisitor {
-    type Item = (String, String);
-    type IntoIter = std::vec::IntoIter<Self::Item>;
-
-    fn into_iter(self) -> Self::IntoIter {
-        self.values.into_iter()
-    }
-}
-
-impl Visit for CollectOptionsVisitor {
-    fn record_set(&mut self, name: &str, group: OptionSet) {
-        let fully_qualified_name = self
-            .parents
-            .iter()
-            .map(String::as_str)
-            .chain(std::iter::once(name))
-            .collect::<Vec<_>>()
-            .join(".");
-
-        // Only add the set to completion list if it has it's own documentation.
-        self.values.push((
-            fully_qualified_name,
-            group.documentation().unwrap_or("").to_owned(),
-        ));
-
-        self.parents.push(name.to_owned());
-        group.record(self);
-        self.parents.pop();
-    }
-
-    fn record_field(&mut self, name: &str, field: OptionField) {
-        let fqn = self
-            .parents
-            .iter()
-            .map(String::as_str)
-            .chain(std::iter::once(name))
-            .collect::<Vec<_>>()
-            .join(".");
-
-        self.values.push((fqn, field.doc.to_owned()));
-    }
-}
-
-/// Opaque type used solely to enable tab completions
-/// for `ruff option [OPTION]` command.
-#[derive(Clone, Debug)]
-pub struct OptionString(String);
-
-impl From<String> for OptionString {
-    fn from(s: String) -> Self {
-        OptionString(s)
-    }
-}
-
-impl From<OptionString> for String {
-    fn from(value: OptionString) -> Self {
-        value.0
-    }
-}
-
-impl From<&str> for OptionString {
-    fn from(s: &str) -> Self {
-        OptionString(s.to_string())
-    }
-}
-
-impl std::ops::Deref for OptionString {
-    type Target = str;
-
-    fn deref(&self) -> &Self::Target {
-        &self.0
-    }
-}
-
-impl FromStr for OptionString {
-    type Err = ();
-
-    fn from_str(s: &str) -> Result<Self, Self::Err> {
-        Options::metadata()
-            .has(s)
-            .then(|| OptionString(s.to_owned()))
-            .ok_or(())
-    }
-}
-
-#[derive(Clone)]
-pub struct OptionStringParser;
-
-impl ValueParserFactory for OptionString {
-    type Parser = OptionStringParser;
-
-    fn value_parser() -> Self::Parser {
-        OptionStringParser
-    }
-}
-
-impl TypedValueParser for OptionStringParser {
-    type Value = OptionString;
-
-    fn parse_ref(
-        &self,
-        cmd: &clap::Command,
-        arg: Option<&clap::Arg>,
-        value: &std::ffi::OsStr,
-    ) -> Result<Self::Value, clap::Error> {
-        let value = value
-            .to_str()
-            .ok_or_else(|| clap::Error::new(clap::error::ErrorKind::InvalidUtf8))?;
-
-        value.parse().map_err(|()| {
-            let mut error = clap::Error::new(clap::error::ErrorKind::ValueValidation).with_cmd(cmd);
-            if let Some(arg) = arg {
-                error.insert(
-                    clap::error::ContextKind::InvalidArg,
-                    clap::error::ContextValue::String(arg.to_string()),
-                );
-            }
-            error.insert(
-                clap::error::ContextKind::InvalidValue,
-                clap::error::ContextValue::String(value.to_string()),
-            );
-            error
-        })
-    }
-
-    fn possible_values(&self) -> Option<Box<dyn Iterator<Item = PossibleValue> + '_>> {
-        let mut visitor = CollectOptionsVisitor::default();
-        Options::metadata().record(&mut visitor);
-
-        Some(Box::new(visitor.into_iter().map(|(name, doc)| {
-            let first_paragraph = doc
-                .lines()
-                .take_while(|line| !line.trim_end().is_empty())
-                // Replace double quotes with single quotes,to avoid clap's lack of escaping
-                // when creating zsh completions. This has no security implications, as it only
-                // affects the help string, which is never executed
-                .map(|s| s.replace('"', "'"))
-                .join(" ");
-
-            PossibleValue::new(name).help(first_paragraph)
-        })))
-    }
-}

crates/ruff/src/commands/completions/mod.rs

@@ -1 +0,0 @@
-pub(crate) mod config;

crates/ruff/src/commands/config.rs

@@ -1,38 +1,19 @@
-use anyhow::{Result, anyhow};
+use anyhow::{anyhow, Result};
 
-use crate::args::HelpFormat;
-
-use ruff_options_metadata::OptionsMetadata;
 use ruff_workspace::options::Options;
+use ruff_workspace::options_base::OptionsMetadata;
 
-#[expect(clippy::print_stdout)]
-pub(crate) fn config(key: Option<&str>, format: HelpFormat) -> Result<()> {
+#[allow(clippy::print_stdout)]
+pub(crate) fn config(key: Option<&str>) -> Result<()> {
     match key {
-        None => {
-            let metadata = Options::metadata();
-            match format {
-                HelpFormat::Text => {
-                    println!("{metadata}");
-                }
-
-                HelpFormat::Json => {
-                    println!("{}", &serde_json::to_string_pretty(&metadata)?);
-                }
-            }
-        }
+        None => print!("{}", Options::metadata()),
         Some(key) => match Options::metadata().find(key) {
             None => {
                 return Err(anyhow!("Unknown option: {key}"));
             }
-            Some(entry) => match format {
-                HelpFormat::Text => {
-                    print!("{entry}");
-                }
-
-                HelpFormat::Json => {
-                    println!("{}", &serde_json::to_string_pretty(&entry)?);
-                }
-            },
+            Some(entry) => {
+                print!("{entry}");
+            }
         },
     }
     Ok(())

crates/ruff/src/commands/format.rs

@@ -1,7 +1,7 @@
 use std::fmt::{Display, Formatter};
 use std::fs::File;
 use std::io;
-use std::io::{Write, stderr, stdout};
+use std::io::{stderr, stdout, Write};
 use std::path::{Path, PathBuf};
 use std::time::Instant;
 
@@ -11,31 +11,29 @@ use itertools::Itertools;
 use log::{error, warn};
 use rayon::iter::Either::{Left, Right};
 use rayon::iter::{IntoParallelRefIterator, ParallelIterator};
-use ruff_python_parser::ParseError;
 use rustc_hash::FxHashSet;
 use thiserror::Error;
 use tracing::debug;
 
-use ruff_db::panic::{PanicError, catch_unwind};
 use ruff_diagnostics::SourceMap;
 use ruff_linter::fs;
 use ruff_linter::logging::{DisplayParseError, LogLevel};
-use ruff_linter::package::PackageRoot;
 use ruff_linter::registry::Rule;
 use ruff_linter::rules::flake8_quotes::settings::Quote;
 use ruff_linter::source_kind::{SourceError, SourceKind};
 use ruff_linter::warn_user_once;
 use ruff_python_ast::{PySourceType, SourceType};
-use ruff_python_formatter::{FormatModuleError, QuoteStyle, format_module_source, format_range};
+use ruff_python_formatter::{format_module_source, format_range, FormatModuleError, QuoteStyle};
 use ruff_source_file::LineIndex;
 use ruff_text_size::{TextLen, TextRange, TextSize};
+use ruff_workspace::resolver::{match_exclusion, python_files_in_path, ResolvedFile, Resolver};
 use ruff_workspace::FormatterSettings;
-use ruff_workspace::resolver::{ResolvedFile, Resolver, match_exclusion, python_files_in_path};
 
 use crate::args::{ConfigArguments, FormatArguments, FormatRange};
 use crate::cache::{Cache, FileCacheKey, PackageCacheMap, PackageCaches};
+use crate::panic::{catch_unwind, PanicError};
 use crate::resolve::resolve;
-use crate::{ExitStatus, resolve_default_files};
+use crate::{resolve_default_files, ExitStatus};
 
 #[derive(Debug, Copy, Clone, is_macro::Is)]
 pub(crate) enum FormatMode {
@@ -138,9 +136,7 @@ pub(crate) fn format(
                         .parent()
                         .and_then(|parent| package_roots.get(parent).copied())
                         .flatten();
-                    let cache_root = package
-                        .map(PackageRoot::path)
-                        .unwrap_or_else(|| path.parent().unwrap_or(path));
+                    let cache_root = package.unwrap_or_else(|| path.parent().unwrap_or(path));
                     let cache = caches.get(cache_root);
 
                     Some(
@@ -160,7 +156,7 @@ pub(crate) fn format(
                             }),
                             Err(error) => Err(FormatCommandError::Panic(
                                 Some(resolved_file.path().to_path_buf()),
-                                Box::new(error),
+                                error,
                             )),
                         },
                     )
@@ -180,7 +176,6 @@ pub(crate) fn format(
         duration
     );
 
-    // Store the caches.
     caches.persist()?;
 
     // Report on any errors.
@@ -214,11 +209,7 @@ pub(crate) fn format(
     match mode {
         FormatMode::Write => {
             if errors.is_empty() {
-                if cli.exit_non_zero_on_format && results.any_formatted() {
-                    Ok(ExitStatus::Failure)
-                } else {
-                    Ok(ExitStatus::Success)
-                }
+                Ok(ExitStatus::Success)
             } else {
                 Ok(ExitStatus::Error)
             }
@@ -238,7 +229,7 @@ pub(crate) fn format(
 }
 
 /// Format the file at the given [`Path`].
-#[tracing::instrument(level = "debug", skip_all, fields(path = %path.display()))]
+#[tracing::instrument(level="debug", skip_all, fields(path = %path.display()))]
 pub(crate) fn format_path(
     path: &Path,
     settings: &FormatterSettings,
@@ -346,7 +337,7 @@ pub(crate) fn format_source(
 ) -> Result<FormattedSource, FormatCommandError> {
     match &source_kind {
         SourceKind::Python(unformatted) => {
-            let options = settings.to_format_options(source_type, unformatted, path);
+            let options = settings.to_format_options(source_type, unformatted);
 
             let formatted = if let Some(range) = range {
                 let line_index = LineIndex::from_source_text(unformatted);
@@ -362,7 +353,7 @@ pub(crate) fn format_source(
                 })
             } else {
                 // Using `Printed::into_code` requires adding `ruff_formatter` as a direct dependency, and I suspect that Rust can optimize the closure away regardless.
-                #[expect(clippy::redundant_closure_for_method_calls)]
+                #[allow(clippy::redundant_closure_for_method_calls)]
                 format_module_source(unformatted, options).map(|formatted| formatted.into_code())
             };
 
@@ -396,7 +387,7 @@ pub(crate) fn format_source(
                 ));
             }
 
