[ty] Move node_reachability from UseDefMap to SemanticIndex

## Summary

Part of #18972

This PR makes [invalid-envvar-value
(PLE1507)](https://docs.astral.sh/ruff/rules/invalid-envvar-value/#invalid-envvar-value-ple1507)'s
example error out-of-the-box.

[Old example](https://play.ruff.rs/a46a9bca-edd5-4474-b20d-e6b6d87291ca)
```py
os.getenv(1)
```

[New example](https://play.ruff.rs/8348d32d-71fa-422c-b228-e2bc343765b1)
```py
import os

os.getenv(1)
```

The "Use instead" section was also updated similarly.

## Test Plan

<!-- How was it tested? -->

N/A, no functionality/tests affected

.github/workflows/ci.yaml

@@ -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"

.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/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/zizmor.yml

@@ -10,6 +10,7 @@ rules:
     ignore:
       - build-docker.yml
       - publish-playground.yml
+      - ty-ecosystem-analyzer.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/.*|

CHANGELOG.md

@@ -1,5 +1,33 @@
 # Changelog
 
+## 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

Cargo.lock

@@ -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"
@@ -2262,7 +2244,7 @@ dependencies = [
  "once_cell",
  "pep440_rs",
  "regex",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "smallvec",
  "thiserror 1.0.69",
@@ -2729,7 +2711,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.2"
+version = "0.12.3"
 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",
@@ -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",
 ]
@@ -2917,6 +2901,7 @@ dependencies = [
  "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 = "0.12.3"
 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",
@@ -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",
@@ -3276,7 +3261,7 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "ruff_workspace",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "serde",
  "serde_json",
  "shellexpand",
@@ -3310,7 +3295,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.2"
+version = "0.12.3"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3365,7 +3350,7 @@ dependencies = [
  "ruff_python_semantic",
  "ruff_python_stdlib",
  "ruff_source_file",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "schemars",
  "serde",
  "shellexpand",
@@ -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"
@@ -3444,7 +3423,7 @@ dependencies = [
  "parking_lot",
  "portable-atomic",
  "rayon",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa-macro-rules",
  "salsa-macros",
  "smallvec",
@@ -4142,7 +4121,6 @@ dependencies = [
  "clap",
  "clap_complete_command",
  "colored 3.0.0",
- "countme",
  "crossbeam",
  "ctrlc",
  "dunce",
@@ -4165,6 +4143,7 @@ dependencies = [
  "ty_project",
  "ty_python_semantic",
  "ty_server",
+ "ty_static",
  "wild",
 ]
 
@@ -4174,11 +4153,14 @@ 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",
@@ -4210,7 +4192,7 @@ dependencies = [
  "ruff_python_ast",
  "ruff_python_formatter",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
@@ -4231,7 +4213,6 @@ dependencies = [
  "camino",
  "colored 3.0.0",
  "compact_str",
- "countme",
  "dir-test",
  "drop_bomb",
  "get-size2",
@@ -4255,7 +4236,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "salsa",
  "schemars",
  "serde",
@@ -4268,6 +4249,7 @@ dependencies = [
  "thiserror 2.0.12",
  "tracing",
  "ty_python_semantic",
+ "ty_static",
  "ty_test",
  "ty_vendored",
 ]
@@ -4286,11 +4268,12 @@ dependencies = [
  "ruff_notebook",
  "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 +4282,13 @@ dependencies = [
  "ty_vendored",
 ]
 
+[[package]]
+name = "ty_static"
+version = "0.0.1"
+dependencies = [
+ "ruff_macros",
+]
+
 [[package]]
 name = "ty_test"
 version = "0.0.0"
@@ -4317,7 +4307,7 @@ dependencies = [
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
- "rustc-hash 2.1.1",
+ "rustc-hash",
  "rustc-stable-hash",
  "salsa",
  "serde",
@@ -4327,6 +4317,7 @@ dependencies = [
  "toml",
  "tracing",
  "ty_python_semantic",
+ "ty_static",
  "ty_vendored",
 ]
 

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" }
@@ -173,7 +174,7 @@ 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 +184,7 @@ 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 +219,8 @@ 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/0.12.3/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.12.3/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: v0.12.3
   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 = "0.12.3"
 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

@@ -439,7 +439,7 @@ 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,
+    PylintEmitter, RdjsonEmitter, 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 +231,21 @@ 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)?;
             }
             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)?;
@@ -283,7 +293,11 @@ impl Printer {
                 PylintEmitter.emit(writer, &diagnostics.inner, &context)?;
             }
             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/lint.rs

@@ -5692,3 +5692,57 @@ 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}");
+
+    insta::with_settings!({
+        filters => vec![
+            (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(())
+}

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: 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 +1,103 @@
+---
+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": {
+        "url": null,
+        "value": null
+      },
+      "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_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 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,
@@ -365,7 +364,7 @@ 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 +379,8 @@ 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 +431,9 @@ 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 +447,16 @@ 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(),
+        ))
     }
 }
 
@@ -1178,6 +1174,12 @@ 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 +1200,14 @@ 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 +1216,7 @@ impl Default for DisplayDiagnosticConfig {
             format: DiagnosticFormat::default(),
             color: false,
             context: 2,
+            preview: false,
         }
     }
 }
@@ -1233,6 +1244,21 @@ 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,
 }
 
 /// A representation of the kinds of messages inside a diagnostic.

crates/ruff_db/src/diagnostic/render.rs

@@ -4,6 +4,7 @@ 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 +18,17 @@ use crate::{
 
 use super::{
     Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig, Severity,
-    SubDiagnostic,
+    SubDiagnostic, UnifiedFile,
 };
 
+use azure::AzureRenderer;
+
+mod azure;
+#[cfg(feature = "serde")]
+mod json;
+#[cfg(feature = "serde")]
+mod json_lines;
+
 /// A type that implements `std::fmt::Display` for diagnostic rendering.
 ///
 /// It is created via [`Diagnostic::display`].
@@ -34,7 +43,6 @@ use super::{
 pub struct DisplayDiagnostic<'a> {
     config: &'a DisplayDiagnosticConfig,
     resolver: &'a dyn FileResolver,
-    annotate_renderer: AnnotateRenderer,
     diag: &'a Diagnostic,
 }
 
@@ -44,16 +52,9 @@ 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 +62,131 @@ 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)?;
+            }
         }
 
-        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 +699,12 @@ 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;
 }
 
 impl<T> FileResolver for T
@@ -651,6 +721,25 @@ 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"),
+        }
+    }
 }
 
 impl FileResolver for &dyn Db {
@@ -664,6 +753,25 @@ 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"),
+        }
+    }
 }
 
 /// An abstraction over a unit of user input.
@@ -724,7 +832,9 @@ 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 +2231,7 @@ 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 +2240,7 @@ 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 +2259,26 @@ 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 +2328,7 @@ 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 +2354,12 @@ 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 +2369,18 @@ 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 +2389,14 @@ 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 +2445,25 @@ 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 +2543,199 @@ 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 +1,393 @@
+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 ruff_diagnostics::{Edit, Fix};
+    use ruff_text_size::TextSize;
+
+    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()
+            .fix(Fix::safe_edit(Edit::insertion(
+                "edit".to_string(),
+                TextSize::from(0),
+            )))
+            .build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @r#"
+        [
+          {
+            "cell": null,
+            "code": null,
+            "end_location": {
+              "column": 1,
+              "row": 1
+            },
+            "filename": "",
+            "fix": {
+              "applicability": "safe",
+              "edits": [
+                {
+                  "content": "edit",
+                  "end_location": {
+                    "column": 1,
+                    "row": 1
+                  },
+                  "location": {
+                    "column": 1,
+                    "row": 1
+                  }
+                }
+              ],
+              "message": 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()
+            .fix(Fix::safe_edit(Edit::insertion(
+                "edit".to_string(),
+                TextSize::from(0),
+            )))
+            .build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @r#"
+        [
+          {
+            "cell": null,
+            "code": null,
+            "end_location": null,
+            "filename": null,
+            "fix": {
+              "applicability": "safe",
+              "edits": [
+                {
+                  "content": "edit",
+                  "end_location": null,
+                  "location": null
+                }
+              ],
+              "message": 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/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/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;
@@ -50,8 +51,8 @@ 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 = "0.12.3"
 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_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/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/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/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/src/checkers/ast/analyze/bindings.rs

