convert to serializable diagnostics

This reverts commit e1219bc27c.

.github/workflows/ci.yaml

@@ -238,13 +238,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-insta
       - name: ty mdtests (GitHub annotations)
@@ -296,13 +296,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-insta
       - name: "Run tests"
@@ -325,7 +325,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Run tests"
@@ -381,12 +381,12 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Build"
         run: cargo build --release --locked
 
-  cargo-test-msrv:
-    name: "cargo test (msrv)"
+  cargo-build-msrv:
+    name: "cargo build (msrv)"
     runs-on: depot-ubuntu-latest-8
     needs: determine_changes
     if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-test') && (needs.determine_changes.outputs.code == 'true' || github.ref == 'refs/heads/main') }}
@@ -406,21 +406,12 @@ jobs:
           MSRV: ${{ steps.msrv.outputs.value }}
         run: rustup default "${MSRV}"
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
-      - name: "Install cargo nextest"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
-        with:
-          tool: cargo-nextest
-      - name: "Install cargo insta"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
-        with:
-          tool: cargo-insta
-      - name: "Run tests"
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
+      - name: "Build tests"
         shell: bash
         env:
-          NEXTEST_PROFILE: "ci"
           MSRV: ${{ steps.msrv.outputs.value }}
-        run: cargo "+${MSRV}" insta test --all-features --unreferenced reject --test-runner nextest
+        run: cargo "+${MSRV}" test --no-run --all-features
 
   cargo-fuzz-build:
     name: "cargo fuzz build"
@@ -912,7 +903,7 @@ jobs:
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-codspeed
 
@@ -920,7 +911,7 @@ jobs:
         run: cargo codspeed build --features "codspeed,instrumented" --no-default-features -p ruff_benchmark
 
       - name: "Run benchmarks"
-        uses: CodSpeedHQ/action@0010eb0ca6e89b80c88e8edaaa07cfe5f3e6664d # v3.5.0
+        uses: CodSpeedHQ/action@c28fe9fbe7d57a3da1b7834ae3761c1d8217612d # v3.7.0
         with:
           run: cargo codspeed run
           token: ${{ secrets.CODSPEED_TOKEN }}
@@ -945,7 +936,7 @@ jobs:
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-codspeed
 
@@ -953,7 +944,7 @@ jobs:
         run: cargo codspeed build --features "codspeed,walltime" --no-default-features -p ruff_benchmark
 
       - name: "Run benchmarks"
-        uses: CodSpeedHQ/action@0010eb0ca6e89b80c88e8edaaa07cfe5f3e6664d # v3.5.0
+        uses: CodSpeedHQ/action@c28fe9fbe7d57a3da1b7834ae3761c1d8217612d # v3.7.0
         with:
           run: cargo codspeed run
           token: ${{ secrets.CODSPEED_TOKEN }}

.github/workflows/daily_fuzz.yaml

@@ -38,7 +38,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
       - name: Build ruff
         # A debug build means the script runs slower once it gets started,

.github/workflows/sync_typeshed.yaml

@@ -1,5 +1,25 @@
 name: Sync typeshed
 
+# How this works:
+#
+# 1. A Linux worker:
+#    a. Checks out Ruff and typeshed
+#    b. Deletes the vendored typeshed stdlib stubs from Ruff
+#    c. Copies the latest versions of the stubs from typeshed
+#    d. Uses docstring-adder to sync all docstrings available on Linux
+#    e. Creates a new branch on the upstream astral-sh/ruff repository
+#    f. Commits the changes it's made and pushes them to the new upstream branch
+# 2. Once the Linux worker is done, a Windows worker:
+#    a. Checks out the branch created by the Linux worker
+#    b. Syncs all docstrings available on Windows that are not available on Linux
+#    c. Commits the changes and pushes them to the same upstream branch
+# 3. Once the Windows worker is done, a MacOS worker:
+#    a. Checks out the branch created by the Linux worker
+#    b. Syncs all docstrings available on MacOS that are not available on Linux or Windows
+#    c. Commits the changes and pushes them to the same upstream branch
+#    d. Creates a PR against the `main` branch using the branch all three workers have pushed to
+# 4. If any of steps 1-3 failed, an issue is created in the `astral-sh/ruff` repository
+
 on:
   workflow_dispatch:
   schedule:
@@ -10,7 +30,17 @@ env:
   FORCE_COLOR: 1
   GH_TOKEN: ${{ github.token }}
 
+  # The name of the upstream branch that the first worker creates,
+  # and which all three workers push to.
+  UPSTREAM_BRANCH: typeshedbot/sync-typeshed
+
+  # The path to the directory that contains the vendored typeshed stubs,
+  # relative to the root of the Ruff repository.
+  VENDORED_TYPESHED: crates/ty_vendored/vendor/typeshed
+
 jobs:
+  # Sync typeshed stubs, and sync all docstrings available on Linux.
+  # Push the changes to a new branch on the upstream repository.
   sync:
     name: Sync typeshed
     runs-on: ubuntu-latest
@@ -19,7 +49,6 @@ jobs:
     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
@@ -36,37 +65,130 @@ jobs:
         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: ${{ steps.sync.outcome == 'success' }}
+      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - name: Sync typeshed stubs
         run: |
+          rm -rf "ruff/${VENDORED_TYPESHED}"
+          mkdir "ruff/${VENDORED_TYPESHED}"
+          cp typeshed/README.md "ruff/${VENDORED_TYPESHED}"
+          cp typeshed/LICENSE "ruff/${VENDORED_TYPESHED}"
+
+          # The pyproject.toml file is needed by a later job for the black configuration.
+          # It's deleted before creating the PR.
+          cp typeshed/pyproject.toml "ruff/${VENDORED_TYPESHED}"
+
+          cp -r typeshed/stdlib "ruff/${VENDORED_TYPESHED}/stdlib"
+          rm -rf "ruff/${VENDORED_TYPESHED}/stdlib/@tests"
+          git -C typeshed rev-parse HEAD > "ruff/${VENDORED_TYPESHED}/source_commit.txt"
           cd ruff
-          git checkout -b typeshedbot/sync-typeshed
+          git checkout -b "${UPSTREAM_BRANCH}"
           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: ${{ steps.sync.outcome == 'success' && steps.commit.outcome == 'success' }}
+          git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)" --allow-empty
+      - name: Sync Linux docstrings
+        if: ${{ success() }}
         run: |
           cd ruff
-          git push --force origin typeshedbot/sync-typeshed
-          gh pr list --repo "$GITHUB_REPOSITORY" --head typeshedbot/sync-typeshed --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
+          ./scripts/codemod_docstrings.sh
+          git commit -am "Sync Linux docstrings" --allow-empty
+      - name: Push the changes
+        id: commit
+        if: ${{ success() }}
+        run: git -C ruff push --force --set-upstream origin "${UPSTREAM_BRANCH}"
+
+  # Checkout the branch created by the sync job,
+  # and sync all docstrings available on Windows that are not available on Linux.
+  # Commit the changes and push them to the same branch.
+  docstrings-windows:
+    runs-on: windows-latest
+    timeout-minutes: 20
+    needs: [sync]
+
+    # Don't run the cron job on forks.
+    # The job will also be skipped if the sync job failed, because it's specified in `needs` above,
+    # and we haven't used `always()` in the `if` condition here
+    # (https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#example-requiring-successful-dependent-jobs)
+    if: ${{ github.repository == 'astral-sh/ruff' || github.event_name != 'schedule' }}
+
+    permissions:
+      contents: write
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        name: Checkout Ruff
+        with:
+          persist-credentials: true
+          ref: ${{ env.UPSTREAM_BRANCH}}
+      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - name: Setup git
+        run: |
+          git config --global user.name typeshedbot
+          git config --global user.email '<>'
+      - name: Sync Windows docstrings
+        id: docstrings
+        shell: bash
+        run: ./scripts/codemod_docstrings.sh
+      - name: Commit the changes
+        if: ${{ steps.docstrings.outcome == 'success' }}
+        run: |
+          git commit -am "Sync Windows docstrings" --allow-empty
+          git push
+
+  # Checkout the branch created by the sync job,
+  # and sync all docstrings available on macOS that are not available on Linux or Windows.
+  # Push the changes to the same branch and create a PR against the `main` branch using that branch.
+  docstrings-macos-and-pr:
+    runs-on: macos-latest
+    timeout-minutes: 20
+    needs: [sync, docstrings-windows]
+
+    # Don't run the cron job on forks.
+    # The job will also be skipped if the sync or docstrings-windows jobs failed,
+    # because they're specified in `needs` above and we haven't used an `always()` condition in the `if` here
+    # (https://docs.github.com/en/actions/reference/workflow-syntax-for-github-actions#example-requiring-successful-dependent-jobs)
+    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:
+          persist-credentials: true
+          ref: ${{ env.UPSTREAM_BRANCH}}
+      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - name: Setup git
+        run: |
+          git config --global user.name typeshedbot
+          git config --global user.email '<>'
+      - name: Sync macOS docstrings
+        run: ./scripts/codemod_docstrings.sh
+      - name: Commit and push the changes
+        if: ${{ success() }}
+        run: |
+          git commit -am "Sync macOS docstrings" --allow-empty
+
+          # Here we just reformat the codemodded stubs so that they are
+          # consistent with the other typeshed stubs around them.
+          # Typeshed formats code using black in their CI, so we just invoke
+          # black on the stubs the same way that typeshed does.
+          uvx black "${VENDORED_TYPESHED}/stdlib" --config "${VENDORED_TYPESHED}/pyproject.toml" || true
+          git commit -am "Format codemodded docstrings" --allow-empty
+
+          rm "${VENDORED_TYPESHED}/pyproject.toml"
+          git commit -am "Remove pyproject.toml file"
+
+          git push
+      - name: Create a PR
+        if: ${{ success() }}
+        run: |
+          gh pr list --repo "${GITHUB_REPOSITORY}" --head "${UPSTREAM_BRANCH}" --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
           gh pr create --title "[ty] Sync vendored typeshed stubs" --body "Close and reopen this PR to trigger CI" --label "ty"
 
   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' }}
+    needs: [sync, docstrings-windows, docstrings-macos-and-pr]
+    if: ${{ github.repository == 'astral-sh/ruff' && always() && github.event_name == 'schedule' && (needs.sync.result == 'failure' || needs.docstrings-windows.result == 'failure' || needs.docstrings-macos-and-pr.result == 'failure') }}
     permissions:
       issues: write
     steps:

.github/workflows/ty-ecosystem-report.yaml

@@ -0,0 +1,76 @@
+name: ty ecosystem-report
+
+permissions: {}
+
+on:
+  workflow_dispatch:
+  schedule:
+    # Run every Wednesday at 5:00 UTC:
+    - cron: 0 5 * * 3
+
+env:
+  CARGO_INCREMENTAL: 0
+  CARGO_NET_RETRY: 10
+  CARGO_TERM_COLOR: always
+  RUSTUP_MAX_RETRIES: 10
+  RUST_BACKTRACE: 1
+  CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
+
+jobs:
+  ty-ecosystem-report:
+    name: Create ecosystem report
+    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@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
+        with:
+          workspaces: "ruff"
+
+      - name: Install Rust toolchain
+        run: rustup show
+
+      - name: Create report
+        shell: bash
+        run: |
+          cd ruff
+
+          echo "Enabling configuration overloads (see .github/mypy-primer-ty.toml)"
+          mkdir -p ~/.config/ty
+          cp .github/mypy-primer-ty.toml ~/.config/ty/ty.toml
+
+          cd ..
+
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"
+
+          ecosystem-analyzer \
+            --verbose \
+            --repository ruff \
+            analyze \
+            --projects ruff/crates/ty_python_semantic/resources/primer/good.txt \
+            --output ecosystem-diagnostics.json
+
+          mkdir dist
+
+          ecosystem-analyzer \
+            generate-report \
+            --max-diagnostics-per-project=1200 \
+            ecosystem-diagnostics.json \
+            --output dist/index.html
+
+      - name: "Deploy to Cloudflare Pages"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        id: deploy
+        uses: cloudflare/wrangler-action@da0e0dfe58b7a431659754fdf3f186c529afbe65 # v3.14.1
+        with:
+          apiToken: ${{ secrets.CF_API_TOKEN }}
+          accountId: ${{ secrets.CF_ACCOUNT_ID }}
+          command: pages deploy dist --project-name=ty-ecosystem --branch main --commit-hash ${GITHUB_SHA}

.github/zizmor.yml

@@ -11,6 +11,7 @@ rules:
       - build-docker.yml
       - publish-playground.yml
       - ty-ecosystem-analyzer.yaml
+      - ty-ecosystem-report.yaml
   excessive-permissions:
     # it's hard to test what the impact of removing these ignores would be
     # without actually running the release workflow...

.pre-commit-config.yaml

@@ -81,7 +81,7 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.12.2
+    rev: v0.12.4
     hooks:
       - id: ruff-format
       - id: ruff
@@ -128,5 +128,10 @@ repos:
           # but the integration only works if shellcheck is installed
           - "github.com/wasilibs/go-shellcheck/cmd/shellcheck@v0.10.0"
 
+  - repo: https://github.com/shellcheck-py/shellcheck-py
+    rev: v0.10.0.1
+    hooks:
+      - id: shellcheck
+
 ci:
   skip: [cargo-fmt, dev-generate-all]

CHANGELOG.md

@@ -1,5 +1,64 @@
 # Changelog
 
+## 0.12.4
+
+### Preview features
+
+- \[`flake8-type-checking`, `pyupgrade`, `ruff`\] Add `from __future__ import annotations` when it would allow new fixes (`TC001`, `TC002`, `TC003`, `UP037`, `RUF013`) ([#19100](https://github.com/astral-sh/ruff/pull/19100))
+- \[`flake8-use-pathlib`\] Add autofix for `PTH109` ([#19245](https://github.com/astral-sh/ruff/pull/19245))
+- \[`pylint`\] Detect indirect `pathlib.Path` usages for `unspecified-encoding` (`PLW1514`) ([#19304](https://github.com/astral-sh/ruff/pull/19304))
+
+### Bug fixes
+
+- \[`flake8-bugbear`\] Fix `B017` false negatives for keyword exception arguments ([#19217](https://github.com/astral-sh/ruff/pull/19217))
+- \[`flake8-use-pathlib`\] Fix false negative on direct `Path()` instantiation (`PTH210`) ([#19388](https://github.com/astral-sh/ruff/pull/19388))
+- \[`flake8-django`\] Fix `DJ008` false positive for abstract models with type-annotated `abstract` field ([#19221](https://github.com/astral-sh/ruff/pull/19221))
+- \[`isort`\] Fix `I002` import insertion after docstring with multiple string statements ([#19222](https://github.com/astral-sh/ruff/pull/19222))
+- \[`isort`\] Treat form feed as valid whitespace before a semicolon ([#19343](https://github.com/astral-sh/ruff/pull/19343))
+- \[`pydoclint`\] Fix `SyntaxError` from fixes with line continuations (`D201`, `D202`) ([#19246](https://github.com/astral-sh/ruff/pull/19246))
+- \[`refurb`\] `FURB164` fix should validate arguments and should usually be marked unsafe ([#19136](https://github.com/astral-sh/ruff/pull/19136))
+
+### Rule changes
+
+- \[`flake8-use-pathlib`\] Skip single dots for `invalid-pathlib-with-suffix` (`PTH210`) on versions >= 3.14 ([#19331](https://github.com/astral-sh/ruff/pull/19331))
+- \[`pep8_naming`\] Avoid false positives on standard library functions with uppercase names (`N802`) ([#18907](https://github.com/astral-sh/ruff/pull/18907))
+- \[`pycodestyle`\] Handle brace escapes for t-strings in logical lines ([#19358](https://github.com/astral-sh/ruff/pull/19358))
+- \[`pylint`\] Extend invalid string character rules to include t-strings ([#19355](https://github.com/astral-sh/ruff/pull/19355))
+- \[`ruff`\] Allow `strict` kwarg when checking for `starmap-zip` (`RUF058`) in Python 3.14+ ([#19333](https://github.com/astral-sh/ruff/pull/19333))
+
+### Documentation
+
+- \[`flake8-type-checking`\] Make `TC010` docs example more realistic ([#19356](https://github.com/astral-sh/ruff/pull/19356))
+- Make more documentation examples error out-of-the-box ([#19288](https://github.com/astral-sh/ruff/pull/19288),[#19272](https://github.com/astral-sh/ruff/pull/19272),[#19291](https://github.com/astral-sh/ruff/pull/19291),[#19296](https://github.com/astral-sh/ruff/pull/19296),[#19292](https://github.com/astral-sh/ruff/pull/19292),[#19295](https://github.com/astral-sh/ruff/pull/19295),[#19297](https://github.com/astral-sh/ruff/pull/19297),[#19309](https://github.com/astral-sh/ruff/pull/19309))
+
+## 0.12.3
+
+### Preview features
+
+- \[`flake8-bugbear`\] Support non-context-manager calls in `B017` ([#19063](https://github.com/astral-sh/ruff/pull/19063))
+- \[`flake8-use-pathlib`\] Add autofixes for `PTH100`, `PTH106`, `PTH107`, `PTH108`, `PTH110`, `PTH111`, `PTH112`, `PTH113`, `PTH114`, `PTH115`, `PTH117`, `PTH119`, `PTH120` ([#19213](https://github.com/astral-sh/ruff/pull/19213))
+- \[`flake8-use-pathlib`\] Add autofixes for `PTH203`, `PTH204`, `PTH205` ([#18922](https://github.com/astral-sh/ruff/pull/18922))
+
+### Bug fixes
+
+- \[`flake8-return`\] Fix false-positive for variables used inside nested functions in `RET504` ([#18433](https://github.com/astral-sh/ruff/pull/18433))
+- Treat form feed as valid whitespace before a line continuation ([#19220](https://github.com/astral-sh/ruff/pull/19220))
+- \[`flake8-type-checking`\] Fix syntax error introduced by fix (`TC008`) ([#19150](https://github.com/astral-sh/ruff/pull/19150))
+- \[`pyupgrade`\] Keyword arguments in `super` should suppress the `UP008` fix ([#19131](https://github.com/astral-sh/ruff/pull/19131))
+
+### Documentation
+
+- \[`flake8-pyi`\] Make example error out-of-the-box (`PYI007`, `PYI008`) ([#19103](https://github.com/astral-sh/ruff/pull/19103))
+- \[`flake8-simplify`\] Make example error out-of-the-box (`SIM116`) ([#19111](https://github.com/astral-sh/ruff/pull/19111))
+- \[`flake8-type-checking`\] Make example error out-of-the-box (`TC001`) ([#19151](https://github.com/astral-sh/ruff/pull/19151))
+- \[`flake8-use-pathlib`\] Make example error out-of-the-box (`PTH210`) ([#19189](https://github.com/astral-sh/ruff/pull/19189))
+- \[`pycodestyle`\] Make example error out-of-the-box (`E272`) ([#19191](https://github.com/astral-sh/ruff/pull/19191))
+- \[`pycodestyle`\] Make example not raise unnecessary `SyntaxError` (`E114`) ([#19190](https://github.com/astral-sh/ruff/pull/19190))
+- \[`pydoclint`\] Make example error out-of-the-box (`DOC501`) ([#19218](https://github.com/astral-sh/ruff/pull/19218))
+- \[`pylint`, `pyupgrade`\] Fix syntax errors in examples (`PLW1501`, `UP028`) ([#19127](https://github.com/astral-sh/ruff/pull/19127))
+- \[`pylint`\] Update `missing-maxsplit-arg` docs and error to suggest proper usage (`PLC0207`) ([#18949](https://github.com/astral-sh/ruff/pull/18949))
+- \[`flake8-bandit`\] Make example error out-of-the-box (`S412`) ([#19241](https://github.com/astral-sh/ruff/pull/19241))
+
 ## 0.12.2
 
 ### Preview features

CONTRIBUTING.md

@@ -266,6 +266,13 @@ Finally, regenerate the documentation and generated code with `cargo dev generat
 
 ## MkDocs
 
+> [!NOTE]
+>
+> The documentation uses Material for MkDocs Insiders, which is closed-source software.
+> This means only members of the Astral organization can preview the documentation exactly as it
+> will appear in production.
+> Outside contributors can still preview the documentation, but there will be some differences. Consult [the Material for MkDocs documentation](https://squidfunk.github.io/mkdocs-material/insiders/benefits/#features) for which features are exclusively available in the insiders version.
+
 To preview any changes to the documentation locally:
 
 1. Install the [Rust toolchain](https://www.rust-lang.org/tools/install).

Cargo.lock

@@ -396,9 +396,9 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.5.40"
+version = "4.5.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "40b6887a1d8685cebccf115538db5c0efe625ccac9696ad45c409d96566e910f"
+checksum = "be92d32e80243a54711e5d7ce823c35c41c9d929dc4ab58e1276f625841aadf9"
 dependencies = [
  "clap_builder",
  "clap_derive",
@@ -406,9 +406,9 @@ dependencies = [
 