-            let options = settings.to_format_options(source_type, notebook.source_code(), path);
+            let options = settings.to_format_options(source_type, notebook.source_code());
 
             let mut output: Option<String> = None;
             let mut last: Option<TextSize> = None;
@@ -411,12 +402,8 @@ pub(crate) fn format_source(
                 let formatted =
                     format_module_source(unformatted, options.clone()).map_err(|err| {
                         if let FormatModuleError::ParseError(err) = err {
-                            // Offset the error by the start of the cell
                             DisplayParseError::from_source_kind(
-                                ParseError {
-                                    error: err.error,
-                                    location: err.location.checked_add(*start).unwrap(),
-                                },
+                                err,
                                 path.map(Path::to_path_buf),
                                 source_kind,
                             )
@@ -635,7 +622,7 @@ impl<'a> FormatResults<'a> {
 pub(crate) enum FormatCommandError {
     Ignore(#[from] ignore::Error),
     Parse(#[from] DisplayParseError),
-    Panic(Option<PathBuf>, Box<PanicError>),
+    Panic(Option<PathBuf>, PanicError),
     Read(Option<PathBuf>, SourceError),
     Format(Option<PathBuf>, FormatModuleError),
     Write(Option<PathBuf>, SourceError),
@@ -797,6 +784,8 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
     let mut incompatible_rules = FxHashSet::default();
     for setting in resolver.settings() {
         for rule in [
+            // The formatter might collapse implicit string concatenation on a single line.
+            Rule::SingleLineImplicitStringConcatenation,
             // Flags missing trailing commas when all arguments are on its own line:
             // ```python
             // def args(
@@ -805,8 +794,6 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
             //     pass
             // ```
             Rule::MissingTrailingComma,
-            // The formatter always removes blank lines before the docstring.
-            Rule::IncorrectBlankLineBeforeClass,
         ] {
             if setting.linter.rules.enabled(rule) {
                 incompatible_rules.insert(rule);
@@ -820,16 +807,7 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
             .map(|rule| format!("`{}`", rule.noqa_code()))
             .collect();
         rule_names.sort();
-        if let [rule] = rule_names.as_slice() {
-            warn_user_once!(
-                "The following rule may cause conflicts when used with the formatter: {rule}. To avoid unexpected behavior, we recommend disabling this rule, either by removing it from the `lint.select` or `lint.extend-select` configuration, or adding it to the `lint.ignore` configuration."
-            );
-        } else {
-            warn_user_once!(
-                "The following rules may cause conflicts when used with the formatter: {}. To avoid unexpected behavior, we recommend disabling these rules, either by removing them from the `lint.select` or `lint.extend-select` configuration, or adding them to the `lint.ignore` configuration.",
-                rule_names.join(", ")
-            );
-        }
+        warn_user_once!("The following rules may cause conflicts when used with the formatter: {}. To avoid unexpected behavior, we recommend disabling these rules, either by removing them from the `select` or `extend-select` configuration, or adding them to the `ignore` configuration.", rule_names.join(", "));
     }
 
     // Next, validate settings-specific incompatibilities.
@@ -838,33 +816,14 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
         if setting.linter.rules.enabled(Rule::TabIndentation)
             && setting.formatter.indent_style.is_tab()
         {
-            warn_user_once!(
-                "The `format.indent-style=\"tab\"` option is incompatible with `W191`, which lints against all uses of tabs. We recommend disabling these rules when using the formatter, which enforces a consistent indentation style. Alternatively, set the `format.indent-style` option to `\"space\"`."
-            );
-        }
-
-        if !setting
-            .linter
-            .rules
-            .enabled(Rule::SingleLineImplicitStringConcatenation)
-            && setting
-                .linter
-                .rules
-                .enabled(Rule::MultiLineImplicitStringConcatenation)
-            && !setting.linter.flake8_implicit_str_concat.allow_multiline
-        {
-            warn_user_once!(
-                "The `lint.flake8-implicit-str-concat.allow-multiline = false` option is incompatible with the formatter unless `ISC001` is enabled. We recommend enabling `ISC001` or setting `allow-multiline=true`."
-            );
+            warn_user_once!("The `format.indent-style=\"tab\"` option is incompatible with `W191`, which lints against all uses of tabs. We recommend disabling these rules when using the formatter, which enforces a consistent indentation style. Alternatively, set the `format.indent-style` option to `\"space\"`.");
         }
 
         // Validate all rules that rely on tab styles.
-        if setting.linter.rules.enabled(Rule::DocstringTabIndentation)
+        if setting.linter.rules.enabled(Rule::IndentWithSpaces)
             && setting.formatter.indent_style.is_tab()
         {
-            warn_user_once!(
-                "The `format.indent-style=\"tab\"` option is incompatible with `D206`, with requires space-based indentation. We recommend disabling these rules when using the formatter, which enforces a consistent indentation style. Alternatively, set the `format.indent-style` option to `\"space\"`."
-            );
+            warn_user_once!("The `format.indent-style=\"tab\"` option is incompatible with `D206`, with requires space-based indentation. We recommend disabling these rules when using the formatter, which enforces a consistent indentation style. Alternatively, set the `format.indent-style` option to `\"space\"`.");
         }
 
         // Validate all rules that rely on custom indent widths.
@@ -873,9 +832,7 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
             Rule::IndentationWithInvalidMultipleComment,
         ]) && setting.formatter.indent_width.value() != 4
         {
-            warn_user_once!(
-                "The `format.indent-width` option with a value other than 4 is incompatible with `E111` and `E114`. We recommend disabling these rules when using the formatter, which enforces a consistent indentation width. Alternatively, set the `format.indent-width` option to `4`."
-            );
+            warn_user_once!("The `format.indent-width` option with a value other than 4 is incompatible with `E111` and `E114`. We recommend disabling these rules when using the formatter, which enforces a consistent indentation width. Alternatively, set the `format.indent-width` option to `4`.");
         }
 
         // Validate all rules that rely on quote styles.
@@ -889,14 +846,10 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
                 setting.formatter.quote_style,
             ) {
                 (Quote::Double, QuoteStyle::Single) => {
-                    warn_user_once!(
-                        "The `flake8-quotes.inline-quotes=\"double\"` option is incompatible with the formatter's `format.quote-style=\"single\"`. We recommend disabling `Q000` and `Q003` when using the formatter, which enforces a consistent quote style. Alternatively, set both options to either `\"single\"` or `\"double\"`."
-                    );
+                    warn_user_once!("The `flake8-quotes.inline-quotes=\"double\"` option is incompatible with the formatter's `format.quote-style=\"single\"`. We recommend disabling `Q000` and `Q003` when using the formatter, which enforces a consistent quote style. Alternatively, set both options to either `\"single\"` or `\"double\"`.");
                 }
                 (Quote::Single, QuoteStyle::Double) => {
-                    warn_user_once!(
-                        "The `flake8-quotes.inline-quotes=\"single\"` option is incompatible with the formatter's `format.quote-style=\"double\"`. We recommend disabling `Q000` and `Q003` when using the formatter, which enforces a consistent quote style. Alternatively, set both options to either `\"single\"` or `\"double\"`."
-                    );
+                    warn_user_once!("The `flake8-quotes.inline-quotes=\"single\"` option is incompatible with the formatter's `format.quote-style=\"double\"`. We recommend disabling `Q000` and `Q003` when using the formatter, which enforces a consistent quote style. Alternatively, set both options to either `\"single\"` or `\"double\"`.");
                 }
                 _ => {}
             }
@@ -904,26 +857,14 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
 
         if setting.linter.rules.enabled(Rule::BadQuotesMultilineString)
             && setting.linter.flake8_quotes.multiline_quotes == Quote::Single
-            && matches!(
-                setting.formatter.quote_style,
-                QuoteStyle::Single | QuoteStyle::Double
-            )
         {
-            warn_user_once!(
-                "The `flake8-quotes.multiline-quotes=\"single\"` option is incompatible with the formatter. We recommend disabling `Q001` when using the formatter, which enforces double quotes for multiline strings. Alternatively, set the `flake8-quotes.multiline-quotes` option to `\"double\"`.`"
-            );
+            warn_user_once!("The `flake8-quotes.multiline-quotes=\"single\"` option is incompatible with the formatter. We recommend disabling `Q001` when using the formatter, which enforces double quotes for multiline strings. Alternatively, set the `flake8-quotes.multiline-quotes` option to `\"double\"`.`");
         }
 
         if setting.linter.rules.enabled(Rule::BadQuotesDocstring)
             && setting.linter.flake8_quotes.docstring_quotes == Quote::Single
-            && matches!(
-                setting.formatter.quote_style,
-                QuoteStyle::Single | QuoteStyle::Double
-            )
         {
-            warn_user_once!(
-                "The `flake8-quotes.docstring-quotes=\"single\"` option is incompatible with the formatter. We recommend disabling `Q002` when using the formatter, which enforces double quotes for docstrings. Alternatively, set the `flake8-quotes.docstring-quotes` option to `\"double\"`.`"
-            );
+            warn_user_once!("The `flake8-quotes.multiline-quotes=\"single\"` option is incompatible with the formatter. We recommend disabling `Q002` when using the formatter, which enforces double quotes for docstrings. Alternatively, set the `flake8-quotes.docstring-quotes` option to `\"double\"`.`");
         }
 
         // Validate all isort settings.
@@ -931,16 +872,12 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
             // The formatter removes empty lines if the value is larger than 2 but always inserts a empty line after imports.
             // Two empty lines are okay because `isort` only uses this setting for top-level imports (not in nested blocks).
             if !matches!(setting.linter.isort.lines_after_imports, 1 | 2 | -1) {
-                warn_user_once!(
-                    "The isort option `isort.lines-after-imports` with a value other than `-1`, `1` or `2` is incompatible with the formatter. To avoid unexpected behavior, we recommend setting the option to one of: `2`, `1`, or `-1` (default)."
-                );
+                warn_user_once!("The isort option `isort.lines-after-imports` with a value other than `-1`, `1` or `2` is incompatible with the formatter. To avoid unexpected behavior, we recommend setting the option to one of: `2`, `1`, or `-1` (default).");
             }
 
             // Values larger than two get reduced to one line by the formatter if the import is in a nested block.
             if setting.linter.isort.lines_between_types > 1 {
-                warn_user_once!(
-                    "The isort option `isort.lines-between-types` with a value greater than 1 is incompatible with the formatter. To avoid unexpected behavior, we recommend setting the option to one of: `1` or `0` (default)."
-                );
+                warn_user_once!("The isort option `isort.lines-between-types` with a value greater than 1 is incompatible with the formatter. To avoid unexpected behavior, we recommend setting the option to one of: `1` or `0` (default).");
             }
 