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

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

@@ -7,7 +7,9 @@ use ruff_python_semantic::analyze::typing;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
-use crate::preview::is_optional_as_none_in_union_enabled;
+use crate::preview::{
+    is_assert_raises_exception_call_enabled, is_optional_as_none_in_union_enabled,
+};
 use crate::registry::Rule;
 use crate::rules::{
     airflow, flake8_2020, flake8_async, flake8_bandit, flake8_boolean_trap, flake8_bugbear,
@@ -1037,27 +1039,14 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 flake8_simplify::rules::zip_dict_keys_and_values(checker, call);
             }
             if checker.any_rule_enabled(&[
-                Rule::OsPathAbspath,
                 Rule::OsChmod,
                 Rule::OsMkdir,
                 Rule::OsMakedirs,
                 Rule::OsRename,
                 Rule::OsReplace,
-                Rule::OsRmdir,
-                Rule::OsRemove,
-                Rule::OsUnlink,
                 Rule::OsGetcwd,
-                Rule::OsPathExists,
-                Rule::OsPathExpanduser,
-                Rule::OsPathIsdir,
-                Rule::OsPathIsfile,
-                Rule::OsPathIslink,
-                Rule::OsReadlink,
                 Rule::OsStat,
-                Rule::OsPathIsabs,
                 Rule::OsPathJoin,
-                Rule::OsPathBasename,
-                Rule::OsPathDirname,
                 Rule::OsPathSamefile,
                 Rule::OsPathSplitext,
                 Rule::BuiltinOpen,
@@ -1068,21 +1057,66 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
             ]) {
                 flake8_use_pathlib::rules::replaceable_by_pathlib(checker, call);
             }
-            if checker.is_rule_enabled(Rule::OsPathGetsize) {
-                flake8_use_pathlib::rules::os_path_getsize(checker, call);
-            }
-            if checker.is_rule_enabled(Rule::OsPathGetatime) {
-                flake8_use_pathlib::rules::os_path_getatime(checker, call);
-            }
-            if checker.is_rule_enabled(Rule::OsPathGetctime) {
-                flake8_use_pathlib::rules::os_path_getctime(checker, call);
-            }
-            if checker.is_rule_enabled(Rule::OsPathGetmtime) {
-                flake8_use_pathlib::rules::os_path_getmtime(checker, call);
-            }
-            if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
-                flake8_use_pathlib::rules::path_constructor_current_directory(checker, call);
+            if let Some(qualified_name) = checker.semantic().resolve_qualified_name(&call.func) {
+                let segments = qualified_name.segments();
+                if checker.is_rule_enabled(Rule::OsPathGetsize) {
+                    flake8_use_pathlib::rules::os_path_getsize(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathGetatime) {
+                    flake8_use_pathlib::rules::os_path_getatime(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathGetctime) {
+                    flake8_use_pathlib::rules::os_path_getctime(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathGetmtime) {
+                    flake8_use_pathlib::rules::os_path_getmtime(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathAbspath) {
+                    flake8_use_pathlib::rules::os_path_abspath(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsRmdir) {
+                    flake8_use_pathlib::rules::os_rmdir(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsRemove) {
+                    flake8_use_pathlib::rules::os_remove(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsUnlink) {
+                    flake8_use_pathlib::rules::os_unlink(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathExists) {
+                    flake8_use_pathlib::rules::os_path_exists(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathExpanduser) {
+                    flake8_use_pathlib::rules::os_path_expanduser(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathBasename) {
+                    flake8_use_pathlib::rules::os_path_basename(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathDirname) {
+                    flake8_use_pathlib::rules::os_path_dirname(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIsabs) {
+                    flake8_use_pathlib::rules::os_path_isabs(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIsdir) {
+                    flake8_use_pathlib::rules::os_path_isdir(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIsfile) {
+                    flake8_use_pathlib::rules::os_path_isfile(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathIslink) {
+                    flake8_use_pathlib::rules::os_path_islink(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsReadlink) {
+                    flake8_use_pathlib::rules::os_readlink(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
+                    flake8_use_pathlib::rules::path_constructor_current_directory(
+                        checker, call, segments,
+                    );
+                }
             }
+
             if checker.is_rule_enabled(Rule::OsSepSplit) {
                 flake8_use_pathlib::rules::os_sep_split(checker, call);
             }
@@ -1236,6 +1270,11 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
             if checker.is_rule_enabled(Rule::NonOctalPermissions) {
                 ruff::rules::non_octal_permissions(checker, call);
             }
+            if checker.is_rule_enabled(Rule::AssertRaisesException)
+                && is_assert_raises_exception_call_enabled(checker.settings())
+            {
+                flake8_bugbear::rules::assert_raises_exception_call(checker, call);
+            }
         }
         Expr::Dict(dict) => {
             if checker.any_rule_enabled(&[

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

@@ -207,7 +207,6 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
                 Rule::UnnecessaryReturnNone,
                 Rule::ImplicitReturnValue,
                 Rule::ImplicitReturn,
-                Rule::UnnecessaryAssign,
                 Rule::SuperfluousElseReturn,
                 Rule::SuperfluousElseRaise,
                 Rule::SuperfluousElseContinue,

crates/ruff_linter/src/checkers/ast/mod.rs

@@ -64,7 +64,6 @@ use ruff_text_size::{Ranged, TextRange, TextSize};
 use crate::checkers::ast::annotation::AnnotationContext;
 use crate::docstrings::extraction::ExtractionTarget;
 use crate::importer::{ImportRequest, Importer, ResolutionError};
-use crate::message::diagnostic_from_violation;
 use crate::noqa::NoqaMapping;
 use crate::package::PackageRoot;
 use crate::preview::is_undefined_export_in_dunder_init_enabled;
@@ -671,7 +670,11 @@ impl SemanticSyntaxContext for Checker<'_> {
             | SemanticSyntaxErrorKind::InvalidStarExpression
             | SemanticSyntaxErrorKind::AsyncComprehensionInSyncComprehension(_)
             | SemanticSyntaxErrorKind::DuplicateParameter(_)
-            | SemanticSyntaxErrorKind::NonlocalDeclarationAtModuleLevel => {
+            | SemanticSyntaxErrorKind::NonlocalDeclarationAtModuleLevel
+            | SemanticSyntaxErrorKind::LoadBeforeNonlocalDeclaration { .. }
+            | SemanticSyntaxErrorKind::NonlocalAndGlobal(_)
+            | SemanticSyntaxErrorKind::AnnotatedGlobal(_)
+            | SemanticSyntaxErrorKind::AnnotatedNonlocal(_) => {
                 self.semantic_errors.borrow_mut().push(error);
             }
         }
@@ -3158,7 +3161,7 @@ impl<'a> LintContext<'a> {
     ) -> DiagnosticGuard<'chk, 'a> {
         DiagnosticGuard {
             context: self,
-            diagnostic: Some(diagnostic_from_violation(kind, range, &self.source_file)),
+            diagnostic: Some(kind.into_diagnostic(range, &self.source_file)),
             rule: T::rule(),
         }
     }
@@ -3177,7 +3180,7 @@ impl<'a> LintContext<'a> {
         if self.is_rule_enabled(rule) {
             Some(DiagnosticGuard {
                 context: self,
-                diagnostic: Some(diagnostic_from_violation(kind, range, &self.source_file)),
+                diagnostic: Some(kind.into_diagnostic(range, &self.source_file)),
                 rule,
             })
         } else {

crates/ruff_linter/src/codes.rs

@@ -919,27 +919,27 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Tryceratops, "401") => (RuleGroup::Stable, rules::tryceratops::rules::VerboseLogMessage),
 
         // flake8-use-pathlib
-        (Flake8UsePathlib, "100") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathAbspath),
+        (Flake8UsePathlib, "100") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathAbspath),
         (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsChmod),
         (Flake8UsePathlib, "102") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsMkdir),
         (Flake8UsePathlib, "103") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsMakedirs),
         (Flake8UsePathlib, "104") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRename),
         (Flake8UsePathlib, "105") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsReplace),
-        (Flake8UsePathlib, "106") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRmdir),
-        (Flake8UsePathlib, "107") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsRemove),
-        (Flake8UsePathlib, "108") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsUnlink),
+        (Flake8UsePathlib, "106") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRmdir),
+        (Flake8UsePathlib, "107") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRemove),
+        (Flake8UsePathlib, "108") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsUnlink),
         (Flake8UsePathlib, "109") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsGetcwd),
-        (Flake8UsePathlib, "110") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathExists),
-        (Flake8UsePathlib, "111") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathExpanduser),
-        (Flake8UsePathlib, "112") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIsdir),
-        (Flake8UsePathlib, "113") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIsfile),
-        (Flake8UsePathlib, "114") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIslink),
-        (Flake8UsePathlib, "115") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsReadlink),
+        (Flake8UsePathlib, "110") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathExists),
+        (Flake8UsePathlib, "111") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathExpanduser),
+        (Flake8UsePathlib, "112") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsdir),
+        (Flake8UsePathlib, "113") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsfile),
+        (Flake8UsePathlib, "114") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIslink),
+        (Flake8UsePathlib, "115") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsReadlink),
         (Flake8UsePathlib, "116") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsStat),
-        (Flake8UsePathlib, "117") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathIsabs),
+        (Flake8UsePathlib, "117") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathIsabs),
         (Flake8UsePathlib, "118") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathJoin),
-        (Flake8UsePathlib, "119") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathBasename),
-        (Flake8UsePathlib, "120") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathDirname),
+        (Flake8UsePathlib, "119") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathBasename),
+        (Flake8UsePathlib, "120") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathDirname),
         (Flake8UsePathlib, "121") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSamefile),
         (Flake8UsePathlib, "122") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSplitext),
         (Flake8UsePathlib, "123") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::BuiltinOpen),

crates/ruff_linter/src/fix/edits.rs

@@ -618,8 +618,7 @@ mod tests {
     use crate::fix::edits::{
         add_to_dunder_all, make_redundant_alias, next_stmt_break, trailing_semicolon,
     };
-    use crate::message::diagnostic_from_violation;
-    use crate::{Edit, Fix, Locator};
+    use crate::{Edit, Fix, Locator, Violation};
 
     /// Parse the given source using [`Mode::Module`] and return the first statement.
     fn parse_first_stmt(source: &str) -> Result<Stmt> {
@@ -750,8 +749,8 @@ x = 1 \
         let diag = {
             use crate::rules::pycodestyle::rules::MissingNewlineAtEndOfFile;
             let mut iter = edits.into_iter();
-            let mut diagnostic = diagnostic_from_violation(
-                MissingNewlineAtEndOfFile, // The choice of rule here is arbitrary.
+            // The choice of rule here is arbitrary.
+            let mut diagnostic = MissingNewlineAtEndOfFile.into_diagnostic(
                 TextRange::default(),
                 &SourceFileBuilder::new("<filename>", "<code>").finish(),
             );

crates/ruff_linter/src/fix/mod.rs

@@ -172,11 +172,10 @@ mod tests {
     use ruff_source_file::SourceFileBuilder;
     use ruff_text_size::{Ranged, TextSize};
 
-    use crate::Locator;
     use crate::fix::{FixResult, apply_fixes};
-    use crate::message::diagnostic_from_violation;
     use crate::rules::pycodestyle::rules::MissingNewlineAtEndOfFile;
     use crate::{Edit, Fix};
+    use crate::{Locator, Violation};
     use ruff_db::diagnostic::Diagnostic;
 
     fn create_diagnostics(
@@ -187,8 +186,7 @@ mod tests {
         edit.into_iter()
             .map(|edit| {
                 // The choice of rule here is arbitrary.
-                let mut diagnostic = diagnostic_from_violation(
-                    MissingNewlineAtEndOfFile,
+                let mut diagnostic = MissingNewlineAtEndOfFile.into_diagnostic(
                     edit.range(),
                     &SourceFileBuilder::new(filename, source).finish(),
                 );

crates/ruff_linter/src/importer/insertion.rs

@@ -5,6 +5,7 @@ use ruff_python_ast::Stmt;
 use ruff_python_ast::helpers::is_docstring_stmt;
 use ruff_python_codegen::Stylist;
 use ruff_python_parser::{TokenKind, Tokens};
+use ruff_python_trivia::is_python_whitespace;
 use ruff_python_trivia::{PythonWhitespace, textwrap::indent};
 use ruff_source_file::{LineRanges, UniversalNewlineIterator};
 use ruff_text_size::{Ranged, TextSize};
@@ -274,19 +275,12 @@ impl<'a> Insertion<'a> {
     }
 }
 
