[ty] Use ThinVec in various places

## Summary

This came up on
[Discord](https://discord.com/channels/1039017663004942429/1343692072921731082/1395447082520678440)
and also in #19387, but on macOS the tmp directory is a symlink to
`/private/tmp`, which breaks this filter. I'm still not quite sure why
only these tests are affected when we use the `tempdir_filter`
elsewhere, but hopefully this fixes the immediate issue. Just
`tempdir.path().canonicalize()` also worked, but I used `dunce` since
that's what I saw in other tests (I guess it's not _just_ these tests).

Some related links from uv:
-
1b2f212e8b/crates/uv/tests/it/common/mod.rs (L1161-L1178)
-
1b2f212e8b/crates/uv/tests/it/common/mod.rs (L424-L438)
- https://github.com/astral-sh/uv/pull/14290

Thanks to @zanieb for those!

## Test Plan

I tested the `main` branch on my MacBook and reproduced the test
failure, then confirmed that the tests pass after the change. Now to
make sure it passes on Windows, which caused most of the trouble in the
first PR!

.github/workflows/ci.yaml

@@ -240,11 +240,11 @@ jobs:
       - name: "Install mold"
         uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         with:
           tool: cargo-insta
       - name: ty mdtests (GitHub annotations)
@@ -298,11 +298,11 @@ jobs:
       - name: "Install mold"
         uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@f3a27926ea13d7be3ee2f4cbb925883cf9442b56 # v2.56.7
+        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         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@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         with:
           tool: cargo-nextest
       - name: "Run tests"
@@ -407,20 +407,11 @@ jobs:
         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"
+      - 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@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         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@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
         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/mypy_primer.yaml

@@ -12,6 +12,7 @@ on:
       - ".github/workflows/mypy_primer.yaml"
       - ".github/workflows/mypy_primer_comment.yaml"
       - "Cargo.lock"
+      - "!**.md"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref_name }}-${{ github.event.pull_request.number || github.sha }}

.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 +30,13 @@ 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
+
 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 +45,6 @@ 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 +61,130 @@ jobs:
         run: |
           git config --global user.name typeshedbot
           git config --global user.email '<>'
-      - name: Sync typeshed
-        id: sync
+      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - name: Sync typeshed stubs
         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
+
+          # 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/crates/ty_vendored/vendor/typeshed
+
           cp -r typeshed/stdlib ruff/crates/ty_vendored/vendor/typeshed/stdlib
           rm -rf ruff/crates/ty_vendored/vendor/typeshed/stdlib/@tests
           git -C typeshed rev-parse HEAD > ruff/crates/ty_vendored/vendor/typeshed/source_commit.txt
-      - name: Commit the changes
-        id: commit
-        if: ${{ steps.sync.outcome == 'success' }}
-        run: |
           cd ruff
           git checkout -b typeshedbot/sync-typeshed
           git add .
-          git diff --staged --quiet || git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)"
-      - name: Create a PR
-        if: ${{ steps.sync.outcome == 'success' && steps.commit.outcome == 'success' }}
+          git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)" --allow-empty
+      - name: Sync Linux docstrings
+        if: ${{ success() }}
         run: |
           cd ruff
-          git push --force origin typeshedbot/sync-typeshed
+          ./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 crates/ty_vendored/vendor/typeshed/stdlib --config crates/ty_vendored/vendor/typeshed/pyproject.toml || true
+          git commit -am "Format codemodded docstrings" --allow-empty
+
+          rm crates/ty_vendored/vendor/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 typeshedbot/sync-typeshed --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-analyzer.yaml

@@ -17,6 +17,7 @@ env:
   RUSTUP_MAX_RETRIES: 10
   RUST_BACKTRACE: 1
   REF_NAME: ${{ github.ref_name }}
+  CF_API_TOKEN_EXISTS: ${{ secrets.CF_API_TOKEN != '' }}
 
 jobs:
   ty-ecosystem-analyzer:
@@ -63,32 +64,75 @@ jobs:
 
           cd ..
 
-          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@9c34dc514ee9aef6735db1dfebb80f63acbc3440"
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"
 
           ecosystem-analyzer \
             --repository ruff \
-            analyze \
-            --projects ruff/projects_old.txt \
-            --commit old_commit \
-            --output diagnostics_old.json
+            diff \
+            --projects-old ruff/projects_old.txt \
+            --projects-new ruff/projects_new.txt \
+            --old old_commit \
+            --new new_commit \
+            --output-old diagnostics-old.json \
+            --output-new diagnostics-new.json
 
-          ecosystem-analyzer \
-            --repository ruff \
-            analyze \
-            --projects ruff/projects_new.txt \
-            --commit new_commit \
-            --output diagnostics_new.json
+          mkdir dist
 
           ecosystem-analyzer \
             generate-diff \
-            diagnostics_old.json \
-            diagnostics_new.json \
+            diagnostics-old.json \
+            diagnostics-new.json \
             --old-name "main (merge base)" \
             --new-name "$REF_NAME" \
-            --output-html diff.html
+            --output-html dist/diff.html
 