             // isort inserts a trailing comma which the formatter preserves, but only if `skip-magic-trailing-comma` isn't false.
@@ -949,15 +886,11 @@ pub(super) fn warn_incompatible_formatter_settings(resolver: &Resolver) {
                 && !setting.linter.isort.force_single_line
             {
                 if setting.linter.isort.force_wrap_aliases {
-                    warn_user_once!(
-                        "The isort option `isort.force-wrap-aliases` is incompatible with the formatter `format.skip-magic-trailing-comma=true` option. To avoid unexpected behavior, we recommend either setting `isort.force-wrap-aliases=false` or `format.skip-magic-trailing-comma=false`."
-                    );
+                    warn_user_once!("The isort option `isort.force-wrap-aliases` is incompatible with the formatter `format.skip-magic-trailing-comma=true` option. To avoid unexpected behavior, we recommend either setting `isort.force-wrap-aliases=false` or `format.skip-magic-trailing-comma=false`.");
                 }
 
                 if setting.linter.isort.split_on_trailing_comma {
-                    warn_user_once!(
-                        "The isort option `isort.split-on-trailing-comma` is incompatible with the formatter `format.skip-magic-trailing-comma=true` option. To avoid unexpected behavior, we recommend either setting `isort.split-on-trailing-comma=false` or `format.skip-magic-trailing-comma=false`."
-                    );
+                    warn_user_once!("The isort option `isort.split-on-trailing-comma` is incompatible with the formatter `format.skip-magic-trailing-comma=true` option. To avoid unexpected behavior, we recommend either setting `isort.split-on-trailing-comma=false` or `format.skip-magic-trailing-comma=false`.");
                 }
             }
         }

crates/ruff/src/commands/format_stdin.rs

@@ -6,17 +6,17 @@ use log::error;
 
 use ruff_linter::source_kind::SourceKind;
 use ruff_python_ast::{PySourceType, SourceType};
+use ruff_workspace::resolver::{match_exclusion, python_file_at_path, Resolver};
 use ruff_workspace::FormatterSettings;
-use ruff_workspace::resolver::{Resolver, match_exclusion, python_file_at_path};
 
-use crate::ExitStatus;
 use crate::args::{ConfigArguments, FormatArguments, FormatRange};
 use crate::commands::format::{
-    FormatCommandError, FormatMode, FormatResult, FormattedSource, format_source,
-    warn_incompatible_formatter_settings,
+    format_source, warn_incompatible_formatter_settings, FormatCommandError, FormatMode,
+    FormatResult, FormattedSource,
 };
 use crate::resolve::resolve;
 use crate::stdin::{parrot_stdin, read_from_stdin};
+use crate::ExitStatus;
 
 /// Run the formatter over a single file, read from `stdin`.
 pub(crate) fn format_stdin(

crates/ruff/src/commands/mod.rs

@@ -1,7 +1,4 @@
-pub(crate) mod completions;
-
 pub(crate) mod add_noqa;
-pub(crate) mod analyze_graph;
 pub(crate) mod check;
 pub(crate) mod check_stdin;
 pub(crate) mod clean;

crates/ruff/src/commands/rule.rs

@@ -1,4 +1,3 @@
-use std::fmt::Write as _;
 use std::io::{self, BufWriter, Write};
 
 use anyhow::Result;
@@ -19,7 +18,7 @@ struct Explanation<'a> {
     summary: &'a str,
     message_formats: &'a [&'a str],
     fix: String,
-    #[expect(clippy::struct_field_names)]
+    #[allow(clippy::struct_field_names)]
     explanation: Option<&'a str>,
     preview: bool,
 }
@@ -37,23 +36,19 @@ impl<'a> Explanation<'a> {
             message_formats: rule.message_formats(),
             fix,
             explanation: rule.explanation(),
-            preview: rule.is_preview(),
+            preview: rule.is_preview() || rule.is_nursery(),
         }
     }
 }
 
 fn format_rule_text(rule: Rule) -> String {
     let mut output = String::new();
-    let _ = write!(&mut output, "# {} ({})", rule.as_ref(), rule.noqa_code());
+    output.push_str(&format!("# {} ({})", rule.as_ref(), rule.noqa_code()));
     output.push('\n');
     output.push('\n');
 
     let (linter, _) = Linter::parse_code(&rule.noqa_code().to_string()).unwrap();
-    let _ = write!(
-        &mut output,
-        "Derived from the **{}** linter.",
-        linter.name()
-    );
+    output.push_str(&format!("Derived from the **{}** linter.", linter.name()));
     output.push('\n');
     output.push('\n');
 
@@ -67,7 +62,7 @@ fn format_rule_text(rule: Rule) -> String {
         output.push('\n');
     }
 
-    if rule.is_preview() {
+    if rule.is_preview() || rule.is_nursery() {
         output.push_str(
             r"This rule is in preview and is not stable. The `--preview` flag is required for use.",
         );
@@ -81,7 +76,7 @@ fn format_rule_text(rule: Rule) -> String {
         output.push_str("Message formats:");
         for format in rule.message_formats() {
             output.push('\n');
-            let _ = write!(&mut output, "* {format}");
+            output.push_str(&format!("* {format}"));
         }
     }
     output
@@ -97,7 +92,7 @@ pub(crate) fn rule(rule: Rule, format: HelpFormat) -> Result<()> {
         HelpFormat::Json => {
             serde_json::to_writer_pretty(stdout, &Explanation::from_rule(&rule))?;
         }
-    }
+    };
     Ok(())
 }
 

crates/ruff/src/commands/server.rs

@@ -2,13 +2,78 @@ use std::num::NonZeroUsize;
 
 use crate::ExitStatus;
 use anyhow::Result;
+use ruff_linter::logging::LogLevel;
 use ruff_server::Server;
+use tracing::{level_filters::LevelFilter, metadata::Level, subscriber::Interest, Metadata};
+use tracing_subscriber::{
+    layer::{Context, Filter, SubscriberExt},
+    Layer, Registry,
+};
+use tracing_tree::time::Uptime;
 
 pub(crate) fn run_server(
+    preview: bool,
     worker_threads: NonZeroUsize,
-    preview: Option<bool>,
+    log_level: LogLevel,
 ) -> Result<ExitStatus> {
-    let server = Server::new(worker_threads, preview)?;
+    if !preview {
+        tracing::error!("--preview needs to be provided as a command line argument while the server is still unstable.\nFor example: `ruff server --preview`");
+        return Ok(ExitStatus::Error);
+    }
+    let trace_level = if log_level == LogLevel::Verbose {
+        Level::TRACE
+    } else {
+        Level::DEBUG
+    };
+
+    let subscriber = Registry::default().with(
+        tracing_tree::HierarchicalLayer::default()
+            .with_indent_lines(true)
+            .with_indent_amount(2)
+            .with_bracketed_fields(true)
+            .with_targets(true)
+            .with_writer(|| Box::new(std::io::stderr()))
+            .with_timer(Uptime::default())
+            .with_filter(LoggingFilter { trace_level }),
+    );
+
+    tracing::subscriber::set_global_default(subscriber)?;
+
+    let server = Server::new(worker_threads)?;
 
     server.run().map(|()| ExitStatus::Success)
 }
+
+struct LoggingFilter {
+    trace_level: Level,
+}
+
+impl LoggingFilter {
+    fn is_enabled(&self, meta: &Metadata<'_>) -> bool {
+        let filter = if meta.target().starts_with("ruff") {
+            self.trace_level
+        } else {
+            Level::INFO
+        };
+
+        meta.level() <= &filter
+    }
+}
+
+impl<S> Filter<S> for LoggingFilter {
+    fn enabled(&self, meta: &Metadata<'_>, _cx: &Context<'_, S>) -> bool {
+        self.is_enabled(meta)
+    }
+
+    fn callsite_enabled(&self, meta: &'static Metadata<'static>) -> Interest {
+        if self.is_enabled(meta) {
+            Interest::always()
+        } else {
+            Interest::never()
+        }
+    }
+
+    fn max_level_hint(&self) -> Option<LevelFilter> {
+        Some(LevelFilter::from_level(self.trace_level))
+    }
+}

crates/ruff/src/commands/show_files.rs

@@ -5,7 +5,7 @@ use anyhow::Result;
 use itertools::Itertools;
 
 use ruff_linter::warn_user_once;
-use ruff_workspace::resolver::{PyprojectConfig, ResolvedFile, python_files_in_path};
+use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile};
 
 use crate::args::ConfigArguments;
 

crates/ruff/src/commands/show_settings.rs

@@ -1,10 +1,10 @@
 use std::io::Write;
 use std::path::PathBuf;
 
-use anyhow::{Result, bail};
+use anyhow::{bail, Result};
 use itertools::Itertools;
 
-use ruff_workspace::resolver::{PyprojectConfig, ResolvedFile, python_files_in_path};
+use ruff_workspace::resolver::{python_files_in_path, PyprojectConfig, ResolvedFile};
 
 use crate::args::ConfigArguments;
 

crates/ruff/src/commands/version.rs

@@ -16,6 +16,6 @@ pub(crate) fn version(output_format: HelpFormat) -> Result<()> {
         HelpFormat::Json => {
             serde_json::to_writer_pretty(stdout, &version_info)?;
         }
-    }
+    };
     Ok(())
 }

crates/ruff/src/diagnostics.rs

@@ -9,23 +9,24 @@ use std::path::Path;
 
 use anyhow::{Context, Result};
 use colored::Colorize;
-use log::{debug, warn};
+use log::{debug, error, warn};
 use rustc_hash::FxHashMap;
 
 use ruff_diagnostics::Diagnostic;
-use ruff_linter::codes::Rule;
-use ruff_linter::linter::{FixTable, FixerResult, LinterResult, ParseSource, lint_fix, lint_only};
+use ruff_linter::linter::{lint_fix, lint_only, FixTable, FixerResult, LinterResult, ParseSource};
+use ruff_linter::logging::DisplayParseError;
 use ruff_linter::message::Message;
-use ruff_linter::package::PackageRoot;
 use ruff_linter::pyproject_toml::lint_pyproject_toml;
+use ruff_linter::registry::AsRule;
 use ruff_linter::settings::types::UnsafeFixes;
-use ruff_linter::settings::{LinterSettings, flags};
+use ruff_linter::settings::{flags, LinterSettings};
 use ruff_linter::source_kind::{SourceError, SourceKind};
-use ruff_linter::{IOError, fs};
+use ruff_linter::{fs, IOError, SyntaxError};
 use ruff_notebook::{Notebook, NotebookError, NotebookIndex};
+use ruff_python_ast::imports::ImportMap;
 use ruff_python_ast::{PySourceType, SourceType, TomlSourceType};
 use ruff_source_file::SourceFileBuilder;
-use ruff_text_size::TextRange;
+use ruff_text_size::{TextRange, TextSize};
 use ruff_workspace::Settings;
 
