[ty] enum.Flag

## Summary

This was previously the last commit in #19415, split out to make it
easier to review. This applies the fixes from c9b99e4, 5021f32, and
2922490cb8 to the new rendering code in `ruff_db`. I initially intended
only to fix the empty span after a line terminator (as you can see in
the branch name), but the two fixes were tied pretty closely together,
and my initial fix for the empty spans needed a big change after trying
to handle unprintable characters too. I can still split this up if it
would help with review. I would just start with the unprintable
characters first.

The implementation here is essentially copy-pasted from
`ruff_linter::message::text.rs`, with the `SourceCode` struct renamed to
`EscapedSourceCode` since there's already a `SourceCode` in scope in
`render.rs`. It's also updated slightly to account for the multiple
annotations for a single snippet. The original implementation used some
types from the `line_width` module from `ruff_linter`. I copied over
heavily stripped-down versions of these instead of trying to import
them. We could inline the remaining code entirely, if we want, but I
thought it was nice enough to keep.

I also moved over `ceil_char_boundary`, which is unchanged except to
make it a free function taking a `&str` instead of a `Locator` method.
All of this code could be deleted from `ruff_linter` if we also move
over the `grouped` output format, which will be the last user after
#19415.

## Test Plan

I added new tests in `ruff_linter` that call into the new rendering code
to snapshot the diagnostics for the affected cases. These are copies of
existing snapshots in Ruff, so it's helpful to compare them. These are a
bit noisy because of the other rendering differences in the header, but
all of the `^^^` indicators should be the same.

<details><summary>`empty_span_after_line_terminator` diff</summary>

```diff
diff --git a/crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E112_E11.py.snap b/crates/ruff_linter/src/message/snapshots/ruff_linter__message__text__tests__empty_span_after_line_terminator.snap
index 5ade4346e0..6df75c16f0 100644
--- a/crates/ruff_linter/src/rules/pycodestyle/snapshots/ruff_linter__rules__pycodestyle__tests__E112_E11.py.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_linter__message__text__tests__empty_span_after_line_terminator.snap
@@ -1,17 +1,20 @@
 ---
-source: crates/ruff_linter/src/rules/pycodestyle/mod.rs
+source: crates/ruff_linter/src/message/text.rs
+expression: value.to_string()
 ---
-E11.py:9:1: E112 Expected an indented block
+error[no-indented-block]: Expected an indented block
+  --> E11.py:9:1
    |
  7 | #: E112
  8 | if False:
  9 | print()
-   | ^ E112
+   | ^
 10 | #: E113
 11 | print()
    |
 
-E11.py:9:1: SyntaxError: Expected an indented block after `if` statement
+error[invalid-syntax]: SyntaxError: Expected an indented block after `if` statement
+  --> E11.py:9:1
    |
  7 | #: E112
  8 | if False:
@@ -21,7 +24,8 @@ E11.py:9:1: SyntaxError: Expected an indented block after `if` statement
 11 | print()
    |
 
-E11.py:12:1: SyntaxError: Unexpected indentation
+error[invalid-syntax]: SyntaxError: Unexpected indentation
+  --> E11.py:12:1
    |
 10 | #: E113
 11 | print()
@@ -31,7 +35,8 @@ E11.py:12:1: SyntaxError: Unexpected indentation
 14 | mimetype = 'application/x-directory'
    |
 
-E11.py:14:1: SyntaxError: Expected a statement
+error[invalid-syntax]: SyntaxError: Expected a statement
+  --> E11.py:14:1
    |
 12 |     print()
 13 | #: E114 E116
@@ -41,17 +46,19 @@ E11.py:14:1: SyntaxError: Expected a statement
 16 | create_date = False
    |
 
-E11.py:45:1: E112 Expected an indented block
+error[no-indented-block]: Expected an indented block
+  --> E11.py:45:1
    |
 43 | #: E112
 44 | if False:  #
 45 | print()
-   | ^ E112
+   | ^
 46 | #:
 47 | if False:
    |
 
-E11.py:45:1: SyntaxError: Expected an indented block after `if` statement
+error[invalid-syntax]: SyntaxError: Expected an indented block after `if` statement
+  --> E11.py:45:1
    |
 43 | #: E112
 44 | if False:  #
```