-      - name: Upload HTML diff report
+          ecosystem-analyzer \
+            generate-diff-statistics \
+            diagnostics-old.json \
+            diagnostics-new.json \
+            --old-name "main (merge base)" \
+            --new-name "$REF_NAME" \
+            --output diff-statistics.md
+
+          echo '## `ecosystem-analyzer` results' > comment.md
+          echo >> comment.md
+          cat diff-statistics.md >> comment.md
+
+          cat diff-statistics.md >> "$GITHUB_STEP_SUMMARY"
+
+          echo ${{ github.event.number }} > pr-number
+
+      - 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 ${{ github.head_ref }} --commit-hash ${GITHUB_SHA}
+
+      - name: "Append deployment URL"
+        if: ${{ env.CF_API_TOKEN_EXISTS == 'true' }}
+        env:
+          DEPLOYMENT_URL: ${{ steps.deploy.outputs.pages-deployment-alias-url }}
+        run: |
+          echo >> comment.md
+          echo "**[Full report with detailed diff]($DEPLOYMENT_URL/diff)**" >> comment.md
+
+      - name: Upload comment
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: comment.md
+          path: comment.md
+
+      - name: Upload pr-number
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: pr-number
+          path: pr-number
+
+      - name: Upload diagnostics diff
         uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
         with:
           name: diff.html
-          path: diff.html
+          path: dist/diff.html

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

@@ -0,0 +1,85 @@
+name: PR comment (ty ecosystem-analyzer)
+
+on: # zizmor: ignore[dangerous-triggers]
+  workflow_run:
+    workflows: [ty ecosystem-analyzer]
+    types: [completed]
+  workflow_dispatch:
+    inputs:
+      workflow_run_id:
+        description: The ty ecosystem-analyzer workflow that triggers the workflow run
+        required: true
+
+jobs:
+  comment:
+    runs-on: ubuntu-24.04
+    permissions:
+      pull-requests: write
+    steps:
+      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+        name: Download PR number
+        with:
+          name: pr-number
+          run_id: ${{ github.event.workflow_run.id ||  github.event.inputs.workflow_run_id }}
+          if_no_artifact_found: ignore
+          allow_forks: true
+
+      - name: Parse pull request number
+        id: pr-number
+        run: |
+          if [[ -f pr-number ]]
+          then
+            echo "pr-number=$(<pr-number)" >> "$GITHUB_OUTPUT"
+          fi
+
+      - uses: dawidd6/action-download-artifact@20319c5641d495c8a52e688b7dc5fada6c3a9fbc # v8
+        name: "Download comment.md"
+        id: download-comment
+        if: steps.pr-number.outputs.pr-number
+        with:
+          name: comment.md
+          workflow: ty-ecosystem-analyzer.yaml
+          pr: ${{ steps.pr-number.outputs.pr-number }}
+          path: pr/comment
+          workflow_conclusion: completed
+          if_no_artifact_found: ignore
+          allow_forks: true
+
+      - name: Generate comment content
+        id: generate-comment
+        if: ${{ steps.download-comment.outputs.found_artifact == 'true' }}
+        run: |
+          # Guard against malicious ty ecosystem-analyzer results that symlink to a secret
+          # file on this runner
+          if [[ -L pr/comment/comment.md ]]
+          then
+              echo "Error: comment.md cannot be a symlink"
+              exit 1
+          fi
+
+          # Note: this identifier is used to find the comment to update on subsequent runs
+          echo '<!-- generated-comment ty ecosystem-analyzer -->' > comment.md
+          echo >> comment.md
+          cat pr/comment/comment.md >> comment.md
+
+          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
+          cat comment.md >> "$GITHUB_OUTPUT"
+          echo 'EOF' >> "$GITHUB_OUTPUT"
+
+      - name: Find existing comment
+        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
+        if: steps.generate-comment.outcome == 'success'
+        id: find-comment
+        with:
+          issue-number: ${{ steps.pr-number.outputs.pr-number }}
+          comment-author: "github-actions[bot]"
+          body-includes: "<!-- generated-comment ty ecosystem-analyzer -->"
+
+      - name: Create or update comment
+        if: steps.find-comment.outcome == 'success'
+        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4
+        with:
+          comment-id: ${{ steps.find-comment.outputs.comment-id }}
+          issue-number: ${{ steps.pr-number.outputs.pr-number }}
+          body-path: comment.md
+          edit-mode: replace

.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

@@ -10,6 +10,8 @@ rules:
     ignore:
       - 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

@@ -6,7 +6,7 @@ exclude: |
     crates/ty_vendored/vendor/.*|
     crates/ty_project/resources/.*|
     crates/ty_python_semantic/resources/corpus/.*|
-    crates/ty/docs/(configuration|rules|cli).md|
+    crates/ty/docs/(configuration|rules|cli|environment).md|
     crates/ruff_benchmark/resources/.*|
     crates/ruff_linter/resources/.*|
     crates/ruff_linter/src/rules/.*/snapshots/.*|
@@ -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: v0.12.3
     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]]
@@ -680,11 +680,6 @@ name = "countme"
 version = "3.0.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "7704b5fdd17b18ae31c4c1da5a2e0305a2bf17b5249300a9ee9ed7b72114c636"
-dependencies = [
- "dashmap 5.5.3",
- "once_cell",
- "rustc-hash 1.1.0",
-]
 