 [[package]]
 name = "clap_builder"
-version = "4.5.40"
+version = "4.5.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e0c66c08ce9f0c698cbce5c0279d0bb6ac936d8674174fe48f736533b964f59e"
+checksum = "707eab41e9622f9139419d573eca0900137718000c517d47da73045f54331c3d"
 dependencies = [
  "anstream",
  "anstyle",
@@ -449,9 +449,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.5.40"
+version = "4.5.41"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "d2c7947ae4cc3d851207c1adb5b5e260ff0cca11446b1d6d1423788e442257ce"
+checksum = "ef4f52386a59ca4c860f7393bcf8abd8dfd91ecccc0f774635ff68e92eeef491"
 dependencies = [
  "heck",
  "proc-macro2",
@@ -591,7 +591,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "117725a109d387c937a1533ce01b450cbde6b88abceea8473c4d7a85853cda3c"
 dependencies = [
  "lazy_static",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -600,7 +600,7 @@ version = "3.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "fde0e0ec90c9dfb3b4b1a0891a7dcd0e2bffde2f7efed5fe7c9bb00e5bfb915e"
 dependencies = [
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -933,7 +933,7 @@ dependencies = [
  "libc",
  "option-ext",
  "redox_users",
- "windows-sys 0.59.0",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1013,7 +1013,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cea14ef9355e3beab063703aa9dab15afd25f0667c341310c1e5274bb1d0da18"
 dependencies = [
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1133,9 +1133,9 @@ dependencies = [
 
 [[package]]
 name = "get-size-derive2"
-version = "0.5.1"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "1aac2af9f9a6a50e31b1e541d05b7925add83d3982c2793193fe9d4ee584323c"
+checksum = "028f3cfad7c3e3b1d8d04ef0a1c03576f2d62800803fe1301a4cd262849f2dea"
 dependencies = [
  "attribute-derive",
  "quote",
@@ -1144,9 +1144,9 @@ dependencies = [
 
 [[package]]
 name = "get-size2"
-version = "0.5.1"
+version = "0.5.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "624a0312efd19e1c45922dfcc2d6806d3ffc4bca261f89f31fcc4f63f438d885"
+checksum = "3a09c2043819a3def7bfbb4927e7df96aab0da4cfd8824484b22d0c94e84458e"
 dependencies = [
  "compact_str",
  "get-size-derive2",
@@ -1557,6 +1557,15 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "inventory"
+version = "0.3.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab08d7cd2c5897f2c949e5383ea7c7db03fb19130ffcfbf7eda795137ae3cb83"
+dependencies = [
+ "rustversion",
+]
+
 [[package]]
 name = "is-docker"
 version = "0.2.0"
@@ -1586,7 +1595,7 @@ checksum = "e04d7f318608d35d4b61ddd75cbdaee86b023ebe2bd5a66ee0915f0bf93095a9"
 dependencies = [
  "hermit-abi 0.5.1",
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1650,7 +1659,7 @@ dependencies = [
  "portable-atomic",
  "portable-atomic-util",
  "serde",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -2123,16 +2132,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
 
-[[package]]
-name = "papaya"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f92dd0b07c53a0a0c764db2ace8c541dc47320dad97c2200c2a637ab9dd2328f"
-dependencies = [
- "equivalent",
- "seize",
-]
-
 [[package]]
 name = "parking_lot"
 version = "0.12.3"
@@ -2465,7 +2464,7 @@ dependencies = [
  "pep508_rs",
  "serde",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.8.23",
 ]
 
 [[package]]
@@ -2562,9 +2561,9 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9fbfd9d094a40bf3ae768db9361049ace4c0e04a4fd6b359518bd7b73a73dd97"
+checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
 dependencies = [
  "rand_chacha 0.9.0",
  "rand_core 0.9.3",
@@ -2711,7 +2710,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.2"
+version = "0.12.4"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2763,7 +2762,7 @@ dependencies = [
  "test-case",
  "thiserror 2.0.12",
  "tikv-jemallocator",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "walkdir",
  "wild",
@@ -2779,7 +2778,7 @@ dependencies = [
  "ruff_annotate_snippets",
  "serde",
  "snapbox",
- "toml",
+ "toml 0.9.2",
  "tryfn",
  "unicode-width 0.2.1",
 ]
@@ -2839,6 +2838,7 @@ dependencies = [
  "insta",
  "matchit",
  "path-slash",
+ "quick-junit",
  "ruff_annotate_snippets",
  "ruff_cache",
  "ruff_diagnostics",
@@ -2852,6 +2852,7 @@ dependencies = [
  "salsa",
  "schemars",
  "serde",
+ "serde_json",
  "tempfile",
  "thiserror 2.0.12",
  "tracing",
@@ -2894,7 +2895,7 @@ dependencies = [
  "similar",
  "strum",
  "tempfile",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "tracing-indicatif",
  "tracing-subscriber",
@@ -2961,7 +2962,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.12.2"
+version = "0.12.4"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -2986,7 +2987,6 @@ dependencies = [
  "pathdiff",
  "pep440_rs",
  "pyproject-toml",
- "quick-junit",
  "regex",
  "ruff_annotate_snippets",
  "ruff_cache",
@@ -3015,7 +3015,7 @@ dependencies = [
  "tempfile",
  "test-case",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "typed-arena",
  "unicode-normalization",
  "unicode-width 0.2.1",
@@ -3041,7 +3041,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "itertools 0.14.0",
- "rand 0.9.1",
+ "rand 0.9.2",
  "ruff_diagnostics",
  "ruff_source_file",
  "ruff_text_size",
@@ -3265,7 +3265,7 @@ dependencies = [
  "serde_json",
  "shellexpand",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "tracing-log",
  "tracing-subscriber",
@@ -3294,7 +3294,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.2"
+version = "0.12.4"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3355,7 +3355,7 @@ dependencies = [
  "shellexpand",
  "strum",
  "tempfile",
- "toml",
+ "toml 0.9.2",
 ]
 
 [[package]]
@@ -3390,7 +3390,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3408,7 +3408,7 @@ checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
 [[package]]
 name = "salsa"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa?rev=fc00eba89e5dcaa5edba51c41aa5f309b5cb126b#fc00eba89e5dcaa5edba51c41aa5f309b5cb126b"
+source = "git+https://github.com/salsa-rs/salsa?rev=dba66f1a37acca014c2402f231ed5b361bd7d8fe#dba66f1a37acca014c2402f231ed5b361bd7d8fe"
 dependencies = [
  "boxcar",
  "compact_str",
@@ -3418,7 +3418,7 @@ dependencies = [
  "hashlink",
  "indexmap",
  "intrusive-collections",
- "papaya",
+ "inventory",
  "parking_lot",
  "portable-atomic",
  "rayon",
@@ -3433,12 +3433,12 @@ dependencies = [
 [[package]]
 name = "salsa-macro-rules"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa?rev=fc00eba89e5dcaa5edba51c41aa5f309b5cb126b#fc00eba89e5dcaa5edba51c41aa5f309b5cb126b"
+source = "git+https://github.com/salsa-rs/salsa?rev=dba66f1a37acca014c2402f231ed5b361bd7d8fe#dba66f1a37acca014c2402f231ed5b361bd7d8fe"
 
 [[package]]
 name = "salsa-macros"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa?rev=fc00eba89e5dcaa5edba51c41aa5f309b5cb126b#fc00eba89e5dcaa5edba51c41aa5f309b5cb126b"
+source = "git+https://github.com/salsa-rs/salsa?rev=dba66f1a37acca014c2402f231ed5b361bd7d8fe#dba66f1a37acca014c2402f231ed5b361bd7d8fe"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3491,16 +3491,6 @@ version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1c107b6f4780854c8b126e228ea8869f4d7b71260f962fefb57b996b8959ba6b"
 
-[[package]]
-name = "seize"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e4b8d813387d566f627f3ea1b914c068aac94c40ae27ec43f5f33bde65abefe7"
-dependencies = [
- "libc",
- "windows-sys 0.52.0",
-]
-
 [[package]]
 name = "serde"
 version = "1.0.219"
@@ -3545,9 +3535,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.140"
+version = "1.0.141"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20068b6e96dc6c9bd23e01df8827e6c7e1f2fddd43c21810382803c136b99373"
+checksum = "30b9eff21ebe718216c6ec64e1d9ac57087aad11efc64e32002bce4a0d4c03d3"
 dependencies = [
  "itoa",
  "memchr",
@@ -3575,6 +3565,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "serde_spanned"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "40734c41988f7306bb04f0ecf60ec0f3f1caa34290e4e8ea471dcd3346483b83"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "serde_test"
 version = "1.0.177"
@@ -3728,23 +3727,22 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
 [[package]]
 name = "strum"
-version = "0.27.1"
+version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f64def088c51c9510a8579e3c5d67c65349dcf755e5479ad3d010aa6454e2c32"
+checksum = "af23d6f6c1a224baef9d3f61e287d2761385a5b88fdab4eb4c6f11aeb54c4bcf"
 dependencies = [
  "strum_macros",
 ]
 
 [[package]]
 name = "strum_macros"
-version = "0.27.1"
+version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c77a8c5abcaf0f9ce05d62342b7d298c346515365c36b673df4ebe3ced01fde8"
+checksum = "7695ce3845ea4b33927c055a39dc438a45b059f7c1b3d91d38d10355fb8cbca7"
 dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "rustversion",
  "syn",
 ]
 
@@ -3780,7 +3778,7 @@ dependencies = [
  "getrandom 0.3.3",
  "once_cell",
  "rustix",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3980,11 +3978,26 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "dc1beb996b9d83529a9e75c17a1686767d148d70663143c7854d8b4a09ced362"
 dependencies = [
  "serde",
- "serde_spanned",
- "toml_datetime",
+ "serde_spanned 0.6.9",
+ "toml_datetime 0.6.11",
  "toml_edit",
 ]
 
+[[package]]
+name = "toml"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ed0aee96c12fa71097902e0bb061a5e1ebd766a6636bb605ba401c45c1650eac"
+dependencies = [
+ "indexmap",
+ "serde",
+ "serde_spanned 1.0.0",
+ "toml_datetime 0.7.0",
+ "toml_parser",
+ "toml_writer",
+ "winnow",
+]
+
 [[package]]
 name = "toml_datetime"
 version = "0.6.11"
@@ -3994,6 +4007,15 @@ dependencies = [
  "serde",
 ]
 
+[[package]]
+name = "toml_datetime"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bade1c3e902f58d73d3f294cd7f20391c1cb2fbcb643b73566bc773971df91e3"
+dependencies = [
+ "serde",
+]
+
 [[package]]
 name = "toml_edit"
 version = "0.22.27"
@@ -4002,17 +4024,25 @@ checksum = "41fe8c660ae4257887cf66394862d21dbca4a6ddd26f04a3560410406a2f819a"
 dependencies = [
  "indexmap",
  "serde",
- "serde_spanned",
- "toml_datetime",
- "toml_write",
+ "serde_spanned 0.6.9",
+ "toml_datetime 0.6.11",
  "winnow",
 ]
 
 [[package]]
-name = "toml_write"
-version = "0.1.2"
+name = "toml_parser"
+version = "1.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "5d99f8c9a7727884afe522e9bd5edbfc91a3312b36a77b5fb8926e4c31a41801"
+checksum = "97200572db069e74c512a14117b296ba0a80a30123fbbb5aa1f4a348f639ca30"
+dependencies = [
+ "winnow",
+]
+
+[[package]]
+name = "toml_writer"
+version = "1.0.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fcc842091f2def52017664b53082ecbbeb5c7731092bad69d2c63050401dfd64"
 
 [[package]]
 name = "tracing"
@@ -4135,7 +4165,7 @@ dependencies = [
  "ruff_python_trivia",
  "salsa",
  "tempfile",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "tracing-flame",
  "tracing-subscriber",
@@ -4152,9 +4182,12 @@ version = "0.0.0"
 dependencies = [
  "bitflags 2.9.1",
  "insta",
+ "regex",
  "ruff_db",
  "ruff_python_ast",
  "ruff_python_parser",
+ "ruff_python_trivia",
+ "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
  "salsa",
@@ -4193,7 +4226,7 @@ dependencies = [
  "schemars",
  "serde",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "ty_ide",
  "ty_python_semantic",
@@ -4255,6 +4288,7 @@ name = "ty_server"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "bitflags 2.9.1",
  "crossbeam",
  "jod-thread",
  "libc",
@@ -4262,6 +4296,7 @@ dependencies = [
  "lsp-types",
  "ruff_db",
  "ruff_notebook",
+ "ruff_python_ast",
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
@@ -4269,6 +4304,7 @@ dependencies = [
  "serde",
  "serde_json",
  "shellexpand",
+ "thiserror 2.0.12",
  "tracing",
  "tracing-subscriber",
  "ty_ide",
@@ -4309,7 +4345,7 @@ dependencies = [
  "smallvec",
  "tempfile",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "ty_python_semantic",
  "ty_static",
@@ -4527,7 +4563,7 @@ checksum = "3cf4199d1e5d15ddd86a694e4d0dffa9c323ce759fea589f00fef9d81cc1931d"
 dependencies = [
  "getrandom 0.3.3",
  "js-sys",
- "rand 0.9.1",
+ "rand 0.9.2",
  "uuid-macro-internal",
  "wasm-bindgen",
 ]
@@ -4803,7 +4839,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "cf221c93e13a30d793f7645a0e7762c55d169dbb0a49671918a2319d289b10bb"
 dependencies = [
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]

Cargo.toml

@@ -138,7 +138,7 @@ regex-automata = { version = "0.4.9" }
 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", rev = "fc00eba89e5dcaa5edba51c41aa5f309b5cb126b" }
+salsa = { git = "https://github.com/salsa-rs/salsa", rev = "dba66f1a37acca014c2402f231ed5b361bd7d8fe" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }
@@ -150,7 +150,7 @@ serde_with = { version = "3.6.0", default-features = false, features = [
 ] }
 shellexpand = { version = "3.0.0" }
 similar = { version = "2.4.0", features = ["inline"] }
-smallvec = { version = "1.13.2" }
+smallvec = { version = "1.13.2", features = ["union", "const_generics", "const_new"] }
 snapbox = { version = "0.6.0", features = [
     "diff",
     "term-svg",
@@ -165,7 +165,7 @@ tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
 thiserror = { version = "2.0.0" }
 tikv-jemallocator = { version = "0.6.0" }
-toml = { version = "0.8.11" }
+toml = { version = "0.9.0" }
 tracing = { version = "0.1.40" }
 tracing-flame = { version = "0.2.0" }
 tracing-indicatif = { version = "0.3.11" }

README.md

@@ -148,8 +148,8 @@ curl -LsSf https://astral.sh/ruff/install.sh | sh
 powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
 
 # For a specific version.
-curl -LsSf https://astral.sh/ruff/0.12.2/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.12.2/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.12.4/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.12.4/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 +182,7 @@ 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: v0.12.2
+  rev: v0.12.4
   hooks:
     # Run the linter.
     - id: ruff-check

crates/ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.12.2"
+version = "0.12.4"
 publish = true
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff/src/cache.rs

@@ -18,14 +18,12 @@ use rustc_hash::FxHashMap;
 use tempfile::NamedTempFile;
 
 use ruff_cache::{CacheKey, CacheKeyHasher};
-use ruff_db::diagnostic::Diagnostic;
+use ruff_db::diagnostic::{Diagnostic, SerializableDiagnostics};
 use ruff_diagnostics::Fix;
-use ruff_linter::message::create_lint_diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::{VERSION, warn_user};
 use ruff_macros::CacheKey;
 use ruff_notebook::NotebookIndex;
-use ruff_source_file::SourceFileBuilder;
 use ruff_text_size::{TextRange, TextSize};
 use ruff_workspace::Settings;
 use ruff_workspace::resolver::Resolver;
@@ -345,22 +343,7 @@ impl FileCache {
             let diagnostics = if lint.messages.is_empty() {
                 Vec::new()
             } else {
-                let file = SourceFileBuilder::new(path.to_string_lossy(), &*lint.source).finish();
-                lint.messages
-                    .iter()
-                    .map(|msg| {
-                        create_lint_diagnostic(
-                            &msg.body,
-                            msg.suggestion.as_ref(),
-                            msg.range,
-                            msg.fix.clone(),
-                            msg.parent,
-                            file.clone(),
-                            msg.noqa_offset,
-                            msg.rule,
-                        )
-                    })
-                    .collect()
+                lint.messages.to_diagnostics()
             };
             let notebook_indexes = if let Some(notebook_index) = lint.notebook_index.as_ref() {
                 FxHashMap::from_iter([(path.to_string_lossy().to_string(), notebook_index.clone())])
@@ -415,7 +398,8 @@ pub(crate) struct LintCacheData {
     /// Imports made.
     // pub(super) imports: ImportMap,
     /// Diagnostic messages.
-    pub(super) messages: Vec<CacheMessage>,
+    #[bincode(with_serde)]
+    pub(super) messages: SerializableDiagnostics,
     /// Source code of the file.
     ///
     /// # Notes
@@ -438,30 +422,7 @@ impl LintCacheData {
             String::new() // No messages, no need to keep the source!
         };
 
-        let messages = diagnostics
-            .iter()
-            // Parse the kebab-case rule name into a `Rule`. This will fail for syntax errors, so
-            // this also serves to filter them out, but we shouldn't be caching files with syntax
-            // errors anyway.
-            .filter_map(|msg| Some((msg.name().parse().ok()?, msg)))
-            .map(|(rule, msg)| {
-                // Make sure that all message use the same source file.
-                assert_eq!(
-                    msg.expect_ruff_source_file(),
-                    diagnostics.first().unwrap().expect_ruff_source_file(),
-                    "message uses a different source file"
-                );
-                CacheMessage {
-                    rule,
-                    body: msg.body().to_string(),
-                    suggestion: msg.suggestion().map(ToString::to_string),
-                    range: msg.expect_range(),
-                    parent: msg.parent(),
-                    fix: msg.fix().cloned(),
-                    noqa_offset: msg.noqa_offset(),
-                }
-            })
-            .collect();
+        let messages = SerializableDiagnostics::new(diagnostics);
 
         Self {
             messages,

crates/ruff/src/lib.rs

@@ -131,6 +131,7 @@ pub fn run(
     }: Args,
 ) -> Result<ExitStatus> {
     {
+        ruff_db::set_program_version(crate::version::version().to_string()).unwrap();
         let default_panic_hook = std::panic::take_hook();
         std::panic::set_hook(Box::new(move |info| {
             #[expect(clippy::print_stderr)]
@@ -439,7 +440,7 @@ pub fn check(args: CheckCommand, global_options: GlobalConfigArgs) -> Result<Exi
         if cli.statistics {
             printer.write_statistics(&diagnostics, &mut summary_writer)?;
         } else {
-            printer.write_once(&diagnostics, &mut summary_writer)?;
+            printer.write_once(&diagnostics, &mut summary_writer, preview)?;
         }
 
         if !cli.exit_zero {

crates/ruff/src/printer.rs

@@ -9,12 +9,13 @@ use itertools::{Itertools, iterate};
 use ruff_linter::linter::FixTable;
 use serde::Serialize;
 
-use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
+use ruff_db::diagnostic::{
+    Diagnostic, DiagnosticFormat, DisplayDiagnosticConfig, DisplayDiagnostics, SecondaryCode,
+};
 use ruff_linter::fs::relativize_path;
 use ruff_linter::logging::LogLevel;
 use ruff_linter::message::{
-    AzureEmitter, Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter,
-    JsonEmitter, JsonLinesEmitter, JunitEmitter, PylintEmitter, RdjsonEmitter, SarifEmitter,
+    Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter, SarifEmitter,
     TextEmitter,
 };
 use ruff_linter::notify_user;
@@ -202,6 +203,7 @@ impl Printer {
         &self,
         diagnostics: &Diagnostics,
         writer: &mut dyn Write,
+        preview: bool,
     ) -> Result<()> {
         if matches!(self.log_level, LogLevel::Silent) {
             return Ok(());
@@ -229,16 +231,32 @@ impl Printer {
 
         match self.format {
             OutputFormat::Json => {
-                JsonEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Json)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Rdjson => {
-                RdjsonEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Rdjson)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::JsonLines => {
-                JsonLinesEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::JsonLines)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Junit => {
-                JunitEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Junit)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Concise | OutputFormat::Full => {
                 TextEmitter::default()
@@ -280,10 +298,18 @@ impl Printer {
                 GitlabEmitter::default().emit(writer, &diagnostics.inner, &context)?;
             }
             OutputFormat::Pylint => {
-                PylintEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Pylint)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Azure => {
-                AzureEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Azure)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Sarif => {
                 SarifEmitter.emit(writer, &diagnostics.inner, &context)?;

crates/ruff/tests/format.rs

@@ -120,7 +120,7 @@ fn nonexistent_config_file() {
 #[test]
 fn config_override_rejected_if_invalid_toml() {
     assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
-        .args(["format", "--config", "foo = bar", "."]), @r#"
+        .args(["format", "--config", "foo = bar", "."]), @r"
     success: false
     exit_code: 2
     ----- stdout -----
@@ -137,12 +137,11 @@ fn config_override_rejected_if_invalid_toml() {
     TOML parse error at line 1, column 7
       |
     1 | foo = bar
-      |       ^
-    invalid string
-    expected `"`, `'`
+      |       ^^^
+    string values must be quoted, expected literal string
 
     For more information, try '--help'.
-    "#);
+    ");
 }
 
 #[test]

crates/ruff/tests/integration_test.rs

@@ -2246,8 +2246,7 @@ fn pyproject_toml_stdin_syntax_error() {
     success: false
     exit_code: 1
     ----- stdout -----
-    pyproject.toml:1:9: RUF200 Failed to parse pyproject.toml: invalid table header
-    expected `.`, `]`
+    pyproject.toml:1:9: RUF200 Failed to parse pyproject.toml: unclosed table, expected `]`
       |
     1 | [project
       |         ^ RUF200

crates/ruff/tests/lint.rs

@@ -534,7 +534,7 @@ fn nonexistent_config_file() {
 fn config_override_rejected_if_invalid_toml() {
     assert_cmd_snapshot!(Command::new(get_cargo_bin(BIN_NAME))
         .args(STDIN_BASE_OPTIONS)
-        .args(["--config", "foo = bar", "."]), @r#"
+        .args(["--config", "foo = bar", "."]), @r"
     success: false
     exit_code: 2
     ----- stdout -----
@@ -551,12 +551,11 @@ fn config_override_rejected_if_invalid_toml() {
     TOML parse error at line 1, column 7
       |
     1 | foo = bar
-      |       ^
-    invalid string
-    expected `"`, `'`
+      |       ^^^
+    string values must be quoted, expected literal string
 