 use crate::cache::{Cache, FileCacheKey, LintCacheData};
@@ -34,17 +35,20 @@ use crate::cache::{Cache, FileCacheKey, LintCacheData};
 pub(crate) struct Diagnostics {
     pub(crate) messages: Vec<Message>,
     pub(crate) fixed: FixMap,
+    pub(crate) imports: ImportMap,
     pub(crate) notebook_indexes: FxHashMap<String, NotebookIndex>,
 }
 
 impl Diagnostics {
     pub(crate) fn new(
         messages: Vec<Message>,
+        imports: ImportMap,
         notebook_indexes: FxHashMap<String, NotebookIndex>,
     ) -> Self {
         Self {
             messages,
             fixed: FixMap::default(),
+            imports,
             notebook_indexes,
         }
     }
@@ -55,57 +59,58 @@ impl Diagnostics {
         path: Option<&Path>,
         settings: &LinterSettings,
     ) -> Self {
-        match err {
+        let diagnostic = match err {
             // IO errors.
             SourceError::Io(_)
             | SourceError::Notebook(NotebookError::Io(_) | NotebookError::Json(_)) => {
-                if settings.rules.enabled(Rule::IOError) {
-                    let name = path.map_or_else(|| "-".into(), Path::to_string_lossy);
-                    let source_file = SourceFileBuilder::new(name, "").finish();
-                    Self::new(
-                        vec![Message::from_diagnostic(
-                            Diagnostic::new(
-                                IOError {
-                                    message: err.to_string(),
-                                },
-                                TextRange::default(),
-                            ),
-                            source_file,
-                            None,
-                        )],
-                        FxHashMap::default(),
-                    )
-                } else {
-                    match path {
-                        Some(path) => {
-                            warn!(
-                                "{}{}{} {err}",
-                                "Failed to lint ".bold(),
-                                fs::relativize_path(path).bold(),
-                                ":".bold()
-                            );
-                        }
-                        None => {
-                            warn!("{}{} {err}", "Failed to lint".bold(), ":".bold());
-                        }
-                    }
-
-                    Self::default()
-                }
+                Diagnostic::new(
+                    IOError {
+                        message: err.to_string(),
+                    },
+                    TextRange::default(),
+                )
             }
             // Syntax errors.
             SourceError::Notebook(
                 NotebookError::InvalidJson(_)
                 | NotebookError::InvalidSchema(_)
                 | NotebookError::InvalidFormat(_),
-            ) => {
-                let name = path.map_or_else(|| "-".into(), Path::to_string_lossy);
-                let dummy = SourceFileBuilder::new(name, "").finish();
-                Self::new(
-                    vec![Message::syntax_error(err, TextRange::default(), dummy)],
-                    FxHashMap::default(),
-                )
+            ) => Diagnostic::new(
+                SyntaxError {
+                    message: err.to_string(),
+                },
+                TextRange::default(),
+            ),
+        };
+
+        if settings.rules.enabled(diagnostic.kind.rule()) {
+            let name = path.map_or_else(|| "-".into(), Path::to_string_lossy);
+            let dummy = SourceFileBuilder::new(name, "").finish();
+            Self::new(
+                vec![Message::from_diagnostic(
+                    diagnostic,
+                    dummy,
+                    TextSize::default(),
+                )],
+                ImportMap::default(),
+                FxHashMap::default(),
+            )
+        } else {
+            match path {
+                Some(path) => {
+                    warn!(
+                        "{}{}{} {err}",
+                        "Failed to lint ".bold(),
+                        fs::relativize_path(path).bold(),
+                        ":".bold()
+                    );
+                }
+                None => {
+                    warn!("{}{} {err}", "Failed to lint".bold(), ":".bold());
+                }
             }
+
+            Self::default()
         }
     }
 }
@@ -122,6 +127,7 @@ impl Add for Diagnostics {
 impl AddAssign for Diagnostics {
     fn add_assign(&mut self, other: Self) {
         self.messages.extend(other.messages);
+        self.imports.extend(other.imports);
         self.fixed += other.fixed;
         self.notebook_indexes.extend(other.notebook_indexes);
     }
@@ -177,7 +183,7 @@ impl AddAssign for FixMap {
 /// Lint the source code at the given `Path`.
 pub(crate) fn lint_path(
     path: &Path,
-    package: Option<PackageRoot<'_>>,
+    package: Option<&Path>,
     settings: &LinterSettings,
     cache: Option<&Cache>,
     noqa: flags::Noqa,
@@ -186,7 +192,7 @@ pub(crate) fn lint_path(
 ) -> Result<Diagnostics> {
     // Check the cache.
     let caching = match cache {
-        Some(cache) if noqa.is_enabled() => {
+        Some(cache) if noqa.into() => {
             let relative_path = cache
                 .relative_path(path)
                 .expect("wrong package cache for file");
@@ -259,56 +265,48 @@ pub(crate) fn lint_path(
     };
 
     // Lint the file.
-    let (result, transformed, fixed) =
-        if matches!(fix_mode, flags::FixMode::Apply | flags::FixMode::Diff) {
-            if let Ok(FixerResult {
-                result,
-                transformed,
-                fixed,
-            }) = lint_fix(
-                path,
-                package,
-                noqa,
-                unsafe_fixes,
-                settings,
-                &source_kind,
-                source_type,
-            ) {
-                if !fixed.is_empty() {
-                    match fix_mode {
-                        flags::FixMode::Apply => transformed.write(&mut File::create(path)?)?,
-                        flags::FixMode::Diff => {
-                            write!(
-                                &mut io::stdout().lock(),
-                                "{}",
-                                source_kind.diff(&transformed, Some(path)).unwrap()
-                            )?;
-                        }
-                        flags::FixMode::Generate => {}
+    let (
+        LinterResult {
+            data: (messages, imports),
+            error: parse_error,
+        },
+        transformed,
+        fixed,
+    ) = if matches!(fix_mode, flags::FixMode::Apply | flags::FixMode::Diff) {
+        if let Ok(FixerResult {
+            result,
+            transformed,
+            fixed,
+        }) = lint_fix(
+            path,
+            package,
+            noqa,
+            unsafe_fixes,
+            settings,
+            &source_kind,
+            source_type,
+        ) {
+            if !fixed.is_empty() {
+                match fix_mode {
+                    flags::FixMode::Apply => transformed.write(&mut File::create(path)?)?,
+                    flags::FixMode::Diff => {
+                        write!(
+                            &mut io::stdout().lock(),
+                            "{}",
+                            source_kind.diff(&transformed, Some(path)).unwrap()
+                        )?;
                     }
+                    flags::FixMode::Generate => {}
                 }
-                let transformed = if let Cow::Owned(transformed) = transformed {
-                    transformed
-                } else {
-                    source_kind
-                };
-                (result, transformed, fixed)
-            } else {
-                // If we fail to fix, lint the original source code.
-                let result = lint_only(
-                    path,
-                    package,
-                    settings,
-                    noqa,
-                    &source_kind,
-                    source_type,
-                    ParseSource::None,
-                );
-                let transformed = source_kind;
-                let fixed = FxHashMap::default();
-                (result, transformed, fixed)
             }
+            let transformed = if let Cow::Owned(transformed) = transformed {
+                transformed
+            } else {
+                source_kind
+            };
+            (result, transformed, fixed)
         } else {
+            // If we fail to fix, lint the original source code.
             let result = lint_only(
                 path,
                 package,
@@ -321,14 +319,27 @@ pub(crate) fn lint_path(
             let transformed = source_kind;
             let fixed = FxHashMap::default();
             (result, transformed, fixed)
-        };
+        }
+    } else {
+        let result = lint_only(
+            path,
+            package,
+            settings,
+            noqa,
+            &source_kind,
+            source_type,
+            ParseSource::None,
+        );
+        let transformed = source_kind;
+        let fixed = FxHashMap::default();
+        (result, transformed, fixed)
+    };
 
-    let has_error = result.has_syntax_errors();
-    let messages = result.messages;
+    let imports = imports.unwrap_or_default();
 
     if let Some((cache, relative_path, key)) = caching {
         // We don't cache parsing errors.
-        if !has_error {
+        if parse_error.is_none() {
             // `FixMode::Apply` and `FixMode::Diff` rely on side-effects (writing to disk,
             // and writing the diff to stdout, respectively). If a file has diagnostics, we
             // need to avoid reading from and writing to the cache in these modes.
@@ -343,6 +354,7 @@ pub(crate) fn lint_path(
                     &key,
                     LintCacheData::from_messages(
                         &messages,
+                        imports.clone(),
                         transformed.as_ipy_notebook().map(Notebook::index).cloned(),
                     ),
                 );
@@ -350,6 +362,13 @@ pub(crate) fn lint_path(
         }
     }
 
+    if let Some(error) = parse_error {
+        error!(
+            "{}",
+            DisplayParseError::from_source_kind(error, Some(path.to_path_buf()), &transformed)
+        );
+    }
+
     let notebook_indexes = if let SourceKind::IpyNotebook(notebook) = transformed {
         FxHashMap::from_iter([(path.to_string_lossy().to_string(), notebook.into_index())])
     } else {
@@ -359,50 +378,28 @@ pub(crate) fn lint_path(
     Ok(Diagnostics {
         messages,
         fixed: FixMap::from_iter([(fs::relativize_path(path), fixed)]),
+        imports,
         notebook_indexes,
     })
 }
 
-/// Generate `Diagnostic`s from source code content derived from stdin.
+/// Generate `Diagnostic`s from source code content derived from
+/// stdin.
 pub(crate) fn lint_stdin(
     path: Option<&Path>,
-    package: Option<PackageRoot<'_>>,
+    package: Option<&Path>,
     contents: String,
     settings: &Settings,
     noqa: flags::Noqa,
     fix_mode: flags::FixMode,
 ) -> Result<Diagnostics> {
+    // TODO(charlie): Support `pyproject.toml`.
     let source_type = match path.and_then(|path| settings.linter.extension.get(path)) {
         None => match path.map(SourceType::from).unwrap_or_default() {
             SourceType::Python(source_type) => source_type,
-
-            SourceType::Toml(source_type) if source_type.is_pyproject() => {
-                if !settings
-                    .linter
-                    .rules
-                    .iter_enabled()
-                    .any(|rule_code| rule_code.lint_source().is_pyproject_toml())
-                {
-                    return Ok(Diagnostics::default());
-                }
-
-                let path = path.unwrap();
-                let source_file =
-                    SourceFileBuilder::new(path.to_string_lossy(), contents.clone()).finish();
-
-                match fix_mode {
-                    flags::FixMode::Diff | flags::FixMode::Generate => {}
-                    flags::FixMode::Apply => write!(&mut io::stdout().lock(), "{contents}")?,
-                }
-
-                return Ok(Diagnostics {
-                    messages: lint_pyproject_toml(source_file, &settings.linter),
-                    fixed: FixMap::from_iter([(fs::relativize_path(path), FixTable::default())]),
-                    notebook_indexes: FxHashMap::default(),
-                });
+            SourceType::Toml(_) => {
+                return Ok(Diagnostics::default());
             }
-
-            SourceType::Toml(_) => return Ok(Diagnostics::default()),
         },
         Some(language) => PySourceType::from(language),
     };
@@ -417,66 +414,52 @@ pub(crate) fn lint_stdin(
     };
 