 [[package]]
 name = "cpufeatures"
@@ -852,19 +847,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "dashmap"
-version = "5.5.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "978747c1d849a7d2ee5e8adc0159961c48fb7e5db2f06af6723b80123bb53856"
-dependencies = [
- "cfg-if",
- "hashbrown 0.14.5",
- "lock_api",
- "once_cell",
- "parking_lot_core",
-]
-
 [[package]]
 name = "dashmap"
 version = "6.1.0"
@@ -951,7 +933,7 @@ dependencies = [
  "libc",
  "option-ext",
  "redox_users",
- "windows-sys 0.59.0",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1031,7 +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]]
@@ -1151,9 +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",
@@ -1162,9 +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",
@@ -1604,7 +1586,7 @@ checksum = "e04d7f318608d35d4b61ddd75cbdaee86b023ebe2bd5a66ee0915f0bf93095a9"
 dependencies = [
  "hermit-abi 0.5.1",
  "libc",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1668,7 +1650,7 @@ dependencies = [
  "portable-atomic",
  "portable-atomic-util",
  "serde",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -2262,7 +2244,7 @@ dependencies = [
  "once_cell",
  "pep440_rs",
  "regex",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "smallvec",
  "thiserror 1.0.69",
@@ -2483,7 +2465,7 @@ dependencies = [
  "pep508_rs",
  "serde",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.8.23",
 ]
 
 [[package]]
@@ -2729,7 +2711,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.2"
+version = "0.12.4"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2772,7 +2754,7 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "ruff_workspace",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "serde_json",
  "shellexpand",
@@ -2781,7 +2763,7 @@ dependencies = [
  "test-case",
  "thiserror 2.0.12",
  "tikv-jemallocator",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "walkdir",
  "wild",
@@ -2797,7 +2779,7 @@ dependencies = [
  "ruff_annotate_snippets",
  "serde",
  "snapbox",
- "toml",
+ "toml 0.9.2",
  "tryfn",
  "unicode-width 0.2.1",
 ]
@@ -2818,7 +2800,7 @@ dependencies = [
  "ruff_python_formatter",
  "ruff_python_parser",
  "ruff_python_trivia",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "serde_json",
  "tikv-jemallocator",
@@ -2847,7 +2829,7 @@ dependencies = [
  "arc-swap",
  "camino",
  "countme",
- "dashmap 6.1.0",
+ "dashmap",
  "dunce",
  "etcetera",
  "filetime",
@@ -2866,14 +2848,16 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
+ "serde_json",
  "tempfile",
  "thiserror 2.0.12",
  "tracing",
  "tracing-subscriber",
+ "ty_static",
  "web-time",
  "zip",
 ]
@@ -2911,12 +2895,13 @@ dependencies = [
  "similar",
  "strum",
  "tempfile",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "tracing-indicatif",
  "tracing-subscriber",
  "ty",
  "ty_project",
+ "ty_static",
  "url",
 ]
 
@@ -2938,7 +2923,7 @@ dependencies = [
  "ruff_cache",
  "ruff_macros",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "schemars",
  "serde",
  "static_assertions",
@@ -2977,7 +2962,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.12.2"
+version = "0.12.4"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -3020,7 +3005,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "schemars",
  "serde",
  "serde_json",
@@ -3031,7 +3016,7 @@ dependencies = [
  "tempfile",
  "test-case",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "typed-arena",
  "unicode-normalization",
  "unicode-width 0.2.1",
@@ -3092,7 +3077,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
@@ -3142,7 +3127,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
@@ -3191,7 +3176,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "serde_json",
  "static_assertions",
@@ -3215,7 +3200,7 @@ dependencies = [
  "ruff_python_parser",
  "ruff_python_stdlib",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "schemars",
  "serde",
  "smallvec",
@@ -3276,12 +3261,12 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "ruff_workspace",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "serde_json",
  "shellexpand",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "tracing-log",
  "tracing-subscriber",
@@ -3310,7 +3295,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.2"
+version = "0.12.4"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3365,13 +3350,13 @@ dependencies = [
  "ruff_python_semantic",
  "ruff_python_stdlib",
  "ruff_source_file",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "schemars",
  "serde",
  "shellexpand",
  "strum",
  "tempfile",
- "toml",
+ "toml 0.9.2",
 ]
 
 [[package]]
@@ -3384,12 +3369,6 @@ dependencies = [
  "serde_derive",
 ]
 