</details>

<details><summary>`unprintable_characters` diff</summary>

```diff
diff --git a/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE2512_invalid_characters.py.snap b/crates/ruff_linter/src/message/snapshots/ruff_linter__message__text__tests__unprintable_characters.snap
index 52cfdf9cce..fcfa1ac9f1 100644
--- a/crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLE2512_invalid_characters.py.snap
+++ b/crates/ruff_linter/src/message/snapshots/ruff_linter__message__text__tests__unprintable_characters.snap
@@ -1,161 +1,115 @@
 ---
-source: crates/ruff_linter/src/rules/pylint/mod.rs
+source: crates/ruff_linter/src/message/text.rs
+expression: value.to_string()
 ---
-invalid_characters.py:24:12: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:24:12
    |
 22 | cr_ok = f'\\r'
 23 |
 24 | sub = 'sub '
-   |            ^ PLE2512
+   |            ^
 25 | sub = f'sub '
    |
-   = help: Replace with escape sequence
+help: Replace with escape sequence
 
-ℹ Safe fix
-21 21 | cr_ok = '\\r'
-22 22 | cr_ok = f'\\r'
-23 23 | 
-24    |-sub = 'sub '
-   24 |+sub = 'sub \x1A'
-25 25 | sub = f'sub '
-26 26 | 
-27 27 | sub_ok = '\x1a'
-
-invalid_characters.py:25:13: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:25:13
    |
 24 | sub = 'sub '
 25 | sub = f'sub '
-   |             ^ PLE2512
+   |             ^
 26 |
 27 | sub_ok = '\x1a'
    |
-   = help: Replace with escape sequence
-
-ℹ Safe fix
-22 22 | cr_ok = f'\\r'
-23 23 | 
-24 24 | sub = 'sub '
-25    |-sub = f'sub '
-   25 |+sub = f'sub \x1A'
-26 26 | 
-27 27 | sub_ok = '\x1a'
-28 28 | sub_ok = f'\x1a'
+help: Replace with escape sequence
 
-invalid_characters.py:55:25: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:55:25
    |
 53 | zwsp_after_multicharacter_grapheme_cluster = f"ಫ್ರಾನ್ಸಿಸ್ಕೊ ​​"
 54 |
 55 | nested_fstrings = f'␈{f'{f'␛'}'}'
-   |                         ^ PLE2512
+   |                         ^
 56 |
 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
    |
-   = help: Replace with escape sequence
-
-ℹ Safe fix
-52 52 | zwsp_after_multicharacter_grapheme_cluster = "ಫ್ರಾನ್ಸಿಸ್ಕೊ ​​"
-53 53 | zwsp_after_multicharacter_grapheme_cluster = f"ಫ್ರಾನ್ಸಿಸ್ಕೊ ​​"
-54 54 | 
-55    |-nested_fstrings = f'␈{f'{f'␛'}'}'
-   55 |+nested_fstrings = f'␈{f'\x1A{f'␛'}'}'
-56 56 | 
-57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
-58 58 | x = f"""}}ab"""
+help: Replace with escape sequence
 
-invalid_characters.py:58:12: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:58:12
    |
 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
 58 | x = f"""}}ab"""
-   |            ^ PLE2512
+   |            ^
 59 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256
 60 | x = f"""}}a␛b"""
    |
-   = help: Replace with escape sequence
+help: Replace with escape sequence
 
-ℹ Safe fix
-55 55 | nested_fstrings = f'␈{f'{f'␛'}'}'