     // Lint the inputs.
-    let (LinterResult { messages, .. }, transformed, fixed) =
-        if matches!(fix_mode, flags::FixMode::Apply | flags::FixMode::Diff) {
-            if let Ok(FixerResult {
-                result,
-                transformed,
-                fixed,
-            }) = lint_fix(
-                path.unwrap_or_else(|| Path::new("-")),
-                package,
-                noqa,
-                settings.unsafe_fixes,
-                &settings.linter,
-                &source_kind,
-                source_type,
-            ) {
-                match fix_mode {
-                    flags::FixMode::Apply => {
-                        // Write the contents to stdout, regardless of whether any errors were fixed.
-                        transformed.write(&mut io::stdout().lock())?;
-                    }
-                    flags::FixMode::Diff => {
-                        // But only write a diff if it's non-empty.
-                        if !fixed.is_empty() {
-                            write!(
-                                &mut io::stdout().lock(),
-                                "{}",
-                                source_kind.diff(&transformed, path).unwrap()
-                            )?;
-                        }
-                    }
-                    flags::FixMode::Generate => {}
+    let (
+        LinterResult {
+            data: (messages, imports),
+            error: parse_error,
+        },
+        transformed,
+        fixed,
+    ) = if matches!(fix_mode, flags::FixMode::Apply | flags::FixMode::Diff) {
+        if let Ok(FixerResult {
+            result,
+            transformed,
+            fixed,
+        }) = lint_fix(
+            path.unwrap_or_else(|| Path::new("-")),
+            package,
+            noqa,
+            settings.unsafe_fixes,
+            &settings.linter,
+            &source_kind,
+            source_type,
+        ) {
+            match fix_mode {
+                flags::FixMode::Apply => {
+                    // Write the contents to stdout, regardless of whether any errors were fixed.
+                    transformed.write(&mut io::stdout().lock())?;
                 }
-                let transformed = if let Cow::Owned(transformed) = transformed {
-                    transformed
-                } else {
-                    source_kind
-                };
-                (result, transformed, fixed)
-            } else {
-                // If we fail to fix, lint the original source code.
-                let result = lint_only(
-                    path.unwrap_or_else(|| Path::new("-")),
-                    package,
-                    &settings.linter,
-                    noqa,
-                    &source_kind,
-                    source_type,
-                    ParseSource::None,
-                );
-
-                // Write the contents to stdout anyway.
-                if fix_mode.is_apply() {
-                    source_kind.write(&mut io::stdout().lock())?;
+                flags::FixMode::Diff => {
+                    // But only write a diff if it's non-empty.
+                    if !fixed.is_empty() {
+                        write!(
+                            &mut io::stdout().lock(),
+                            "{}",
+                            source_kind.diff(&transformed, path).unwrap()
+                        )?;
+                    }
                 }
-
-                let transformed = source_kind;
-                let fixed = FxHashMap::default();
-                (result, transformed, fixed)
+                flags::FixMode::Generate => {}
             }
+            let transformed = if let Cow::Owned(transformed) = transformed {
+                transformed
+            } else {
+                source_kind
+            };
+            (result, transformed, fixed)
         } else {
+            // If we fail to fix, lint the original source code.
             let result = lint_only(
                 path.unwrap_or_else(|| Path::new("-")),
                 package,
@@ -486,10 +469,39 @@ pub(crate) fn lint_stdin(
                 source_type,
                 ParseSource::None,
             );
+
+            // Write the contents to stdout anyway.
+            if fix_mode.is_apply() {
+                source_kind.write(&mut io::stdout().lock())?;
+            }
+
             let transformed = source_kind;
             let fixed = FxHashMap::default();
             (result, transformed, fixed)
-        };
+        }
+    } else {
+        let result = lint_only(
+            path.unwrap_or_else(|| Path::new("-")),
+            package,
+            &settings.linter,
+            noqa,
+            &source_kind,
+            source_type,
+            ParseSource::None,
+        );
+        let transformed = source_kind;
+        let fixed = FxHashMap::default();
+        (result, transformed, fixed)
+    };
+
+    let imports = imports.unwrap_or_default();
+
+    if let Some(error) = parse_error {
+        error!(
+            "{}",
+            DisplayParseError::from_source_kind(error, path.map(Path::to_path_buf), &transformed)
+        );
+    }
 
     let notebook_indexes = if let SourceKind::IpyNotebook(notebook) = transformed {
         FxHashMap::from_iter([(
@@ -506,6 +518,7 @@ pub(crate) fn lint_stdin(
             fs::relativize_path(path.unwrap_or_else(|| Path::new("-"))),
             fixed,
         )]),
+        imports,
         notebook_indexes,
     })
 }

crates/ruff/src/lib.rs

@@ -1,34 +1,33 @@
 #![allow(clippy::print_stdout)]
 
 use std::fs::File;
-use std::io::{self, BufWriter, Write, stdout};
+use std::io::{self, stdout, BufWriter, Write};
 use std::num::NonZeroUsize;
 use std::path::{Path, PathBuf};
 use std::process::ExitCode;
 use std::sync::mpsc::channel;
 
 use anyhow::Result;
+use args::{GlobalConfigArgs, ServerCommand};
 use clap::CommandFactory;
 use colored::Colorize;
 use log::warn;
-use notify::{RecursiveMode, Watcher, recommended_watcher};
+use notify::{recommended_watcher, RecursiveMode, Watcher};
 
-use args::{GlobalConfigArgs, ServerCommand};
-use ruff_linter::logging::{LogLevel, set_up_logging};
+use ruff_linter::logging::{set_up_logging, LogLevel};
 use ruff_linter::settings::flags::FixMode;
-use ruff_linter::settings::types::OutputFormat;
+use ruff_linter::settings::types::SerializationFormat;
 use ruff_linter::{fs, warn_user, warn_user_once};
 use ruff_workspace::Settings;
 
-use crate::args::{
-    AnalyzeCommand, AnalyzeGraphCommand, Args, CheckCommand, Command, FormatCommand,
-};
+use crate::args::{Args, CheckCommand, Command, FormatCommand};
 use crate::printer::{Flags as PrinterFlags, Printer};
 
 pub mod args;
 mod cache;
 mod commands;
 mod diagnostics;
+mod panic;
 mod printer;
 pub mod resolve;
 mod stdin;
@@ -63,19 +62,11 @@ enum ChangeKind {
 /// Return the [`ChangeKind`] based on the list of modified file paths.
 ///
 /// Returns `None` if no relevant changes were detected.
-fn change_detected(event: &notify::Event) -> Option<ChangeKind> {
+fn change_detected(paths: &[PathBuf]) -> Option<ChangeKind> {
     // If any `.toml` files were modified, return `ChangeKind::Configuration`. Otherwise, return
     // `ChangeKind::SourceFile` if any `.py`, `.pyi`, `.pyw`, or `.ipynb` files were modified.
     let mut source_file = false;
-
-    if event.kind.is_access() || event.kind.is_other() {
-        return None;
-    }
-
-    if event.need_rescan() {
-        return Some(ChangeKind::Configuration);
-    }
-    for path in &event.paths {
+    for path in paths {
         if let Some(suffix) = path.extension() {
             match suffix.to_str() {
                 Some("toml") => {
@@ -112,7 +103,7 @@ fn is_stdin(files: &[PathBuf], stdin_filename: Option<&Path>) -> bool {
     file == Path::new("-")
 }
 
-/// Returns the default set of files if none are provided, otherwise returns provided files.
+/// Returns the default set of files if none are provided, otherwise returns `None`.
 fn resolve_default_files(files: Vec<PathBuf>, is_stdin: bool) -> Vec<PathBuf> {
     if files.is_empty() {
         if is_stdin {
@@ -130,11 +121,12 @@ pub fn run(
         command,
         global_options,
     }: Args,
+    deprecated_alias_warning: Option<&'static str>,
 ) -> Result<ExitStatus> {
     {
         let default_panic_hook = std::panic::take_hook();
         std::panic::set_hook(Box::new(move |info| {
-            #[expect(clippy::print_stderr)]
+            #[allow(clippy::print_stderr)]
             {
                 eprintln!(
                     r#"
@@ -153,10 +145,21 @@ pub fn run(
         }));
     }
 
-    // Don't set up logging for the server command, as it has its own logging setup
-    // and setting the global logger can only be done once.
-    if !matches!(command, Command::Server { .. }) {
-        set_up_logging(global_options.log_level())?;
+    // Enabled ANSI colors on Windows 10.
+    #[cfg(windows)]
+    assert!(colored::control::set_virtual_terminal(true).is_ok());
+
+    // support FORCE_COLOR env var
+    if let Some(force_color) = std::env::var_os("FORCE_COLOR") {
+        if force_color.len() > 0 {
+            colored::control::set_override(true);
+        }
+    }
+
+    set_up_logging(global_options.log_level())?;
+
+    if let Some(deprecated_alias_warning) = deprecated_alias_warning {
+        warn_user!("{}", deprecated_alias_warning);
     }
 
     match command {
@@ -177,11 +180,8 @@ pub fn run(
             }
             Ok(ExitStatus::Success)
         }
-        Command::Config {
-            option,
-            output_format,
-        } => {
-            commands::config::config(option.as_deref(), output_format)?;
+        Command::Config { option } => {
+            commands::config::config(option.as_deref())?;
             Ok(ExitStatus::Success)
         }
         Command::Linter { output_format } => {
@@ -198,8 +198,7 @@ pub fn run(
         }
         Command::Check(args) => check(args, global_options),
         Command::Format(args) => format(args, global_options),
-        Command::Server(args) => server(args),
-        Command::Analyze(AnalyzeCommand::Graph(args)) => analyze_graph(args, global_options),
+        Command::Server(args) => server(args, global_options.log_level()),
     }
 }
 
@@ -213,23 +212,15 @@ fn format(args: FormatCommand, global_options: GlobalConfigArgs) -> Result<ExitS
     }
 }
 