-/// Find the end of the last docstring.
+/// Find the end of the docstring (first string statement).
 fn match_docstring_end(body: &[Stmt]) -> Option<TextSize> {
-    let mut iter = body.iter();
-    let mut stmt = iter.next()?;
+    let stmt = body.first()?;
     if !is_docstring_stmt(stmt) {
         return None;
     }
-    for next in iter {
-        if !is_docstring_stmt(next) {
-            break;
-        }
-        stmt = next;
-    }
     Some(stmt.end())
 }
 
@@ -306,7 +300,7 @@ fn match_semicolon(s: &str) -> Option<TextSize> {
 fn match_continuation(s: &str) -> Option<TextSize> {
     for (offset, c) in s.char_indices() {
         match c {
-            ' ' | '\t' => continue,
+            _ if is_python_whitespace(c) => continue,
             '\\' => return Some(TextSize::try_from(offset).unwrap()),
             _ => break,
         }
@@ -366,7 +360,7 @@ mod tests {
         .trim_start();
         assert_eq!(
             insert(contents)?,
-            Insertion::own_line("", TextSize::from(40), "\n")
+            Insertion::own_line("", TextSize::from(20), "\n")
         );
 
         let contents = r"

crates/ruff_linter/src/linter.rs

@@ -514,7 +514,7 @@ pub fn lint_only(
 
     LinterResult {
         has_valid_syntax: parsed.has_valid_syntax(),
-        has_no_syntax_errors: !diagnostics.iter().any(Diagnostic::is_syntax_error),
+        has_no_syntax_errors: !diagnostics.iter().any(Diagnostic::is_invalid_syntax),
         diagnostics,
     }
 }
@@ -629,7 +629,7 @@ pub fn lint_fix<'a>(
 
         if iterations == 0 {
             has_valid_syntax = parsed.has_valid_syntax();
-            has_no_syntax_errors = !diagnostics.iter().any(Diagnostic::is_syntax_error);
+            has_no_syntax_errors = !diagnostics.iter().any(Diagnostic::is_invalid_syntax);
         } else {
             // If the source code had no syntax errors on the first pass, but
             // does on a subsequent pass, then we've introduced a

crates/ruff_linter/src/message/azure.rs

@@ -1,71 +0,0 @@
-use std::io::Write;
-
-use ruff_db::diagnostic::Diagnostic;
-use ruff_source_file::LineColumn;
-
-use crate::message::{Emitter, EmitterContext};
-
-/// Generate error logging commands for Azure Pipelines format.
-/// See [documentation](https://learn.microsoft.com/en-us/azure/devops/pipelines/scripts/logging-commands?view=azure-devops&tabs=bash#logissue-log-an-error-or-warning)
-#[derive(Default)]
-pub struct AzureEmitter;
-
-impl Emitter for AzureEmitter {
-    fn emit(
-        &mut self,
-        writer: &mut dyn Write,
-        diagnostics: &[Diagnostic],
-        context: &EmitterContext,
-    ) -> anyhow::Result<()> {
-        for diagnostic in diagnostics {
-            let filename = diagnostic.expect_ruff_filename();
-            let location = if context.is_notebook(&filename) {
-                // We can't give a reasonable location for the structured formats,
-                // so we show one that's clearly a fallback
-                LineColumn::default()
-            } else {
-                diagnostic.expect_ruff_start_location()
-            };
-
-            writeln!(
-                writer,
-                "##vso[task.logissue type=error\
-                        ;sourcepath={filename};linenumber={line};columnnumber={col};{code}]{body}",
-                line = location.line,
-                col = location.column,
-                code = diagnostic
-                    .secondary_code()
-                    .map_or_else(String::new, |code| format!("code={code};")),
-                body = diagnostic.body(),
-            )?;
-        }
-
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use insta::assert_snapshot;
-
-    use crate::message::AzureEmitter;
-    use crate::message::tests::{
-        capture_emitter_output, create_diagnostics, create_syntax_error_diagnostics,
-    };
-
-    #[test]
-    fn output() {
-        let mut emitter = AzureEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn syntax_errors() {
-        let mut emitter = AzureEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_syntax_error_diagnostics());
-
-        assert_snapshot!(content);
-    }
-}

crates/ruff_linter/src/message/diff.rs

@@ -21,7 +21,7 @@ use crate::{Applicability, Fix};
 /// * Compute the diff from the [`Edit`] because diff calculation is expensive.
 pub(super) struct Diff<'a> {
     fix: &'a Fix,
-    source_code: SourceFile,
+    source_code: &'a SourceFile,
 }
 
 impl<'a> Diff<'a> {

crates/ruff_linter/src/message/json.rs

@@ -1,220 +0,0 @@
-use std::io::Write;
-
-use serde::ser::SerializeSeq;
-use serde::{Serialize, Serializer};
-use serde_json::{Value, json};
-
-use ruff_db::diagnostic::Diagnostic;
-use ruff_notebook::NotebookIndex;
-use ruff_source_file::{LineColumn, OneIndexed, SourceCode};
-use ruff_text_size::Ranged;
-
-use crate::Edit;
-use crate::message::{Emitter, EmitterContext};
-
-#[derive(Default)]
-pub struct JsonEmitter;
-
-impl Emitter for JsonEmitter {
-    fn emit(
-        &mut self,
-        writer: &mut dyn Write,
-        diagnostics: &[Diagnostic],
-        context: &EmitterContext,
-    ) -> anyhow::Result<()> {
-        serde_json::to_writer_pretty(
-            writer,
-            &ExpandedMessages {
-                diagnostics,
-                context,
-            },
-        )?;
-
-        Ok(())
-    }
-}
-
-struct ExpandedMessages<'a> {
-    diagnostics: &'a [Diagnostic],
-    context: &'a EmitterContext<'a>,
-}
-
-impl Serialize for ExpandedMessages<'_> {
-    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 message in self.diagnostics {
-            let value = message_to_json_value(message, self.context);
-            s.serialize_element(&value)?;
-        }
-
-        s.end()
-    }
-}
-
-pub(crate) fn message_to_json_value(message: &Diagnostic, context: &EmitterContext) -> Value {
-    let source_file = message.expect_ruff_source_file();
-    let source_code = source_file.to_source_code();
-    let filename = message.expect_ruff_filename();
-    let notebook_index = context.notebook_index(&filename);
-
-    let fix = message.fix().map(|fix| {
-        json!({
-            "applicability": fix.applicability(),
-            "message": message.suggestion(),
-            "edits": &ExpandedEdits { edits: fix.edits(), source_code: &source_code, notebook_index },
-        })
-    });
-
-    let mut start_location = source_code.line_column(message.expect_range().start());
-    let mut end_location = source_code.line_column(message.expect_range().end());
-    let mut noqa_location = message
-        .noqa_offset()
-        .map(|offset| source_code.line_column(offset));
-    let mut notebook_cell_index = None;
-
-    if let Some(notebook_index) = notebook_index {
-        notebook_cell_index = Some(
-            notebook_index
-                .cell(start_location.line)
-                .unwrap_or(OneIndexed::MIN),
-        );
-        start_location = notebook_index.translate_line_column(&start_location);
-        end_location = notebook_index.translate_line_column(&end_location);
-        noqa_location =
-            noqa_location.map(|location| notebook_index.translate_line_column(&location));
-    }
-
-    json!({
-        "code": message.secondary_code(),
-        "url": message.to_url(),
-        "message": message.body(),
-        "fix": fix,
-        "cell": notebook_cell_index,
-        "location": location_to_json(start_location),
-        "end_location": location_to_json(end_location),
-        "filename": filename,
-        "noqa_row": noqa_location.map(|location| location.line)
-    })
-}
-
-fn location_to_json(location: LineColumn) -> serde_json::Value {
-    json!({
-        "row": location.line,
-        "column": location.column
-    })
-}
-
-struct ExpandedEdits<'a> {
-    edits: &'a [Edit],
-    source_code: &'a SourceCode<'a, 'a>,
-    notebook_index: Option<&'a NotebookIndex>,
-}
-
-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 mut location = self.source_code.line_column(edit.start());
-            let mut end_location = self.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: self
-                                .source_code
-                                .line_column(self.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: self
-                                .source_code
-                                .line_column(self.source_code.line_end_exclusive(prev_row))
-                                .column,
-                        };
-                    }
-                    _ => {
-                        end_location = notebook_index.translate_line_column(&end_location);
-                    }
-                }
-                location = notebook_index.translate_line_column(&location);
-            }
-
-            let value = json!({
-                "content": edit.content().unwrap_or_default(),
-                "location": location_to_json(location),
-                "end_location": location_to_json(end_location)
-            });
-
-            s.serialize_element(&value)?;
-        }
-
-        s.end()
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use insta::assert_snapshot;
-
-    use crate::message::JsonEmitter;
-    use crate::message::tests::{
-        capture_emitter_notebook_output, capture_emitter_output, create_diagnostics,
-        create_notebook_diagnostics, create_syntax_error_diagnostics,
-    };
-
-    #[test]
-    fn output() {
-        let mut emitter = JsonEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn syntax_errors() {
-        let mut emitter = JsonEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_syntax_error_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn notebook_output() {
-        let mut emitter = JsonEmitter;
-        let (diagnostics, notebook_indexes) = create_notebook_diagnostics();
-        let content =
-            capture_emitter_notebook_output(&mut emitter, &diagnostics, &notebook_indexes);
-
-        assert_snapshot!(content);
-    }
-}