     For more information, try '--help'.
-    "#);
+    ");
 }
 
 #[test]
@@ -733,9 +732,8 @@ select = [E501]
       Cause: TOML parse error at line 3, column 11
       |
     3 | select = [E501]
-      |           ^
-    invalid array
-    expected `]`
+      |           ^^^^
+    string values must be quoted, expected literal string
     ");
     });
 
@@ -876,7 +874,7 @@ fn each_toml_option_requires_a_new_flag_1() {
       |
     1 | extend-select=['F841'], line-length=90
       |                       ^
-    expected newline, `#`
+    unexpected key or value, expected newline, `#`
 
     For more information, try '--help'.
     ");
@@ -907,7 +905,7 @@ fn each_toml_option_requires_a_new_flag_2() {
       |
     1 | extend-select=['F841'] line-length=90
       |                        ^
-    expected newline, `#`
+    unexpected key or value, expected newline, `#`
 
     For more information, try '--help'.
     ");
@@ -995,6 +993,7 @@ fn value_given_to_table_key_is_not_inline_table_2() {
     - `lint.exclude`
     - `lint.preview`
     - `lint.typing-extensions`
+    - `lint.future-annotations`
 
     For more information, try '--help'.
     ");
@@ -5692,3 +5691,82 @@ class Foo:
     "
     );
 }
+
+#[test_case::test_case("concise")]
+#[test_case::test_case("full")]
+#[test_case::test_case("json")]
+#[test_case::test_case("json-lines")]
+#[test_case::test_case("junit")]
+#[test_case::test_case("grouped")]
+#[test_case::test_case("github")]
+#[test_case::test_case("gitlab")]
+#[test_case::test_case("pylint")]
+#[test_case::test_case("rdjson")]
+#[test_case::test_case("azure")]
+#[test_case::test_case("sarif")]
+fn output_format(output_format: &str) -> Result<()> {
+    const CONTENT: &str = "\
+import os  # F401
+x = y      # F821
+match 42:  # invalid-syntax
+    case _: ...
+";
+
+    let tempdir = TempDir::new()?;
+    let input = tempdir.path().join("input.py");
+    fs::write(&input, CONTENT)?;
+
+    let snapshot = format!("output_format_{output_format}");
+
+    let project_dir = dunce::canonicalize(tempdir.path())?;
+
+    insta::with_settings!({
+        filters => vec![
+            (tempdir_filter(&project_dir).as_str(), "[TMP]/"),
+            (tempdir_filter(&tempdir).as_str(), "[TMP]/"),
+            (r#""[^"]+\\?/?input.py"#, r#""[TMP]/input.py"#),
+            (ruff_linter::VERSION, "[VERSION]"),
+        ]
+    }, {
+        assert_cmd_snapshot!(
+            snapshot,
+            Command::new(get_cargo_bin(BIN_NAME))
+                .args([
+                    "check",
+                    "--no-cache",
+                    "--output-format",
+                    output_format,
+                    "--select",
+                    "F401,F821",
+                    "--target-version",
+                    "py39",
+                    "input.py",
+                ])
+                .current_dir(&tempdir),
+        );
+    });
+
+    Ok(())
+}
+
+#[test]
+fn future_annotations_preview_warning() {
+    assert_cmd_snapshot!(
+        Command::new(get_cargo_bin(BIN_NAME))
+            .args(STDIN_BASE_OPTIONS)
+            .args(["--config", "lint.future-annotations = true"])
+            .args(["--select", "F"])
+            .arg("--no-preview")
+            .arg("-")
+            .pass_stdin("1"),
+        @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    All checks passed!
+
+    ----- stderr -----
+    warning: The `lint.future-annotations` setting will have no effect because `preview` is disabled
+    ",
+    );
+}

crates/ruff/tests/snapshots/lint__output_format_azure.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - azure
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+##vso[task.logissue type=error;sourcepath=[TMP]/input.py;linenumber=1;columnnumber=8;code=F401;]`os` imported but unused
+##vso[task.logissue type=error;sourcepath=[TMP]/input.py;linenumber=2;columnnumber=5;code=F821;]Undefined name `y`
+##vso[task.logissue type=error;sourcepath=[TMP]/input.py;linenumber=3;columnnumber=1;]SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_concise.snap

@@ -0,0 +1,25 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - concise
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:1:8: F401 [*] `os` imported but unused
+input.py:2:5: F821 Undefined name `y`
+input.py:3:1: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+Found 3 errors.
+[*] 1 fixable with the `--fix` option.
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_full.snap

@@ -0,0 +1,49 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - full
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:1:8: F401 [*] `os` imported but unused
+  |
+1 | import os  # F401
+  |        ^^ F401
+2 | x = y      # F821
+3 | match 42:  # invalid-syntax
+  |
+  = help: Remove unused import: `os`
+
+input.py:2:5: F821 Undefined name `y`
+  |
+1 | import os  # F401
+2 | x = y      # F821
+  |     ^ F821
+3 | match 42:  # invalid-syntax
+4 |     case _: ...
+  |
+
+input.py:3:1: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+  |
+1 | import os  # F401
+2 | x = y      # F821
+3 | match 42:  # invalid-syntax
+  | ^^^^^
+4 |     case _: ...
+  |
+
+Found 3 errors.
+[*] 1 fixable with the `--fix` option.
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_github.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - github
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+::error title=Ruff (F401),file=[TMP]/input.py,line=1,col=8,endLine=1,endColumn=10::input.py:1:8: F401 `os` imported but unused
+::error title=Ruff (F821),file=[TMP]/input.py,line=2,col=5,endLine=2,endColumn=6::input.py:2:5: F821 Undefined name `y`
+::error title=Ruff,file=[TMP]/input.py,line=3,col=1,endLine=3,endColumn=6::input.py:3:1: SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_gitlab.snap

@@ -0,0 +1,60 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - gitlab
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+[
+  {
+    "check_name": "F401",
+    "description": "`os` imported but unused",
+    "fingerprint": "4dbad37161e65c72",
+    "location": {
+      "lines": {
+        "begin": 1,
+        "end": 1
+      },
+      "path": "input.py"
+    },
+    "severity": "major"
+  },
+  {
+    "check_name": "F821",
+    "description": "Undefined name `y`",
+    "fingerprint": "7af59862a085230",
+    "location": {
+      "lines": {
+        "begin": 2,
+        "end": 2
+      },
+      "path": "input.py"
+    },
+    "severity": "major"
+  },
+  {
+    "check_name": "syntax-error",
+    "description": "Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)",
+    "fingerprint": "e558cec859bb66e8",
+    "location": {
+      "lines": {
+        "begin": 3,
+        "end": 3
+      },
+      "path": "input.py"
+    },
+    "severity": "major"
+  }
+]
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_grouped.snap

@@ -0,0 +1,27 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - grouped
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:
+  1:8 F401 [*] `os` imported but unused
+  2:5 F821 Undefined name `y`
+  3:1 SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+Found 3 errors.
+[*] 1 fixable with the `--fix` option.
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_json-lines.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - json-lines
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+{"cell":null,"code":"F401","end_location":{"column":10,"row":1},"filename":"[TMP]/input.py","fix":{"applicability":"safe","edits":[{"content":"","end_location":{"column":1,"row":2},"location":{"column":1,"row":1}}],"message":"Remove unused import: `os`"},"location":{"column":8,"row":1},"message":"`os` imported but unused","noqa_row":1,"url":"https://docs.astral.sh/ruff/rules/unused-import"}
+{"cell":null,"code":"F821","end_location":{"column":6,"row":2},"filename":"[TMP]/input.py","fix":null,"location":{"column":5,"row":2},"message":"Undefined name `y`","noqa_row":2,"url":"https://docs.astral.sh/ruff/rules/undefined-name"}
+{"cell":null,"code":null,"end_location":{"column":6,"row":3},"filename":"[TMP]/input.py","fix":null,"location":{"column":1,"row":3},"message":"SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)","noqa_row":null,"url":null}
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_json.snap

@@ -0,0 +1,88 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - json
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+[
+  {
+    "cell": null,
+    "code": "F401",
+    "end_location": {
+      "column": 10,
+      "row": 1
+    },
+    "filename": "[TMP]/input.py",
+    "fix": {
+      "applicability": "safe",
+      "edits": [
+        {
+          "content": "",
+          "end_location": {
+            "column": 1,
+            "row": 2
+          },
+          "location": {
+            "column": 1,
+            "row": 1
+          }
+        }
+      ],
+      "message": "Remove unused import: `os`"
+    },
+    "location": {
+      "column": 8,
+      "row": 1
+    },
+    "message": "`os` imported but unused",
+    "noqa_row": 1,
+    "url": "https://docs.astral.sh/ruff/rules/unused-import"
+  },
+  {
+    "cell": null,
+    "code": "F821",
+    "end_location": {
+      "column": 6,
+      "row": 2
+    },
+    "filename": "[TMP]/input.py",
+    "fix": null,
+    "location": {
+      "column": 5,
+      "row": 2
+    },
+    "message": "Undefined name `y`",
+    "noqa_row": 2,
+    "url": "https://docs.astral.sh/ruff/rules/undefined-name"
+  },
+  {
+    "cell": null,
+    "code": null,
+    "end_location": {
+      "column": 6,
+      "row": 3
+    },
+    "filename": "[TMP]/input.py",
+    "fix": null,
+    "location": {
+      "column": 1,
+      "row": 3
+    },
+    "message": "SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)",
+    "noqa_row": null,
+    "url": null
+  }
+]
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_junit.snap

@@ -0,0 +1,34 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - junit
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+<?xml version="1.0" encoding="UTF-8"?>
+<testsuites name="ruff" tests="3" failures="3" errors="0">
+    <testsuite name="[TMP]/input.py" tests="3" disabled="0" errors="0" failures="3" package="org.ruff">
+        <testcase name="org.ruff.F401" classname="[TMP]/input" line="1" column="8">
+            <failure message="`os` imported but unused">line 1, col 8, `os` imported but unused</failure>
+        </testcase>
+        <testcase name="org.ruff.F821" classname="[TMP]/input" line="2" column="5">
+            <failure message="Undefined name `y`">line 2, col 5, Undefined name `y`</failure>
+        </testcase>
+        <testcase name="org.ruff.invalid-syntax" classname="[TMP]/input" line="3" column="1">
+            <failure message="SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)">line 3, col 1, SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)</failure>
+        </testcase>
+    </testsuite>
+</testsuites>
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_pylint.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - pylint
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+input.py:1: [F401] `os` imported but unused
+input.py:2: [F821] Undefined name `y`
+input.py:3: [invalid-syntax] SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)
+
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_rdjson.snap

@@ -0,0 +1,102 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - rdjson
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+{
+  "diagnostics": [
+    {
+      "code": {
+        "url": "https://docs.astral.sh/ruff/rules/unused-import",
+        "value": "F401"
+      },
+      "location": {
+        "path": "[TMP]/input.py",
+        "range": {
+          "end": {
+            "column": 10,
+            "line": 1
+          },
+          "start": {
+            "column": 8,
+            "line": 1
+          }
+        }
+      },
+      "message": "`os` imported but unused",
+      "suggestions": [
+        {
+          "range": {
+            "end": {
+              "column": 1,
+              "line": 2
+            },
+            "start": {
+              "column": 1,
+              "line": 1
+            }
+          },
+          "text": ""
+        }
+      ]
+    },
+    {
+      "code": {
+        "url": "https://docs.astral.sh/ruff/rules/undefined-name",
+        "value": "F821"
+      },
+      "location": {
+        "path": "[TMP]/input.py",
+        "range": {
+          "end": {
+            "column": 6,
+            "line": 2
+          },
+          "start": {
+            "column": 5,
+            "line": 2
+          }
+        }
+      },
+      "message": "Undefined name `y`"
+    },
+    {
+      "code": {
+        "value": "invalid-syntax"
+      },
+      "location": {
+        "path": "[TMP]/input.py",
+        "range": {
+          "end": {
+            "column": 6,
+            "line": 3
+          },
+          "start": {
+            "column": 1,
+            "line": 3
+          }
+        }
+      },
+      "message": "SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)"
+    }
+  ],
+  "severity": "WARNING",
+  "source": {
+    "name": "ruff",
+    "url": "https://docs.astral.sh/ruff"
+  }
+}
+----- stderr -----

crates/ruff/tests/snapshots/lint__output_format_sarif.snap

@@ -0,0 +1,142 @@
+---
+source: crates/ruff/tests/lint.rs
+info:
+  program: ruff
+  args:
+    - check
+    - "--no-cache"
+    - "--output-format"
+    - sarif
+    - "--select"
+    - "F401,F821"
+    - "--target-version"
+    - py39
+    - input.py
+---
+success: false
+exit_code: 1
+----- stdout -----
+{
+  "$schema": "https://json.schemastore.org/sarif-2.1.0.json",
+  "runs": [
+    {
+      "results": [
+        {
+          "level": "error",
+          "locations": [
+            {
+              "physicalLocation": {
+                "artifactLocation": {
+                  "uri": "[TMP]/input.py"
+                },
+                "region": {
+                  "endColumn": 10,
+                  "endLine": 1,
+                  "startColumn": 8,
+                  "startLine": 1
+                }
+              }
+            }
+          ],
+          "message": {
+            "text": "`os` imported but unused"
+          },
+          "ruleId": "F401"
+        },
+        {
+          "level": "error",
+          "locations": [
+            {
+              "physicalLocation": {
+                "artifactLocation": {
+                  "uri": "[TMP]/input.py"
+                },
+                "region": {
+                  "endColumn": 6,
+                  "endLine": 2,
+                  "startColumn": 5,
+                  "startLine": 2
+                }
+              }
+            }
+          ],
+          "message": {
+            "text": "Undefined name `y`"
+          },
+          "ruleId": "F821"
+        },
+        {
+          "level": "error",
+          "locations": [
+            {
+              "physicalLocation": {
+                "artifactLocation": {
+                  "uri": "[TMP]/input.py"
+                },
+                "region": {
+                  "endColumn": 6,
+                  "endLine": 3,
+                  "startColumn": 1,
+                  "startLine": 3
+                }
+              }
+            }
+          ],
+          "message": {
+            "text": "SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)"
+          },
+          "ruleId": null
+        }
+      ],
+      "tool": {
+        "driver": {
+          "informationUri": "https://github.com/astral-sh/ruff",
+          "name": "ruff",
+          "rules": [
+            {
+              "fullDescription": {
+                "text": "## What it does\nChecks for unused imports.\n\n## Why is this bad?\nUnused imports add a performance overhead at runtime, and risk creating\nimport cycles. They also increase the cognitive load of reading the code.\n\nIf an import statement is used to check for the availability or existence\nof a module, consider using `importlib.util.find_spec` instead.\n\nIf an import statement is used to re-export a symbol as part of a module's\npublic interface, consider using a \"redundant\" import alias, which\ninstructs Ruff (and other tools) to respect the re-export, and avoid\nmarking it as unused, as in:\n\n```python\nfrom module import member as member\n```\n\nAlternatively, you can use `__all__` to declare a symbol as part of the module's\ninterface, as in:\n\n```python\n# __init__.py\nimport some_module\n\n__all__ = [\"some_module\"]\n```\n\n## Fix safety\n\nFixes to remove unused imports are safe, except in `__init__.py` files.\n\nApplying fixes to `__init__.py` files is currently in preview. The fix offered depends on the\ntype of the unused import. Ruff will suggest a safe fix to export first-party imports with\neither a redundant alias or, if already present in the file, an `__all__` entry. If multiple\n`__all__` declarations are present, Ruff will not offer a fix. Ruff will suggest an unsafe fix\nto remove third-party and standard library imports -- the fix is unsafe because the module's\ninterface changes.\n\n## Example\n\n```python\nimport numpy as np  # unused import\n\n\ndef area(radius):\n    return 3.14 * radius**2\n```\n\nUse instead:\n\n```python\ndef area(radius):\n    return 3.14 * radius**2\n```\n\nTo check the availability of a module, use `importlib.util.find_spec`:\n\n```python\nfrom importlib.util import find_spec\n\nif find_spec(\"numpy\") is not None:\n    print(\"numpy is installed\")\nelse:\n    print(\"numpy is not installed\")\n```\n\n## Preview\nWhen [preview](https://docs.astral.sh/ruff/preview/) is enabled,\nthe criterion for determining whether an import is first-party\nis stricter, which could affect the suggested fix. See [this FAQ section](https://docs.astral.sh/ruff/faq/#how-does-ruff-determine-which-of-my-imports-are-first-party-third-party-etc) for more details.\n\n## Options\n- `lint.ignore-init-module-imports`\n- `lint.pyflakes.allowed-unused-imports`\n\n## References\n- [Python documentation: `import`](https://docs.python.org/3/reference/simple_stmts.html#the-import-statement)\n- [Python documentation: `importlib.util.find_spec`](https://docs.python.org/3/library/importlib.html#importlib.util.find_spec)\n- [Typing documentation: interface conventions](https://typing.python.org/en/latest/source/libraries.html#library-interface-public-and-private-symbols)\n"
+              },
+              "help": {
+                "text": "`{name}` imported but unused; consider using `importlib.util.find_spec` to test for availability"
+              },
+              "helpUri": "https://docs.astral.sh/ruff/rules/unused-import",
+              "id": "F401",
+              "properties": {
+                "id": "F401",
+                "kind": "Pyflakes",
+                "name": "unused-import",
+                "problem.severity": "error"
+              },
+              "shortDescription": {
+                "text": "`{name}` imported but unused; consider using `importlib.util.find_spec` to test for availability"
+              }
+            },
+            {
+              "fullDescription": {
+                "text": "## What it does\nChecks for uses of undefined names.\n\n## Why is this bad?\nAn undefined name is likely to raise `NameError` at runtime.\n\n## Example\n```python\ndef double():\n    return n * 2  # raises `NameError` if `n` is undefined when `double` is called\n```\n\nUse instead:\n```python\ndef double(n):\n    return n * 2\n```\n\n## Options\n- [`target-version`]: Can be used to configure which symbols Ruff will understand\n  as being available in the `builtins` namespace.\n\n## References\n- [Python documentation: Naming and binding](https://docs.python.org/3/reference/executionmodel.html#naming-and-binding)\n"
+              },
+              "help": {
+                "text": "Undefined name `{name}`. {tip}"
+              },
+              "helpUri": "https://docs.astral.sh/ruff/rules/undefined-name",
+              "id": "F821",
+              "properties": {
+                "id": "F821",
+                "kind": "Pyflakes",
+                "name": "undefined-name",
+                "problem.severity": "error"
+              },
+              "shortDescription": {
+                "text": "Undefined name `{name}`. {tip}"
+              }
+            }
+          ],
+          "version": "[VERSION]"
+        }
+      }
+    }
+  ],
+  "version": "2.1.0"
+}
+----- stderr -----

crates/ruff/tests/version.rs

@@ -60,7 +60,7 @@ fn config_option_ignored_but_validated() {
         assert_cmd_snapshot!(
             Command::new(get_cargo_bin(BIN_NAME))
                 .arg("version")
-                .args(["--config", "foo = bar"]), @r#"
+                .args(["--config", "foo = bar"]), @r"
         success: false
         exit_code: 2
         ----- stdout -----
@@ -77,12 +77,11 @@ fn config_option_ignored_but_validated() {
         TOML parse error at line 1, column 7
           |
         1 | foo = bar
-          |       ^
-        invalid string
-        expected `"`, `'`
+          |       ^^^
+        string values must be quoted, expected literal string
 
         For more information, try '--help'.
-        "#
+        "
         );
     });
 }

crates/ruff_benchmark/benches/ty.rs

@@ -2,6 +2,7 @@
 use ruff_benchmark::criterion;
 use ruff_benchmark::real_world_projects::{InstalledProject, RealWorldProject};
 
+use std::fmt::Write;
 use std::ops::Range;
 
 use criterion::{BatchSize, Criterion, criterion_group, criterion_main};
@@ -17,7 +18,7 @@ use ruff_python_ast::PythonVersion;
 use ty_project::metadata::options::{EnvironmentOptions, Options};
 use ty_project::metadata::value::{RangedValue, RelativePathBuf};
 use ty_project::watch::{ChangeEvent, ChangedKind};
-use ty_project::{Db, ProjectDatabase, ProjectMetadata};
+use ty_project::{CheckMode, Db, ProjectDatabase, ProjectMetadata};
 
 struct Case {
     db: ProjectDatabase,
@@ -101,6 +102,7 @@ fn setup_tomllib_case() -> Case {
 
     let re = re.unwrap();
 
+    db.set_check_mode(CheckMode::OpenFiles);
     db.project().set_open_files(&mut db, tomllib_files);
 
     let re_path = re.path(&db).as_system_path().unwrap().to_owned();
@@ -236,6 +238,7 @@ fn setup_micro_case(code: &str) -> Case {
     let mut db = ProjectDatabase::new(metadata, system).unwrap();
     let file = system_path_to_file(&db, SystemPathBuf::from(file_path)).unwrap();
 
+    db.set_check_mode(CheckMode::OpenFiles);
     db.project()
         .set_open_files(&mut db, FxHashSet::from_iter([file]));
 
@@ -441,6 +444,37 @@ fn benchmark_complex_constrained_attributes_2(criterion: &mut Criterion) {
     });
 }
 