-fn analyze_graph(
-    args: AnalyzeGraphCommand,
-    global_options: GlobalConfigArgs,
-) -> Result<ExitStatus> {
-    let (cli, config_arguments) = args.partition(global_options)?;
-
-    commands::analyze_graph::analyze_graph(cli, &config_arguments)
-}
-
-fn server(args: ServerCommand) -> Result<ExitStatus> {
-    let four = NonZeroUsize::new(4).unwrap();
-
+fn server(args: ServerCommand, log_level: LogLevel) -> Result<ExitStatus> {
+    let ServerCommand { preview } = args;
     // by default, we set the number of worker threads to `num_cpus`, with a maximum of 4.
-    let worker_threads = std::thread::available_parallelism()
-        .unwrap_or(four)
-        .min(four);
-    commands::server::run_server(worker_threads, args.resolve_preview())
+    let worker_threads = num_cpus::get().max(4);
+    commands::server::run_server(
+        preview,
+        NonZeroUsize::try_from(worker_threads).expect("a non-zero worker thread count"),
+        log_level,
+    )
 }
 
 pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<ExitStatus> {
@@ -242,9 +233,6 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
     let mut writer: Box<dyn Write> = match cli.output_file {
         Some(path) if !cli.watch => {
             colored::control::set_override(false);
-            if let Some(parent) = path.parent() {
-                std::fs::create_dir_all(parent)?;
-            }
             let file = File::create(path)?;
             Box::new(BufWriter::new(file))
         }
@@ -290,8 +278,8 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
     // - If `--fix` or `--fix-only` is set, apply applicable fixes to the filesystem (or
     //   print them to stdout, if we're reading from stdin).
     // - If `--diff` or `--fix-only` are set, don't print any violations (only applicable fixes)
-    // - By default, applicable fixes only include [`Applicability::Automatic`], but if
-    //   `--unsafe-fixes` is set, then [`Applicability::Suggested`] fixes are included.
+    // - By default, applicable fixes only include [`Applicablility::Automatic`], but if
+    //   `--unsafe-fixes` is set, then [`Applicablility::Suggested`] fixes are included.
 
     let fix_mode = if cli.diff {
         FixMode::Diff
@@ -310,6 +298,13 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
     if show_fixes {
         printer_flags |= PrinterFlags::SHOW_FIX_SUMMARY;
     }
+    if cli.ecosystem_ci {
+        warn_user!(
+            "The formatting of fixes emitted by this option is a work-in-progress, subject to \
+            change at any time, and intended only for internal use."
+        );
+        printer_flags |= PrinterFlags::SHOW_FIX_DIFF;
+    }
 
     #[cfg(debug_assertions)]
     if cache {
@@ -326,7 +321,7 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
             commands::add_noqa::add_noqa(&files, &pyproject_config, &config_arguments)?;
         if modifications > 0 && config_arguments.log_level >= LogLevel::Default {
             let s = if modifications == 1 { "" } else { "s" };
-            #[expect(clippy::print_stderr)]
+            #[allow(clippy::print_stderr)]
             {
                 eprintln!("Added {modifications} noqa directive{s}.");
             }
@@ -349,10 +344,10 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
     let preview = pyproject_config.settings.linter.preview.is_enabled();
 
     if cli.watch {
-        if output_format != OutputFormat::default() {
+        if output_format != SerializationFormat::default(preview) {
             warn_user!(
                 "`--output-format {}` is always used in watch mode.",
-                OutputFormat::default()
+                SerializationFormat::default(preview)
             );
         }
 
@@ -388,7 +383,7 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
         loop {
             match rx.recv() {
                 Ok(event) => {
-                    let Some(change_kind) = change_detected(&event?) else {
+                    let Some(change_kind) = change_detected(&event?.paths) else {
                         continue;
                     };
 
@@ -488,119 +483,79 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
 mod test_file_change_detector {
     use std::path::PathBuf;
 
-    use crate::{ChangeKind, change_detected};
+    use crate::{change_detected, ChangeKind};
 
     #[test]
     fn detect_correct_file_change() {
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/pyproject.toml"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/pyproject.toml"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("pyproject.toml"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("pyproject.toml"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp1/tmp2/tmp3/pyproject.toml"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp1/tmp2/tmp3/pyproject.toml"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/ruff.toml"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/ruff.toml"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/.ruff.toml"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/.ruff.toml"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::SourceFile),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/rule.py"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/rule.py"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::SourceFile),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/rule.pyi"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/rule.pyi"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("pyproject.toml"),
-                    PathBuf::from("tmp/rule.py"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("pyproject.toml"),
+                PathBuf::from("tmp/rule.py"),
+            ]),
         );
         assert_eq!(
             Some(ChangeKind::Configuration),
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/rule.py"),
-                    PathBuf::from("pyproject.toml"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/rule.py"),
+                PathBuf::from("pyproject.toml"),
+            ]),
         );
         assert_eq!(
             None,
-            change_detected(&notify::Event {
-                kind: notify::EventKind::Create(notify::event::CreateKind::File),
-                paths: vec![
-                    PathBuf::from("tmp/rule.js"),
-                    PathBuf::from("tmp/bin/ruff.rs"),
-                ],
-                attrs: notify::event::EventAttributes::default(),
-            }),
+            change_detected(&[
+                PathBuf::from("tmp/rule.js"),
+                PathBuf::from("tmp/bin/ruff.rs"),
+            ]),
         );
     }
 }

crates/ruff/src/main.rs

@@ -1,11 +1,10 @@
-use std::io::Write;
 use std::process::ExitCode;
 
-use clap::Parser;
+use clap::{Parser, Subcommand};
 use colored::Colorize;
 
-use ruff::args::Args;
-use ruff::{ExitStatus, run};
+use ruff::args::{Args, Command};
+use ruff::{run, ExitStatus};
 
 #[cfg(target_os = "windows")]
 #[global_allocator]
@@ -14,8 +13,6 @@ static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 #[cfg(all(
     not(target_os = "windows"),
     not(target_os = "openbsd"),
-    not(target_os = "aix"),
-    not(target_os = "android"),
     any(
         target_arch = "x86_64",
         target_arch = "aarch64",
@@ -26,48 +23,58 @@ static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 static GLOBAL: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
 
 pub fn main() -> ExitCode {
-    // Enabled ANSI colors on Windows 10.
-    #[cfg(windows)]
-    assert!(colored::control::set_virtual_terminal(true).is_ok());
-
-    // support FORCE_COLOR env var
-    if let Some(force_color) = std::env::var_os("FORCE_COLOR") {
-        if !force_color.is_empty() {
-            colored::control::set_override(true);
-        }
-    }
-
     let args = wild::args_os();
-    let args = argfile::expand_args_from(args, argfile::parse_fromfile, argfile::PREFIX).unwrap();
+    let mut args =
+        argfile::expand_args_from(args, argfile::parse_fromfile, argfile::PREFIX).unwrap();
+
+    // We can't use `warn_user` here because logging isn't set up at this point
+    // and we also don't know if the user runs ruff with quiet.
+    // Keep the message and pass it to `run` that is responsible for emitting the warning.
+    let deprecated_alias_warning = match args.get(1).and_then(|arg| arg.to_str()) {
+        // Deprecated aliases that are handled by clap
+        Some("--explain") => {
+            Some("`ruff --explain <RULE>` is deprecated. Use `ruff rule <RULE>` instead.")
+        }
+        Some("--clean") => {
+            Some("`ruff --clean` is deprecated. Use `ruff clean` instead.")
+        }
+        Some("--generate-shell-completion") => {
+            Some("`ruff --generate-shell-completion <SHELL>` is deprecated. Use `ruff generate-shell-completion <SHELL>` instead.")
+        }
+        // Deprecated `ruff` alias to `ruff check`
+        // Clap doesn't support default subcommands but we want to run `check` by
+        // default for convenience and backwards-compatibility, so we just
+        // preprocess the arguments accordingly before passing them to Clap.
+        Some(arg) if !Command::has_subcommand(arg)
+            && arg != "-h"
+            && arg != "--help"
+            && arg != "-V"
+            && arg != "--version"
+            && arg != "help" => {
+
+            {
+                args.insert(1, "check".into());
+                Some("`ruff <path>` is deprecated. Use `ruff check <path>` instead.")
+            }
+        },
+        _ => None
+    };
 
     let args = Args::parse_from(args);
 
-    match run(args) {
+    match run(args, deprecated_alias_warning) {
         Ok(code) => code.into(),
         Err(err) => {
+            #[allow(clippy::print_stderr)]
             {
-                // Exit "gracefully" on broken pipe errors.
-                //
-                // See: https://github.com/BurntSushi/ripgrep/blob/bf63fe8f258afc09bae6caa48f0ae35eaf115005/crates/core/main.rs#L47C1-L61C14
-                for cause in err.chain() {
-                    if let Some(ioerr) = cause.downcast_ref::<std::io::Error>() {
-                        if ioerr.kind() == std::io::ErrorKind::BrokenPipe {
-                            return ExitCode::from(0);
-                        }
-                    }
-                }
-
-                // Use `writeln` instead of `eprintln` to avoid panicking when the stderr pipe is broken.
-                let mut stderr = std::io::stderr().lock();
-
                 // This communicates that this isn't a linter error but ruff itself hard-errored for
                 // some reason (e.g. failed to resolve the configuration)
-                writeln!(stderr, "{}", "ruff failed".red().bold()).ok();
+                eprintln!("{}", "ruff failed".red().bold());
                 // Currently we generally only see one error, but e.g. with io errors when resolving
                 // the configuration it is help to chain errors ("resolving configuration failed" ->
                 // "failed to read file: subdir/pyproject.toml")
                 for cause in err.chain() {
-                    writeln!(stderr, "  {} {cause}", "Cause:".bold()).ok();
+                    eprintln!("  {} {cause}", "Cause:".bold());
                 }
             }
             ExitStatus::Error.into()

crates/ruff/src/panic.rs

@@ -0,0 +1,46 @@
+#[derive(Default, Debug)]
+pub(crate) struct PanicError {
+    pub(crate) info: String,
+    pub(crate) backtrace: Option<std::backtrace::Backtrace>,
+}
+
+impl std::fmt::Display for PanicError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        writeln!(f, "{}", self.info)?;
+        if let Some(backtrace) = &self.backtrace {
+            writeln!(f, "Backtrace: {backtrace}")
+        } else {
+            Ok(())
+        }
+    }
+}
+
+thread_local! {
+    static LAST_PANIC: std::cell::Cell<Option<PanicError>> = const { std::cell::Cell::new(None) };
+}
+
+/// [`catch_unwind`](std::panic::catch_unwind) wrapper that sets a custom [`set_hook`](std::panic::set_hook)
+/// to extract the backtrace. The original panic-hook gets restored before returning.
+pub(crate) fn catch_unwind<F, R>(f: F) -> Result<R, PanicError>
+where
+    F: FnOnce() -> R + std::panic::UnwindSafe,
+{
+    let prev = std::panic::take_hook();
+    std::panic::set_hook(Box::new(|info| {
+        let info = info.to_string();
+        let backtrace = std::backtrace::Backtrace::force_capture();
+        LAST_PANIC.with(|cell| {
+            cell.set(Some(PanicError {
+                info,
+                backtrace: Some(backtrace),
+            }));
+        });
+    }));
+
+    let result = std::panic::catch_unwind(f)
+        .map_err(|_| LAST_PANIC.with(std::cell::Cell::take).unwrap_or_default());
+
+    std::panic::set_hook(prev);
+
+    result
+}