crates/ruff_linter/src/message/json_lines.rs

@@ -1,60 +0,0 @@
-use std::io::Write;
-
-use ruff_db::diagnostic::Diagnostic;
-
-use crate::message::json::message_to_json_value;
-use crate::message::{Emitter, EmitterContext};
-
-#[derive(Default)]
-pub struct JsonLinesEmitter;
-
-impl Emitter for JsonLinesEmitter {
-    fn emit(
-        &mut self,
-        writer: &mut dyn Write,
-        diagnostics: &[Diagnostic],
-        context: &EmitterContext,
-    ) -> anyhow::Result<()> {
-        for diagnostic in diagnostics {
-            serde_json::to_writer(&mut *writer, &message_to_json_value(diagnostic, context))?;
-            writer.write_all(b"\n")?;
-        }
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use insta::assert_snapshot;
-
-    use crate::message::json_lines::JsonLinesEmitter;
-    use crate::message::tests::{
-        capture_emitter_notebook_output, capture_emitter_output, create_diagnostics,
-        create_notebook_diagnostics, create_syntax_error_diagnostics,
-    };
-
-    #[test]
-    fn output() {
-        let mut emitter = JsonLinesEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn syntax_errors() {
-        let mut emitter = JsonLinesEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_syntax_error_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn notebook_output() {
-        let mut emitter = JsonLinesEmitter;
-        let (messages, notebook_indexes) = create_notebook_diagnostics();
-        let content = capture_emitter_notebook_output(&mut emitter, &messages, &notebook_indexes);
-
-        assert_snapshot!(content);
-    }
-}

crates/ruff_linter/src/message/mod.rs

@@ -3,17 +3,17 @@ use std::fmt::Display;
 use std::io::Write;
 use std::ops::Deref;
 
-use ruff_db::diagnostic::{
-    Annotation, Diagnostic, DiagnosticId, LintName, SecondaryCode, Severity, Span,
-};
 use rustc_hash::FxHashMap;
 
-pub use azure::AzureEmitter;
+use ruff_db::diagnostic::{
+    Annotation, Diagnostic, DiagnosticId, FileResolver, Input, LintName, SecondaryCode, Severity,
+    Span, UnifiedFile,
+};
+use ruff_db::files::File;
+
 pub use github::GithubEmitter;
 pub use gitlab::GitlabEmitter;
 pub use grouped::GroupedEmitter;
-pub use json::JsonEmitter;
-pub use json_lines::JsonLinesEmitter;
 pub use junit::JunitEmitter;
 pub use pylint::PylintEmitter;
 pub use rdjson::RdjsonEmitter;
@@ -24,16 +24,12 @@ pub use sarif::SarifEmitter;
 pub use text::TextEmitter;
 
 use crate::Fix;
-use crate::Violation;
 use crate::registry::Rule;
 
-mod azure;
 mod diff;
 mod github;
 mod gitlab;
 mod grouped;
-mod json;
-mod json_lines;
 mod junit;
 mod pylint;
 mod rdjson;
@@ -108,26 +104,32 @@ where
     diagnostic
 }
 
-// TODO(brent) We temporarily allow this to avoid updating all of the call sites to add
-// references. I expect this method to go away or change significantly with the rest of the
-// diagnostic refactor, but if it still exists in this form at the end of the refactor, we
-// should just update the call sites.
-#[expect(clippy::needless_pass_by_value)]
-pub fn diagnostic_from_violation<T: Violation>(
-    kind: T,
-    range: TextRange,
-    file: &SourceFile,
-) -> Diagnostic {
-    create_lint_diagnostic(
-        Violation::message(&kind),
-        Violation::fix_title(&kind),
-        range,
-        None,
-        None,
-        file.clone(),
-        None,
-        T::rule(),
-    )
+impl FileResolver for EmitterContext<'_> {
+    fn path(&self, _file: File) -> &str {
+        unimplemented!("Expected a Ruff file for rendering a Ruff diagnostic");
+    }
+
+    fn input(&self, _file: File) -> Input {
+        unimplemented!("Expected a Ruff file for rendering a Ruff diagnostic");
+    }
+
+    fn notebook_index(&self, file: &UnifiedFile) -> Option<NotebookIndex> {
+        match file {
+            UnifiedFile::Ty(_) => {
+                unimplemented!("Expected a Ruff file for rendering a Ruff diagnostic")
+            }
+            UnifiedFile::Ruff(file) => self.notebook_indexes.get(file.name()).cloned(),
+        }
+    }
+
+    fn is_notebook(&self, file: &UnifiedFile) -> bool {
+        match file {
+            UnifiedFile::Ty(_) => {
+                unimplemented!("Expected a Ruff file for rendering a Ruff diagnostic")
+            }
+            UnifiedFile::Ruff(file) => self.notebook_indexes.get(file.name()).is_some(),
+        }
+    }
 }
 
 struct MessageWithLocation<'a> {

crates/ruff_linter/src/message/rdjson.rs

@@ -73,7 +73,7 @@ fn message_to_rdjson_value(message: &Diagnostic) -> Value {
             },
             "code": {
                 "value": message.secondary_code(),
-                "url": message.to_url(),
+                "url": message.to_ruff_url(),
             },
             "suggestions": rdjson_suggestions(fix.edits(), &source_code),
         })
@@ -86,7 +86,7 @@ fn message_to_rdjson_value(message: &Diagnostic) -> Value {
             },
             "code": {
                 "value": message.secondary_code(),
-                "url": message.to_url(),
+                "url": message.to_ruff_url(),
             },
         })
     }

crates/ruff_linter/src/noqa.rs

@@ -1225,8 +1225,6 @@ mod tests {
     use ruff_source_file::{LineEnding, SourceFileBuilder};
     use ruff_text_size::{TextLen, TextRange, TextSize};
 
-    use crate::Edit;
-    use crate::message::diagnostic_from_violation;
     use crate::noqa::{
         Directive, LexicalError, NoqaLexerOutput, NoqaMapping, add_noqa_inner, lex_codes,
         lex_file_exemption, lex_inline_noqa,
@@ -1234,6 +1232,7 @@ mod tests {
     use crate::rules::pycodestyle::rules::{AmbiguousVariableName, UselessSemicolon};
     use crate::rules::pyflakes::rules::UnusedVariable;
     use crate::rules::pyupgrade::rules::PrintfStringFormatting;
+    use crate::{Edit, Violation};
     use crate::{Locator, generate_noqa_edits};
 
     fn assert_lexed_ranges_match_slices(
@@ -2832,10 +2831,10 @@ mod tests {
         assert_eq!(output, format!("{contents}"));
 
         let source_file = SourceFileBuilder::new(path.to_string_lossy(), contents).finish();
-        let messages = [diagnostic_from_violation(
-            UnusedVariable {
-                name: "x".to_string(),
-            },
+        let messages = [UnusedVariable {
+            name: "x".to_string(),
+        }
+        .into_diagnostic(
             TextRange::new(TextSize::from(0), TextSize::from(0)),
             &source_file,
         )];
@@ -2856,15 +2855,14 @@ mod tests {
 
         let source_file = SourceFileBuilder::new(path.to_string_lossy(), contents).finish();
         let messages = [
-            diagnostic_from_violation(
-                AmbiguousVariableName("x".to_string()),
+            AmbiguousVariableName("x".to_string()).into_diagnostic(
                 TextRange::new(TextSize::from(0), TextSize::from(0)),
                 &source_file,
             ),
-            diagnostic_from_violation(
-                UnusedVariable {
-                    name: "x".to_string(),
-                },
+            UnusedVariable {
+                name: "x".to_string(),
+            }
+            .into_diagnostic(
                 TextRange::new(TextSize::from(0), TextSize::from(0)),
                 &source_file,
             ),
@@ -2887,15 +2885,14 @@ mod tests {
 
         let source_file = SourceFileBuilder::new(path.to_string_lossy(), contents).finish();
         let messages = [
-            diagnostic_from_violation(
-                AmbiguousVariableName("x".to_string()),
+            AmbiguousVariableName("x".to_string()).into_diagnostic(
                 TextRange::new(TextSize::from(0), TextSize::from(0)),
                 &source_file,
             ),
-            diagnostic_from_violation(
-                UnusedVariable {
-                    name: "x".to_string(),
-                },
+            UnusedVariable {
+                name: "x".to_string(),
+            }
+            .into_diagnostic(
                 TextRange::new(TextSize::from(0), TextSize::from(0)),
                 &source_file,
             ),
@@ -2931,11 +2928,8 @@ print(
 "#;
         let noqa_line_for = [TextRange::new(8.into(), 68.into())].into_iter().collect();
         let source_file = SourceFileBuilder::new(path.to_string_lossy(), source).finish();
-        let messages = [diagnostic_from_violation(
-            PrintfStringFormatting,
-            TextRange::new(12.into(), 79.into()),
-            &source_file,
-        )];
+        let messages = [PrintfStringFormatting
+            .into_diagnostic(TextRange::new(12.into(), 79.into()), &source_file)];
         let comment_ranges = CommentRanges::default();
         let edits = generate_noqa_edits(
             path,
@@ -2964,11 +2958,8 @@ foo;
 bar =
 ";
         let source_file = SourceFileBuilder::new(path.to_string_lossy(), source).finish();
-        let messages = [diagnostic_from_violation(
-            UselessSemicolon,
-            TextRange::new(4.into(), 5.into()),
-            &source_file,
-        )];
+        let messages =
+            [UselessSemicolon.into_diagnostic(TextRange::new(4.into(), 5.into()), &source_file)];
         let noqa_line_for = NoqaMapping::default();
         let comment_ranges = CommentRanges::default();
         let edits = generate_noqa_edits(

crates/ruff_linter/src/preview.rs

@@ -69,6 +69,71 @@ pub(crate) const fn is_fix_os_path_getctime_enabled(settings: &LinterSettings) -
     settings.preview.is_enabled()
 }
 