+fn benchmark_many_enum_members(criterion: &mut Criterion) {
+    const NUM_ENUM_MEMBERS: usize = 512;
+
+    setup_rayon();
+
+    let mut code = String::new();
+    writeln!(&mut code, "from enum import Enum").ok();
+
+    writeln!(&mut code, "class E(Enum):").ok();
+    for i in 0..NUM_ENUM_MEMBERS {
+        writeln!(&mut code, "    m{i} = {i}").ok();
+    }
+    writeln!(&mut code).ok();
+
+    for i in 0..NUM_ENUM_MEMBERS {
+        writeln!(&mut code, "print(E.m{i})").ok();
+    }
+
+    criterion.bench_function("ty_micro[many_enum_members]", |b| {
+        b.iter_batched_ref(
+            || setup_micro_case(&code),
+            |case| {
+                let Case { db, .. } = case;
+                let result = db.check();
+                assert_eq!(result.len(), 0);
+            },
+            BatchSize::SmallInput,
+        );
+    });
+}
+
 struct ProjectBenchmark<'a> {
     project: InstalledProject<'a>,
     fs: MemoryFileSystem,
@@ -493,14 +527,21 @@ impl<'a> ProjectBenchmark<'a> {
 
 #[track_caller]
 fn bench_project(benchmark: &ProjectBenchmark, criterion: &mut Criterion) {
-    fn check_project(db: &mut ProjectDatabase, max_diagnostics: usize) {
+    fn check_project(db: &mut ProjectDatabase, project_name: &str, max_diagnostics: usize) {
         let result = db.check();
         let diagnostics = result.len();
 
-        assert!(
-            diagnostics <= max_diagnostics,
-            "Expected <={max_diagnostics} diagnostics but got {diagnostics}"
-        );
+        if diagnostics > max_diagnostics {
+            let details = result
+                .into_iter()
+                .map(|diagnostic| diagnostic.concise_message().to_string())
+                .collect::<Vec<_>>()
+                .join("\n  ");
+            assert!(
+                diagnostics <= max_diagnostics,
+                "{project_name}: Expected <={max_diagnostics} diagnostics but got {diagnostics}:\n  {details}",
+            );
+        }
     }
 
     setup_rayon();
@@ -510,7 +551,7 @@ fn bench_project(benchmark: &ProjectBenchmark, criterion: &mut Criterion) {
     group.bench_function(benchmark.project.config.name, |b| {
         b.iter_batched_ref(
             || benchmark.setup_iteration(),
-            |db| check_project(db, benchmark.max_diagnostics),
+            |db| check_project(db, benchmark.project.config.name, benchmark.max_diagnostics),
             BatchSize::SmallInput,
         );
     });
@@ -578,7 +619,7 @@ fn datetype(criterion: &mut Criterion) {
             max_dep_date: "2025-07-04",
             python_version: PythonVersion::PY313,
         },
-        0,
+        2,
     );
 
     bench_project(&benchmark, criterion);
@@ -591,6 +632,7 @@ criterion_group!(
     benchmark_many_tuple_assignments,
     benchmark_complex_constrained_attributes_1,
     benchmark_complex_constrained_attributes_2,
+    benchmark_many_enum_members,
 );
 criterion_group!(project, anyio, attrs, hydra, datetype);
 criterion_main!(check_file, micro, project);

crates/ruff_db/Cargo.toml

@@ -34,10 +34,12 @@ glob = { workspace = true }
 ignore = { workspace = true, optional = true }
 matchit = { workspace = true }
 path-slash = { workspace = true }
+quick-junit = { workspace = true, optional = true }
 rustc-hash = { workspace = true }
 salsa = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true, optional = true }
+serde_json = { workspace = true, optional = true }
 thiserror = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true, optional = true }
@@ -55,7 +57,8 @@ tempfile = { workspace = true }
 
 [features]
 cache = ["ruff_cache"]
+junit = ["dep:quick-junit"]
 os = ["ignore", "dep:etcetera"]
-serde = ["dep:serde", "camino/serde1"]
+serde = ["camino/serde1", "dep:serde", "dep:serde_json", "ruff_diagnostics/serde"]
 # Exposes testing utilities.
 testing = ["tracing-subscriber"]

crates/ruff_db/src/diagnostic/mod.rs

@@ -1,15 +1,17 @@
-use std::{fmt::Formatter, sync::Arc};
+use std::{fmt::Formatter, path::Path, sync::Arc};
 
-use render::{FileResolver, Input};
 use ruff_diagnostics::Fix;
 use ruff_source_file::{LineColumn, SourceCode, SourceFile};
 
 use ruff_annotate_snippets::Level as AnnotateLevel;
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
-pub use self::render::DisplayDiagnostic;
+pub use self::render::{DisplayDiagnostic, DisplayDiagnostics, FileResolver, Input};
 use crate::{Db, files::File};
 
+#[cfg(feature = "serde")]
+pub use serde_diagnostics::SerializableDiagnostics;
+
 mod render;
 mod stylesheet;
 
@@ -309,6 +311,10 @@ impl Diagnostic {
 
     /// Set the fix for this diagnostic.
     pub fn set_fix(&mut self, fix: Fix) {
+        debug_assert!(
+            self.primary_span().is_some(),
+            "Expected a source file for a diagnostic with a fix"
+        );
         Arc::make_mut(&mut self.inner).fix = Some(fix);
     }
 
@@ -380,7 +386,7 @@ impl Diagnostic {
     }
 
     /// Returns the URL for the rule documentation, if it exists.
-    pub fn to_url(&self) -> Option<String> {
+    pub fn to_ruff_url(&self) -> Option<String> {
         if self.is_invalid_syntax() {
             None
         } else {
@@ -432,8 +438,9 @@ impl Diagnostic {
     /// Returns the [`SourceFile`] which the message belongs to.
     ///
     /// Panics if the diagnostic has no primary span, or if its file is not a `SourceFile`.
-    pub fn expect_ruff_source_file(&self) -> SourceFile {
-        self.expect_primary_span().expect_ruff_file().clone()
+    pub fn expect_ruff_source_file(&self) -> &SourceFile {
+        self.ruff_source_file()
+            .expect("Expected a ruff source file")
     }
 
     /// Returns the [`TextRange`] for the diagnostic.
@@ -786,6 +793,7 @@ impl Annotation {
 /// These tags are used to provide additional information about the annotation.
 /// and are passed through to the language server protocol.
 #[derive(Debug, Clone, Eq, PartialEq, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum DiagnosticTag {
     /// Unused or unnecessary code. Used for unused parameters, unreachable code, etc.
     Unnecessary,
@@ -800,6 +808,7 @@ pub enum DiagnosticTag {
 ///
 /// Rules use kebab case, e.g. `no-foo`.
 #[derive(Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize))]
 pub struct LintName(&'static str);
 
 impl LintName {
@@ -840,6 +849,7 @@ impl PartialEq<&str> for LintName {
 
 /// Uniquely identifies the kind of a diagnostic.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum DiagnosticId {
     Panic,
 
@@ -1008,6 +1018,18 @@ impl UnifiedFile {
         }
     }
 
+    /// Return the file's path relative to the current working directory.
+    pub fn relative_path<'a>(&'a self, resolver: &'a dyn FileResolver) -> &'a Path {
+        let cwd = resolver.current_directory();
+        let path = Path::new(self.path(resolver));
+
+        if let Ok(path) = path.strip_prefix(cwd) {
+            return path;
+        }
+
+        path
+    }
+
     fn diagnostic_source(&self, resolver: &dyn FileResolver) -> DiagnosticSource {
         match self {
             UnifiedFile::Ty(file) => DiagnosticSource::Ty(resolver.input(*file)),
@@ -1125,6 +1147,7 @@ impl From<crate::files::FileRange> for Span {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub enum Severity {
     Info,
     Warning,
@@ -1174,6 +1197,12 @@ pub struct DisplayDiagnosticConfig {
     /// here for now as the most "sensible" place for it to live until
     /// we had more concrete use cases. ---AG
     context: usize,
+    /// Whether to use preview formatting for Ruff diagnostics.
+    #[allow(
+        dead_code,
+        reason = "This is currently only used for JSON but will be needed soon for other formats"
+    )]
+    preview: bool,
 }
 
 impl DisplayDiagnosticConfig {
@@ -1194,6 +1223,14 @@ impl DisplayDiagnosticConfig {
             ..self
         }
     }
+
+    /// Whether to enable preview behavior or not.
+    pub fn preview(self, yes: bool) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            preview: yes,
+            ..self
+        }
+    }
 }
 
 impl Default for DisplayDiagnosticConfig {
@@ -1202,6 +1239,7 @@ impl Default for DisplayDiagnosticConfig {
             format: DiagnosticFormat::default(),
             color: false,
             context: 2,
+            preview: false,
         }
     }
 }
@@ -1229,6 +1267,31 @@ pub enum DiagnosticFormat {
     ///
     /// This may use color when printing to a `tty`.
     Concise,
+    /// Print diagnostics in the [Azure Pipelines] format.
+    ///
+    /// [Azure Pipelines]: https://learn.microsoft.com/en-us/azure/devops/pipelines/scripts/logging-commands?view=azure-devops&tabs=bash#logissue-log-an-error-or-warning
+    Azure,
+    /// Print diagnostics in JSON format.
+    ///
+    /// Unlike `json-lines`, this prints all of the diagnostics as a JSON array.
+    #[cfg(feature = "serde")]
+    Json,
+    /// Print diagnostics in JSON format, one per line.
+    ///
+    /// This will print each diagnostic as a separate JSON object on its own line. See the `json`
+    /// format for an array of all diagnostics. See <https://jsonlines.org/> for more details.
+    #[cfg(feature = "serde")]
+    JsonLines,
+    /// Print diagnostics in the JSON format expected by [reviewdog].
+    ///
+    /// [reviewdog]: https://github.com/reviewdog/reviewdog
+    #[cfg(feature = "serde")]
+    Rdjson,
+    /// Print diagnostics in the format emitted by Pylint.
+    Pylint,
+    /// Print diagnostics in the format expected by JUnit.
+    #[cfg(feature = "junit")]
+    Junit,
 }
 
 /// A representation of the kinds of messages inside a diagnostic.
@@ -1288,6 +1351,7 @@ impl std::fmt::Display for ConciseMessage<'_> {
 /// a blanket trait implementation for `IntoDiagnosticMessage` for
 /// anything that implements `std::fmt::Display`.
 #[derive(Clone, Debug, Eq, PartialEq, get_size2::GetSize)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct DiagnosticMessage(Box<str>);
 
 impl DiagnosticMessage {
@@ -1351,7 +1415,11 @@ impl<T: std::fmt::Display> IntoDiagnosticMessage for T {
 ///
 /// For Ruff rules this means the noqa code.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize), serde(transparent))]
+#[cfg_attr(
+    feature = "serde",
+    derive(serde::Serialize, serde::Deserialize),
+    serde(transparent)
+)]
 pub struct SecondaryCode(String);
 
 impl SecondaryCode {
@@ -1396,3 +1464,205 @@ impl From<&SecondaryCode> for SecondaryCode {
         value.clone()
     }
 }
+
+#[cfg(feature = "serde")]
+mod serde_diagnostics {
+    use std::sync::Arc;
+
+    use ruff_diagnostics::Fix;
+    use ruff_source_file::{SourceFile, SourceFileBuilder};
+    use ruff_text_size::{TextRange, TextSize};
+    use rustc_hash::FxHashMap;
+    use serde::{Deserialize, Serialize};
+
+    use super::{
+        Annotation, Diagnostic, DiagnosticId, DiagnosticInner, DiagnosticMessage, DiagnosticTag,
+        LintName, SecondaryCode, Severity, Span, SubDiagnostic, SubDiagnosticInner, UnifiedFile,
+    };
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    pub struct SerializableDiagnostics {
+        source_files: FxHashMap<String, String>,
+        diagnostics: Vec<SerializableDiagnostic>,
+    }
+
+    impl SerializableDiagnostics {
+        pub fn new(diagnostics: &[Diagnostic]) -> Self {
+            let mut source_files = FxHashMap::default();
+            let mut serializable_diagnostics = Vec::with_capacity(diagnostics.len());
+            for diagnostic in diagnostics {
+                let mut subs = Vec::with_capacity(diagnostic.inner.subs.len());
+                for sub in &diagnostic.inner.subs {
+                    subs.push(SerializableSubDiagnostic {
+                        severity: sub.inner.severity,
+                        message: sub.inner.message.clone(),
+                        annotations: serializable_annotations(
+                            &mut source_files,
+                            &sub.inner.annotations,
+                        ),
+                    });
+                }
+
+                serializable_diagnostics.push(SerializableDiagnostic {
+                    id: diagnostic.inner.id,
+                    severity: diagnostic.inner.severity,
+                    message: diagnostic.inner.message.clone(),
+                    annotations: serializable_annotations(
+                        &mut source_files,
+                        &diagnostic.inner.annotations,
+                    ),
+                    subs,
+                    fix: diagnostic.inner.fix.clone(),
+                    parent: diagnostic.inner.parent,
+                    noqa_offset: diagnostic.inner.noqa_offset,
+                    secondary_code: diagnostic.inner.secondary_code.clone(),
+                });
+            }
+
+            Self {
+                source_files,
+                diagnostics: serializable_diagnostics,
+            }
+        }
+
+        pub fn is_empty(&self) -> bool {
+            self.diagnostics.is_empty()
+        }
+
+        pub fn to_diagnostics(&self) -> Vec<Diagnostic> {
+            let source_files: FxHashMap<&str, SourceFile> = self
+                .source_files
+                .iter()
+                .map(|(name, contents)| {
+                    (
+                        name.as_str(),
+                        SourceFileBuilder::new(name.clone(), contents.clone()).finish(),
+                    )
+                })
+                .collect();
+            self.diagnostics
+                .iter()
+                .map(|diag| Diagnostic {
+                    inner: Arc::new(DiagnosticInner {
+                        id: diag.id,
+                        severity: diag.severity,
+                        message: diag.message.clone(),
+                        annotations: annotations(&source_files, &diag.annotations),
+                        subs: subdiagnostics(&source_files, &diag.subs),
+                        fix: diag.fix.clone(),
+                        parent: diag.parent,
+                        noqa_offset: diag.noqa_offset,
+                        secondary_code: diag.secondary_code.clone(),
+                    }),
+                })
+                .collect()
+        }
+    }
+
+    fn serializable_annotations(
+        source_files: &mut FxHashMap<String, String>,
+        annotations: &[Annotation],
+    ) -> Vec<SerializableAnnotation> {
+        let mut serializable_annotations = Vec::with_capacity(annotations.len());
+        for annotation in annotations {
+            let file = annotation.span.expect_ruff_file();
+            source_files.insert(file.name().to_string(), file.source_text().to_string());
+            serializable_annotations.push(SerializableAnnotation {
+                span: SerializableSpan {
+                    name: file.name().to_string(),
+                    range: annotation.span.range,
+                },
+                message: annotation.message.clone(),
+                is_primary: annotation.is_primary,
+                tags: annotation.tags.clone(),
+            });
+        }
+        serializable_annotations
+    }
+
+    fn annotations(
+        source_files: &FxHashMap<&str, SourceFile>,
+        serializable_annotations: &[SerializableAnnotation],
+    ) -> Vec<Annotation> {
+        serializable_annotations
+            .iter()
+            .map(|ann| {
+                let span = Span {
+                    file: UnifiedFile::Ruff(
+                        source_files
+                            .get(ann.span.name.as_str())
+                            .expect("Expected source file in cache")
+                            .clone(),
+                    ),
+                    range: ann.span.range,
+                };
+                Annotation {
+                    span,
+                    message: ann.message.clone(),
+                    is_primary: ann.is_primary,
+                    tags: ann.tags.clone(),
+                }
+            })
+            .collect()
+    }
+
+    fn subdiagnostics(
+        source_files: &FxHashMap<&str, SourceFile>,
+        serializable_annotations: &[SerializableSubDiagnostic],
+    ) -> Vec<SubDiagnostic> {
+        serializable_annotations
+            .iter()
+            .map(|sub| SubDiagnostic {
+                inner: Box::new(SubDiagnosticInner {
+                    severity: sub.severity,
+                    message: sub.message.clone(),
+                    annotations: annotations(source_files, &sub.annotations),
+                }),
+            })
+            .collect()
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableDiagnostic {
+        id: DiagnosticId,
+        severity: Severity,
+        message: DiagnosticMessage,
+        annotations: Vec<SerializableAnnotation>,
+        subs: Vec<SerializableSubDiagnostic>,
+        fix: Option<Fix>,
+        parent: Option<TextSize>,
+        noqa_offset: Option<TextSize>,
+        secondary_code: Option<SecondaryCode>,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableAnnotation {
+        span: SerializableSpan,
+        message: Option<DiagnosticMessage>,
+        is_primary: bool,
+        tags: Vec<DiagnosticTag>,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableSubDiagnostic {
+        severity: Severity,
+        message: DiagnosticMessage,
+        annotations: Vec<SerializableAnnotation>,
+    }
+
+    #[derive(Debug, PartialEq, Serialize, Deserialize)]
+    struct SerializableSpan {
+        name: String,
+        range: Option<TextRange>,
+    }
+
+    impl<'de> Deserialize<'de> for LintName {
+        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where
+            D: serde::Deserializer<'de>,
+        {
+            let s = String::deserialize(deserializer)?.into_boxed_str();
+            Ok(LintName::of(Box::leak(s)))
+        }
+    }
+}

crates/ruff_db/src/diagnostic/render.rs

@@ -1,9 +1,11 @@
 use std::collections::BTreeMap;
+use std::path::Path;
 
 use ruff_annotate_snippets::{
     Annotation as AnnotateAnnotation, Level as AnnotateLevel, Message as AnnotateMessage,
     Renderer as AnnotateRenderer, Snippet as AnnotateSnippet,
 };
+use ruff_notebook::{Notebook, NotebookIndex};
 use ruff_source_file::{LineIndex, OneIndexed, SourceCode};
 use ruff_text_size::{TextRange, TextSize};
 
@@ -17,9 +19,23 @@ use crate::{
 
 use super::{
     Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig, Severity,
-    SubDiagnostic,
+    SubDiagnostic, UnifiedFile,
 };
 
+use azure::AzureRenderer;
+use pylint::PylintRenderer;
+
+mod azure;
+#[cfg(feature = "serde")]
+mod json;
+#[cfg(feature = "serde")]
+mod json_lines;
+#[cfg(feature = "junit")]
+mod junit;
+mod pylint;
+#[cfg(feature = "serde")]
+mod rdjson;
+
 /// A type that implements `std::fmt::Display` for diagnostic rendering.
 ///
 /// It is created via [`Diagnostic::display`].
@@ -34,7 +50,6 @@ use super::{
 pub struct DisplayDiagnostic<'a> {
     config: &'a DisplayDiagnosticConfig,
     resolver: &'a dyn FileResolver,
-    annotate_renderer: AnnotateRenderer,
     diag: &'a Diagnostic,
 }
 
@@ -44,16 +59,9 @@ impl<'a> DisplayDiagnostic<'a> {
         config: &'a DisplayDiagnosticConfig,
         diag: &'a Diagnostic,
     ) -> DisplayDiagnostic<'a> {
-        let annotate_renderer = if config.color {
-            AnnotateRenderer::styled()
-        } else {
-            AnnotateRenderer::plain()
-        };
-
         DisplayDiagnostic {
             config,
             resolver,
-            annotate_renderer,
             diag,
         }
     }
@@ -61,68 +69,143 @@ impl<'a> DisplayDiagnostic<'a> {
 
 impl std::fmt::Display for DisplayDiagnostic<'_> {
     fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
-        let stylesheet = if self.config.color {
-            DiagnosticStylesheet::styled()
-        } else {
-            DiagnosticStylesheet::plain()
-        };
+        DisplayDiagnostics::new(self.resolver, self.config, std::slice::from_ref(self.diag)).fmt(f)
+    }
+}
 
-        if matches!(self.config.format, DiagnosticFormat::Concise) {
-            let (severity, severity_style) = match self.diag.severity() {
-                Severity::Info => ("info", stylesheet.info),
-                Severity::Warning => ("warning", stylesheet.warning),
-                Severity::Error => ("error", stylesheet.error),
-                Severity::Fatal => ("fatal", stylesheet.error),
-            };
+/// A type that implements `std::fmt::Display` for rendering a collection of diagnostics.
+///
+/// It is intended for collections of diagnostics that need to be serialized together, as is the
+/// case for JSON, for example.
+///
+/// See [`DisplayDiagnostic`] for rendering individual `Diagnostic`s and details about the lifetime
+/// constraints.
+pub struct DisplayDiagnostics<'a> {
+    config: &'a DisplayDiagnosticConfig,
+    resolver: &'a dyn FileResolver,
+    diagnostics: &'a [Diagnostic],
+}
 
-            write!(
-                f,
-                "{severity}[{id}]",
-                severity = fmt_styled(severity, severity_style),
-                id = fmt_styled(self.diag.id(), stylesheet.emphasis)
-            )?;
+impl<'a> DisplayDiagnostics<'a> {
+    pub fn new(
+        resolver: &'a dyn FileResolver,
+        config: &'a DisplayDiagnosticConfig,
+        diagnostics: &'a [Diagnostic],
+    ) -> DisplayDiagnostics<'a> {
+        DisplayDiagnostics {
+            config,
+            resolver,
+            diagnostics,
+        }
+    }
+}
 