-56 56 | 
-57 57 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998106
-58    |-x = f"""}}ab"""
-   58 |+x = f"""}}a\x1Ab"""
-59 59 | # https://github.com/astral-sh/ruff/issues/7455#issuecomment-1741998256
-60 60 | x = f"""}}a␛b"""
-61 61 | 
-
-invalid_characters.py:64:12: PLE2512 Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:64:12
    |
 63 | # https://github.com/astral-sh/ruff/issues/13294
 64 | print(r"""␈␛�​
-   |            ^ PLE2512
+   |            ^
 65 | """)
 66 | print(fr"""␈␛�​
    |
-   = help: Replace with escape sequence
+help: Replace with escape sequence
 
-invalid_characters.py:66:13: PLE2512 Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:66:13
    |
 64 | print(r"""␈␛�​
 65 | """)
 66 | print(fr"""␈␛�​
-   |             ^ PLE2512
+   |             ^
 67 | """)
 68 | print(Rf"""␈␛�​
    |
-   = help: Replace with escape sequence
+help: Replace with escape sequence
 
-invalid_characters.py:68:13: PLE2512 Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:68:13
    |
 66 | print(fr"""␈␛�​
 67 | """)
 68 | print(Rf"""␈␛�​
-   |             ^ PLE2512
+   |             ^
 69 | """)
    |
-   = help: Replace with escape sequence
+help: Replace with escape sequence
 
-invalid_characters.py:73:9: PLE2512 Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:73:9
    |
 71 | # https://github.com/astral-sh/ruff/issues/18815
 72 | b = "\␈"
 73 | sub = "\"
-   |         ^ PLE2512
+   |         ^
 74 | esc = "\␛"
 75 | zwsp = "\​"
    |
-   = help: Replace with escape sequence
+help: Replace with escape sequence
 
-invalid_characters.py:80:25: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:80:25
    |
 78 | # tstrings
 79 | esc = t'esc esc ␛'
 80 | nested_tstrings = t'␈{t'{t'␛'}'}'
-   |                         ^ PLE2512
+   |                         ^
 81 | nested_ftstrings = t'␈{f'{t'␛'}'}'
    |
-   = help: Replace with escape sequence
-
-ℹ Safe fix
-77 77 | 
-78 78 | # tstrings
-79 79 | esc = t'esc esc ␛'
-80    |-nested_tstrings = t'␈{t'{t'␛'}'}'
-   80 |+nested_tstrings = t'␈{t'\x1A{t'␛'}'}'
-81 81 | nested_ftstrings = t'␈{f'{t'␛'}'}'
-82 82 | 
+help: Replace with escape sequence
 
-invalid_characters.py:81:26: PLE2512 [*] Invalid unescaped character SUB, use "\x1A" instead
+error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+  --> invalid_characters.py:81:26
    |
 79 | esc = t'esc esc ␛'
 80 | nested_tstrings = t'␈{t'{t'␛'}'}'
 81 | nested_ftstrings = t'␈{f'{t'␛'}'}'
-   |                          ^ PLE2512
+   |                          ^
    |
-   = help: Replace with escape sequence
-
-ℹ Safe fix
-78 78 | # tstrings
-79 79 | esc = t'esc esc ␛'
-80 80 | nested_tstrings = t'␈{t'{t'␛'}'}'
-81    |-nested_ftstrings = t'␈{f'{t'␛'}'}'
-   81 |+nested_ftstrings = t'␈{f'\x1A{t'␛'}'}'
-82 82 |
+help: Replace with escape sequence
```