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_abspath_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_rmdir_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_unlink_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_remove_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_exists_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_expanduser_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_isdir_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_isfile_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_islink_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_isabs_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_readlink_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_basename_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19213
+pub(crate) const fn is_fix_os_path_dirname_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
 // https://github.com/astral-sh/ruff/pull/11436
 // https://github.com/astral-sh/ruff/pull/11168
 pub(crate) const fn is_dunder_init_fix_unused_import_enabled(settings: &LinterSettings) -> bool {
@@ -125,3 +190,8 @@ pub(crate) const fn is_safe_super_call_with_parameters_fix_enabled(
 ) -> bool {
     settings.preview.is_enabled()
 }
+
+// https://github.com/astral-sh/ruff/pull/19063
+pub(crate) const fn is_assert_raises_exception_call_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}

crates/ruff_linter/src/pyproject_toml.rs

@@ -6,11 +6,10 @@ use ruff_text_size::{TextRange, TextSize};
 use ruff_db::diagnostic::Diagnostic;
 use ruff_source_file::SourceFile;
 
-use crate::IOError;
-use crate::message::diagnostic_from_violation;
 use crate::registry::Rule;
 use crate::rules::ruff::rules::InvalidPyprojectToml;
 use crate::settings::LinterSettings;
+use crate::{IOError, Violation};
 
 /// RUF200
 pub fn lint_pyproject_toml(source_file: &SourceFile, settings: &LinterSettings) -> Vec<Diagnostic> {
@@ -30,11 +29,8 @@ pub fn lint_pyproject_toml(source_file: &SourceFile, settings: &LinterSettings)
                     source_file.name(),
                 );
                 if settings.rules.enabled(Rule::IOError) {
-                    let diagnostic = diagnostic_from_violation(
-                        IOError { message },
-                        TextRange::default(),
-                        source_file,
-                    );
+                    let diagnostic =
+                        IOError { message }.into_diagnostic(TextRange::default(), source_file);
                     messages.push(diagnostic);
                 } else {
                     warn!(
@@ -56,11 +52,8 @@ pub fn lint_pyproject_toml(source_file: &SourceFile, settings: &LinterSettings)
 
     if settings.rules.enabled(Rule::InvalidPyprojectToml) {
         let toml_err = err.message().to_string();
-        let diagnostic = diagnostic_from_violation(
-            InvalidPyprojectToml { message: toml_err },
-            range,
-            source_file,
-        );
+        let diagnostic =
+            InvalidPyprojectToml { message: toml_err }.into_diagnostic(range, source_file);
         messages.push(diagnostic);
     }
 

crates/ruff_linter/src/rules/flake8_bandit/rules/suspicious_imports.rs

@@ -283,7 +283,7 @@ impl Violation for SuspiciousXmlrpcImport {
 ///
 /// ## Example
 /// ```python
-/// import wsgiref.handlers.CGIHandler
+/// from wsgiref.handlers import CGIHandler
 /// ```
 ///
 /// ## References

crates/ruff_linter/src/rules/flake8_bugbear/mod.rs

@@ -16,11 +16,14 @@ mod tests {
     use crate::settings::LinterSettings;
     use crate::test::test_path;
 
+    use crate::settings::types::PreviewMode;
+
     use ruff_python_ast::PythonVersion;
 
     #[test_case(Rule::AbstractBaseClassWithoutAbstractMethod, Path::new("B024.py"))]
     #[test_case(Rule::AssertFalse, Path::new("B011.py"))]
-    #[test_case(Rule::AssertRaisesException, Path::new("B017.py"))]
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_0.py"))]
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_1.py"))]
     #[test_case(Rule::AssignmentToOsEnviron, Path::new("B003.py"))]
     #[test_case(Rule::CachedInstanceMethod, Path::new("B019.py"))]
     #[test_case(Rule::ClassAsDataStructure, Path::new("class_as_data_structure.py"))]
@@ -174,4 +177,23 @@ mod tests {
         assert_diagnostics!(snapshot, diagnostics);
         Ok(())
     }
+
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_0.py"))]
+    #[test_case(Rule::AssertRaisesException, Path::new("B017_1.py"))]
+    fn rules_preview(rule_code: Rule, path: &Path) -> Result<()> {
+        let snapshot = format!(
+            "preview__{}_{}",
+            rule_code.noqa_code(),
+            path.to_string_lossy()
+        );
+        let diagnostics = test_path(
+            Path::new("flake8_bugbear").join(path).as_path(),
+            &LinterSettings {
+                preview: PreviewMode::Enabled,
+                ..LinterSettings::for_rule(rule_code)
+            },
+        )?;
+        assert_diagnostics!(snapshot, diagnostics);
+        Ok(())
+    }
 }

crates/ruff_linter/src/rules/flake8_bugbear/rules/assert_raises_exception.rs

@@ -1,7 +1,7 @@
 use std::fmt;
 
 use ruff_macros::{ViolationMetadata, derive_message_formats};
-use ruff_python_ast::{self as ast, Expr, WithItem};
+use ruff_python_ast::{self as ast, Arguments, Expr, WithItem};
 use ruff_text_size::Ranged;
 
 use crate::Violation;
@@ -56,6 +56,53 @@ impl fmt::Display for ExceptionKind {
     }
 }
 
+fn detect_blind_exception(
+    semantic: &ruff_python_semantic::SemanticModel<'_>,
+    func: &Expr,
+    arguments: &Arguments,
+) -> Option<ExceptionKind> {
+    let is_assert_raises = matches!(
+        func,
+        &Expr::Attribute(ast::ExprAttribute { ref attr, .. }) if attr.as_str() == "assertRaises"
+    );
+
+    let is_pytest_raises = semantic
+        .resolve_qualified_name(func)
+        .is_some_and(|qualified_name| matches!(qualified_name.segments(), ["pytest", "raises"]));
+
+    if !(is_assert_raises || is_pytest_raises) {
+        return None;
+    }
+
+    if is_pytest_raises {
+        if arguments.find_keyword("match").is_some() {
+            return None;
+        }
+
+        if arguments
+            .find_positional(1)
+            .is_some_and(|arg| matches!(arg, Expr::StringLiteral(_) | Expr::BytesLiteral(_)))
+        {
+            return None;
+        }
+    }
+
+    let exception_argument_name = if is_pytest_raises {
+        "expected_exception"
+    } else {
+        "exception"
+    };
+
+    let exception_expr = arguments.find_argument_value(exception_argument_name, 0)?;
+    let builtin_symbol = semantic.resolve_builtin_symbol(exception_expr)?;
+
+    match builtin_symbol {
+        "Exception" => Some(ExceptionKind::Exception),
+        "BaseException" => Some(ExceptionKind::BaseException),
+        _ => None,
+    }
+}
+
 /// B017
 pub(crate) fn assert_raises_exception(checker: &Checker, items: &[WithItem]) {
     for item in items {
@@ -73,33 +120,31 @@ pub(crate) fn assert_raises_exception(checker: &Checker, items: &[WithItem]) {
             continue;
         }
 
-        let [arg] = &*arguments.args else {
-            continue;
-        };
-
-        let semantic = checker.semantic();
-
-        let Some(builtin_symbol) = semantic.resolve_builtin_symbol(arg) else {
-            continue;
-        };
-
-        let exception = match builtin_symbol {
-            "Exception" => ExceptionKind::Exception,
-            "BaseException" => ExceptionKind::BaseException,
-            _ => continue,
-        };
-
-        if !(matches!(func.as_ref(), Expr::Attribute(ast::ExprAttribute { attr, .. }) if attr == "assertRaises")
-            || semantic
-                .resolve_qualified_name(func)
-                .is_some_and(|qualified_name| {
-                    matches!(qualified_name.segments(), ["pytest", "raises"])
-                })
-                && arguments.find_keyword("match").is_none())
+        if let Some(exception) =
+            detect_blind_exception(checker.semantic(), func.as_ref(), arguments)
         {
-            continue;
+            checker.report_diagnostic(AssertRaisesException { exception }, item.range());
         }
-
-        checker.report_diagnostic(AssertRaisesException { exception }, item.range());
+    }
+}
+
+/// B017 (call form)
+pub(crate) fn assert_raises_exception_call(
+    checker: &Checker,
+    ast::ExprCall {
+        func,
+        arguments,
+        range,
+        node_index: _,
+    }: &ast::ExprCall,
+) {
+    let semantic = checker.semantic();
+
+    if arguments.args.len() < 2 && arguments.find_argument("func", 1).is_none() {
+        return;
+    }
+
+    if let Some(exception) = detect_blind_exception(semantic, func.as_ref(), arguments) {
+        checker.report_diagnostic(AssertRaisesException { exception }, *range);
     }
 }

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B017_B017.py.snap

@@ -1,45 +0,0 @@
----
-source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
----
-B017.py:23:14: B017 Do not assert blind exception: `Exception`
-   |
-21 | class Foobar(unittest.TestCase):
-22 |     def evil_raises(self) -> None:
-23 |         with self.assertRaises(Exception):
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
-24 |             raise Exception("Evil I say!")
-   |
-
-B017.py:27:14: B017 Do not assert blind exception: `BaseException`
-   |
-26 |     def also_evil_raises(self) -> None:
-27 |         with self.assertRaises(BaseException):
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
-28 |             raise Exception("Evil I say!")
-   |
-
-B017.py:45:10: B017 Do not assert blind exception: `Exception`
-   |
-44 | def test_pytest_raises():
-45 |     with pytest.raises(Exception):
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
-46 |         raise ValueError("Hello")
-   |
-
-B017.py:48:10: B017 Do not assert blind exception: `Exception`
-   |
-46 |         raise ValueError("Hello")
-47 |
-48 |     with pytest.raises(Exception), pytest.raises(ValueError):
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
-49 |         raise ValueError("Hello")
-   |
-
-B017.py:57:36: B017 Do not assert blind exception: `Exception`
-   |
-55 |         raise ValueError("This is also fine")
-56 |
-57 |     with contextlib.nullcontext(), pytest.raises(Exception):
-   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^ B017
-58 |         raise ValueError("Multiple context managers")
-   |