-[[package]]
-name = "rustc-hash"
-version = "1.1.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "08d43f7aa6b08d49f382cde6a7982047c3426db949b1424bc4b7ec9ae12c6ce2"
-
 [[package]]
 name = "rustc-hash"
 version = "2.1.1"
@@ -3412,7 +3391,7 @@ dependencies = [
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3444,7 +3423,7 @@ dependencies = [
  "parking_lot",
  "portable-atomic",
  "rayon",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa-macro-rules",
  "salsa-macros",
  "smallvec",
@@ -3597,6 +3576,15 @@ 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"
@@ -3802,7 +3790,7 @@ dependencies = [
  "getrandom 0.3.3",
  "once_cell",
  "rustix",
- "windows-sys 0.52.0",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -4002,11 +3990,26 @@ 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"
@@ -4016,6 +4019,15 @@ 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"
@@ -4024,17 +4036,25 @@ 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"
@@ -4142,7 +4162,6 @@ dependencies = [
  "clap",
  "clap_complete_command",
  "colored 3.0.0",
- "countme",
  "crossbeam",
  "ctrlc",
  "dunce",
@@ -4158,13 +4177,14 @@ dependencies = [
  "ruff_python_trivia",
  "salsa",
  "tempfile",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "tracing-flame",
  "tracing-subscriber",
  "ty_project",
  "ty_python_semantic",
  "ty_server",
+ "ty_static",
  "wild",
 ]
 
@@ -4174,11 +4194,14 @@ 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 2.1.1",
+ "rustc-hash",
  "salsa",
  "smallvec",
  "tracing",
@@ -4210,12 +4233,12 @@ dependencies = [
  "ruff_python_ast",
  "ruff_python_formatter",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "ty_ide",
  "ty_python_semantic",
@@ -4231,7 +4254,6 @@ dependencies = [
  "camino",
  "colored 3.0.0",
  "compact_str",
- "countme",
  "dir-test",
  "drop_bomb",
  "get-size2",
@@ -4255,7 +4277,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
@@ -4265,9 +4287,11 @@ dependencies = [
  "strum_macros",
  "tempfile",
  "test-case",
+ "thin-vec",
  "thiserror 2.0.12",
  "tracing",
  "ty_python_semantic",
+ "ty_static",
  "ty_test",
  "ty_vendored",
 ]
@@ -4277,6 +4301,7 @@ name = "ty_server"
 version = "0.0.0"
 dependencies = [
  "anyhow",
+ "bitflags 2.9.1",
  "crossbeam",
  "jod-thread",
  "libc",
@@ -4284,13 +4309,15 @@ dependencies = [
  "lsp-types",
  "ruff_db",
  "ruff_notebook",
+ "ruff_python_ast",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "serde",
  "serde_json",
  "shellexpand",
+ "thiserror 2.0.12",
  "tracing",
  "tracing-subscriber",
  "ty_ide",
@@ -4299,6 +4326,13 @@ dependencies = [
  "ty_vendored",
 ]
 
+[[package]]
+name = "ty_static"
+version = "0.0.1"
+dependencies = [
+ "ruff_macros",
+]
+
 [[package]]
 name = "ty_test"
 version = "0.0.0"
@@ -4317,16 +4351,17 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "rustc-stable-hash",
  "salsa",
  "serde",
  "smallvec",
  "tempfile",
  "thiserror 2.0.12",
- "toml",
+ "toml 0.9.2",
  "tracing",
  "ty_python_semantic",
+ "ty_static",
  "ty_vendored",
 ]
 
@@ -4817,7 +4852,7 @@ 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

@@ -44,6 +44,7 @@ ty_ide = { path = "crates/ty_ide" }
 ty_project = { path = "crates/ty_project", default-features = false }
 ty_python_semantic = { path = "crates/ty_python_semantic" }
 ty_server = { path = "crates/ty_server" }
+ty_static = { path = "crates/ty_static" }
 ty_test = { path = "crates/ty_test" }
 ty_vendored = { path = "crates/ty_vendored" }
 
@@ -83,7 +84,7 @@ get-size2 = { version = "0.5.0", features = [
     "derive",
     "smallvec",
     "hashbrown",
-    "compact-str"
+    "compact-str",
 ] }
 glob = { version = "0.3.1" }
 globset = { version = "0.4.14" }
@@ -162,9 +163,10 @@ strum_macros = { version = "0.27.0" }
 syn = { version = "2.0.55" }
 tempfile = { version = "3.9.0" }
 test-case = { version = "3.3.1" }
+thin-vec = { version = "0.2.14" }
 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" }
@@ -173,7 +175,7 @@ tracing-subscriber = { version = "0.3.18", default-features = false, features =
     "env-filter",
     "fmt",
     "ansi",
-    "smallvec"
+    "smallvec",
 ] }
 tryfn = { version = "0.2.1" }
 typed-arena = { version = "2.0.2" }
@@ -183,11 +185,7 @@ unicode-width = { version = "0.2.0" }
 unicode_names2 = { version = "1.2.2" }
 unicode-normalization = { version = "0.1.23" }
 url = { version = "2.5.0" }
-uuid = { version = "1.6.1", features = [
-    "v4",
-    "fast-rng",
-    "macro-diagnostics",
-] }
+uuid = { version = "1.6.1", features = ["v4", "fast-rng", "macro-diagnostics"] }
 walkdir = { version = "2.3.2" }
 wasm-bindgen = { version = "0.2.92" }
 wasm-bindgen-test = { version = "0.3.42" }
@@ -222,8 +220,8 @@ must_use_candidate = "allow"
 similar_names = "allow"
 single_match_else = "allow"
 too_many_lines = "allow"
-needless_continue = "allow"       # An explicit continue can be more readable, especially if the alternative is an empty block.
-unnecessary_debug_formatting = "allow"  # too many instances, the display also doesn't quote the path which is often desired in logs where we use them the most often.
+needless_continue = "allow" # An explicit continue can be more readable, especially if the alternative is an empty block.
+unnecessary_debug_formatting = "allow" # too many instances, the display also doesn't quote the path which is often desired in logs where we use them the most often.
 # Without the hashes we run into a `rustfmt` bug in some snapshot tests, see #13250
 needless_raw_string_hashes = "allow"
 # Disallowed restriction lints