-            if let Some(span) = self.diag.primary_span() {
-                write!(
-                    f,
-                    " {path}",
-                    path = fmt_styled(span.file().path(self.resolver), stylesheet.emphasis)
-                )?;
-                if let Some(range) = span.range() {
-                    let diagnostic_source = span.file().diagnostic_source(self.resolver);
-                    let start = diagnostic_source
-                        .as_source_code()
-                        .line_column(range.start());
+impl std::fmt::Display for DisplayDiagnostics<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
+        match self.config.format {
+            DiagnosticFormat::Concise => {
+                let stylesheet = if self.config.color {
+                    DiagnosticStylesheet::styled()
+                } else {
+                    DiagnosticStylesheet::plain()
+                };
 
+                for diag in self.diagnostics {
+                    let (severity, severity_style) = match diag.severity() {
+                        Severity::Info => ("info", stylesheet.info),
+                        Severity::Warning => ("warning", stylesheet.warning),
+                        Severity::Error => ("error", stylesheet.error),
+                        Severity::Fatal => ("fatal", stylesheet.error),
+                    };
                     write!(
                         f,
-                        ":{line}:{col}",
-                        line = fmt_styled(start.line, stylesheet.emphasis),
-                        col = fmt_styled(start.column, stylesheet.emphasis),
+                        "{severity}[{id}]",
+                        severity = fmt_styled(severity, severity_style),
+                        id = fmt_styled(diag.id(), stylesheet.emphasis)
                     )?;
+                    if let Some(span) = diag.primary_span() {
+                        write!(
+                            f,
+                            " {path}",
+                            path = fmt_styled(span.file().path(self.resolver), stylesheet.emphasis)
+                        )?;
+                        if let Some(range) = span.range() {
+                            let diagnostic_source = span.file().diagnostic_source(self.resolver);
+                            let start = diagnostic_source
+                                .as_source_code()
+                                .line_column(range.start());
+
+                            write!(
+                                f,
+                                ":{line}:{col}",
+                                line = fmt_styled(start.line, stylesheet.emphasis),
+                                col = fmt_styled(start.column, stylesheet.emphasis),
+                            )?;
+                        }
+                        write!(f, ":")?;
+                    }
+                    writeln!(f, " {message}", message = diag.concise_message())?;
                 }
-                write!(f, ":")?;
             }
-            return writeln!(f, " {message}", message = self.diag.concise_message());
+            DiagnosticFormat::Full => {
+                let stylesheet = if self.config.color {
+                    DiagnosticStylesheet::styled()
+                } else {
+                    DiagnosticStylesheet::plain()
+                };
+
+                let mut renderer = if self.config.color {
+                    AnnotateRenderer::styled()
+                } else {
+                    AnnotateRenderer::plain()
+                }
+                .cut_indicator("…");
+
+                renderer = renderer
+                    .error(stylesheet.error)
+                    .warning(stylesheet.warning)
+                    .info(stylesheet.info)
+                    .note(stylesheet.note)
+                    .help(stylesheet.help)
+                    .line_no(stylesheet.line_no)
+                    .emphasis(stylesheet.emphasis)
+                    .none(stylesheet.none);
+
+                for diag in self.diagnostics {
+                    let resolved = Resolved::new(self.resolver, diag);
+                    let renderable = resolved.to_renderable(self.config.context);
+                    for diag in renderable.diagnostics.iter() {
+                        writeln!(f, "{}", renderer.render(diag.to_annotate()))?;
+                    }
+                    writeln!(f)?;
+                }
+            }
+            DiagnosticFormat::Azure => {
+                AzureRenderer::new(self.resolver).render(f, self.diagnostics)?;
+            }
+            #[cfg(feature = "serde")]
+            DiagnosticFormat::Json => {
+                json::JsonRenderer::new(self.resolver, self.config).render(f, self.diagnostics)?;
+            }
+            #[cfg(feature = "serde")]
+            DiagnosticFormat::JsonLines => {
+                json_lines::JsonLinesRenderer::new(self.resolver, self.config)
+                    .render(f, self.diagnostics)?;
+            }
+            #[cfg(feature = "serde")]
+            DiagnosticFormat::Rdjson => {
+                rdjson::RdjsonRenderer::new(self.resolver).render(f, self.diagnostics)?;
+            }
+            DiagnosticFormat::Pylint => {
+                PylintRenderer::new(self.resolver).render(f, self.diagnostics)?;
+            }
+            #[cfg(feature = "junit")]
+            DiagnosticFormat::Junit => {
+                junit::JunitRenderer::new(self.resolver).render(f, self.diagnostics)?;
+            }
         }
 
-        let mut renderer = self.annotate_renderer.clone();
-        renderer = renderer
-            .error(stylesheet.error)
-            .warning(stylesheet.warning)
-            .info(stylesheet.info)
-            .note(stylesheet.note)
-            .help(stylesheet.help)
-            .line_no(stylesheet.line_no)
-            .emphasis(stylesheet.emphasis)
-            .none(stylesheet.none);
-
-        let resolved = Resolved::new(self.resolver, self.diag);
-        let renderable = resolved.to_renderable(self.config.context);
-        for diag in renderable.diagnostics.iter() {
-            writeln!(f, "{}", renderer.render(diag.to_annotate()))?;
-        }
-        writeln!(f)
+        Ok(())
     }
 }
 
@@ -635,6 +718,15 @@ pub trait FileResolver {
 
     /// Returns the input contents associated with the file given.
     fn input(&self, file: File) -> Input;
+
+    /// Returns the [`NotebookIndex`] associated with the file given, if it's a Jupyter notebook.
+    fn notebook_index(&self, file: &UnifiedFile) -> Option<NotebookIndex>;
+
+    /// Returns whether the file given is a Jupyter notebook.
+    fn is_notebook(&self, file: &UnifiedFile) -> bool;
+
+    /// Returns the current working directory.
+    fn current_directory(&self) -> &Path;
 }
 
 impl<T> FileResolver for T
@@ -651,6 +743,29 @@ where
             line_index: line_index(self, file),
         }
     }
+
+    fn notebook_index(&self, file: &UnifiedFile) -> Option<NotebookIndex> {
+        match file {
+            UnifiedFile::Ty(file) => self
+                .input(*file)
+                .text
+                .as_notebook()
+                .map(Notebook::index)
+                .cloned(),
+            UnifiedFile::Ruff(_) => unimplemented!("Expected an interned ty file"),
+        }
+    }
+
+    fn is_notebook(&self, file: &UnifiedFile) -> bool {
+        match file {
+            UnifiedFile::Ty(file) => self.input(*file).text.as_notebook().is_some(),
+            UnifiedFile::Ruff(_) => unimplemented!("Expected an interned ty file"),
+        }
+    }
+
+    fn current_directory(&self) -> &Path {
+        self.system().current_directory().as_std_path()
+    }
 }
 
 impl FileResolver for &dyn Db {
@@ -664,6 +779,29 @@ impl FileResolver for &dyn Db {
             line_index: line_index(*self, file),
         }
     }
+
+    fn notebook_index(&self, file: &UnifiedFile) -> Option<NotebookIndex> {
+        match file {
+            UnifiedFile::Ty(file) => self
+                .input(*file)
+                .text
+                .as_notebook()
+                .map(Notebook::index)
+                .cloned(),
+            UnifiedFile::Ruff(_) => unimplemented!("Expected an interned ty file"),
+        }
+    }
+
+    fn is_notebook(&self, file: &UnifiedFile) -> bool {
+        match file {
+            UnifiedFile::Ty(file) => self.input(*file).text.as_notebook().is_some(),
+            UnifiedFile::Ruff(_) => unimplemented!("Expected an interned ty file"),
+        }
+    }
+
+    fn current_directory(&self) -> &Path {
+        self.system().current_directory().as_std_path()
+    }
 }
 
 /// An abstraction over a unit of user input.
@@ -724,7 +862,9 @@ fn relativize_path<'p>(cwd: &SystemPath, path: &'p str) -> &'p str {
 #[cfg(test)]
 mod tests {
 
-    use crate::diagnostic::{Annotation, DiagnosticId, Severity, Span};
+    use ruff_diagnostics::{Edit, Fix};
+
+    use crate::diagnostic::{Annotation, DiagnosticId, SecondaryCode, Severity, Span};
     use crate::files::system_path_to_file;
     use crate::system::{DbWithWritableSystem, SystemPath};
     use crate::tests::TestDb;
@@ -2121,7 +2261,7 @@ watermelon
 
     /// A small harness for setting up an environment specifically for testing
     /// diagnostic rendering.
-    struct TestEnvironment {
+    pub(super) struct TestEnvironment {
         db: TestDb,
         config: DisplayDiagnosticConfig,
     }
@@ -2130,7 +2270,7 @@ watermelon
         /// Create a new test harness.
         ///
         /// This uses the default diagnostic rendering configuration.
-        fn new() -> TestEnvironment {
+        pub(super) fn new() -> TestEnvironment {
             TestEnvironment {
                 db: TestDb::new(),
                 config: DisplayDiagnosticConfig::default(),
@@ -2149,8 +2289,26 @@ watermelon
             self.config = config;
         }
 
+        /// Set the output format to use in diagnostic rendering.
+        pub(super) fn format(&mut self, format: DiagnosticFormat) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.format(format);
+            self.config = config;
+        }
+
+        /// Enable preview functionality for diagnostic rendering.
+        #[allow(
+            dead_code,
+            reason = "This is currently only used for JSON but will be needed soon for other formats"
+        )]
+        pub(super) fn preview(&mut self, yes: bool) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.preview(yes);
+            self.config = config;
+        }
+
         /// Add a file with the given path and contents to this environment.
-        fn add(&mut self, path: &str, contents: &str) {
+        pub(super) fn add(&mut self, path: &str, contents: &str) {
             let path = SystemPath::new(path);
             self.db.write_file(path, contents).unwrap();
         }
@@ -2200,7 +2358,7 @@ watermelon
         /// A convenience function for returning a builder for a diagnostic
         /// with "error" severity and canned values for its identifier
         /// and message.
-        fn err(&mut self) -> DiagnosticBuilder<'_> {
+        pub(super) fn err(&mut self) -> DiagnosticBuilder<'_> {
             self.builder(
                 "test-diagnostic",
                 Severity::Error,
@@ -2226,6 +2384,12 @@ watermelon
             DiagnosticBuilder { env: self, diag }
         }
 
+        /// A convenience function for returning a builder for an invalid syntax diagnostic.
+        fn invalid_syntax(&mut self, message: &str) -> DiagnosticBuilder<'_> {
+            let diag = Diagnostic::new(DiagnosticId::InvalidSyntax, Severity::Error, message);
+            DiagnosticBuilder { env: self, diag }
+        }
+
         /// Returns a builder for tersely constructing sub-diagnostics.
         fn sub_builder(&mut self, severity: Severity, message: &str) -> SubDiagnosticBuilder<'_> {
             let subdiag = SubDiagnostic::new(severity, message);
@@ -2235,9 +2399,18 @@ watermelon
         /// Render the given diagnostic into a `String`.
         ///
         /// (This will set the "printed" flag on `Diagnostic`.)
-        fn render(&self, diag: &Diagnostic) -> String {
+        pub(super) fn render(&self, diag: &Diagnostic) -> String {
             diag.display(&self.db, &self.config).to_string()
         }
+
+        /// Render the given diagnostics into a `String`.
+        ///
+        /// See `render` for rendering a single diagnostic.
+        ///
+        /// (This will set the "printed" flag on `Diagnostic`.)
+        pub(super) fn render_diagnostics(&self, diagnostics: &[Diagnostic]) -> String {
+            DisplayDiagnostics::new(&self.db, &self.config, diagnostics).to_string()
+        }
     }
 
     /// A helper builder for tersely populating a `Diagnostic`.
@@ -2246,14 +2419,14 @@ watermelon
     /// supported by this builder, and this only needs to be done
     /// infrequently, consider doing it more verbosely on `diag`
     /// itself.
-    struct DiagnosticBuilder<'e> {
+    pub(super) struct DiagnosticBuilder<'e> {
         env: &'e mut TestEnvironment,
         diag: Diagnostic,
     }
 
     impl<'e> DiagnosticBuilder<'e> {
         /// Return the built diagnostic.
-        fn build(self) -> Diagnostic {
+        pub(super) fn build(self) -> Diagnostic {
             self.diag
         }
 
@@ -2302,6 +2475,25 @@ watermelon
             self.diag.annotate(ann);
             self
         }
+
+        /// Set the secondary code on the diagnostic.
+        fn secondary_code(mut self, secondary_code: &str) -> DiagnosticBuilder<'e> {
+            self.diag
+                .set_secondary_code(SecondaryCode::new(secondary_code.to_string()));
+            self
+        }
+
+        /// Set the fix on the diagnostic.
+        pub(super) fn fix(mut self, fix: Fix) -> DiagnosticBuilder<'e> {
+            self.diag.set_fix(fix);
+            self
+        }
+
+        /// Set the noqa offset on the diagnostic.
+        fn noqa_offset(mut self, noqa_offset: TextSize) -> DiagnosticBuilder<'e> {
+            self.diag.set_noqa_offset(noqa_offset);
+            self
+        }
     }
 
     /// A helper builder for tersely populating a `SubDiagnostic`.
@@ -2381,4 +2573,199 @@ watermelon
         let offset = TextSize::from(offset.parse::<u32>().unwrap());
         (line_number, Some(offset))
     }
+
+    /// Create Ruff-style diagnostics for testing the various output formats.
+    pub(crate) fn create_diagnostics(
+        format: DiagnosticFormat,
+    ) -> (TestEnvironment, Vec<Diagnostic>) {
+        let mut env = TestEnvironment::new();
+        env.add(
+            "fib.py",
+            r#"import os
+
+
+def fibonacci(n):
+    """Compute the nth number in the Fibonacci sequence."""
+    x = 1
+    if n == 0:
+        return 0
+    elif n == 1:
+        return 1
+    else:
+        return fibonacci(n - 1) + fibonacci(n - 2)
+"#,
+        );
+        env.add("undef.py", r"if a == 1: pass");
+        env.format(format);
+
+        let diagnostics = vec![
+            env.builder("unused-import", Severity::Error, "`os` imported but unused")
+                .primary("fib.py", "1:7", "1:9", "Remove unused import: `os`")
+                .secondary_code("F401")
+                .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
+                    TextSize::from(0),
+                    TextSize::from(10),
+                ))))
+                .noqa_offset(TextSize::from(7))
+                .build(),
+            env.builder(
+                "unused-variable",
+                Severity::Error,
+                "Local variable `x` is assigned to but never used",
+            )
+            .primary(
+                "fib.py",
+                "6:4",
+                "6:5",
+                "Remove assignment to unused variable `x`",
+            )
+            .secondary_code("F841")
+            .fix(Fix::unsafe_edit(Edit::deletion(
+                TextSize::from(94),
+                TextSize::from(99),
+            )))
+            .noqa_offset(TextSize::from(94))
+            .build(),
+            env.builder("undefined-name", Severity::Error, "Undefined name `a`")
+                .primary("undef.py", "1:3", "1:4", "")
+                .secondary_code("F821")
+                .noqa_offset(TextSize::from(3))
+                .build(),
+        ];
+
+        (env, diagnostics)
+    }
+
+    /// Create Ruff-style syntax error diagnostics for testing the various output formats.
+    pub(crate) fn create_syntax_error_diagnostics(
+        format: DiagnosticFormat,
+    ) -> (TestEnvironment, Vec<Diagnostic>) {
+        let mut env = TestEnvironment::new();
+        env.add(
+            "syntax_errors.py",
+            r"from os import
+
+if call(foo
+    def bar():
+        pass
+",
+        );
+        env.format(format);
+
+        let diagnostics = vec![
+            env.invalid_syntax("SyntaxError: Expected one or more symbol names after import")
+                .primary("syntax_errors.py", "1:14", "1:15", "")
+                .build(),
+            env.invalid_syntax("SyntaxError: Expected ')', found newline")
+                .primary("syntax_errors.py", "3:11", "3:12", "")
+                .build(),
+        ];
+
+        (env, diagnostics)
+    }
+
+    /// Create Ruff-style diagnostics for testing the various output formats for a notebook.
+    #[allow(
+        dead_code,
+        reason = "This is currently only used for JSON but will be needed soon for other formats"
+    )]
+    pub(crate) fn create_notebook_diagnostics(
+        format: DiagnosticFormat,
+    ) -> (TestEnvironment, Vec<Diagnostic>) {
+        let mut env = TestEnvironment::new();
+        env.add(
+            "notebook.ipynb",
+            r##"
+        {
+ "cells": [
+  {
+   "cell_type": "code",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# cell 1\n",
+    "import os"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# cell 2\n",
+    "import math\n",
+    "\n",
+    "print('hello world')"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# cell 3\n",
+    "def foo():\n",
+    "    print()\n",
+    "    x = 1\n"
+   ]
+  }
+ ],
+ "metadata": {},
+ "nbformat": 4,
+ "nbformat_minor": 5
+}
+"##,
+        );
+        env.format(format);
+
+        let diagnostics = vec![
+            env.builder("unused-import", Severity::Error, "`os` imported but unused")
+                .primary("notebook.ipynb", "2:7", "2:9", "Remove unused import: `os`")
+                .secondary_code("F401")
+                .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
+                    TextSize::from(9),
+                    TextSize::from(19),
+                ))))
+                .noqa_offset(TextSize::from(16))
+                .build(),
+            env.builder(
+                "unused-import",
+                Severity::Error,
+                "`math` imported but unused",
+            )
+            .primary(
+                "notebook.ipynb",
+                "4:7",
+                "4:11",
+                "Remove unused import: `math`",
+            )
+            .secondary_code("F401")
+            .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
+                TextSize::from(28),
+                TextSize::from(40),
+            ))))
+            .noqa_offset(TextSize::from(35))
+            .build(),
+            env.builder(
+                "unused-variable",
+                Severity::Error,
+                "Local variable `x` is assigned to but never used",
+            )
+            .primary(
+                "notebook.ipynb",
+                "10:4",
+                "10:5",
+                "Remove assignment to unused variable `x`",
+            )
+            .secondary_code("F841")
+            .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
+                TextSize::from(94),
+                TextSize::from(104),
+            ))))
+            .noqa_offset(TextSize::from(98))
+            .build(),
+        ];
+
+        (env, diagnostics)
+    }
 }

crates/ruff_db/src/diagnostic/render/azure.rs

@@ -0,0 +1,83 @@
+use ruff_source_file::LineColumn;
+
+use crate::diagnostic::{Diagnostic, Severity};
+
+use super::FileResolver;
+
+pub(super) struct AzureRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+}
+
+impl<'a> AzureRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver) -> Self {
+        Self { resolver }
+    }
+}
+
+impl AzureRenderer<'_> {
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        for diag in diagnostics {
+            let severity = match diag.severity() {
+                Severity::Info | Severity::Warning => "warning",
+                Severity::Error | Severity::Fatal => "error",
+            };
+            write!(f, "##vso[task.logissue type={severity};")?;
+            if let Some(span) = diag.primary_span() {
+                let filename = span.file().path(self.resolver);
+                write!(f, "sourcepath={filename};")?;
+                if let Some(range) = span.range() {
+                    let location = if self.resolver.notebook_index(span.file()).is_some() {
+                        // We can't give a reasonable location for the structured formats,
+                        // so we show one that's clearly a fallback
+                        LineColumn::default()
+                    } else {
+                        span.file()
+                            .diagnostic_source(self.resolver)
+                            .as_source_code()
+                            .line_column(range.start())
+                    };
+                    write!(
+                        f,
+                        "linenumber={line};columnnumber={col};",
+                        line = location.line,
+                        col = location.column,
+                    )?;
+                }
+            }
+            writeln!(
+                f,
+                "{code}]{body}",
+                code = diag
+                    .secondary_code()
+                    .map_or_else(String::new, |code| format!("code={code};")),
+                body = diag.body(),
+            )?;
+        }
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Azure);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Azure);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+}