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B017_B017_0.py.snap

@@ -0,0 +1,71 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+B017_0.py:23:14: B017 Do not assert blind exception: `Exception`
+   |
+21 | class Foobar(unittest.TestCase):
+22 |     def evil_raises(self) -> None:
+23 |         with self.assertRaises(Exception):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+24 |             raise Exception("Evil I say!")
+   |
+
+B017_0.py:27:14: B017 Do not assert blind exception: `BaseException`
+   |
+26 |     def also_evil_raises(self) -> None:
+27 |         with self.assertRaises(BaseException):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+28 |             raise Exception("Evil I say!")
+   |
+
+B017_0.py:45:10: B017 Do not assert blind exception: `Exception`
+   |
+44 | def test_pytest_raises():
+45 |     with pytest.raises(Exception):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+46 |         raise ValueError("Hello")
+   |
+
+B017_0.py:48:10: B017 Do not assert blind exception: `Exception`
+   |
+46 |         raise ValueError("Hello")
+47 |
+48 |     with pytest.raises(Exception), pytest.raises(ValueError):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+49 |         raise ValueError("Hello")
+   |
+
+B017_0.py:57:36: B017 Do not assert blind exception: `Exception`
+   |
+55 |         raise ValueError("This is also fine")
+56 |
+57 |     with contextlib.nullcontext(), pytest.raises(Exception):
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+58 |         raise ValueError("Multiple context managers")
+   |
+
+B017_0.py:62:10: B017 Do not assert blind exception: `Exception`
+   |
+61 | def test_pytest_raises_keyword():
+62 |     with pytest.raises(expected_exception=Exception):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+63 |         raise ValueError("Should be flagged")
+   |
+
+B017_0.py:68:18: B017 Do not assert blind exception: `Exception`
+   |
+66 |     class TestKwargs(unittest.TestCase):
+67 |         def test_method(self):
+68 |             with self.assertRaises(exception=Exception):
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+69 |                 raise ValueError("Should be flagged")
+   |
+
+B017_0.py:71:18: B017 Do not assert blind exception: `BaseException`
+   |
+69 |                 raise ValueError("Should be flagged")
+70 |
+71 |             with self.assertRaises(exception=BaseException):
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+72 |                 raise ValueError("Should be flagged")
+   |

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__B017_B017_1.py.snap

@@ -0,0 +1,4 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__preview__B017_B017_0.py.snap

@@ -0,0 +1,71 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+B017_0.py:23:14: B017 Do not assert blind exception: `Exception`
+   |
+21 | class Foobar(unittest.TestCase):
+22 |     def evil_raises(self) -> None:
+23 |         with self.assertRaises(Exception):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+24 |             raise Exception("Evil I say!")
+   |
+
+B017_0.py:27:14: B017 Do not assert blind exception: `BaseException`
+   |
+26 |     def also_evil_raises(self) -> None:
+27 |         with self.assertRaises(BaseException):
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+28 |             raise Exception("Evil I say!")
+   |
+
+B017_0.py:45:10: B017 Do not assert blind exception: `Exception`
+   |
+44 | def test_pytest_raises():
+45 |     with pytest.raises(Exception):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+46 |         raise ValueError("Hello")
+   |
+
+B017_0.py:48:10: B017 Do not assert blind exception: `Exception`
+   |
+46 |         raise ValueError("Hello")
+47 |
+48 |     with pytest.raises(Exception), pytest.raises(ValueError):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+49 |         raise ValueError("Hello")
+   |
+
+B017_0.py:57:36: B017 Do not assert blind exception: `Exception`
+   |
+55 |         raise ValueError("This is also fine")
+56 |
+57 |     with contextlib.nullcontext(), pytest.raises(Exception):
+   |                                    ^^^^^^^^^^^^^^^^^^^^^^^^ B017
+58 |         raise ValueError("Multiple context managers")
+   |
+
+B017_0.py:62:10: B017 Do not assert blind exception: `Exception`
+   |
+61 | def test_pytest_raises_keyword():
+62 |     with pytest.raises(expected_exception=Exception):
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+63 |         raise ValueError("Should be flagged")
+   |
+
+B017_0.py:68:18: B017 Do not assert blind exception: `Exception`
+   |
+66 |     class TestKwargs(unittest.TestCase):
+67 |         def test_method(self):
+68 |             with self.assertRaises(exception=Exception):
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+69 |                 raise ValueError("Should be flagged")
+   |
+
+B017_0.py:71:18: B017 Do not assert blind exception: `BaseException`
+   |
+69 |                 raise ValueError("Should be flagged")
+70 |
+71 |             with self.assertRaises(exception=BaseException):
+   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+72 |                 raise ValueError("Should be flagged")
+   |

crates/ruff_linter/src/rules/flake8_bugbear/snapshots/ruff_linter__rules__flake8_bugbear__tests__preview__B017_B017_1.py.snap

@@ -0,0 +1,37 @@
+---
+source: crates/ruff_linter/src/rules/flake8_bugbear/mod.rs
+---
+B017_1.py:20:9: B017 Do not assert blind exception: `Exception`
+   |
+18 | class Foobar(unittest.TestCase):
+19 |     def call_form_raises(self) -> None:
+20 |         self.assertRaises(Exception, something_else)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+21 |         self.assertRaises(BaseException, something_else)
+   |
+
+B017_1.py:21:9: B017 Do not assert blind exception: `BaseException`
+   |
+19 |     def call_form_raises(self) -> None:
+20 |         self.assertRaises(Exception, something_else)
+21 |         self.assertRaises(BaseException, something_else)
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+   |
+
+B017_1.py:25:5: B017 Do not assert blind exception: `Exception`
+   |
+24 | def test_pytest_call_form() -> None:
+25 |     pytest.raises(Exception, something_else)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+26 |     pytest.raises(BaseException, something_else)
+   |
+
+B017_1.py:26:5: B017 Do not assert blind exception: `BaseException`
+   |
+24 | def test_pytest_call_form() -> None:
+25 |     pytest.raises(Exception, something_else)
+26 |     pytest.raises(BaseException, something_else)
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ B017
+27 |
+28 |     pytest.raises(Exception, something_else, match="hello")
+   |

crates/ruff_linter/src/rules/flake8_django/rules/model_without_dunder_str.rs

@@ -96,22 +96,43 @@ fn is_model_abstract(class_def: &ast::StmtClassDef) -> bool {
             continue;
         }
         for element in body {
-            let Stmt::Assign(ast::StmtAssign { targets, value, .. }) = element else {
-                continue;
-            };
-            for target in targets {
-                let Expr::Name(ast::ExprName { id, .. }) = target else {
-                    continue;
-                };
-                if id != "abstract" {
-                    continue;
+            match element {
+                Stmt::Assign(ast::StmtAssign { targets, value, .. }) => {
+                    if targets
+                        .iter()
+                        .any(|target| is_abstract_true_assignment(target, Some(value)))
+                    {
+                        return true;
+                    }
                 }
-                if !is_const_true(value) {
-                    continue;
+                Stmt::AnnAssign(ast::StmtAnnAssign { target, value, .. }) => {
+                    if is_abstract_true_assignment(target, value.as_deref()) {
+                        return true;
+                    }
                 }
-                return true;
+                _ => {}
             }
         }
     }
     false
 }
+
+fn is_abstract_true_assignment(target: &Expr, value: Option<&Expr>) -> bool {
+    let Expr::Name(ast::ExprName { id, .. }) = target else {
+        return false;
+    };
+
+    if id != "abstract" {
+        return false;
+    }
+
+    let Some(value) = value else {
+        return false;
+    };
+
+    if !is_const_true(value) {
+        return false;
+    }
+
+    true
+}

crates/ruff_linter/src/rules/flake8_django/snapshots/ruff_linter__rules__flake8_django__tests__DJ008_DJ008.py.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_django/mod.rs
-snapshot_kind: text
 ---
 DJ008.py:6:7: DJ008 Model does not define `__str__` method
   |
@@ -31,3 +30,11 @@ DJ008.py:182:7: DJ008 Model does not define `__str__` method
     |       ^^^^^^^^^^^^^^^^^^ DJ008
 183 |     pass
     |
+
+DJ008.py:215:7: DJ008 Model does not define `__str__` method
+    |
+215 | class TypeAnnotatedNonAbstractModel(models.Model):
+    |       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ DJ008
+216 |     """Model with type-annotated abstract = False - should trigger DJ008"""
+217 |     new_field = models.CharField(max_length=10)
+    |

crates/ruff_linter/src/rules/flake8_return/rules/function.rs

@@ -539,7 +539,21 @@ fn implicit_return(checker: &Checker, function_def: &ast::StmtFunctionDef, stmt:
 }
 
 /// RET504
-fn unnecessary_assign(checker: &Checker, stack: &Stack) {
+pub(crate) fn unnecessary_assign(checker: &Checker, function_stmt: &Stmt) {
+    let Stmt::FunctionDef(function_def) = function_stmt else {
+        return;
+    };
+    let Some(stack) = create_stack(checker, function_def) else {
+        return;
+    };
+
+    if !result_exists(&stack.returns) {
+        return;
+    }
+
+    let Some(function_scope) = checker.semantic().function_scope(function_def) else {
+        return;
+    };
     for (assign, return_, stmt) in &stack.assignment_return {
         // Identify, e.g., `return x`.
         let Some(value) = return_.value.as_ref() else {
@@ -583,6 +597,22 @@ fn unnecessary_assign(checker: &Checker, stack: &Stack) {
             continue;
         }
 
+        let Some(assigned_binding) = function_scope
+            .get(assigned_id)
+            .map(|binding_id| checker.semantic().binding(binding_id))
+        else {
+            continue;
+        };
+        // Check if there's any reference made to `assigned_binding` in another scope, e.g, nested
+        // functions. If there is, ignore them.
+        if assigned_binding
+            .references()
+            .map(|reference_id| checker.semantic().reference(reference_id))
+            .any(|reference| reference.scope_id() != assigned_binding.scope)
+        {
+            continue;
+        }
+
         let mut diagnostic = checker.report_diagnostic(
             UnnecessaryAssign {
                 name: assigned_id.to_string(),
@@ -665,24 +695,21 @@ fn superfluous_elif_else(checker: &Checker, stack: &Stack) {
     }
 }
 