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
@@ -430,6 +430,7 @@ Ruff is used by a number of major open-source projects and companies, including:
 - [Babel](https://github.com/python-babel/babel)
 - Benchling ([Refac](https://github.com/benchling/refac))
 - [Bokeh](https://github.com/bokeh/bokeh)
+- Capital One ([datacompy](https://github.com/capitalone/datacompy))
 - CrowdCent ([NumerBlox](https://github.com/crowdcent/numerblox)) <!-- typos: ignore -->
 - [Cryptography (PyCA)](https://github.com/pyca/cryptography)
 - CERN ([Indico](https://getindico.io/))

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

@@ -681,7 +681,7 @@ mod tests {
                     UnsafeFixes::Enabled,
                 )
                 .unwrap();
-                if diagnostics.inner.iter().any(Diagnostic::is_syntax_error) {
+                if diagnostics.inner.iter().any(Diagnostic::is_invalid_syntax) {
                     parse_errors.push(path.clone());
                 }
                 paths.push(path);

crates/ruff/src/commands/check.rs

@@ -9,15 +9,15 @@ use ignore::Error;
 use log::{debug, error, warn};
 #[cfg(not(target_family = "wasm"))]
 use rayon::prelude::*;
-use ruff_linter::message::diagnostic_from_violation;
 use rustc_hash::FxHashMap;
 
+use ruff_db::diagnostic::Diagnostic;
 use ruff_db::panic::catch_unwind;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::registry::Rule;
 use ruff_linter::settings::types::UnsafeFixes;
 use ruff_linter::settings::{LinterSettings, flags};
-use ruff_linter::{IOError, fs, warn_user_once};
+use ruff_linter::{IOError, Violation, fs, warn_user_once};
 use ruff_source_file::SourceFileBuilder;
 use ruff_text_size::TextRange;
 use ruff_workspace::resolver::{
@@ -129,11 +129,7 @@ pub(crate) fn check(
                         SourceFileBuilder::new(path.to_string_lossy().as_ref(), "").finish();
 
                     Diagnostics::new(
-                        vec![diagnostic_from_violation(
-                            IOError { message },
-                            TextRange::default(),
-                            &dummy,
-                        )],
+                        vec![IOError { message }.into_diagnostic(TextRange::default(), &dummy)],
                         FxHashMap::default(),
                     )
                 } else {
@@ -166,7 +162,9 @@ pub(crate) fn check(
             |a, b| (a.0 + b.0, a.1 + b.1),
         );
 
-    all_diagnostics.inner.sort();
+    all_diagnostics
+        .inner
+        .sort_by(Diagnostic::ruff_start_ordering);
 
     // Store the caches.
     caches.persist()?;

crates/ruff/src/commands/check_stdin.rs

@@ -1,6 +1,7 @@
 use std::path::Path;
 
 use anyhow::Result;
+use ruff_db::diagnostic::Diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::packaging;
 use ruff_linter::settings::flags;
@@ -52,6 +53,8 @@ pub(crate) fn check_stdin(
         noqa,
         fix_mode,
     )?;
-    diagnostics.inner.sort_unstable();
+    diagnostics
+        .inner
+        .sort_unstable_by(Diagnostic::ruff_start_ordering);
     Ok(diagnostics)
 }