</details>

.github/workflows/ci.yaml

@@ -143,12 +143,12 @@ jobs:
         env:
           MERGE_BASE: ${{ steps.merge_base.outputs.sha }}
         run: |
-          if git diff --quiet "${MERGE_BASE}...HEAD" -- ':**' \
-            ':!**/*.md' \
-            ':crates/ty_python_semantic/resources/mdtest/**/*.md' \
+          # NOTE: Do not exclude all Markdown files here, but rather use
+          # specific exclude patterns like 'docs/**'), because tests for
+          # 'ty' are written in Markdown.
+          if git diff --quiet "${MERGE_BASE}...HEAD" -- \
             ':!docs/**' \
             ':!assets/**' \
-            ':.github/workflows/ci.yaml' \
           ; then
               echo "changed=false" >> "$GITHUB_OUTPUT"
           else
@@ -238,13 +238,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-insta
       - name: ty mdtests (GitHub annotations)
@@ -296,13 +296,13 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Install cargo insta"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-insta
       - name: "Run tests"
@@ -325,7 +325,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo nextest"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-nextest
       - name: "Run tests"
@@ -381,7 +381,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Build"
         run: cargo build --release --locked
 
@@ -406,7 +406,7 @@ jobs:
           MSRV: ${{ steps.msrv.outputs.value }}
         run: rustup default "${MSRV}"
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - name: "Build tests"
         shell: bash
         env:
@@ -429,7 +429,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo-binstall"
-        uses: cargo-bins/cargo-binstall@8aac5aa2bf0dfaa2863eccad9f43c68fe40e5ec8 # v1.14.1
+        uses: cargo-bins/cargo-binstall@808dcb1b503398677d089d3216c51ac7cc11e7ab # v1.14.2
         with:
           tool: cargo-fuzz@0.11.2
       - name: "Install cargo-fuzz"
@@ -451,7 +451,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         name: Download Ruff binary to test
         id: download-cached-binary
@@ -652,7 +652,7 @@ jobs:
           branch: ${{ github.event.pull_request.base.ref }}
           workflow: "ci.yaml"
           check_artifacts: true
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - name: Fuzz
         env:
           FORCE_COLOR: 1
@@ -682,7 +682,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: cargo-bins/cargo-binstall@8aac5aa2bf0dfaa2863eccad9f43c68fe40e5ec8 # v1.14.1
+      - uses: cargo-bins/cargo-binstall@808dcb1b503398677d089d3216c51ac7cc11e7ab # v1.14.2
       - run: cargo binstall --no-confirm cargo-shear
       - run: cargo shear
 
@@ -722,7 +722,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
       - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
         with:
@@ -765,7 +765,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: Install uv
-        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - name: "Install Insiders dependencies"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
         run: uv pip install -r docs/requirements-insiders.txt --system
@@ -897,13 +897,13 @@ jobs:
           persist-credentials: false
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
 
       - name: "Install Rust toolchain"
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-codspeed
 
@@ -911,7 +911,7 @@ jobs:
         run: cargo codspeed build --features "codspeed,instrumented" --no-default-features -p ruff_benchmark
 
       - name: "Run benchmarks"
-        uses: CodSpeedHQ/action@c28fe9fbe7d57a3da1b7834ae3761c1d8217612d # v3.7.0
+        uses: CodSpeedHQ/action@0b6e7a3d96c9d2a6057e7bcea6b45aaf2f7ce60b # v3.8.0
         with:
           run: cargo codspeed run
           token: ${{ secrets.CODSPEED_TOKEN }}
@@ -930,13 +930,13 @@ jobs:
           persist-credentials: false
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
 
       - name: "Install Rust toolchain"
         run: rustup show
 
       - name: "Install codspeed"
-        uses: taiki-e/install-action@c07504cae06f832dc8de08911c9a9c5cddb0d2d3 # v2.56.13
+        uses: taiki-e/install-action@c99cc51b309eee71a866715cfa08c922f11cf898 # v2.56.19
         with:
           tool: cargo-codspeed
 
@@ -944,7 +944,7 @@ jobs:
         run: cargo codspeed build --features "codspeed,walltime" --no-default-features -p ruff_benchmark
 
       - name: "Run benchmarks"
-        uses: CodSpeedHQ/action@c28fe9fbe7d57a3da1b7834ae3761c1d8217612d # v3.7.0
+        uses: CodSpeedHQ/action@0b6e7a3d96c9d2a6057e7bcea6b45aaf2f7ce60b # v3.8.0
         with:
           run: cargo codspeed run
           token: ${{ secrets.CODSPEED_TOKEN }}