-/// Run all checks from the `flake8-return` plugin.
-pub(crate) fn function(checker: &Checker, function_def: &ast::StmtFunctionDef) {
-    let ast::StmtFunctionDef {
-        decorator_list,
-        returns,
-        body,
-        ..
-    } = function_def;
+fn create_stack<'a>(
+    checker: &'a Checker,
+    function_def: &'a ast::StmtFunctionDef,
+) -> Option<Stack<'a>> {
+    let ast::StmtFunctionDef { body, .. } = function_def;
 
     // Find the last statement in the function.
     let Some(last_stmt) = body.last() else {
         // Skip empty functions.
-        return;
+        return None;
     };
 
     // Skip functions that consist of a single return statement.
     if body.len() == 1 && matches!(last_stmt, Stmt::Return(_)) {
-        return;
+        return None;
     }
 
     // Traverse the function body, to collect the stack.
@@ -696,9 +723,29 @@ pub(crate) fn function(checker: &Checker, function_def: &ast::StmtFunctionDef) {
 
     // Avoid false positives for generators.
     if stack.is_generator {
-        return;
+        return None;
     }
 
+    Some(stack)
+}
+
+/// Run all checks from the `flake8-return` plugin, but `RET504` which is ran
+/// after the semantic model is fully built.
+pub(crate) fn function(checker: &Checker, function_def: &ast::StmtFunctionDef) {
+    let ast::StmtFunctionDef {
+        decorator_list,
+        returns,
+        body,
+        ..
+    } = function_def;
+
+    let Some(stack) = create_stack(checker, function_def) else {
+        return;
+    };
+    let Some(last_stmt) = body.last() else {
+        return;
+    };
+
     if checker.any_rule_enabled(&[
         Rule::SuperfluousElseReturn,
         Rule::SuperfluousElseRaise,
@@ -721,10 +768,6 @@ pub(crate) fn function(checker: &Checker, function_def: &ast::StmtFunctionDef) {
         if checker.is_rule_enabled(Rule::ImplicitReturn) {
             implicit_return(checker, function_def, last_stmt);
         }
-
-        if checker.is_rule_enabled(Rule::UnnecessaryAssign) {
-            unnecessary_assign(checker, &stack);
-        }
     } else {
         if checker.is_rule_enabled(Rule::UnnecessaryReturnNone) {
             // Skip functions that have a return annotation that is not `None`.

crates/ruff_linter/src/rules/flake8_return/snapshots/ruff_linter__rules__flake8_return__tests__RET504_RET504.py.snap

@@ -247,8 +247,6 @@ RET504.py:423:16: RET504 [*] Unnecessary assignment to `services` before `return
 422 |         services = a["services"]
 423 |         return services
     |                ^^^^^^^^ RET504
-424 |
-425 | # See: https://github.com/astral-sh/ruff/issues/18411
     |
     = help: Remove unnecessary assignment
 
@@ -260,46 +258,46 @@ RET504.py:423:16: RET504 [*] Unnecessary assignment to `services` before `return
 423     |-        return services
     422 |+        return a["services"]
 424 423 | 
-425 424 | # See: https://github.com/astral-sh/ruff/issues/18411
-426 425 | def f():
+425 424 | 
+426 425 | # See: https://github.com/astral-sh/ruff/issues/14052
 
-RET504.py:429:12: RET504 [*] Unnecessary assignment to `x` before `return` statement
+RET504.py:458:12: RET504 [*] Unnecessary assignment to `x` before `return` statement
     |
-427 |     (#=
-428 |     x) = 1
-429 |     return x
+456 |     (#=
+457 |     x) = 1
+458 |     return x
     |            ^ RET504
-430 |
-431 | def f():
+459 |
+460 | def f():
     |
     = help: Remove unnecessary assignment
 
 ℹ Unsafe fix
-424 424 | 
-425 425 | # See: https://github.com/astral-sh/ruff/issues/18411
-426 426 | def f():
-427     |-    (#=
-428     |-    x) = 1
-429     |-    return x
-    427 |+    return 1
-430 428 | 
-431 429 | def f():
-432 430 |     x = (1
+453 453 | 
+454 454 | # See: https://github.com/astral-sh/ruff/issues/18411
+455 455 | def f():
+456     |-    (#=
+457     |-    x) = 1
+458     |-    return x
+    456 |+    return 1
+459 457 | 
+460 458 | def f():
+461 459 |     x = (1
 
-RET504.py:434:12: RET504 [*] Unnecessary assignment to `x` before `return` statement
+RET504.py:463:12: RET504 [*] Unnecessary assignment to `x` before `return` statement
     |
-432 |     x = (1
-433 |               )
-434 |     return x
+461 |     x = (1
+462 |               )
+463 |     return x
     |            ^ RET504
     |
     = help: Remove unnecessary assignment
 
 ℹ Unsafe fix
-429 429 |     return x
-430 430 | 
-431 431 | def f():
-432     |-    x = (1
-    432 |+    return (1
-433 433 |               )
-434     |-    return x
+458 458 |     return x
+459 459 | 
+460 460 | def f():
+461     |-    x = (1
+    461 |+    return (1
+462 462 |               )
+463     |-    return x

crates/ruff_linter/src/rules/flake8_type_checking/mod.rs

@@ -36,6 +36,7 @@ mod tests {
     #[test_case(Rule::RuntimeImportInTypeCheckingBlock, Path::new("TC004_8.py"))]
     #[test_case(Rule::RuntimeImportInTypeCheckingBlock, Path::new("TC004_9.py"))]
     #[test_case(Rule::RuntimeImportInTypeCheckingBlock, Path::new("quote.py"))]
+    #[test_case(Rule::RuntimeImportInTypeCheckingBlock, Path::new("whitespace.py"))]
     #[test_case(Rule::RuntimeStringUnion, Path::new("TC010_1.py"))]
     #[test_case(Rule::RuntimeStringUnion, Path::new("TC010_2.py"))]
     #[test_case(Rule::TypingOnlyFirstPartyImport, Path::new("TC001.py"))]

crates/ruff_linter/src/rules/flake8_type_checking/snapshots/ruff_linter__rules__flake8_type_checking__tests__runtime-import-in-type-checking-block_whitespace.py.snap

@@ -0,0 +1,22 @@
+---
+source: crates/ruff_linter/src/rules/flake8_type_checking/mod.rs
+---
+whitespace.py:5:26: TC004 [*] Move import `builtins` out of type-checking block. Import is used for more than type hinting.
+  |
+3 | from typing import TYPE_CHECKING\
+4 |
+5 | if TYPE_CHECKING: import builtins
+  |                          ^^^^^^^^ TC004
+6 | builtins.print("!")
+  |
+  = help: Move out of type-checking block
+
+ℹ Unsafe fix
+1 1 | # Regression test for: https://github.com/astral-sh/ruff/issues/19175
+2 2 | # there is a (potentially invisible) unicode formfeed character (000C) between `TYPE_CHECKING` and the backslash
+3   |-from typing import TYPE_CHECKING\
+  3 |+from typing import TYPE_CHECKING; import builtins\
+4 4 | 
+5   |-if TYPE_CHECKING: import builtins
+  5 |+if TYPE_CHECKING: pass
+6 6 | builtins.print("!")

crates/ruff_linter/src/rules/flake8_use_pathlib/helpers.rs

@@ -1,10 +1,17 @@
 use crate::checkers::ast::Checker;
 use crate::importer::ImportRequest;
 use crate::{Applicability, Edit, Fix, Violation};
+use ruff_python_ast::{self as ast};
 use ruff_python_ast::{Expr, ExprCall};
 use ruff_text_size::Ranged;
 
-pub(crate) fn is_path_call(checker: &Checker, expr: &Expr) -> bool {
+pub(crate) fn is_keyword_only_argument_non_default(arguments: &ast::Arguments, name: &str) -> bool {
+    arguments
+        .find_keyword(name)
+        .is_some_and(|keyword| !keyword.value.is_none_literal_expr())
+}
+
+pub(crate) fn is_pathlib_path_call(checker: &Checker, expr: &Expr) -> bool {
     expr.as_call_expr().is_some_and(|expr_call| {
         checker
             .semantic()
@@ -13,27 +20,22 @@ pub(crate) fn is_path_call(checker: &Checker, expr: &Expr) -> bool {
     })
 }
 
-pub(crate) fn check_os_path_get_calls(
+/// We check functions that take only 1 argument,  this does not apply to functions
+/// with `dir_fd` argument, because `dir_fd` is not supported by pathlib,
+/// so check if it's set to non-default values
+pub(crate) fn check_os_pathlib_single_arg_calls(
     checker: &Checker,
     call: &ExprCall,
-    fn_name: &str,
     attr: &str,
+    fn_argument: &str,
     fix_enabled: bool,
     violation: impl Violation,
 ) {
-    if checker
-        .semantic()
-        .resolve_qualified_name(&call.func)
-        .is_none_or(|qualified_name| qualified_name.segments() != ["os", "path", fn_name])
-    {
-        return;
-    }
-
     if call.arguments.len() != 1 {
         return;
     }
 
-    let Some(arg) = call.arguments.find_argument_value("filename", 0) else {
+    let Some(arg) = call.arguments.find_argument_value(fn_argument, 0) else {
         return;
     };
 
@@ -56,10 +58,10 @@ pub(crate) fn check_os_path_get_calls(
                 Applicability::Safe
             };
 
-            let replacement = if is_path_call(checker, arg) {
-                format!("{arg_code}.stat().{attr}")
+            let replacement = if is_pathlib_path_call(checker, arg) {
+                format!("{arg_code}.{attr}")
             } else {
-                format!("{binding}({arg_code}).stat().{attr}")
+                format!("{binding}({arg_code}).{attr}")
             };
 