crates/ruff_db/src/diagnostic/render/json.rs

@@ -0,0 +1,352 @@
+use serde::{Serialize, Serializer, ser::SerializeSeq};
+use serde_json::{Value, json};
+
+use ruff_diagnostics::{Applicability, Edit};
+use ruff_notebook::NotebookIndex;
+use ruff_source_file::{LineColumn, OneIndexed};
+use ruff_text_size::Ranged;
+
+use crate::diagnostic::{Diagnostic, DiagnosticSource, DisplayDiagnosticConfig, SecondaryCode};
+
+use super::FileResolver;
+
+pub(super) struct JsonRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+    config: &'a DisplayDiagnosticConfig,
+}
+
+impl<'a> JsonRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver, config: &'a DisplayDiagnosticConfig) -> Self {
+        Self { resolver, config }
+    }
+}
+
+impl JsonRenderer<'_> {
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        write!(
+            f,
+            "{:#}",
+            diagnostics_to_json_value(diagnostics, self.resolver, self.config)
+        )
+    }
+}
+
+fn diagnostics_to_json_value<'a>(
+    diagnostics: impl IntoIterator<Item = &'a Diagnostic>,
+    resolver: &dyn FileResolver,
+    config: &DisplayDiagnosticConfig,
+) -> Value {
+    let values: Vec<_> = diagnostics
+        .into_iter()
+        .map(|diag| diagnostic_to_json(diag, resolver, config))
+        .collect();
+    json!(values)
+}
+
+pub(super) fn diagnostic_to_json<'a>(
+    diagnostic: &'a Diagnostic,
+    resolver: &'a dyn FileResolver,
+    config: &'a DisplayDiagnosticConfig,
+) -> JsonDiagnostic<'a> {
+    let span = diagnostic.primary_span_ref();
+    let filename = span.map(|span| span.file().path(resolver));
+    let range = span.and_then(|span| span.range());
+    let diagnostic_source = span.map(|span| span.file().diagnostic_source(resolver));
+    let source_code = diagnostic_source
+        .as_ref()
+        .map(|diagnostic_source| diagnostic_source.as_source_code());
+    let notebook_index = span.and_then(|span| resolver.notebook_index(span.file()));
+
+    let mut start_location = None;
+    let mut end_location = None;
+    let mut noqa_location = None;
+    let mut notebook_cell_index = None;
+    if let Some(source_code) = source_code {
+        noqa_location = diagnostic
+            .noqa_offset()
+            .map(|offset| source_code.line_column(offset));
+        if let Some(range) = range {
+            let mut start = source_code.line_column(range.start());
+            let mut end = source_code.line_column(range.end());
+            if let Some(notebook_index) = &notebook_index {
+                notebook_cell_index =
+                    Some(notebook_index.cell(start.line).unwrap_or(OneIndexed::MIN));
+                start = notebook_index.translate_line_column(&start);
+                end = notebook_index.translate_line_column(&end);
+                noqa_location =
+                    noqa_location.map(|location| notebook_index.translate_line_column(&location));
+            }
+            start_location = Some(start);
+            end_location = Some(end);
+        }
+    }
+
+    let fix = diagnostic.fix().map(|fix| JsonFix {
+        applicability: fix.applicability(),
+        message: diagnostic.suggestion(),
+        edits: ExpandedEdits {
+            edits: fix.edits(),
+            notebook_index,
+            config,
+            diagnostic_source,
+        },
+    });
+
+    // In preview, the locations and filename can be optional.
+    if config.preview {
+        JsonDiagnostic {
+            code: diagnostic.secondary_code(),
+            url: diagnostic.to_ruff_url(),
+            message: diagnostic.body(),
+            fix,
+            cell: notebook_cell_index,
+            location: start_location.map(JsonLocation::from),
+            end_location: end_location.map(JsonLocation::from),
+            filename,
+            noqa_row: noqa_location.map(|location| location.line),
+        }
+    } else {
+        JsonDiagnostic {
+            code: diagnostic.secondary_code(),
+            url: diagnostic.to_ruff_url(),
+            message: diagnostic.body(),
+            fix,
+            cell: notebook_cell_index,
+            location: Some(start_location.unwrap_or_default().into()),
+            end_location: Some(end_location.unwrap_or_default().into()),
+            filename: Some(filename.unwrap_or_default()),
+            noqa_row: noqa_location.map(|location| location.line),
+        }
+    }
+}
+
+struct ExpandedEdits<'a> {
+    edits: &'a [Edit],
+    notebook_index: Option<NotebookIndex>,
+    config: &'a DisplayDiagnosticConfig,
+    diagnostic_source: Option<DiagnosticSource>,
+}
+
+impl Serialize for ExpandedEdits<'_> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut s = serializer.serialize_seq(Some(self.edits.len()))?;
+
+        for edit in self.edits {
+            let (location, end_location) = if let Some(diagnostic_source) = &self.diagnostic_source
+            {
+                let source_code = diagnostic_source.as_source_code();
+                let mut location = source_code.line_column(edit.start());
+                let mut end_location = source_code.line_column(edit.end());
+
+                if let Some(notebook_index) = &self.notebook_index {
+                    // There exists a newline between each cell's source code in the
+                    // concatenated source code in Ruff. This newline doesn't actually
+                    // exists in the JSON source field.
+                    //
+                    // Now, certain edits may try to remove this newline, which means
+                    // the edit will spill over to the first character of the next cell.
+                    // If it does, we need to translate the end location to the last
+                    // character of the previous cell.
+                    match (
+                        notebook_index.cell(location.line),
+                        notebook_index.cell(end_location.line),
+                    ) {
+                        (Some(start_cell), Some(end_cell)) if start_cell != end_cell => {
+                            debug_assert_eq!(end_location.column.get(), 1);
+
+                            let prev_row = end_location.line.saturating_sub(1);
+                            end_location = LineColumn {
+                                line: notebook_index.cell_row(prev_row).unwrap_or(OneIndexed::MIN),
+                                column: source_code
+                                    .line_column(source_code.line_end_exclusive(prev_row))
+                                    .column,
+                            };
+                        }
+                        (Some(_), None) => {
+                            debug_assert_eq!(end_location.column.get(), 1);
+
+                            let prev_row = end_location.line.saturating_sub(1);
+                            end_location = LineColumn {
+                                line: notebook_index.cell_row(prev_row).unwrap_or(OneIndexed::MIN),
+                                column: source_code
+                                    .line_column(source_code.line_end_exclusive(prev_row))
+                                    .column,
+                            };
+                        }
+                        _ => {
+                            end_location = notebook_index.translate_line_column(&end_location);
+                        }
+                    }
+                    location = notebook_index.translate_line_column(&location);
+                }
+
+                (Some(location), Some(end_location))
+            } else {
+                (None, None)
+            };
+
+            // In preview, the locations can be optional.
+            let value = if self.config.preview {
+                JsonEdit {
+                    content: edit.content().unwrap_or_default(),
+                    location: location.map(JsonLocation::from),
+                    end_location: end_location.map(JsonLocation::from),
+                }
+            } else {
+                JsonEdit {
+                    content: edit.content().unwrap_or_default(),
+                    location: Some(location.unwrap_or_default().into()),
+                    end_location: Some(end_location.unwrap_or_default().into()),
+                }
+            };
+
+            s.serialize_element(&value)?;
+        }
+
+        s.end()
+    }
+}
+
+/// A serializable version of `Diagnostic`.
+///
+/// The `Old` variant only exists to preserve backwards compatibility. Both this and `JsonEdit`
+/// should become structs with the `New` definitions in a future Ruff release.
+#[derive(Serialize)]
+pub(crate) struct JsonDiagnostic<'a> {
+    cell: Option<OneIndexed>,
+    code: Option<&'a SecondaryCode>,
+    end_location: Option<JsonLocation>,
+    filename: Option<&'a str>,
+    fix: Option<JsonFix<'a>>,
+    location: Option<JsonLocation>,
+    message: &'a str,
+    noqa_row: Option<OneIndexed>,
+    url: Option<String>,
+}
+
+#[derive(Serialize)]
+struct JsonFix<'a> {
+    applicability: Applicability,
+    edits: ExpandedEdits<'a>,
+    message: Option<&'a str>,
+}
+
+#[derive(Serialize)]
+struct JsonLocation {
+    column: OneIndexed,
+    row: OneIndexed,
+}
+
+impl From<LineColumn> for JsonLocation {
+    fn from(location: LineColumn) -> Self {
+        JsonLocation {
+            row: location.line,
+            column: location.column,
+        }
+    }
+}
+
+#[derive(Serialize)]
+struct JsonEdit<'a> {
+    content: &'a str,
+    end_location: Option<JsonLocation>,
+    location: Option<JsonLocation>,
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{
+            TestEnvironment, create_diagnostics, create_notebook_diagnostics,
+            create_syntax_error_diagnostics,
+        },
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Json);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Json);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn notebook_output() {
+        let (env, diagnostics) = create_notebook_diagnostics(DiagnosticFormat::Json);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn missing_file_stable() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Json);
+        env.preview(false);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @r#"
+        [
+          {
+            "cell": null,
+            "code": null,
+            "end_location": {
+              "column": 1,
+              "row": 1
+            },
+            "filename": "",
+            "fix": null,
+            "location": {
+              "column": 1,
+              "row": 1
+            },
+            "message": "main diagnostic message",
+            "noqa_row": null,
+            "url": "https://docs.astral.sh/ruff/rules/test-diagnostic"
+          }
+        ]
+        "#,
+        );
+    }
+
+    #[test]
+    fn missing_file_preview() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Json);
+        env.preview(true);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @r#"
+        [
+          {
+            "cell": null,
+            "code": null,
+            "end_location": null,
+            "filename": null,
+            "fix": null,
+            "location": null,
+            "message": "main diagnostic message",
+            "noqa_row": null,
+            "url": "https://docs.astral.sh/ruff/rules/test-diagnostic"
+          }
+        ]
+        "#,
+        );
+    }
+}

crates/ruff_db/src/diagnostic/render/json_lines.rs

@@ -0,0 +1,59 @@
+use crate::diagnostic::{Diagnostic, DisplayDiagnosticConfig, render::json::diagnostic_to_json};
+
+use super::FileResolver;
+
+pub(super) struct JsonLinesRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+    config: &'a DisplayDiagnosticConfig,
+}
+
+impl<'a> JsonLinesRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver, config: &'a DisplayDiagnosticConfig) -> Self {
+        Self { resolver, config }
+    }
+}
+
+impl JsonLinesRenderer<'_> {
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        for diag in diagnostics {
+            writeln!(
+                f,
+                "{}",
+                serde_json::json!(diagnostic_to_json(diag, self.resolver, self.config))
+            )?;
+        }
+
+        Ok(())
+    }
+}
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{
+            create_diagnostics, create_notebook_diagnostics, create_syntax_error_diagnostics,
+        },
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::JsonLines);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::JsonLines);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn notebook_output() {
+        let (env, diagnostics) = create_notebook_diagnostics(DiagnosticFormat::JsonLines);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+}

crates/ruff_db/src/diagnostic/render/junit.rs

@@ -0,0 +1,195 @@
+use std::{collections::BTreeMap, ops::Deref, path::Path};
+
+use quick_junit::{NonSuccessKind, Report, TestCase, TestCaseStatus, TestSuite, XmlString};
+
+use ruff_source_file::LineColumn;
+
+use crate::diagnostic::{Diagnostic, SecondaryCode, render::FileResolver};
+
+/// A renderer for diagnostics in the [JUnit] format.
+///
+/// See [`junit.xsd`] for the specification in the JUnit repository and an annotated [version]
+/// linked from the [`quick_junit`] docs.
+///
+/// [JUnit]: https://junit.org/
+/// [`junit.xsd`]: https://github.com/junit-team/junit-framework/blob/2870b7d8fd5bf7c1efe489d3991d3ed3900e82bb/platform-tests/src/test/resources/jenkins-junit.xsd
+/// [version]: https://llg.cubic.org/docs/junit/
+/// [`quick_junit`]: https://docs.rs/quick-junit/latest/quick_junit/
+pub struct JunitRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+}
+
+impl<'a> JunitRenderer<'a> {
+    pub fn new(resolver: &'a dyn FileResolver) -> Self {
+        Self { resolver }
+    }
+
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        let mut report = Report::new("ruff");
+
+        if diagnostics.is_empty() {
+            let mut test_suite = TestSuite::new("ruff");
+            test_suite
+                .extra
+                .insert(XmlString::new("package"), XmlString::new("org.ruff"));
+            let mut case = TestCase::new("No errors found", TestCaseStatus::success());
+            case.set_classname("ruff");
+            test_suite.add_test_case(case);
+            report.add_test_suite(test_suite);
+        } else {
+            for (filename, diagnostics) in group_diagnostics_by_filename(diagnostics, self.resolver)
+            {
+                let mut test_suite = TestSuite::new(filename);
+                test_suite
+                    .extra
+                    .insert(XmlString::new("package"), XmlString::new("org.ruff"));
+
+                let classname = Path::new(filename).with_extension("");
+
+                for diagnostic in diagnostics {
+                    let DiagnosticWithLocation {
+                        diagnostic,
+                        start_location: location,
+                    } = diagnostic;
+                    let mut status = TestCaseStatus::non_success(NonSuccessKind::Failure);
+                    status.set_message(diagnostic.body());
+
+                    if let Some(location) = location {
+                        status.set_description(format!(
+                            "line {row}, col {col}, {body}",
+                            row = location.line,
+                            col = location.column,
+                            body = diagnostic.body()
+                        ));
+                    } else {
+                        status.set_description(diagnostic.body());
+                    }
+
+                    let code = diagnostic
+                        .secondary_code()
+                        .map_or_else(|| diagnostic.name(), SecondaryCode::as_str);
+                    let mut case = TestCase::new(format!("org.ruff.{code}"), status);
+                    case.set_classname(classname.to_str().unwrap());
+
+                    if let Some(location) = location {
+                        case.extra.insert(
+                            XmlString::new("line"),
+                            XmlString::new(location.line.to_string()),
+                        );
+                        case.extra.insert(
+                            XmlString::new("column"),
+                            XmlString::new(location.column.to_string()),
+                        );
+                    }
+
+                    test_suite.add_test_case(case);
+                }
+                report.add_test_suite(test_suite);
+            }
+        }
+
+        let adapter = FmtAdapter { fmt: f };
+        report.serialize(adapter).map_err(|_| std::fmt::Error)
+    }
+}
+
+// TODO(brent) this and `group_diagnostics_by_filename` are also used by the `grouped` output
+// format. I think they'd make more sense in that file, but I started here first. I'll move them to
+// that module when adding the `grouped` output format.
+struct DiagnosticWithLocation<'a> {
+    diagnostic: &'a Diagnostic,
+    start_location: Option<LineColumn>,
+}
+
+impl Deref for DiagnosticWithLocation<'_> {
+    type Target = Diagnostic;
+
+    fn deref(&self) -> &Self::Target {
+        self.diagnostic
+    }
+}
+
+fn group_diagnostics_by_filename<'a>(
+    diagnostics: &'a [Diagnostic],
+    resolver: &'a dyn FileResolver,
+) -> BTreeMap<&'a str, Vec<DiagnosticWithLocation<'a>>> {
+    let mut grouped_diagnostics = BTreeMap::default();
+    for diagnostic in diagnostics {
+        let (filename, start_location) = diagnostic
+            .primary_span_ref()
+            .map(|span| {
+                let file = span.file();
+                let start_location =
+                    span.range()
+                        .filter(|_| !resolver.is_notebook(file))
+                        .map(|range| {
+                            file.diagnostic_source(resolver)
+                                .as_source_code()
+                                .line_column(range.start())
+                        });
+
+                (span.file().path(resolver), start_location)
+            })
+            .unwrap_or_default();
+
+        grouped_diagnostics
+            .entry(filename)
+            .or_insert_with(Vec::new)
+            .push(DiagnosticWithLocation {
+                diagnostic,
+                start_location,
+            });
+    }
+    grouped_diagnostics
+}
+
+struct FmtAdapter<'a> {
+    fmt: &'a mut dyn std::fmt::Write,
+}
+
+impl std::io::Write for FmtAdapter<'_> {
+    fn write(&mut self, buf: &[u8]) -> std::io::Result<usize> {
+        self.fmt
+            .write_str(std::str::from_utf8(buf).map_err(|_| {
+                std::io::Error::new(
+                    std::io::ErrorKind::InvalidData,
+                    "Invalid UTF-8 in JUnit report",
+                )
+            })?)
+            .map_err(std::io::Error::other)?;
+
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> std::io::Result<()> {
+        Ok(())
+    }
+
+    fn write_fmt(&mut self, args: std::fmt::Arguments<'_>) -> std::io::Result<()> {
+        self.fmt.write_fmt(args).map_err(std::io::Error::other)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Junit);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Junit);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+}

crates/ruff_db/src/diagnostic/render/pylint.rs

@@ -0,0 +1,97 @@
+use crate::diagnostic::{Diagnostic, SecondaryCode, render::FileResolver};
+
+/// Generate violations in Pylint format.
+///
+/// The format is given by this string:
+///
+/// ```python
+/// "%(path)s:%(row)d: [%(code)s] %(text)s"
+/// ```
+///
+/// See: [Flake8 documentation](https://flake8.pycqa.org/en/latest/internal/formatters.html#pylint-formatter)
+pub(super) struct PylintRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+}
+
+impl<'a> PylintRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver) -> Self {
+        Self { resolver }
+    }
+}
+
+impl PylintRenderer<'_> {
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        for diagnostic in diagnostics {
+            let (filename, row) = diagnostic
+                .primary_span_ref()
+                .map(|span| {
+                    let file = span.file();
+
+                    let row = span
+                        .range()
+                        .filter(|_| !self.resolver.is_notebook(file))
+                        .map(|range| {
+                            file.diagnostic_source(self.resolver)
+                                .as_source_code()
+                                .line_column(range.start())
+                                .line
+                        });
+
+                    (file.relative_path(self.resolver).to_string_lossy(), row)
+                })
+                .unwrap_or_default();
+
+            let code = diagnostic
+                .secondary_code()
+                .map_or_else(|| diagnostic.name(), SecondaryCode::as_str);
+
+            let row = row.unwrap_or_default();
+
+            writeln!(
+                f,
+                "{path}:{row}: [{code}] {body}",
+                path = filename,
+                body = diagnostic.body()
+            )?;
+        }
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{TestEnvironment, create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Pylint);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Pylint);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn missing_file() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Pylint);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @":1: [test-diagnostic] main diagnostic message",
+        );
+    }
+}

crates/ruff_db/src/diagnostic/render/rdjson.rs

@@ -0,0 +1,235 @@
+use serde::ser::SerializeSeq;
+use serde::{Serialize, Serializer};
+
+use ruff_diagnostics::{Edit, Fix};
+use ruff_source_file::{LineColumn, SourceCode};
+use ruff_text_size::Ranged;
+
+use crate::diagnostic::Diagnostic;
+
+use super::FileResolver;
+
+pub struct RdjsonRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+}
+
+impl<'a> RdjsonRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver) -> Self {
+        Self { resolver }
+    }
+
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        write!(
+            f,
+            "{:#}",
+            serde_json::json!(RdjsonDiagnostics::new(diagnostics, self.resolver))
+        )
+    }
+}
+
+struct ExpandedDiagnostics<'a> {
+    resolver: &'a dyn FileResolver,
+    diagnostics: &'a [Diagnostic],
+}
+
+impl Serialize for ExpandedDiagnostics<'_> {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where
+        S: Serializer,
+    {
+        let mut s = serializer.serialize_seq(Some(self.diagnostics.len()))?;
+
+        for diagnostic in self.diagnostics {
+            let value = diagnostic_to_rdjson(diagnostic, self.resolver);
+            s.serialize_element(&value)?;
+        }
+
+        s.end()
+    }
+}
+
+fn diagnostic_to_rdjson<'a>(
+    diagnostic: &'a Diagnostic,
+    resolver: &'a dyn FileResolver,
+) -> RdjsonDiagnostic<'a> {
+    let span = diagnostic.primary_span_ref();
+    let source_file = span.map(|span| {
+        let file = span.file();
+        (file.path(resolver), file.diagnostic_source(resolver))
+    });
+
+    let location = source_file.as_ref().map(|(path, source)| {
+        let range = diagnostic.range().map(|range| {
+            let source_code = source.as_source_code();
+            let start = source_code.line_column(range.start());
+            let end = source_code.line_column(range.end());
+            RdjsonRange::new(start, end)
+        });
+
+        RdjsonLocation { path, range }
+    });
+
+    let edits = diagnostic.fix().map(Fix::edits).unwrap_or_default();
+
+    RdjsonDiagnostic {
+        message: diagnostic.body(),
+        location,
+        code: RdjsonCode {
+            value: diagnostic
+                .secondary_code()
+                .map_or_else(|| diagnostic.name(), |code| code.as_str()),
+            url: diagnostic.to_ruff_url(),
+        },
+        suggestions: rdjson_suggestions(
+            edits,
+            source_file
+                .as_ref()
+                .map(|(_, source)| source.as_source_code()),
+        ),
+    }
+}
+
+fn rdjson_suggestions<'a>(
+    edits: &'a [Edit],
+    source_code: Option<SourceCode>,
+) -> Vec<RdjsonSuggestion<'a>> {
+    if edits.is_empty() {
+        return Vec::new();
+    }
+
+    let Some(source_code) = source_code else {
+        debug_assert!(false, "Expected a source file for a diagnostic with a fix");
+        return Vec::new();
+    };
+
+    edits
+        .iter()
+        .map(|edit| {
+            let start = source_code.line_column(edit.start());
+            let end = source_code.line_column(edit.end());
+            let range = RdjsonRange::new(start, end);
+
+            RdjsonSuggestion {
+                range,
+                text: edit.content().unwrap_or_default(),
+            }
+        })
+        .collect()
+}
+
+#[derive(Serialize)]
+struct RdjsonDiagnostics<'a> {
+    diagnostics: ExpandedDiagnostics<'a>,
+    severity: &'static str,
+    source: RdjsonSource,
+}
+
+impl<'a> RdjsonDiagnostics<'a> {
+    fn new(diagnostics: &'a [Diagnostic], resolver: &'a dyn FileResolver) -> Self {
+        Self {
+            source: RdjsonSource {
+                name: "ruff",
+                url: env!("CARGO_PKG_HOMEPAGE"),
+            },
+            severity: "WARNING",
+            diagnostics: ExpandedDiagnostics {
+                diagnostics,
+                resolver,
+            },
+        }
+    }
+}
+
+#[derive(Serialize)]
+struct RdjsonSource {
+    name: &'static str,
+    url: &'static str,
+}
+
+#[derive(Serialize)]
+struct RdjsonDiagnostic<'a> {
+    code: RdjsonCode<'a>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    location: Option<RdjsonLocation<'a>>,
+    message: &'a str,
+    #[serde(skip_serializing_if = "Vec::is_empty")]
+    suggestions: Vec<RdjsonSuggestion<'a>>,
+}
+
+#[derive(Serialize)]
+struct RdjsonLocation<'a> {
+    path: &'a str,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    range: Option<RdjsonRange>,
+}
+
+#[derive(Default, Serialize)]
+struct RdjsonRange {
+    end: LineColumn,
+    start: LineColumn,
+}
+
+impl RdjsonRange {
+    fn new(start: LineColumn, end: LineColumn) -> Self {
+        Self { start, end }
+    }
+}
+
+#[derive(Serialize)]
+struct RdjsonCode<'a> {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    url: Option<String>,
+    value: &'a str,
+}
+
+#[derive(Serialize)]
+struct RdjsonSuggestion<'a> {
+    range: RdjsonRange,
+    text: &'a str,
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat,
+        render::tests::{TestEnvironment, create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Rdjson);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Rdjson);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics));
+    }
+
+    #[test]
+    fn missing_file_stable() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Rdjson);
+        env.preview(false);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(env.render(&diag));
+    }
+
+    #[test]
+    fn missing_file_preview() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Rdjson);
+        env.preview(true);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(env.render(&diag));
+    }
+}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__azure__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/azure.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/azure.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 ##vso[task.logissue type=error;sourcepath=fib.py;linenumber=1;columnnumber=8;code=F401;]`os` imported but unused
 ##vso[task.logissue type=error;sourcepath=fib.py;linenumber=6;columnnumber=5;code=F841;]Local variable `x` is assigned to but never used