.github/workflows/daily_fuzz.yaml

@@ -34,11 +34,11 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"
-        uses: rui314/setup-mold@85c79d00377f0d32cdbae595a46de6f7c2fa6599 # v1
+        uses: rui314/setup-mold@702b1908b5edf30d71a8d1666b724e0f0c6fa035 # v1
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
       - name: Build ruff
         # A debug build means the script runs slower once it gets started,

.github/workflows/mypy_primer.yaml

@@ -38,7 +38,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:
@@ -81,7 +81,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
 
       - uses: Swatinem/rust-cache@9d47c6ad4b02e050fd481d890b2ea34778fd09d6 # v2.7.8
         with:

.github/workflows/publish-pypi.yml

@@ -22,7 +22,7 @@ jobs:
       id-token: write
     steps:
       - name: "Install uv"
-        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         with:
           pattern: wheels-*

.github/workflows/sync_typeshed.yaml

@@ -34,6 +34,10 @@ env:
   # and which all three workers push to.
   UPSTREAM_BRANCH: typeshedbot/sync-typeshed
 
+  # The path to the directory that contains the vendored typeshed stubs,
+  # relative to the root of the Ruff repository.
+  VENDORED_TYPESHED: crates/ty_vendored/vendor/typeshed
+
 jobs:
   # Sync typeshed stubs, and sync all docstrings available on Linux.
   # Push the changes to a new branch on the upstream repository.
@@ -61,23 +65,23 @@ jobs:
         run: |
           git config --global user.name typeshedbot
           git config --global user.email '<>'
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - name: Sync typeshed stubs
         run: |
-          rm -rf ruff/crates/ty_vendored/vendor/typeshed
-          mkdir ruff/crates/ty_vendored/vendor/typeshed
-          cp typeshed/README.md ruff/crates/ty_vendored/vendor/typeshed
-          cp typeshed/LICENSE ruff/crates/ty_vendored/vendor/typeshed
+          rm -rf "ruff/${VENDORED_TYPESHED}"
+          mkdir "ruff/${VENDORED_TYPESHED}"
+          cp typeshed/README.md "ruff/${VENDORED_TYPESHED}"
+          cp typeshed/LICENSE "ruff/${VENDORED_TYPESHED}"
 
           # The pyproject.toml file is needed by a later job for the black configuration.
           # It's deleted before creating the PR.
-          cp typeshed/pyproject.toml ruff/crates/ty_vendored/vendor/typeshed
+          cp typeshed/pyproject.toml "ruff/${VENDORED_TYPESHED}"
 
-          cp -r typeshed/stdlib ruff/crates/ty_vendored/vendor/typeshed/stdlib
-          rm -rf ruff/crates/ty_vendored/vendor/typeshed/stdlib/@tests
-          git -C typeshed rev-parse HEAD > ruff/crates/ty_vendored/vendor/typeshed/source_commit.txt
+          cp -r typeshed/stdlib "ruff/${VENDORED_TYPESHED}/stdlib"
+          rm -rf "ruff/${VENDORED_TYPESHED}/stdlib/@tests"
+          git -C typeshed rev-parse HEAD > "ruff/${VENDORED_TYPESHED}/source_commit.txt"
           cd ruff
-          git checkout -b typeshedbot/sync-typeshed
+          git checkout -b "${UPSTREAM_BRANCH}"
           git add .
           git commit -m "Sync typeshed. Source commit: https://github.com/python/typeshed/commit/$(git -C ../typeshed rev-parse HEAD)" --allow-empty
       - name: Sync Linux docstrings
@@ -113,7 +117,7 @@ jobs:
         with:
           persist-credentials: true
           ref: ${{ env.UPSTREAM_BRANCH}}
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - name: Setup git
         run: |
           git config --global user.name typeshedbot
@@ -151,7 +155,7 @@ jobs:
         with:
           persist-credentials: true
           ref: ${{ env.UPSTREAM_BRANCH}}
-      - uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
       - name: Setup git
         run: |
           git config --global user.name typeshedbot
@@ -167,17 +171,17 @@ jobs:
           # consistent with the other typeshed stubs around them.
           # Typeshed formats code using black in their CI, so we just invoke
           # black on the stubs the same way that typeshed does.
-          uvx black crates/ty_vendored/vendor/typeshed/stdlib --config crates/ty_vendored/vendor/typeshed/pyproject.toml || true
+          uvx black "${VENDORED_TYPESHED}/stdlib" --config "${VENDORED_TYPESHED}/pyproject.toml" || true
           git commit -am "Format codemodded docstrings" --allow-empty
 