crates/ruff/src/diagnostics.rs

@@ -13,13 +13,13 @@ use log::{debug, warn};
 use ruff_db::diagnostic::Diagnostic;
 use ruff_linter::codes::Rule;
 use ruff_linter::linter::{FixTable, FixerResult, LinterResult, ParseSource, lint_fix, lint_only};
-use ruff_linter::message::{create_syntax_error_diagnostic, diagnostic_from_violation};
+use ruff_linter::message::create_syntax_error_diagnostic;
 use ruff_linter::package::PackageRoot;
 use ruff_linter::pyproject_toml::lint_pyproject_toml;
 use ruff_linter::settings::types::UnsafeFixes;
 use ruff_linter::settings::{LinterSettings, flags};
 use ruff_linter::source_kind::{SourceError, SourceKind};
-use ruff_linter::{IOError, fs};
+use ruff_linter::{IOError, Violation, fs};
 use ruff_notebook::{Notebook, NotebookError, NotebookIndex};
 use ruff_python_ast::{PySourceType, SourceType, TomlSourceType};
 use ruff_source_file::SourceFileBuilder;
@@ -62,13 +62,12 @@ impl Diagnostics {
                     let name = path.map_or_else(|| "-".into(), Path::to_string_lossy);
                     let source_file = SourceFileBuilder::new(name, "").finish();
                     Self::new(
-                        vec![diagnostic_from_violation(
+                        vec![
                             IOError {
                                 message: err.to_string(),
-                            },
-                            TextRange::default(),
-                            &source_file,
-                        )],
+                            }
+                            .into_diagnostic(TextRange::default(), &source_file),
+                        ],
                         FxHashMap::default(),
                     )
                 } else {

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

@@ -9,13 +9,14 @@ 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,
-    TextEmitter,
+    Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter, JunitEmitter,
+    SarifEmitter, TextEmitter,
 };
 use ruff_linter::notify_user;
 use ruff_linter::settings::flags::{self};
@@ -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(());
@@ -229,13 +231,25 @@ 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)?;
@@ -280,10 +294,18 @@ 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" 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};
@@ -441,6 +442,37 @@ 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,
@@ -591,6 +623,7 @@ 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

@@ -20,6 +20,7 @@ ruff_python_parser = { workspace = true }
 ruff_python_trivia = { workspace = true }
 ruff_source_file = { workspace = true, features = ["get-size"] }
 ruff_text_size = { workspace = true }
+ty_static = { workspace = true }
 
 anstyle = { workspace = true }
 arc-swap = { workspace = true }
@@ -37,6 +38,7 @@ 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 }
@@ -55,6 +57,6 @@ tempfile = { workspace = true }
 [features]
 cache = ["ruff_cache"]
 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

@@ -1,13 +1,12 @@
-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};
 
 mod render;
@@ -83,7 +82,7 @@ impl Diagnostic {
     ///
     /// Note that `message` is stored in the primary annotation, _not_ in the primary diagnostic
     /// message.
-    pub fn syntax_error(
+    pub fn invalid_syntax(
         span: impl Into<Span>,
         message: impl IntoDiagnosticMessage,
         range: impl Ranged,
@@ -309,6 +308,10 @@ 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);
     }
 
@@ -365,7 +368,7 @@ impl Diagnostic {
     }
 
     /// Returns `true` if `self` is a syntax error message.
-    pub fn is_syntax_error(&self) -> bool {
+    pub fn is_invalid_syntax(&self) -> bool {
         self.id().is_invalid_syntax()
     }
 
@@ -380,8 +383,8 @@ impl Diagnostic {
     }
 
     /// Returns the URL for the rule documentation, if it exists.
-    pub fn to_url(&self) -> Option<String> {
-        if self.is_syntax_error() {
+    pub fn to_ruff_url(&self) -> Option<String> {
+        if self.is_invalid_syntax() {
             None
         } else {
             Some(format!(
@@ -432,8 +435,9 @@ 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.
@@ -447,20 +451,16 @@ impl Diagnostic {
     pub fn expect_range(&self) -> TextRange {
         self.range().expect("Expected a range for the primary span")
     }
-}
 
-impl Ord for Diagnostic {
-    fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-        self.partial_cmp(other).unwrap_or(std::cmp::Ordering::Equal)
-    }
-}
-
-impl PartialOrd for Diagnostic {
-    fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        Some(
-            (self.ruff_source_file()?, self.range()?.start())
-                .cmp(&(other.ruff_source_file()?, other.range()?.start())),
-        )
+    /// Returns the ordering of diagnostics based on the start of their ranges, if they have any.
+    ///
+    /// Panics if either diagnostic has no primary span, if the span has no range, or if its file is
+    /// not a `SourceFile`.
+    pub fn ruff_start_ordering(&self, other: &Self) -> std::cmp::Ordering {
+        (self.expect_ruff_source_file(), self.expect_range().start()).cmp(&(
+            other.expect_ruff_source_file(),
+            other.expect_range().start(),
+        ))
     }
 }
 
@@ -1012,6 +1012,18 @@ 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)),
@@ -1178,6 +1190,12 @@ 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 {
@@ -1198,6 +1216,14 @@ 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 {
@@ -1206,6 +1232,7 @@ impl Default for DisplayDiagnosticConfig {
             format: DiagnosticFormat::default(),
             color: false,
             context: 2,
+            preview: false,
         }
     }
 }
@@ -1233,6 +1260,28 @@ 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,
 }
 
 /// A representation of the kinds of messages inside a diagnostic.