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__azure__tests__syntax_errors.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/azure.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/azure.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 ##vso[task.logissue type=error;sourcepath=syntax_errors.py;linenumber=1;columnnumber=15;]SyntaxError: Expected one or more symbol names after import
 ##vso[task.logissue type=error;sourcepath=syntax_errors.py;linenumber=3;columnnumber=12;]SyntaxError: Expected ')', found newline

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__json__tests__notebook_output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/json.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/json.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 [
   {
@@ -84,8 +83,8 @@ snapshot_kind: text
         {
           "content": "",
           "end_location": {
-            "column": 10,
-            "row": 4
+            "column": 1,
+            "row": 5
           },
           "location": {
             "column": 1,

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__json__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/json.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/json.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 [
   {

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__json__tests__syntax_errors.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/json.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/json.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 [
   {

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__json_lines__tests__notebook_output.snap

@@ -1,8 +1,7 @@
 ---
-source: crates/ruff_linter/src/message/json_lines.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/json_lines.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 {"cell":1,"code":"F401","end_location":{"column":10,"row":2},"filename":"notebook.ipynb","fix":{"applicability":"safe","edits":[{"content":"","end_location":{"column":10,"row":2},"location":{"column":1,"row":2}}],"message":"Remove unused import: `os`"},"location":{"column":8,"row":2},"message":"`os` imported but unused","noqa_row":2,"url":"https://docs.astral.sh/ruff/rules/unused-import"}
 {"cell":2,"code":"F401","end_location":{"column":12,"row":2},"filename":"notebook.ipynb","fix":{"applicability":"safe","edits":[{"content":"","end_location":{"column":1,"row":3},"location":{"column":1,"row":2}}],"message":"Remove unused import: `math`"},"location":{"column":8,"row":2},"message":"`math` imported but unused","noqa_row":2,"url":"https://docs.astral.sh/ruff/rules/unused-import"}
-{"cell":3,"code":"F841","end_location":{"column":6,"row":4},"filename":"notebook.ipynb","fix":{"applicability":"unsafe","edits":[{"content":"","end_location":{"column":10,"row":4},"location":{"column":1,"row":4}}],"message":"Remove assignment to unused variable `x`"},"location":{"column":5,"row":4},"message":"Local variable `x` is assigned to but never used","noqa_row":4,"url":"https://docs.astral.sh/ruff/rules/unused-variable"}
+{"cell":3,"code":"F841","end_location":{"column":6,"row":4},"filename":"notebook.ipynb","fix":{"applicability":"unsafe","edits":[{"content":"","end_location":{"column":1,"row":5},"location":{"column":1,"row":4}}],"message":"Remove assignment to unused variable `x`"},"location":{"column":5,"row":4},"message":"Local variable `x` is assigned to but never used","noqa_row":4,"url":"https://docs.astral.sh/ruff/rules/unused-variable"}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__json_lines__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/json_lines.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/json_lines.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 {"cell":null,"code":"F401","end_location":{"column":10,"row":1},"filename":"fib.py","fix":{"applicability":"unsafe","edits":[{"content":"","end_location":{"column":1,"row":2},"location":{"column":1,"row":1}}],"message":"Remove unused import: `os`"},"location":{"column":8,"row":1},"message":"`os` imported but unused","noqa_row":1,"url":"https://docs.astral.sh/ruff/rules/unused-import"}
 {"cell":null,"code":"F841","end_location":{"column":6,"row":6},"filename":"fib.py","fix":{"applicability":"unsafe","edits":[{"content":"","end_location":{"column":10,"row":6},"location":{"column":5,"row":6}}],"message":"Remove assignment to unused variable `x`"},"location":{"column":5,"row":6},"message":"Local variable `x` is assigned to but never used","noqa_row":6,"url":"https://docs.astral.sh/ruff/rules/unused-variable"}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__json_lines__tests__syntax_errors.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/json_lines.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/json_lines.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 {"cell":null,"code":null,"end_location":{"column":1,"row":2},"filename":"syntax_errors.py","fix":null,"location":{"column":15,"row":1},"message":"SyntaxError: Expected one or more symbol names after import","noqa_row":null,"url":null}
 {"cell":null,"code":null,"end_location":{"column":1,"row":4},"filename":"syntax_errors.py","fix":null,"location":{"column":12,"row":3},"message":"SyntaxError: Expected ')', found newline","noqa_row":null,"url":null}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__junit__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/junit.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/junit.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuites name="ruff" tests="3" failures="3" errors="0">

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__junit__tests__syntax_errors.snap

@@ -1,15 +1,14 @@
 ---
-source: crates/ruff_linter/src/message/junit.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/junit.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 <?xml version="1.0" encoding="UTF-8"?>
 <testsuites name="ruff" tests="2" failures="2" errors="0">
     <testsuite name="syntax_errors.py" tests="2" disabled="0" errors="0" failures="2" package="org.ruff">
-        <testcase name="org.ruff" classname="syntax_errors" line="1" column="15">
+        <testcase name="org.ruff.invalid-syntax" classname="syntax_errors" line="1" column="15">
             <failure message="SyntaxError: Expected one or more symbol names after import">line 1, col 15, SyntaxError: Expected one or more symbol names after import</failure>
         </testcase>
-        <testcase name="org.ruff" classname="syntax_errors" line="3" column="12">
+        <testcase name="org.ruff.invalid-syntax" classname="syntax_errors" line="3" column="12">
             <failure message="SyntaxError: Expected &apos;)&apos;, found newline">line 3, col 12, SyntaxError: Expected &apos;)&apos;, found newline</failure>
         </testcase>
     </testsuite>

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__pylint__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/pylint.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/pylint.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 fib.py:1: [F401] `os` imported but unused
 fib.py:6: [F841] Local variable `x` is assigned to but never used

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__pylint__tests__syntax_errors.snap

@@ -0,0 +1,6 @@
+---
+source: crates/ruff_db/src/diagnostic/render/pylint.rs
+expression: env.render_diagnostics(&diagnostics)
+---
+syntax_errors.py:1: [invalid-syntax] SyntaxError: Expected one or more symbol names after import
+syntax_errors.py:3: [invalid-syntax] SyntaxError: Expected ')', found newline

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__rdjson__tests__missing_file_preview.snap

@@ -0,0 +1,20 @@
+---
+source: crates/ruff_db/src/diagnostic/render/rdjson.rs
+expression: env.render(&diag)
+---
+{
+  "diagnostics": [
+    {
+      "code": {
+        "url": "https://docs.astral.sh/ruff/rules/test-diagnostic",
+        "value": "test-diagnostic"
+      },
+      "message": "main diagnostic message"
+    }
+  ],
+  "severity": "WARNING",
+  "source": {
+    "name": "ruff",
+    "url": "https://docs.astral.sh/ruff"
+  }
+}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__rdjson__tests__missing_file_stable.snap

@@ -0,0 +1,20 @@
+---
+source: crates/ruff_db/src/diagnostic/render/rdjson.rs
+expression: env.render(&diag)
+---
+{
+  "diagnostics": [
+    {
+      "code": {
+        "url": "https://docs.astral.sh/ruff/rules/test-diagnostic",
+        "value": "test-diagnostic"
+      },
+      "message": "main diagnostic message"
+    }
+  ],
+  "severity": "WARNING",
+  "source": {
+    "name": "ruff",
+    "url": "https://docs.astral.sh/ruff"
+  }
+}

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__rdjson__tests__output.snap

@@ -1,7 +1,6 @@
 ---
-source: crates/ruff_linter/src/message/rdjson.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/rdjson.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 {
   "diagnostics": [
@@ -96,7 +95,7 @@ snapshot_kind: text
       "message": "Undefined name `a`"
     }
   ],
-  "severity": "warning",
+  "severity": "WARNING",
   "source": {
     "name": "ruff",
     "url": "https://docs.astral.sh/ruff"

crates/ruff_db/src/diagnostic/render/snapshots/ruff_db__diagnostic__render__rdjson__tests__syntax_errors.snap

@@ -1,14 +1,12 @@
 ---
-source: crates/ruff_linter/src/message/rdjson.rs
-expression: content
-snapshot_kind: text
+source: crates/ruff_db/src/diagnostic/render/rdjson.rs
+expression: env.render_diagnostics(&diagnostics)
 ---
 {
   "diagnostics": [
     {
       "code": {
-        "url": null,
-        "value": null
+        "value": "invalid-syntax"
       },
       "location": {
         "path": "syntax_errors.py",
@@ -27,8 +25,7 @@ snapshot_kind: text
     },
     {
       "code": {
-        "url": null,
-        "value": null
+        "value": "invalid-syntax"
       },
       "location": {
         "path": "syntax_errors.py",
@@ -46,7 +43,7 @@ snapshot_kind: text
       "message": "SyntaxError: Expected ')', found newline"
     }
   ],
-  "severity": "warning",
+  "severity": "WARNING",
   "source": {
     "name": "ruff",
     "url": "https://docs.astral.sh/ruff"

crates/ruff_db/src/files.rs

@@ -232,7 +232,7 @@ impl Files {
         let roots = inner.roots.read().unwrap();
 
         for root in roots.all() {
-            if root.path(db).starts_with(&path) {
+            if path.starts_with(root.path(db)) {
                 root.set_revision(db).to(FileRevision::now());
             }
         }
@@ -375,12 +375,25 @@ impl File {
     }
 
     /// Refreshes the file metadata by querying the file system if needed.
+    ///
+    /// This also "touches" the file root associated with the given path.
+    /// This means that any Salsa queries that depend on the corresponding
+    /// root's revision will become invalidated.
     pub fn sync_path(db: &mut dyn Db, path: &SystemPath) {
         let absolute = SystemPath::absolute(path, db.system().current_directory());
         Files::touch_root(db, &absolute);
         Self::sync_system_path(db, &absolute, None);
     }
 
+    /// Refreshes *only* the file metadata by querying the file system if needed.
+    ///
+    /// This specifically does not touch any file root associated with the
+    /// given file path.
+    pub fn sync_path_only(db: &mut dyn Db, path: &SystemPath) {
+        let absolute = SystemPath::absolute(path, db.system().current_directory());
+        Self::sync_system_path(db, &absolute, None);
+    }
+
     /// Increments the revision for the virtual file at `path`.
     pub fn sync_virtual_path(db: &mut dyn Db, path: &SystemVirtualPath) {
         if let Some(virtual_file) = db.files().try_virtual_file(path) {
@@ -486,7 +499,7 @@ impl fmt::Debug for File {
 ///
 /// This is a wrapper around a [`File`] that provides additional methods to interact with a virtual
 /// file.
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct VirtualFile(File);
 
 impl VirtualFile {

crates/ruff_db/src/files/file_root.rs

@@ -23,7 +23,7 @@ pub struct FileRoot {
     pub path: SystemPathBuf,
 
     /// The kind of the root at the time of its creation.
-    kind_at_time_of_creation: FileRootKind,
+    pub kind_at_time_of_creation: FileRootKind,
 
     /// A revision that changes when the contents of the source root change.
     ///

crates/ruff_db/src/lib.rs

@@ -28,6 +28,21 @@ pub use web_time::{Instant, SystemTime, SystemTimeError};
 pub type FxDashMap<K, V> = dashmap::DashMap<K, V, BuildHasherDefault<FxHasher>>;
 pub type FxDashSet<K> = dashmap::DashSet<K, BuildHasherDefault<FxHasher>>;
 
+static VERSION: std::sync::OnceLock<String> = std::sync::OnceLock::new();
+
+/// Returns the version of the executing program if set.
+pub fn program_version() -> Option<&'static str> {
+    VERSION.get().map(|version| version.as_str())
+}
+
+/// Sets the version of the executing program.
+///
+/// ## Errors
+/// If the version has already been initialized (can only be set once).
+pub fn set_program_version(version: String) -> Result<(), String> {
+    VERSION.set(version)
+}
+
 /// Most basic database that gives access to files, the host system, source code, and parsed AST.
 #[salsa::db]
 pub trait Db: salsa::Database {

crates/ruff_db/src/vendored.rs

@@ -21,6 +21,19 @@ type LockedZipArchive<'a> = MutexGuard<'a, VendoredZipArchive>;
 ///
 /// "Files" in the `VendoredFileSystem` are read-only and immutable.
 /// Directories are supported, but symlinks and hardlinks cannot exist.
+///
+/// # Path separators
+///
+/// At time of writing (2025-07-11), this implementation always uses `/` as a
+/// path separator, even in Windows environments where `\` is traditionally
+/// used as a file path separator. Namely, this is only currently used with zip
+/// files built by `crates/ty_vendored/build.rs`.
+///
+/// Callers using this may provide paths that use a `\` as a separator. It will
+/// be transparently normalized to `/`.
+///
+/// This is particularly important because the presence of a trailing separator
+/// in a zip file is conventionally used to indicate a directory entry.
 #[derive(Clone)]
 pub struct VendoredFileSystem {
     inner: Arc<Mutex<VendoredZipArchive>>,
@@ -115,6 +128,68 @@ impl VendoredFileSystem {
         read_to_string(self, path.as_ref())
     }
 
+    /// Read the direct children of the directory
+    /// identified by `path`.
+    ///
+    /// If `path` is not a directory, then this will
+    /// return an empty `Vec`.
+    pub fn read_directory(&self, dir: impl AsRef<VendoredPath>) -> Vec<DirectoryEntry> {
+        // N.B. We specifically do not return an iterator here to avoid
+        // holding a lock for the lifetime of the iterator returned.
+        // That is, it seems like a footgun to keep the zip archive
+        // locked during iteration, since the unit of work for each
+        // item in the iterator could be arbitrarily long. Allocating
+        // up front and stuffing all entries into it is probably the
+        // simplest solution and what we do here. If this becomes
+        // a problem, there are other strategies we could pursue.
+        // (Amortizing allocs, using a different synchronization
+        // behavior or even exposing additional APIs.) ---AG
+
+        fn read_directory(fs: &VendoredFileSystem, dir: &VendoredPath) -> Vec<DirectoryEntry> {
+            let mut normalized = NormalizedVendoredPath::from(dir);
+            if !normalized.as_str().ends_with('/') {
+                normalized = normalized.with_trailing_slash();
+            }
+            let archive = fs.lock_archive();
+            let mut entries = vec![];
+            for name in archive.0.file_names() {
+                // Any entry that doesn't have the `path` (with a
+                // trailing slash) as a prefix cannot possibly be in
+                // the directory referenced by `path`.
+                let Some(without_dir_prefix) = name.strip_prefix(normalized.as_str()) else {
+                    continue;
+                };
+                // Filter out an entry equivalent to the path given
+                // since we only want children of the directory.
+                if without_dir_prefix.is_empty() {
+                    continue;
+                }
+                // We only want *direct* children. Files that are
+                // direct children cannot have any slashes (or else
+                // they are not direct children). Directories that
+                // are direct children can only have one slash and
+                // it must be at the end.
+                //
+                // (We do this manually ourselves to avoid doing a
+                // full file lookup and metadata retrieval via the
+                // `zip` crate.)
+                let file_type = FileType::from_zip_file_name(without_dir_prefix);
+                let slash_count = without_dir_prefix.matches('/').count();
+                match file_type {
+                    FileType::File if slash_count > 0 => continue,
+                    FileType::Directory if slash_count > 1 => continue,
+                    _ => {}
+                }
+                entries.push(DirectoryEntry {
+                    path: VendoredPathBuf::from(name),
+                    file_type,
+                });
+            }
+            entries
+        }
+        read_directory(self, dir.as_ref())
+    }
+
     /// Acquire a lock on the underlying zip archive.
     /// The call will block until it is able to acquire the lock.
     ///
@@ -206,6 +281,14 @@ pub enum FileType {
 }
 
 impl FileType {
+    fn from_zip_file_name(name: &str) -> FileType {
+        if name.ends_with('/') {
+            FileType::Directory
+        } else {
+            FileType::File
+        }
+    }
+
     pub const fn is_file(self) -> bool {
         matches!(self, Self::File)
     }
@@ -244,6 +327,30 @@ impl Metadata {
     }
 }
 
+#[derive(Debug, PartialEq, Eq)]
+pub struct DirectoryEntry {
+    path: VendoredPathBuf,
+    file_type: FileType,
+}
+
+impl DirectoryEntry {
+    pub fn new(path: VendoredPathBuf, file_type: FileType) -> Self {
+        Self { path, file_type }
+    }
+
+    pub fn into_path(self) -> VendoredPathBuf {
+        self.path
+    }
+
+    pub fn path(&self) -> &VendoredPath {
+        &self.path
+    }
+
+    pub fn file_type(&self) -> FileType {
+        self.file_type
+    }
+}
+
 /// Newtype wrapper around a ZipArchive.
 #[derive(Debug)]
 struct VendoredZipArchive(ZipArchive<io::Cursor<Cow<'static, [u8]>>>);
@@ -498,6 +605,60 @@ pub(crate) mod tests {
         test_directory("./stdlib/asyncio/../asyncio/")
     }
 
+    fn readdir_snapshot(fs: &VendoredFileSystem, path: &str) -> String {
+        let mut paths = fs
+            .read_directory(VendoredPath::new(path))
+            .into_iter()
+            .map(|entry| entry.path().to_string())
+            .collect::<Vec<String>>();
+        paths.sort();
+        paths.join("\n")
+    }
+
+    #[test]
+    fn read_directory_stdlib() {
+        let mock_typeshed = mock_typeshed();
+
+        assert_snapshot!(readdir_snapshot(&mock_typeshed, "stdlib"), @r"
+        vendored://stdlib/asyncio/
+        vendored://stdlib/functools.pyi
+        ");
+        assert_snapshot!(readdir_snapshot(&mock_typeshed, "stdlib/"), @r"
+        vendored://stdlib/asyncio/
+        vendored://stdlib/functools.pyi
+        ");
+        assert_snapshot!(readdir_snapshot(&mock_typeshed, "./stdlib"), @r"
+        vendored://stdlib/asyncio/
+        vendored://stdlib/functools.pyi
+        ");
+        assert_snapshot!(readdir_snapshot(&mock_typeshed, "./stdlib/"), @r"
+        vendored://stdlib/asyncio/
+        vendored://stdlib/functools.pyi
+        ");
+    }
+
+    #[test]
+    fn read_directory_asyncio() {
+        let mock_typeshed = mock_typeshed();
+
+        assert_snapshot!(
+            readdir_snapshot(&mock_typeshed, "stdlib/asyncio"),
+            @"vendored://stdlib/asyncio/tasks.pyi",
+        );
+        assert_snapshot!(
+            readdir_snapshot(&mock_typeshed, "./stdlib/asyncio"),
+            @"vendored://stdlib/asyncio/tasks.pyi",
+        );
+        assert_snapshot!(
+            readdir_snapshot(&mock_typeshed, "stdlib/asyncio/"),
+            @"vendored://stdlib/asyncio/tasks.pyi",
+        );
+        assert_snapshot!(
+            readdir_snapshot(&mock_typeshed, "./stdlib/asyncio/"),
+            @"vendored://stdlib/asyncio/tasks.pyi",
+        );
+    }
+
     fn test_nonexistent_path(path: &str) {
         let mock_typeshed = mock_typeshed();
         let path = VendoredPath::new(path);

crates/ruff_db/src/vendored/path.rs

@@ -17,6 +17,10 @@ impl VendoredPath {
         unsafe { &*(path as *const Utf8Path as *const VendoredPath) }
     }
 