-          rm crates/ty_vendored/vendor/typeshed/pyproject.toml
+          rm "${VENDORED_TYPESHED}/pyproject.toml"
           git commit -am "Remove pyproject.toml file"
 
           git push
       - name: Create a PR
         if: ${{ success() }}
         run: |
-          gh pr list --repo "$GITHUB_REPOSITORY" --head typeshedbot/sync-typeshed --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
+          gh pr list --repo "${GITHUB_REPOSITORY}" --head "${UPSTREAM_BRANCH}" --json id --jq length | grep 1 && exit 0 # exit if there is existing pr
           gh pr create --title "[ty] Sync vendored typeshed stubs" --body "Close and reopen this PR to trigger CI" --label "ty"
 
   create-issue-on-failure:

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

@@ -33,7 +33,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:
@@ -64,7 +64,7 @@ jobs:
 
           cd ..
 
-          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@27dd66d9e397d986ef9c631119ee09556eab8af9"
 
           ecosystem-analyzer \
             --repository ruff \

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

@@ -29,7 +29,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@bd01e18f51369d5a26f1651c3cb451d3417e3bba # v6.3.1
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:
@@ -49,7 +49,7 @@ jobs:
 
           cd ..
 
-          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@f0eec0e549684d8e1d7b8bc3e351202124b63bda"
+          uv tool install "git+https://github.com/astral-sh/ecosystem-analyzer@27dd66d9e397d986ef9c631119ee09556eab8af9"
 