crates/ruff/src/printer.rs

@@ -1,24 +1,24 @@
 use std::cmp::Reverse;
+use std::fmt::Display;
 use std::hash::Hash;
 use std::io::Write;
 
 use anyhow::Result;
 use bitflags::bitflags;
 use colored::Colorize;
-use itertools::{Itertools, iterate};
-use ruff_linter::codes::NoqaCode;
+use itertools::{iterate, Itertools};
 use serde::Serialize;
 
 use ruff_linter::fs::relativize_path;
 use ruff_linter::logging::LogLevel;
 use ruff_linter::message::{
     AzureEmitter, Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter,
-    JsonEmitter, JsonLinesEmitter, JunitEmitter, Message, PylintEmitter, RdjsonEmitter,
-    SarifEmitter, TextEmitter,
+    JsonEmitter, JsonLinesEmitter, JunitEmitter, PylintEmitter, SarifEmitter, TextEmitter,
 };
 use ruff_linter::notify_user;
+use ruff_linter::registry::{AsRule, Rule};
 use ruff_linter::settings::flags::{self};
-use ruff_linter::settings::types::{OutputFormat, UnsafeFixes};
+use ruff_linter::settings::types::{SerializationFormat, UnsafeFixes};
 
 use crate::diagnostics::{Diagnostics, FixMap};
 
@@ -26,24 +26,47 @@ bitflags! {
     #[derive(Default, Debug, Copy, Clone)]
     pub(crate) struct Flags: u8 {
         /// Whether to show violations when emitting diagnostics.
-        const SHOW_VIOLATIONS = 1 << 0;
+        const SHOW_VIOLATIONS = 0b0000_0001;
         /// Whether to show a summary of the fixed violations when emitting diagnostics.
-        const SHOW_FIX_SUMMARY = 1 << 1;
+        const SHOW_FIX_SUMMARY = 0b0000_0100;
         /// Whether to show a diff of each fixed violation when emitting diagnostics.
-        const SHOW_FIX_DIFF = 1 << 2;
+        const SHOW_FIX_DIFF = 0b0000_1000;
     }
 }
 
 #[derive(Serialize)]
-struct ExpandedStatistics {
-    code: Option<NoqaCode>,
-    name: &'static str,
+struct ExpandedStatistics<'a> {
+    code: SerializeRuleAsCode,
+    message: &'a str,
     count: usize,
     fixable: bool,
 }
 
+struct SerializeRuleAsCode(Rule);
+
+impl Serialize for SerializeRuleAsCode {
+    fn serialize<S>(&self, serializer: S) -> std::result::Result<S::Ok, S::Error>
+    where
+        S: serde::Serializer,
+    {
+        serializer.serialize_str(&self.0.noqa_code().to_string())
+    }
+}
+
+impl Display for SerializeRuleAsCode {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0.noqa_code())
+    }
+}
+
+impl From<Rule> for SerializeRuleAsCode {
+    fn from(rule: Rule) -> Self {
+        Self(rule)
+    }
+}
+
 pub(crate) struct Printer {
-    format: OutputFormat,
+    format: SerializationFormat,
     log_level: LogLevel,
     fix_mode: flags::FixMode,
     unsafe_fixes: UnsafeFixes,
@@ -52,7 +75,7 @@ pub(crate) struct Printer {
 
 impl Printer {
     pub(crate) const fn new(
-        format: OutputFormat,
+        format: SerializationFormat,
         log_level: LogLevel,
         fix_mode: flags::FixMode,
         unsafe_fixes: UnsafeFixes,
@@ -103,16 +126,15 @@ impl Printer {
                     let fix_prefix = format!("[{}]", "*".cyan());
 
                     if self.unsafe_fixes.is_hint() {
-                        if fixables.applicable > 0 && fixables.inapplicable_unsafe > 0 {
-                            let es = if fixables.inapplicable_unsafe == 1 {
+                        if fixables.applicable > 0 && fixables.unapplicable_unsafe > 0 {
+                            let es = if fixables.unapplicable_unsafe == 1 {
                                 ""
                             } else {
                                 "es"
                             };
-                            writeln!(
-                                writer,
+                            writeln!(writer,
                                 "{fix_prefix} {} fixable with the `--fix` option ({} hidden fix{es} can be enabled with the `--unsafe-fixes` option).",
-                                fixables.applicable, fixables.inapplicable_unsafe
+                                fixables.applicable, fixables.unapplicable_unsafe
                             )?;
                         } else if fixables.applicable > 0 {
                             // Only applicable fixes
@@ -122,16 +144,15 @@ impl Printer {
                                 fixables.applicable,
                             )?;
                         } else {
-                            // Only inapplicable fixes
-                            let es = if fixables.inapplicable_unsafe == 1 {
+                            // Only unapplicable fixes
+                            let es = if fixables.unapplicable_unsafe == 1 {
                                 ""
                             } else {
                                 "es"
                             };
-                            writeln!(
-                                writer,
+                            writeln!(writer,
                                 "No fixes available ({} hidden fix{es} can be enabled with the `--unsafe-fixes` option).",
-                                fixables.inapplicable_unsafe
+                                fixables.unapplicable_unsafe
                             )?;
                         }
                     } else {
@@ -148,7 +169,7 @@ impl Printer {
                 // Check if there are unapplied fixes
                 let unapplied = {
                     if let Some(fixables) = fixables {
-                        fixables.inapplicable_unsafe
+                        fixables.unapplicable_unsafe
                     } else {
                         0
                     }
@@ -159,27 +180,15 @@ impl Printer {
                     if fixed > 0 {
                         let s = if fixed == 1 { "" } else { "s" };
                         if self.fix_mode.is_apply() {
-                            writeln!(
-                                writer,
-                                "Fixed {fixed} error{s} ({unapplied} additional fix{es} available with `--unsafe-fixes`)."
-                            )?;
+                            writeln!(writer, "Fixed {fixed} error{s} ({unapplied} additional fix{es} available with `--unsafe-fixes`).")?;
                         } else {
-                            writeln!(
-                                writer,
-                                "Would fix {fixed} error{s} ({unapplied} additional fix{es} available with `--unsafe-fixes`)."
-                            )?;
+                            writeln!(writer, "Would fix {fixed} error{s} ({unapplied} additional fix{es} available with `--unsafe-fixes`).")?;
                         }
                     } else {
                         if self.fix_mode.is_apply() {
-                            writeln!(
-                                writer,
-                                "No errors fixed ({unapplied} fix{es} available with `--unsafe-fixes`)."
-                            )?;
+                            writeln!(writer, "No errors fixed ({unapplied} fix{es} available with `--unsafe-fixes`).")?;
                         } else {
-                            writeln!(
-                                writer,
-                                "No errors would be fixed ({unapplied} fix{es} available with `--unsafe-fixes`)."
-                            )?;
+                            writeln!(writer, "No errors would be fixed ({unapplied} fix{es} available with `--unsafe-fixes`).")?;
                         }
                     }
                 } else {
@@ -209,7 +218,10 @@ impl Printer {
         if !self.flags.intersects(Flags::SHOW_VIOLATIONS) {
             if matches!(
                 self.format,
-                OutputFormat::Full | OutputFormat::Concise | OutputFormat::Grouped
+                SerializationFormat::Text
+                    | SerializationFormat::Full
+                    | SerializationFormat::Concise
+                    | SerializationFormat::Grouped
             ) {
                 if self.flags.intersects(Flags::SHOW_FIX_SUMMARY) {
                     if !diagnostics.fixed.is_empty() {
@@ -227,23 +239,21 @@ impl Printer {
         let fixables = FixableStatistics::try_from(diagnostics, self.unsafe_fixes);
 
         match self.format {
-            OutputFormat::Json => {
+            SerializationFormat::Json => {
                 JsonEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Rdjson => {
-                RdjsonEmitter.emit(writer, &diagnostics.messages, &context)?;
-            }
-            OutputFormat::JsonLines => {
+            SerializationFormat::JsonLines => {
                 JsonLinesEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Junit => {
+            SerializationFormat::Junit => {
                 JunitEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Concise | OutputFormat::Full => {
+            SerializationFormat::Concise
+            | SerializationFormat::Full => {
                 TextEmitter::default()
                     .with_show_fix_status(show_fix_status(self.fix_mode, fixables.as_ref()))
                     .with_show_fix_diff(self.flags.intersects(Flags::SHOW_FIX_DIFF))
-                    .with_show_source(self.format == OutputFormat::Full)
+                    .with_show_source(self.format == SerializationFormat::Full)
                     .with_unsafe_fixes(self.unsafe_fixes)
                     .emit(writer, &diagnostics.messages, &context)?;
 