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 +19,21 @@ 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;
+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 +48,6 @@ use super::{
 pub struct DisplayDiagnostic<'a> {
     config: &'a DisplayDiagnosticConfig,
     resolver: &'a dyn FileResolver,
-    annotate_renderer: AnnotateRenderer,
     diag: &'a Diagnostic,
 }
 
@@ -44,16 +57,9 @@ 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 +67,138 @@ 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()
+                };
+
+                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)?;
+            }
         }
 
-        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 +711,15 @@ 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 +736,29 @@ 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 +772,29 @@ 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 +855,9 @@ 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 +2254,7 @@ 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 +2263,7 @@ 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 +2282,26 @@ 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 +2351,7 @@ 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 +2377,12 @@ 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 +2392,18 @@ 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 +2412,14 @@ 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 +2468,25 @@ 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 +2566,199 @@ 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/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__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/lib.rs

@@ -5,6 +5,7 @@ use ruff_python_ast::PythonVersion;
 use rustc_hash::FxHasher;
 use std::hash::BuildHasherDefault;
 use std::num::NonZeroUsize;
+use ty_static::EnvVars;
 
 pub mod diagnostic;
 pub mod display;
@@ -27,6 +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 {
@@ -50,8 +66,8 @@ pub trait Db: salsa::Database {
 /// ty can still spawn more threads for other tasks, e.g. to wait for a Ctrl+C signal or
 /// watching the files for changes.
 pub fn max_parallelism() -> NonZeroUsize {
-    std::env::var("TY_MAX_PARALLELISM")
-        .or_else(|_| std::env::var("RAYON_NUM_THREADS"))
+    std::env::var(EnvVars::TY_MAX_PARALLELISM)
+        .or_else(|_| std::env::var(EnvVars::RAYON_NUM_THREADS))
         .ok()
         .and_then(|s| s.parse().ok())
         .unwrap_or_else(|| {

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_dev/Cargo.toml

@@ -13,6 +13,7 @@ license = { workspace = true }
 [dependencies]
 ty = { workspace = true }
 ty_project = { workspace = true, features = ["schemars"] }
+ty_static = { workspace = true }
 ruff = { workspace = true }
 ruff_formatter = { workspace = true }
 ruff_linter = { workspace = true, features = ["schemars"] }

crates/ruff_dev/src/generate_all.rs

@@ -4,7 +4,7 @@ use anyhow::Result;
 
 use crate::{
     generate_cli_help, generate_docs, generate_json_schema, generate_ty_cli_reference,
-    generate_ty_options, generate_ty_rules, generate_ty_schema,
+    generate_ty_env_vars_reference, generate_ty_options, generate_ty_rules, generate_ty_schema,
 };
 
 pub(crate) const REGENERATE_ALL_COMMAND: &str = "cargo dev generate-all";
@@ -44,5 +44,8 @@ pub(crate) fn main(args: &Args) -> Result<()> {
     generate_ty_options::main(&generate_ty_options::Args { mode: args.mode })?;
     generate_ty_rules::main(&generate_ty_rules::Args { mode: args.mode })?;
     generate_ty_cli_reference::main(&generate_ty_cli_reference::Args { mode: args.mode })?;
+    generate_ty_env_vars_reference::main(&generate_ty_env_vars_reference::Args {
+        mode: args.mode,
+    })?;
     Ok(())
 }

crates/ruff_dev/src/generate_ty_env_vars_reference.rs

@@ -0,0 +1,119 @@
+//! Generate the environment variables reference from `ty_static::EnvVars`.
+
+use std::collections::BTreeSet;
+use std::fs;
+use std::path::PathBuf;
+
+use anyhow::bail;
+use pretty_assertions::StrComparison;
+
+use ty_static::EnvVars;
+
+use crate::generate_all::Mode;
+
+#[derive(clap::Args)]
+pub(crate) struct Args {
+    #[arg(long, default_value_t, value_enum)]
+    pub(crate) mode: Mode,
+}
+
+pub(crate) fn main(args: &Args) -> anyhow::Result<()> {
+    let reference_string = generate();
+    let filename = "environment.md";
+    let reference_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .parent()
+        .unwrap()
+        .parent()
+        .unwrap()
+        .join("crates")
+        .join("ty")
+        .join("docs")
+        .join(filename);
+
+    match args.mode {
+        Mode::DryRun => {
+            println!("{reference_string}");
+        }
+        Mode::Check => match fs::read_to_string(&reference_path) {
+            Ok(current) => {
+                if current == reference_string {
+                    println!("Up-to-date: {filename}");
+                } else {
+                    let comparison = StrComparison::new(&current, &reference_string);
+                    bail!(
+                        "{filename} changed, please run `cargo dev generate-ty-env-vars-reference`:\n{comparison}"
+                    );
+                }
+            }
+            Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                bail!(
+                    "{filename} not found, please run `cargo dev generate-ty-env-vars-reference`"
+                );
+            }
+            Err(err) => {
+                bail!(
+                    "{filename} changed, please run `cargo dev generate-ty-env-vars-reference`:\n{err}"
+                );
+            }
+        },
+        Mode::Write => {
+            // Ensure the docs directory exists
+            if let Some(parent) = reference_path.parent() {
+                fs::create_dir_all(parent)?;
+            }
+
+            match fs::read_to_string(&reference_path) {
+                Ok(current) => {
+                    if current == reference_string {
+                        println!("Up-to-date: {filename}");
+                    } else {
+                        println!("Updating: {filename}");
+                        fs::write(&reference_path, reference_string.as_bytes())?;
+                    }
+                }
+                Err(err) if err.kind() == std::io::ErrorKind::NotFound => {
+                    println!("Updating: {filename}");
+                    fs::write(&reference_path, reference_string.as_bytes())?;
+                }
+                Err(err) => {
+                    bail!(
+                        "{filename} changed, please run `cargo dev generate-ty-env-vars-reference`:\n{err}"
+                    );
+                }
+            }
+        }
+    }
+
+    Ok(())
+}
+
+fn generate() -> String {
+    let mut output = String::new();
+
+    output.push_str("# Environment variables\n\n");
+
+    // Partition and sort environment variables into TY_ and external variables.
+    let (ty_vars, external_vars): (BTreeSet<_>, BTreeSet<_>) = EnvVars::metadata()
+        .iter()
+        .partition(|(var, _)| var.starts_with("TY_"));
+
+    output.push_str("ty defines and respects the following environment variables:\n\n");
+
+    for (var, doc) in ty_vars {
+        output.push_str(&render(var, doc));
+    }
+
+    output.push_str("## Externally-defined variables\n\n");
+    output.push_str("ty also reads the following externally defined environment variables:\n\n");
+
+    for (var, doc) in external_vars {
+        output.push_str(&render(var, doc));
+    }
+
+    output
+}
+
+/// Render an environment variable and its documentation.
+fn render(var: &str, doc: &str) -> String {
+    format!("### `{var}`\n\n{doc}\n\n")
+}