           ecosystem-analyzer \
             --verbose \

.github/workflows/typing_conformance.yaml

@@ -0,0 +1,109 @@
+name: Run typing conformance
+
+permissions: {}
+
+on:
+  pull_request:
+    paths:
+      - "crates/ty*/**"
+      - "crates/ruff_db"
+      - "crates/ruff_python_ast"
+      - "crates/ruff_python_parser"
+      - ".github/workflows/typing_conformance.yaml"
+      - ".github/workflows/typing_conformance_comment.yaml"
+      - "Cargo.lock"
+      - "!**.md"
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref_name }}-${{ github.event.pull_request.number || github.sha }}
+  cancel-in-progress: true
+
+env:
+  CARGO_INCREMENTAL: 0
+  CARGO_NET_RETRY: 10
+  CARGO_TERM_COLOR: always
+  RUSTUP_MAX_RETRIES: 10
+  RUST_BACKTRACE: 1
+
+jobs:
+  typing_conformance:
+    name: Compute diagnostic diff
+    runs-on: depot-ubuntu-22.04-32
+    timeout-minutes: 10
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          path: ruff
+          fetch-depth: 0
+          persist-credentials: false
+
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          repository: python/typing
+          ref: d4f39b27a4a47aac8b6d4019e1b0b5b3156fabdc
+          path: typing
+          persist-credentials: false
+
+      - name: Install the latest version of uv
+        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+
+      - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
+        with:
+          workspaces: "ruff"
+
+      - name: Install Rust toolchain
+        run: rustup show
+
+      - name: Compute diagnostic diff
+        shell: bash
+        run: |
+          RUFF_DIR="$GITHUB_WORKSPACE/ruff"
+
+          # Build the executable for the old and new commit
+          (
+            cd ruff
+
+            echo "new commit"
+            git checkout -b new_commit "${{ github.event.pull_request.head.sha }}"
+            git rev-list --format=%s --max-count=1 new_commit
+            cargo build --release --bin ty
+            mv target/release/ty ty-new
+
+            echo "old commit (merge base)"
+            MERGE_BASE="$(git merge-base "$GITHUB_SHA" "origin/$GITHUB_BASE_REF")"
+            git checkout -b old_commit "$MERGE_BASE"
+            git rev-list --format=%s --max-count=1 old_commit
+            cargo build --release --bin ty
+            mv target/release/ty ty-old
+          )
+
+          (
+            cd typing/conformance/tests
+
+            echo "Running ty on old commit (merge base)"
+            "$RUFF_DIR/ty-old" check --color=never --output-format=concise . > "$GITHUB_WORKSPACE/old-output.txt" 2>&1 || true
+
+            echo "Running ty on new commit"
+            "$RUFF_DIR/ty-new" check --color=never --output-format=concise . > "$GITHUB_WORKSPACE/new-output.txt" 2>&1 || true
+          )
+
+          if ! diff -u old-output.txt new-output.txt > typing_conformance_diagnostics.diff; then
+            echo "Differences found between base and PR"
+          else
+            echo "No differences found"
+            touch typing_conformance_diagnostics.diff
+          fi
+
+          echo ${{ github.event.number }} > pr-number
+
+      - name: Upload diff
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: typing_conformance_diagnostics_diff
+          path: typing_conformance_diagnostics.diff
+
+      - name: Upload pr-number
+        uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4.6.2
+        with:
+          name: pr-number
+          path: pr-number

.github/workflows/typing_conformance_comment.yaml

@@ -0,0 +1,97 @@
+name: PR comment (typing_conformance)
+
+on: # zizmor: ignore[dangerous-triggers]
+  workflow_run:
+    workflows: [Run typing conformance]
+    types: [completed]
+  workflow_dispatch:
+    inputs:
+      workflow_run_id:
+        description: The typing_conformance 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 typing_conformance results"
+        id: download-typing_conformance_diff
+        if: steps.pr-number.outputs.pr-number
+        with:
+          name: typing_conformance_diagnostics_diff
+          workflow: typing_conformance.yaml
+          pr: ${{ steps.pr-number.outputs.pr-number }}
+          path: pr/typing_conformance_diagnostics_diff
+          workflow_conclusion: completed
+          if_no_artifact_found: ignore
+          allow_forks: true
+
+      - name: Generate comment content
+        id: generate-comment
+        if: ${{ steps.download-typing_conformance_diff.outputs.found_artifact == 'true' }}
+        run: |
+          # Guard against malicious typing_conformance results that symlink to a secret
+          # file on this runner
+          if [[ -L pr/typing_conformance_diagnostics_diff/typing_conformance_diagnostics.diff ]]
+          then
+              echo "Error: typing_conformance_diagnostics.diff cannot be a symlink"
+              exit 1
+          fi
+
+          # Note this identifier is used to find the comment to update on
+          # subsequent runs
+          echo '<!-- generated-comment typing_conformance_diagnostics_diff -->' >> comment.txt
+
+          echo '## Diagnostic diff on typing conformance tests' >> comment.txt
+          if [ -s "pr/typing_conformance_diagnostics_diff/typing_conformance_diagnostics.diff" ]; then
+            echo '<details>' >> comment.txt
+            echo '<summary>Changes were detected when running ty on typing conformance tests</summary>' >> comment.txt
+            echo '' >> comment.txt
+            echo '```diff' >> comment.txt
+            cat pr/typing_conformance_diagnostics_diff/typing_conformance_diagnostics.diff >> comment.txt
+            echo '```' >> comment.txt
+            echo '</details>' >> comment.txt
+          else
+            echo 'No changes detected when running ty on typing conformance tests ✅' >> comment.txt
+          fi
+
+          echo 'comment<<EOF' >> "$GITHUB_OUTPUT"
+          cat comment.txt >> "$GITHUB_OUTPUT"
+          echo 'EOF' >> "$GITHUB_OUTPUT"
+
+      - name: Find existing comment
+        uses: peter-evans/find-comment@3eae4d37986fb5a8592848f6a574fdf654e61f9e # v3.1.0
+        if: steps.generate-comment.outcome == 'success'
+        id: find-comment
+        with:
+          issue-number: ${{ steps.pr-number.outputs.pr-number }}
+          comment-author: "github-actions[bot]"
+          body-includes: "<!-- generated-comment typing_conformance_diagnostics_diff -->"
+
+      - name: Create or update comment
+        if: steps.find-comment.outcome == 'success'
+        uses: peter-evans/create-or-update-comment@71345be0265236311c031f5c7866368bd1eff043 # v4
+        with:
+          comment-id: ${{ steps.find-comment.outputs.comment-id }}
+          issue-number: ${{ steps.pr-number.outputs.pr-number }}
+          body-path: comment.txt
+          edit-mode: replace