             Ok(Fix::applicable_edits(

crates/ruff_linter/src/rules/flake8_use_pathlib/mod.rs

@@ -80,6 +80,48 @@ mod tests {
         Ok(())
     }
 
+    #[test_case(Path::new("full_name.py"))]
+    #[test_case(Path::new("import_as.py"))]
+    #[test_case(Path::new("import_from_as.py"))]
+    #[test_case(Path::new("import_from.py"))]
+    fn preview_rules(path: &Path) -> Result<()> {
+        let snapshot = format!("preview_{}", path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("flake8_use_pathlib").join(path).as_path(),
+            &settings::LinterSettings {
+                preview: PreviewMode::Enabled,
+                ..settings::LinterSettings::for_rules(vec![
+                    Rule::OsPathAbspath,
+                    Rule::OsChmod,
+                    Rule::OsMkdir,
+                    Rule::OsMakedirs,
+                    Rule::OsRename,
+                    Rule::OsReplace,
+                    Rule::OsRmdir,
+                    Rule::OsRemove,
+                    Rule::OsUnlink,
+                    Rule::OsGetcwd,
+                    Rule::OsPathExists,
+                    Rule::OsPathExpanduser,
+                    Rule::OsPathIsdir,
+                    Rule::OsPathIsfile,
+                    Rule::OsPathIslink,
+                    Rule::OsReadlink,
+                    Rule::OsStat,
+                    Rule::OsPathIsabs,
+                    Rule::OsPathJoin,
+                    Rule::OsPathBasename,
+                    Rule::OsPathDirname,
+                    Rule::OsPathSamefile,
+                    Rule::OsPathSplitext,
+                    Rule::BuiltinOpen,
+                ])
+            },
+        )?;
+        assert_diagnostics!(snapshot, diagnostics);
+        Ok(())
+    }
+
     #[test_case(Rule::OsPathGetsize, Path::new("PTH202.py"))]
     #[test_case(Rule::OsPathGetsize, Path::new("PTH202_2.py"))]
     #[test_case(Rule::OsPathGetatime, Path::new("PTH203.py"))]

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/mod.rs

@@ -1,19 +1,45 @@
 pub(crate) use glob_rule::*;
 pub(crate) use invalid_pathlib_with_suffix::*;
+pub(crate) use os_path_abspath::*;
+pub(crate) use os_path_basename::*;
+pub(crate) use os_path_dirname::*;
+pub(crate) use os_path_exists::*;
+pub(crate) use os_path_expanduser::*;
 pub(crate) use os_path_getatime::*;
 pub(crate) use os_path_getctime::*;
 pub(crate) use os_path_getmtime::*;
 pub(crate) use os_path_getsize::*;
+pub(crate) use os_path_isabs::*;
+pub(crate) use os_path_isdir::*;
+pub(crate) use os_path_isfile::*;
+pub(crate) use os_path_islink::*;
+pub(crate) use os_readlink::*;
+pub(crate) use os_remove::*;
+pub(crate) use os_rmdir::*;
 pub(crate) use os_sep_split::*;
+pub(crate) use os_unlink::*;
 pub(crate) use path_constructor_current_directory::*;
 pub(crate) use replaceable_by_pathlib::*;
 
 mod glob_rule;
 mod invalid_pathlib_with_suffix;
+mod os_path_abspath;
+mod os_path_basename;
+mod os_path_dirname;
+mod os_path_exists;
+mod os_path_expanduser;
 mod os_path_getatime;
 mod os_path_getctime;
 mod os_path_getmtime;
 mod os_path_getsize;
+mod os_path_isabs;
+mod os_path_isdir;
+mod os_path_isfile;
+mod os_path_islink;
+mod os_readlink;
+mod os_remove;
+mod os_rmdir;
 mod os_sep_split;
+mod os_unlink;
 mod path_constructor_current_directory;
 mod replaceable_by_pathlib;

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_abspath.rs

@@ -0,0 +1,74 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_abspath_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.path.abspath`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os.path`. When possible, using `Path` object
+/// methods such as `Path.resolve()` can improve readability over the `os.path`
+/// module's counterparts (e.g., `os.path.abspath()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// file_path = os.path.abspath("../path/to/file")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// file_path = Path("../path/to/file").resolve()
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.resolve`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.resolve)
+/// - [Python documentation: `os.path.abspath`](https://docs.python.org/3/library/os.path.html#os.path.abspath)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsPathAbspath;
+
+impl Violation for OsPathAbspath {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.abspath()` should be replaced by `Path.resolve()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).resolve()`".to_string())
+    }
+}
+
+/// PTH100
+pub(crate) fn os_path_abspath(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "abspath"] {
+        return;
+    }
+    check_os_pathlib_single_arg_calls(
+        checker,
+        call,
+        "resolve()",
+        "path",
+        is_fix_os_path_abspath_enabled(checker.settings()),
+        OsPathAbspath,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_basename.rs

@@ -0,0 +1,73 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_basename_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.path.basename`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os.path`. When possible, using `Path` object
+/// methods such as `Path.name` can improve readability over the `os.path`
+/// module's counterparts (e.g., `os.path.basename()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.path.basename(__file__)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path(__file__).name
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `PurePath.name`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.name)
+/// - [Python documentation: `os.path.basename`](https://docs.python.org/3/library/os.path.html#os.path.basename)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsPathBasename;
+
+impl Violation for OsPathBasename {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.basename()` should be replaced by `Path.name`".to_string()
+    }
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).name`".to_string())
+    }
+}
+
+/// PTH119
+pub(crate) fn os_path_basename(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "basename"] {
+        return;
+    }
+    check_os_pathlib_single_arg_calls(
+        checker,
+        call,
+        "name",
+        "p",
+        is_fix_os_path_basename_enabled(checker.settings()),
+        OsPathBasename,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_dirname.rs

@@ -0,0 +1,73 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_dirname_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.path.dirname`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os.path`. When possible, using `Path` object
+/// methods such as `Path.parent` can improve readability over the `os.path`
+/// module's counterparts (e.g., `os.path.dirname()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.path.dirname(__file__)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path(__file__).parent
+/// ```
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## References
+/// - [Python documentation: `PurePath.parent`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.parent)
+/// - [Python documentation: `os.path.dirname`](https://docs.python.org/3/library/os.path.html#os.path.dirname)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsPathDirname;
+
+impl Violation for OsPathDirname {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.dirname()` should be replaced by `Path.parent`".to_string()
+    }
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).parent`".to_string())
+    }
+}
+
+/// PTH120
+pub(crate) fn os_path_dirname(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "dirname"] {
+        return;
+    }
+    check_os_pathlib_single_arg_calls(
+        checker,
+        call,
+        "parent",
+        "p",
+        is_fix_os_path_dirname_enabled(checker.settings()),
+        OsPathDirname,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_exists.rs

@@ -0,0 +1,73 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_exists_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.path.exists`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os.path`. When possible, using `Path` object
+/// methods such as `Path.exists()` can improve readability over the `os.path`
+/// module's counterparts (e.g., `os.path.exists()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.path.exists("file.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("file.py").exists()
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.exists`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.exists)
+/// - [Python documentation: `os.path.exists`](https://docs.python.org/3/library/os.path.html#os.path.exists)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsPathExists;
+
+impl Violation for OsPathExists {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.exists()` should be replaced by `Path.exists()`".to_string()
+    }
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).exists()`".to_string())
+    }
+}
+
+/// PTH110
+pub(crate) fn os_path_exists(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "exists"] {
+        return;
+    }
+    check_os_pathlib_single_arg_calls(
+        checker,
+        call,
+        "exists()",
+        "path",
+        is_fix_os_path_exists_enabled(checker.settings()),
+        OsPathExists,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_expanduser.rs

@@ -0,0 +1,73 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_expanduser_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.path.expanduser`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os.path`. When possible, using `Path` object
+/// methods such as `Path.expanduser()` can improve readability over the `os.path`
+/// module's counterparts (e.g., as `os.path.expanduser()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.path.expanduser("~/films/Monty Python")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("~/films/Monty Python").expanduser()
+/// ```
+///
+/// ## Known issues
+/// While using `pathlib` can improve the readability and type safety of your code,
+/// it can be less performant than the lower-level alternatives that work directly with strings,
+/// especially on older versions of Python.
+///
+/// ## Fix Safety
+/// This rule's fix is marked as unsafe if the replacement would remove comments attached to the original expression.
+///
+/// ## References
+/// - [Python documentation: `Path.expanduser`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.expanduser)
+/// - [Python documentation: `os.path.expanduser`](https://docs.python.org/3/library/os.path.html#os.path.expanduser)
+/// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Why you should be using pathlib](https://treyhunner.com/2018/12/why-you-should-be-using-pathlib/)
+/// - [No really, pathlib is great](https://treyhunner.com/2019/01/no-really-pathlib-is-great/)
+#[derive(ViolationMetadata)]
+pub(crate) struct OsPathExpanduser;
+
+impl Violation for OsPathExpanduser {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.expanduser()` should be replaced by `Path.expanduser()`".to_string()
+    }
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).expanduser()`".to_string())
+    }
+}
+
+/// PTH111
+pub(crate) fn os_path_expanduser(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "expanduser"] {
+        return;
+    }
+    check_os_pathlib_single_arg_calls(
+        checker,
+        call,
+        "expanduser()",
+        "path",
+        is_fix_os_path_expanduser_enabled(checker.settings()),
+        OsPathExpanduser,
+    );
+}

crates/ruff_linter/src/rules/flake8_use_pathlib/rules/os_path_getatime.rs

@@ -1,6 +1,6 @@
 use crate::checkers::ast::Checker;
 use crate::preview::is_fix_os_path_getatime_enabled;
-use crate::rules::flake8_use_pathlib::helpers::check_os_path_get_calls;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
 use crate::{FixAvailability, Violation};
 use ruff_macros::{ViolationMetadata, derive_message_formats};
 use ruff_python_ast::ExprCall;
@@ -61,12 +61,15 @@ impl Violation for OsPathGetatime {
 }
 
 /// PTH203
-pub(crate) fn os_path_getatime(checker: &Checker, call: &ExprCall) {
-    check_os_path_get_calls(
+pub(crate) fn os_path_getatime(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "getatime"] {
+        return;
+    }
+    check_os_pathlib_single_arg_calls(
         checker,
         call,
-        "getatime",
-        "st_atime",
+        "stat().st_atime",
+        "filename",
         is_fix_os_path_getatime_enabled(checker.settings()),
         OsPathGetatime,
     );