crates/ruff_dev/src/main.rs

@@ -18,6 +18,7 @@ mod generate_json_schema;
 mod generate_options;
 mod generate_rules_table;
 mod generate_ty_cli_reference;
+mod generate_ty_env_vars_reference;
 mod generate_ty_options;
 mod generate_ty_rules;
 mod generate_ty_schema;
@@ -53,6 +54,8 @@ enum Command {
     /// Generate a Markdown-compatible listing of configuration options.
     GenerateOptions,
     GenerateTyOptions(generate_ty_options::Args),
+    /// Generate environment variables reference for ty.
+    GenerateTyEnvVarsReference(generate_ty_env_vars_reference::Args),
     /// Generate CLI help.
     GenerateCliHelp(generate_cli_help::Args),
     /// Generate Markdown docs.
@@ -98,6 +101,7 @@ fn main() -> Result<ExitCode> {
         Command::GenerateTyRules(args) => generate_ty_rules::main(&args)?,
         Command::GenerateOptions => println!("{}", generate_options::generate()),
         Command::GenerateTyOptions(args) => generate_ty_options::main(&args)?,
+        Command::GenerateTyEnvVarsReference(args) => generate_ty_env_vars_reference::main(&args)?,
         Command::GenerateCliHelp(args) => generate_cli_help::main(&args)?,
         Command::GenerateDocs(args) => generate_docs::main(&args)?,
         Command::PrintAST(args) => print_ast::main(&args)?,

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 }

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

@@ -1,10 +1,10 @@
 """
 Should emit:
-B017 - on lines 23 and 41
+B017 - on lines 24, 28, 46, 49, 52, 58, 62, 68, and 71
 """
 import asyncio
 import unittest
-import pytest
+import pytest, contextlib
 
 CONSTANT = True
 
@@ -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_bugbear/B017_1.py

@@ -0,0 +1,28 @@
+"""
+Should emit:
+B017 - on lines 20, 21, 25, and 26
+"""
+import unittest
+import pytest
+
+
+def something_else() -> None:
+    for i in (1, 2, 3):
+        print(i)
+
+
+class Foo:
+    pass
+
+
+class Foobar(unittest.TestCase):
+    def call_form_raises(self) -> None:
+        self.assertRaises(Exception, something_else)
+        self.assertRaises(BaseException, something_else)
+
+
+def test_pytest_call_form() -> None:
+    pytest.raises(Exception, something_else)
+    pytest.raises(BaseException, something_else)
+
+    pytest.raises(Exception, something_else, match="hello")

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/UP008.py

@@ -125,3 +125,19 @@ class ClassForCommentEnthusiasts(BaseClass):
             self
             # also a comment
         ).f()
+
+
+# Issue #19096: super calls with keyword arguments should emit diagnostic but not be fixed
+class Ord(int):
+    def __len__(self):
+        return super(Ord, self, uhoh=True, **{"error": True}).bit_length()
+
+class ExampleWithKeywords:
+    def method1(self):
+        super(ExampleWithKeywords, self, invalid=True).some_method()  # Should emit diagnostic but NOT be fixed
+    
+    def method2(self):
+        super(ExampleWithKeywords, self, **{"kwarg": "value"}).some_method()  # Should emit diagnostic but NOT be fixed
+    
+    def method3(self):
+        super(ExampleWithKeywords, self).some_method()  # Should be fixed - no keywords

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/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)