@@ -257,7 +267,7 @@ impl Printer {
 
                 self.write_summary_text(writer, diagnostics)?;
             }
-            OutputFormat::Grouped => {
+            SerializationFormat::Grouped => {
                 GroupedEmitter::default()
                     .with_show_fix_status(show_fix_status(self.fix_mode, fixables.as_ref()))
                     .with_unsafe_fixes(self.unsafe_fixes)
@@ -272,21 +282,22 @@ impl Printer {
                 }
                 self.write_summary_text(writer, diagnostics)?;
             }
-            OutputFormat::Github => {
+            SerializationFormat::Github => {
                 GithubEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Gitlab => {
+            SerializationFormat::Gitlab => {
                 GitlabEmitter::default().emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Pylint => {
+            SerializationFormat::Pylint => {
                 PylintEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Azure => {
+            SerializationFormat::Azure => {
                 AzureEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
-            OutputFormat::Sarif => {
+            SerializationFormat::Sarif => {
                 SarifEmitter.emit(writer, &diagnostics.messages, &context)?;
             }
+            SerializationFormat::Text => unreachable!("Text is deprecated and should have been automatically converted to the default serialization format")
         }
 
         writer.flush()?;
@@ -302,31 +313,30 @@ impl Printer {
         let statistics: Vec<ExpandedStatistics> = diagnostics
             .messages
             .iter()
-            .map(|message| (message.to_noqa_code(), message))
-            .sorted_by_key(|(code, message)| (*code, message.fixable()))
-            .fold(
-                vec![],
-                |mut acc: Vec<((Option<NoqaCode>, &Message), usize)>, (code, message)| {
-                    if let Some(((prev_code, _prev_message), count)) = acc.last_mut() {
-                        if *prev_code == code {
-                            *count += 1;
-                            return acc;
-                        }
+            .map(|message| {
+                (
+                    message.kind.rule(),
+                    &message.kind.body,
+                    message.fix.is_some(),
+                )
+            })
+            .sorted()
+            .fold(vec![], |mut acc, (rule, body, fixable)| {
+                if let Some((prev_rule, _, _, count)) = acc.last_mut() {
+                    if *prev_rule == rule {
+                        *count += 1;
+                        return acc;
                     }
-                    acc.push(((code, message), 1));
-                    acc
-                },
-            )
+                }
+                acc.push((rule, body, fixable, 1));
+                acc
+            })
             .iter()
-            .map(|&((code, message), count)| ExpandedStatistics {
-                code,
-                name: message.name(),
-                count,
-                fixable: if let Some(fix) = message.fix() {
-                    fix.applies(self.unsafe_fixes.required_applicability())
-                } else {
-                    false
-                },
+            .map(|(rule, message, fixable, count)| ExpandedStatistics {
+                code: (*rule).into(),
+                count: *count,
+                message,
+                fixable: *fixable,
             })
             .sorted_by_key(|statistic| Reverse(statistic.count))
             .collect();
@@ -336,7 +346,9 @@ impl Printer {
         }
 
         match self.format {
-            OutputFormat::Full | OutputFormat::Concise => {
+            SerializationFormat::Text
+            | SerializationFormat::Full
+            | SerializationFormat::Concise => {
                 // Compute the maximum number of digits in the count and code, for all messages,
                 // to enable pretty-printing.
                 let count_width = num_digits(
@@ -348,12 +360,7 @@ impl Printer {
                 );
                 let code_width = statistics
                     .iter()
-                    .map(|statistic| {
-                        statistic
-                            .code
-                            .map_or_else(String::new, |rule| rule.to_string())
-                            .len()
-                    })
+                    .map(|statistic| statistic.code.to_string().len())
                     .max()
                     .unwrap();
                 let any_fixable = statistics.iter().any(|statistic| statistic.fixable);
@@ -367,11 +374,7 @@ impl Printer {
                         writer,
                         "{:>count_width$}\t{:<code_width$}\t{}{}",
                         statistic.count.to_string().bold(),
-                        statistic
-                            .code
-                            .map_or_else(String::new, |rule| rule.to_string())
-                            .red()
-                            .bold(),
+                        statistic.code.to_string().red().bold(),
                         if any_fixable {
                             if statistic.fixable {
                                 &fixable
@@ -381,14 +384,12 @@ impl Printer {
                         } else {
                             ""
                         },
-                        statistic.name,
+                        statistic.message,
                     )?;
                 }
-
-                self.write_summary_text(writer, diagnostics)?;
                 return Ok(());
             }
-            OutputFormat::Json => {
+            SerializationFormat::Json => {
                 writeln!(writer, "{}", serde_json::to_string_pretty(&statistics)?)?;
             }
             _ => {
@@ -514,33 +515,33 @@ fn print_fix_summary(writer: &mut dyn Write, fixed: &FixMap) -> Result<()> {
 #[derive(Debug)]
 struct FixableStatistics {
     applicable: u32,
-    inapplicable_unsafe: u32,
+    unapplicable_unsafe: u32,
 }
 
 impl FixableStatistics {
     fn try_from(diagnostics: &Diagnostics, unsafe_fixes: UnsafeFixes) -> Option<Self> {
         let mut applicable = 0;
-        let mut inapplicable_unsafe = 0;
+        let mut unapplicable_unsafe = 0;
 
         for message in &diagnostics.messages {
-            if let Some(fix) = message.fix() {
+            if let Some(fix) = &message.fix {
                 if fix.applies(unsafe_fixes.required_applicability()) {
                     applicable += 1;
                 } else {
-                    // Do not include inapplicable fixes at other levels that do not provide an opt-in
+                    // Do not include unapplicable fixes at other levels that do not provide an opt-in
                     if fix.applicability().is_unsafe() {
-                        inapplicable_unsafe += 1;
+                        unapplicable_unsafe += 1;
                     }
                 }
             }
         }
 
-        if applicable == 0 && inapplicable_unsafe == 0 {
+        if applicable == 0 && unapplicable_unsafe == 0 {
             None
         } else {
             Some(Self {
                 applicable,
-                inapplicable_unsafe,
+                unapplicable_unsafe,
             })
         }
     }

crates/ruff/src/resolve.rs

@@ -1,18 +1,16 @@
 use std::path::Path;
 
-use anyhow::{Result, bail};
+use anyhow::Result;
 use log::debug;
 use path_absolutize::path_dedot;
 
 use ruff_workspace::configuration::Configuration;
-use ruff_workspace::pyproject::{self, find_fallback_target_version};
+use ruff_workspace::pyproject;
 use ruff_workspace::resolver::{
-    ConfigurationOrigin, ConfigurationTransformer, PyprojectConfig, PyprojectDiscoveryStrategy,
-    resolve_root_settings,
+    resolve_root_settings, ConfigurationTransformer, PyprojectConfig, PyprojectDiscoveryStrategy,
+    Relativity,
 };
 
-use ruff_python_ast as ast;
-
 use crate::args::ConfigArguments;
 
 /// Resolve the relevant settings strategy and defaults for the current
@@ -21,14 +19,10 @@ pub fn resolve(
     config_arguments: &ConfigArguments,
     stdin_filename: Option<&Path>,
 ) -> Result<PyprojectConfig> {
-    let Ok(cwd) = std::env::current_dir() else {
-        bail!("Working directory does not exist")
-    };
-
     // First priority: if we're running in isolated mode, use the default settings.
     if config_arguments.isolated {
         let config = config_arguments.transform(Configuration::default());
-        let settings = config.into_settings(&cwd)?;
+        let settings = config.into_settings(&path_dedot::CWD)?;
         debug!("Isolated mode, not reading any pyproject.toml");
         return Ok(PyprojectConfig::new(
             PyprojectDiscoveryStrategy::Fixed,
@@ -41,11 +35,7 @@ pub fn resolve(
     // `pyproject.toml` for _all_ configuration, and resolve paths relative to the
     // current working directory. (This matches ESLint's behavior.)
     if let Some(pyproject) = config_arguments.config_file() {
-        let settings = resolve_root_settings(
-            pyproject,
-            config_arguments,
-            ConfigurationOrigin::UserSpecified,
-        )?;
+        let settings = resolve_root_settings(pyproject, Relativity::Cwd, config_arguments)?;
         debug!(
             "Using user-specified configuration file at: {}",
             pyproject.display()
@@ -62,13 +52,16 @@ pub fn resolve(
     // that directory. (With `Strategy::Hierarchical`, we'll end up finding
     // the "closest" `pyproject.toml` file for every Python file later on,
     // so these act as the "default" settings.)
-    if let Some(pyproject) = pyproject::find_settings_toml(stdin_filename.unwrap_or(&cwd))? {
+    if let Some(pyproject) = pyproject::find_settings_toml(
+        stdin_filename
+            .as_ref()
+            .unwrap_or(&path_dedot::CWD.as_path()),
+    )? {
         debug!(
             "Using configuration file (via parent) at: {}",
             pyproject.display()
         );
-        let settings =
-            resolve_root_settings(&pyproject, config_arguments, ConfigurationOrigin::Ancestor)?;
+        let settings = resolve_root_settings(&pyproject, Relativity::Parent, config_arguments)?;
         return Ok(PyprojectConfig::new(
             PyprojectDiscoveryStrategy::Hierarchical,
             settings,
@@ -81,35 +74,11 @@ pub fn resolve(
     // end up the "closest" `pyproject.toml` file for every Python file later on, so
     // these act as the "default" settings.)
     if let Some(pyproject) = pyproject::find_user_settings_toml() {
-        struct FallbackTransformer<'a> {
-            arguments: &'a ConfigArguments,
-        }
-
-        impl ConfigurationTransformer for FallbackTransformer<'_> {
-            fn transform(&self, mut configuration: Configuration) -> Configuration {
-                // The `requires-python` constraint from the `pyproject.toml` takes precedence
-                // over the `target-version` from the user configuration.
-                let fallback = find_fallback_target_version(&*path_dedot::CWD);
-                if let Some(fallback) = fallback {
-                    debug!("Derived `target-version` from found `requires-python`: {fallback:?}");
-                    configuration.target_version = Some(fallback.into());
-                }
-
-                self.arguments.transform(configuration)
-            }
-        }
-
         debug!(
             "Using configuration file (via cwd) at: {}",
             pyproject.display()
         );
-        let settings = resolve_root_settings(
-            &pyproject,
-            &FallbackTransformer {
-                arguments: config_arguments,
-            },
-            ConfigurationOrigin::UserSettings,
-        )?;
+        let settings = resolve_root_settings(&pyproject, Relativity::Cwd, config_arguments)?;
         return Ok(PyprojectConfig::new(
             PyprojectDiscoveryStrategy::Hierarchical,
             settings,
@@ -122,21 +91,8 @@ pub fn resolve(
     // "closest" `pyproject.toml` file for every Python file later on, so these act
     // as the "default" settings.)
     debug!("Using Ruff default settings");
-    let mut config = config_arguments.transform(Configuration::default());
-    if config.target_version.is_none() {
-        // If we have arrived here we know that there was no `pyproject.toml`
-        // containing a `[tool.ruff]` section found in an ancestral directory.
-        // (This is an implicit requirement in the function
-        // `pyproject::find_settings_toml`.)
-        // However, there may be a `pyproject.toml` with a `requires-python`
-        // specified, and that is what we look for in this step.
-        let fallback = find_fallback_target_version(stdin_filename.unwrap_or(&cwd));
-        if let Some(version) = fallback {
-            debug!("Derived `target-version` from found `requires-python`: {version:?}");
-        }
-        config.target_version = fallback.map(ast::PythonVersion::from);
-    }
-    let settings = config.into_settings(&cwd)?;
+    let config = config_arguments.transform(Configuration::default());
+    let settings = config.into_settings(&path_dedot::CWD)?;
     Ok(PyprojectConfig::new(
         PyprojectDiscoveryStrategy::Hierarchical,
         settings,

crates/ruff/src/snapshots/ruff__version__tests__version_formatting.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff/src/version.rs
 expression: version
-snapshot_kind: text
 ---
 0.0.0

crates/ruff/src/snapshots/ruff__version__tests__version_formatting_with_commit_info.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff/src/version.rs
 expression: version
-snapshot_kind: text
 ---
 0.0.0 (53b0f5d92 2023-10-19)