+    pub fn file_name(&self) -> Option<&str> {
+        self.0.file_name()
+    }
+
     pub fn to_path_buf(&self) -> VendoredPathBuf {
         VendoredPathBuf(self.0.to_path_buf())
     }

crates/ruff_graph/src/db.rs

@@ -87,7 +87,7 @@ impl SourceDb for ModuleDb {
 
 #[salsa::db]
 impl Db for ModuleDb {
-    fn is_file_open(&self, file: File) -> bool {
+    fn should_check_file(&self, file: File) -> bool {
         !file.path(self).is_vendored_path()
     }
 

crates/ruff_linter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.12.2"
+version = "0.12.4"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }
@@ -15,7 +15,7 @@ license = { workspace = true }
 [dependencies]
 ruff_annotate_snippets = { workspace = true }
 ruff_cache = { workspace = true }
-ruff_db = { workspace = true, features = ["serde"] }
+ruff_db = { workspace = true, features = ["junit", "serde"] }
 ruff_diagnostics = { workspace = true, features = ["serde"] }
 ruff_notebook = { workspace = true }
 ruff_macros = { workspace = true }
@@ -55,7 +55,6 @@ path-absolutize = { workspace = true, features = [
 pathdiff = { workspace = true }
 pep440_rs = { workspace = true }
 pyproject-toml = { workspace = true }
-quick-junit = { workspace = true }
 regex = { workspace = true }
 rustc-hash = { workspace = true }
 schemars = { workspace = true, optional = true }

crates/ruff_linter/resources/test/fixtures/flake8_bugbear/B017_0.py

@@ -1,6 +1,6 @@
 """
 Should emit:
-B017 - on lines 24, 28, 46, 49, 52, and 58
+B017 - on lines 24, 28, 46, 49, 52, 58, 62, 68, and 71
 """
 import asyncio
 import unittest
@@ -56,3 +56,17 @@ def test_pytest_raises():
 
     with contextlib.nullcontext(), pytest.raises(Exception):
         raise ValueError("Multiple context managers")
+
+
+def test_pytest_raises_keyword():
+    with pytest.raises(expected_exception=Exception):
+        raise ValueError("Should be flagged")
+
+def test_assert_raises_keyword():
+    class TestKwargs(unittest.TestCase):
+        def test_method(self):
+            with self.assertRaises(exception=Exception):
+                raise ValueError("Should be flagged")
+
+            with self.assertRaises(exception=BaseException):
+                raise ValueError("Should be flagged")

crates/ruff_linter/resources/test/fixtures/flake8_django/DJ008.py

@@ -181,3 +181,51 @@ class SubclassTestModel2(TestModel4):
 # Subclass without __str__
 class SubclassTestModel3(TestModel1):
     pass
+
+
+# Test cases for type-annotated abstract models - these should NOT trigger DJ008
+from typing import ClassVar
+from django_stubs_ext.db.models import TypedModelMeta
+
+
+class TypeAnnotatedAbstractModel1(models.Model):
+    """Model with type-annotated abstract = True - should not trigger DJ008"""
+    new_field = models.CharField(max_length=10)
+
+    class Meta(TypedModelMeta):
+        abstract: ClassVar[bool] = True
+
+
+class TypeAnnotatedAbstractModel2(models.Model):
+    """Model with type-annotated abstract = True using regular Meta - should not trigger DJ008"""  
+    new_field = models.CharField(max_length=10)
+
+    class Meta:
+        abstract: ClassVar[bool] = True
+
+
+class TypeAnnotatedAbstractModel3(models.Model):
+    """Model with type-annotated abstract = True but without ClassVar - should not trigger DJ008"""
+    new_field = models.CharField(max_length=10)
+
+    class Meta:
+        abstract: bool = True
+
+
+class TypeAnnotatedNonAbstractModel(models.Model):
+    """Model with type-annotated abstract = False - should trigger DJ008"""
+    new_field = models.CharField(max_length=10)
+
+    class Meta:
+        abstract: ClassVar[bool] = False
+
+
+class TypeAnnotatedAbstractModelWithStr(models.Model):
+    """Model with type-annotated abstract = True and __str__ method - should not trigger DJ008"""
+    new_field = models.CharField(max_length=10)
+
+    class Meta(TypedModelMeta):
+        abstract: ClassVar[bool] = True
+
+    def __str__(self):
+        return self.new_field

crates/ruff_linter/resources/test/fixtures/flake8_gettext/INT001.py

@@ -1 +1,4 @@
 _(f"{'value'}")
+
+# Don't trigger for t-strings
+_(t"{'value'}")

crates/ruff_linter/resources/test/fixtures/flake8_logging_format/G004.py

@@ -13,3 +13,7 @@ from logging import info
 
 info(f"{name}")
 info(f"{__name__}")
+
+# Don't trigger for t-strings
+info(t"{name}")
+info(t"{__name__}")

crates/ruff_linter/resources/test/fixtures/flake8_pytest_style/PT011.py

@@ -47,3 +47,7 @@ def test_error_match_is_empty():
 
     with pytest.raises(ValueError, match=f""):
         raise ValueError("Can't divide 1 by 0")
+
+def test_ok_t_string_match():
+    with pytest.raises(ValueError, match=t""):
+        raise ValueError("Can't divide 1 by 0")

crates/ruff_linter/resources/test/fixtures/flake8_pytest_style/PT016.py

@@ -23,3 +23,9 @@ def f():
     pytest.fail(msg=f"")
     pytest.fail(reason="")
     pytest.fail(reason=f"")
+
+# Skip for t-strings
+def g():
+    pytest.fail(t"")
+    pytest.fail(msg=t"")
+    pytest.fail(reason=t"")

crates/ruff_linter/resources/test/fixtures/flake8_pytest_style/PT030.py

@@ -32,3 +32,7 @@ def test_error_match_is_empty():
 
     with pytest.warns(UserWarning, match=f""):
         pass
+
+def test_ok_match_t_string():
+    with pytest.warns(UserWarning, match=t""):
+        pass

crates/ruff_linter/resources/test/fixtures/flake8_return/RET504.py

@@ -422,6 +422,35 @@ def func(a: dict[str, int]) -> list[dict[str, int]]:
         services = a["services"]
         return services
 
+
+# See: https://github.com/astral-sh/ruff/issues/14052
+def outer() -> list[object]:
+    @register
+    async def inner() -> None:
+        print(layout)
+
+    layout = [...]
+    return layout
+
+def outer() -> list[object]:
+    with open("") as f:
+        async def inner() -> None:
+            print(layout)
+
+    layout = [...]
+    return layout
+
+
+def outer() -> list[object]:
+    def inner():
+        with open("") as f:
+            async def inner_inner() -> None:
+                print(layout)
+
+    layout = [...]
+    return layout
+
+
 # See: https://github.com/astral-sh/ruff/issues/18411
 def f():
     (#=

crates/ruff_linter/resources/test/fixtures/flake8_type_checking/TC001-3_future.py

@@ -0,0 +1,10 @@
+from collections import Counter
+
+from elsewhere import third_party
+
+from . import first_party
+
+
+def f(x: first_party.foo): ...
+def g(x: third_party.bar): ...
+def h(x: Counter): ...

crates/ruff_linter/resources/test/fixtures/flake8_type_checking/TC001_future.py

@@ -0,0 +1,68 @@
+def f():
+    from . import first_party
+
+    def f(x: first_party.foo): ...
+
+
+# Type parameter bounds
+def g():
+    from . import foo
+
+    class C[T: foo.Ty]: ...
+
+
+def h():
+    from . import foo
+
+    def f[T: foo.Ty](x: T): ...
+
+
+def i():
+    from . import foo
+
+    type Alias[T: foo.Ty] = list[T]
+
+
+# Type parameter defaults
+def j():
+    from . import foo
+
+    class C[T = foo.Ty]: ...
+
+
+def k():
+    from . import foo
+
+    def f[T = foo.Ty](x: T): ...
+
+
+def l():
+    from . import foo
+
+    type Alias[T = foo.Ty] = list[T]
+
+
+# non-generic type alias
+def m():
+    from . import foo
+
+    type Alias = foo.Ty
+
+
+# unions
+from typing import Union
+
+
+def n():
+    from . import foo
+
+    def f(x: Union[foo.Ty, int]): ...
+    def g(x: foo.Ty | int): ...
+
+
+# runtime and typing usage
+def o():
+    from . import foo
+
+    def f(x: foo.Ty):
+        return foo.Ty()

crates/ruff_linter/resources/test/fixtures/flake8_type_checking/TC001_future_present.py

@@ -0,0 +1,6 @@
+from __future__ import annotations
+
+from . import first_party
+
+
+def f(x: first_party.foo): ...

crates/ruff_linter/resources/test/fixtures/flake8_type_checking/whitespace.py

@@ -0,0 +1,6 @@
+# Regression test for: https://github.com/astral-sh/ruff/issues/19175
+# there is a (potentially invisible) unicode formfeed character (000C) between `TYPE_CHECKING` and the backslash
+from typing import TYPE_CHECKING\
+
+if TYPE_CHECKING: import builtins
+builtins.print("!")

crates/ruff_linter/resources/test/fixtures/flake8_unused_arguments/ARG.py

@@ -245,3 +245,14 @@ def f(bar: str):
 class C:
     def __init__(self, x) -> None:
         print(locals())
+
+###
+# Should trigger for t-string here
+# even though the corresponding f-string
+# does not trigger (since it is common in stubs)
+###
+class C:
+    def f(self, x, y):
+        """Docstring."""
+        msg = t"{x}..."
+        raise NotImplementedError(msg)

crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/PTH210.py

@@ -54,6 +54,13 @@ windows_path.with_suffix(r"s")
 windows_path.with_suffix(u'' "json")
 windows_path.with_suffix(suffix="js")
 
+Path().with_suffix(".")
+Path().with_suffix("py")
+PosixPath().with_suffix("py")
+PurePath().with_suffix("py")
+PurePosixPath().with_suffix("py")
+PureWindowsPath().with_suffix("py")
+WindowsPath().with_suffix("py")
 
 ### No errors
 path.with_suffix()

crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/PTH210_2.py

@@ -0,0 +1,26 @@
+from pathlib import (
+    Path,
+    PosixPath,
+    PurePath,
+    PurePosixPath,
+    PureWindowsPath,
+    WindowsPath,
+)
+import pathlib
+
+
+path = Path()
+posix_path: pathlib.PosixPath = PosixPath()
+pure_path: PurePath = PurePath()
+pure_posix_path = pathlib.PurePosixPath()
+pure_windows_path: PureWindowsPath = pathlib.PureWindowsPath()
+windows_path: pathlib.WindowsPath = pathlib.WindowsPath()
+
+
+### No Errors
+path.with_suffix(".")
+posix_path.with_suffix(".")
+pure_path.with_suffix(".")
+pure_posix_path.with_suffix(".")
+pure_windows_path.with_suffix(".")
+windows_path.with_suffix(".")

crates/ruff_linter/resources/test/fixtures/flake8_use_pathlib/full_name.py

@@ -104,3 +104,6 @@ os.chmod(x)
 os.replace("src", "dst", src_dir_fd=1, dst_dir_fd=2)
 os.replace("src", "dst", src_dir_fd=1)
 os.replace("src", "dst", dst_dir_fd=2)
+
+os.getcwd()
+os.getcwdb()

crates/ruff_linter/resources/test/fixtures/isort/required_imports/multiple_strings.py

@@ -0,0 +1,5 @@
+"""This is a docstring."""
+"This is not a docstring."
+"This is also not a docstring."
+
+x = 1 

crates/ruff_linter/resources/test/fixtures/isort/required_imports/whitespace.py

@@ -0,0 +1,5 @@
+# This is a regression test for https://github.com/astral-sh/ruff/issues/19310
+# there is a (potentially invisible) unicode formfeed character (000C) between "docstring" and the semicolon
+"docstring"; print(
+    f"{__doc__=}",
+)

crates/ruff_linter/resources/test/fixtures/pep8_naming/N802.py

@@ -48,6 +48,39 @@ from typing import override, overload
 def BAD_FUNC():
     pass
 
+
 @overload
 def BAD_FUNC():
     pass
+
+
+import ast
+from ast import NodeTransformer
+
+
+class Visitor(ast.NodeVisitor):
+    def visit_Constant(self, node):
+        pass
+
+    def bad_Name(self):
+        pass
+
+class ExtendsVisitor(Visitor):
+    def visit_Constant(self, node):
+        pass
+
+class Transformer(NodeTransformer):
+    def visit_Constant(self, node):
+        pass
+
+
+from http.server import BaseHTTPRequestHandler
+
+
+class MyRequestHandler(BaseHTTPRequestHandler):
+    def do_GET(self):
+        pass
+
+    def dont_GET(self):
+        pass
+

crates/ruff_linter/resources/test/fixtures/pycodestyle/E20.py

@@ -189,3 +189,18 @@ f"{ham[lower + 1  :, "columnname"]}"
 #: Okay: https://github.com/astral-sh/ruff/issues/12023
 f"{x = :.2f}"
 f"{(x) = :.2f}"
+
+# t-strings
+t"{ {'a': 1} }"
+t"{[ { {'a': 1} } ]}"
+t"normal { {t"{ { [1, 2] } }" } } normal"
+
+t"{x = :.2f}"
+t"{(x) = :.2f}"
+
+#: Okay
+t"{ham[lower +1 :, "columnname"]}"
+
+#: E203:1:13
+t"{ham[lower + 1  :, "columnname"]}"
+

crates/ruff_linter/resources/test/fixtures/pycodestyle/E23.py

@@ -142,3 +142,20 @@ class PEP696GoodWithEmptyBases[A: object="foo"[::-1], B: object =[[["foo", "bar"
 
 class PEP696GoodWithNonEmptyBases[A: object="foo"[::-1], B: object =[[["foo", "bar"]]], C: object= bytes](object, something_dynamic[x::-1]):
     pass
+
+# E231
+t"{(a,b)}"
+
+# Okay because it's hard to differentiate between the usages of a colon in a t-string
+t"{a:=1}"
+t"{ {'a':1} }"
+t"{a:.3f}"
+t"{(a:=1)}"
+t"{(lambda x:x)}"
+t"normal{t"{a:.3f}"}normal"
+
+#: Okay
+snapshot.file_uri[len(t's3://{self.s3_bucket_name}/'):]
+
+#: E231
+{len(t's3://{self.s3_bucket_name}/'):1}

crates/ruff_linter/resources/test/fixtures/pydocstyle/D.py

@@ -722,3 +722,10 @@ def inconsistent_indent_byte_size():
 
        Returns:
     """
+
+
+def line_continuation_chars():\
+
+    """No fix should be offered for D201/D202 because of the line continuation chars."""\
+
+    ...

crates/ruff_linter/resources/test/fixtures/pylint/assert_on_string_literal.py

@@ -22,3 +22,10 @@ assert b"hello"  # [assert-on-string-literal]
 assert "", b"hi"  # [assert-on-string-literal]
 assert "WhyNotHere?", "HereIsOk"  # [assert-on-string-literal]
 assert 12, "ok here"
+
+
+# t-strings are always True even when "empty"
+# skip lint in this case
+assert t""
+assert t"hey"
+assert t"{a}"

crates/ruff_linter/resources/test/fixtures/pylint/no_self_use.py

@@ -140,3 +140,15 @@ class Foo:
     def unused_message_2(self, x):
         msg = ""
         raise NotImplementedError(x)
+
+class TPerson:
+    def developer_greeting(self, name):  # [no-self-use]
+        print(t"Greetings {name}!")
+
+    def greeting_1(self):
+        print(t"Hello from {self.name} !")
+
+    def tstring(self, x):
+        msg = t"{x}"
+        raise NotImplementedError(msg)
+

crates/ruff_linter/resources/test/fixtures/pylint/single_string_slots.py

@@ -33,3 +33,11 @@ class Foo:
 
     def __init__(self, bar):
         self.bar = bar
+
+# This is a type error, out of scope for the rule
+class Foo:
+    __slots__ = t"bar{baz}"
+
+    def __init__(self, bar):
+        self.bar = bar
+

crates/ruff_linter/resources/test/fixtures/pylint/unspecified_encoding.py

@@ -91,9 +91,16 @@ Path("foo.txt").write_text(text, encoding="utf-8")
 Path("foo.txt").write_text(text, *args)
 Path("foo.txt").write_text(text, **kwargs)
 
-# Violation but not detectable
+# https://github.com/astral-sh/ruff/issues/19294
 x = Path("foo.txt")
 x.open()
 
 # https://github.com/astral-sh/ruff/issues/18107
 codecs.open("plw1514.py", "r", "utf-8").close() # this is fine
+
+# function argument annotated as Path
+from pathlib import Path
+
+def format_file(file: Path):
+    with file.open() as f:
+        contents = f.read()

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP012.py

@@ -84,3 +84,7 @@ def _match_ignore(line):
 # Not a valid type annotation but this test shouldn't result in a panic.
 # Refer: https://github.com/astral-sh/ruff/issues/11736
 x: '"foo".encode("utf-8")'
+
+# AttributeError for t-strings so skip lint
+(t"foo{bar}").encode("utf-8")
+(t"foo{bar}").encode(encoding="utf-8")

crates/ruff_linter/resources/test/fixtures/pyupgrade/UP018.py

@@ -90,3 +90,7 @@ bool(True)and None
 int(1)and None
 float(1.)and None
 bool(True)and()
+
+
+# t-strings are not native literals
+str(t"hey")

crates/ruff_linter/resources/test/fixtures/refurb/FURB164.py

@@ -27,7 +27,24 @@ _ = Decimal.from_float(float("   -inF\n \t"))
 _ = Decimal.from_float(float("  InfinIty \n\t "))
 _ = Decimal.from_float(float("   -InfinIty\n \t"))
 
-# OK
+# Cases with keyword arguments - should produce unsafe fixes
+_ = Fraction.from_decimal(dec=Decimal("4.2"))
+_ = Decimal.from_float(f=4.2)
+
+# Cases with invalid argument counts - should not get fixes
+_ = Fraction.from_decimal(Decimal("4.2"), 1)
+_ = Decimal.from_float(4.2, None)
+
+# Cases with wrong keyword arguments - should not get fixes  
+_ = Fraction.from_decimal(numerator=Decimal("4.2"))
+_ = Decimal.from_float(value=4.2)
+
+# Cases with type validation issues - should produce unsafe fixes
+_ = Decimal.from_float("4.2")  # Invalid type for from_float
+_ = Fraction.from_decimal(4.2)  # Invalid type for from_decimal
+_ = Fraction.from_float("4.2")  # Invalid type for from_float
+
+# OK - should not trigger the rule
 _ = Fraction(0.1)
 _ = Fraction(-0.5)
 _ = Fraction(5.0)

crates/ruff_linter/resources/test/fixtures/ruff/RUF027_0.py

@@ -79,3 +79,8 @@ def in_type_def():
     from typing import cast
     a = 'int'
     cast('f"{a}"','11')
+
+# Regression test for parser bug
+# https://github.com/astral-sh/ruff/issues/18860
+def fuzz_bug():
+    c('{\t"i}')

crates/ruff_linter/resources/test/fixtures/ruff/RUF055_3.py

@@ -0,0 +1,24 @@
+import re
+
+b_src = b"abc"
+
+# Should be replaced with `b_src.replace(rb"x", b"y")`
+re.sub(rb"x", b"y", b_src)
+
+# Should be replaced with `b_src.startswith(rb"abc")`
+if re.match(rb"abc", b_src):
+    pass
+
+# Should be replaced with `rb"x" in b_src`
+if re.search(rb"x", b_src):
+    pass
+
+# Should be replaced with `b_src.split(rb"abc")`
+re.split(rb"abc", b_src)
+
+# Patterns containing metacharacters should NOT be replaced
+re.sub(rb"ab[c]", b"", b_src)
+re.match(rb"ab[c]", b_src)
+re.search(rb"ab[c]", b_src)
+re.fullmatch(rb"ab[c]", b_src)
+re.split(rb"ab[c]", b_src) 

crates/ruff_linter/resources/test/fixtures/ruff/RUF058_2.py

@@ -0,0 +1,16 @@
+from itertools import starmap
+import itertools
+
+# Errors in Python 3.14+
+starmap(func, zip(a, b, c, strict=True))
+starmap(func, zip(a, b, c, strict=False))
+starmap(func, zip(a, b, c, strict=strict))
+
+
+# No errors
+
+starmap(func)
+starmap(func, zip(a, b, c, **kwargs))
+starmap(func, zip(a, b, c), foo)
+starmap(func, zip(a, b, c, lorem=ipsum))
+starmap(func, zip(a, b, c), lorem=ipsum)

crates/ruff_linter/src/checkers/ast/analyze/bindings.rs

@@ -4,8 +4,8 @@ use crate::Fix;
 use crate::checkers::ast::Checker;
 use crate::codes::Rule;
 use crate::rules::{
-    flake8_import_conventions, flake8_pyi, flake8_pytest_style, flake8_type_checking, pyflakes,
-    pylint, pyupgrade, refurb, ruff,
+    flake8_import_conventions, flake8_pyi, flake8_pytest_style, flake8_return,
+    flake8_type_checking, pyflakes, pylint, pyupgrade, refurb, ruff,
 };
 
 /// Run lint rules over the [`Binding`]s.
@@ -25,11 +25,20 @@ pub(crate) fn bindings(checker: &Checker) {
         Rule::ForLoopWrites,
         Rule::CustomTypeVarForSelf,
         Rule::PrivateTypeParameter,
+        Rule::UnnecessaryAssign,
     ]) {
         return;
     }
 
     for (binding_id, binding) in checker.semantic.bindings.iter_enumerated() {
+        if checker.is_rule_enabled(Rule::UnnecessaryAssign) {
+            if binding.kind.is_function_definition() {
+                flake8_return::rules::unnecessary_assign(
+                    checker,
+                    binding.statement(checker.semantic()).unwrap(),
+                );
+            }
+        }
         if checker.is_rule_enabled(Rule::UnusedVariable) {
             if binding.kind.is_bound_exception()
                 && binding.is_unused()

crates/ruff_linter/src/checkers/ast/analyze/deferred_scopes.rs

@@ -71,7 +71,7 @@ pub(crate) fn deferred_scopes(checker: &Checker) {
                         flake8_type_checking::helpers::is_valid_runtime_import(
                             binding,
                             &checker.semantic,
-                            &checker.settings().flake8_type_checking,
+                            checker.settings(),
                         )
                     })
                     .collect()

crates/ruff_linter/src/checkers/ast/analyze/expression.rs

@@ -1044,7 +1044,6 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 Rule::OsMakedirs,
                 Rule::OsRename,
                 Rule::OsReplace,
-                Rule::OsGetcwd,
                 Rule::OsStat,
                 Rule::OsPathJoin,
                 Rule::OsPathSamefile,
@@ -1110,6 +1109,9 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 if checker.is_rule_enabled(Rule::OsReadlink) {
                     flake8_use_pathlib::rules::os_readlink(checker, call, segments);
                 }
+                if checker.is_rule_enabled(Rule::OsGetcwd) {
+                    flake8_use_pathlib::rules::os_getcwd(checker, call, segments);
+                }
                 if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
                     flake8_use_pathlib::rules::path_constructor_current_directory(
                         checker, call, segments,