.pre-commit-config.yaml

@@ -81,10 +81,10 @@ repos:
         pass_filenames: false # This makes it a lot faster
 
   - repo: https://github.com/astral-sh/ruff-pre-commit
-    rev: v0.12.3
+    rev: v0.12.5
     hooks:
       - id: ruff-format
-      - id: ruff
+      - id: ruff-check
         args: [--fix, --exit-non-zero-on-fix]
         types_or: [python, pyi]
         require_serial: true

CHANGELOG.md

@@ -1,5 +1,23 @@
 # Changelog
 
+## 0.12.5
+
+### Preview features
+
+- \[`flake8-use-pathlib`\] Add autofix for `PTH101`, `PTH104`, `PTH105`, `PTH121` ([#19404](https://github.com/astral-sh/ruff/pull/19404))
+- \[`ruff`\] Support byte strings (`RUF055`) ([#18926](https://github.com/astral-sh/ruff/pull/18926))
+
+### Bug fixes
+
+- Fix `unreachable` panic in parser ([#19183](https://github.com/astral-sh/ruff/pull/19183))
+- \[`flake8-pyi`\] Skip fix if all `Union` members are `None` (`PYI016`) ([#19416](https://github.com/astral-sh/ruff/pull/19416))
+- \[`perflint`\] Parenthesize generator expressions (`PERF401`) ([#19325](https://github.com/astral-sh/ruff/pull/19325))
+- \[`pylint`\] Handle empty comments after line continuation (`PLR2044`) ([#19405](https://github.com/astral-sh/ruff/pull/19405))
+
+### Rule changes
+
+- \[`pep8-naming`\] Fix `N802` false positives for `CGIHTTPRequestHandler` and `SimpleHTTPRequestHandler` ([#19432](https://github.com/astral-sh/ruff/pull/19432))
+
 ## 0.12.4
 
 ### Preview features

Cargo.lock

@@ -261,6 +261,18 @@ version = "2.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1b8e56985ec62d17e9c1001dc89c88ecd7dc08e47eba5ec7c29c7b5eeecde967"
 
+[[package]]
+name = "bitvec"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1bc2832c24239b0141d5674bb9174f9d68a8b5b3f2753311927c172ca46f7e9c"
+dependencies = [
+ "funty",
+ "radium",
+ "tap",
+ "wyz",
+]
+
 [[package]]
 name = "block-buffer"
 version = "0.10.4"
@@ -518,7 +530,7 @@ dependencies = [
  "ciborium",
  "clap",
  "codspeed",
- "criterion-plot",
+ "criterion-plot 0.5.0",
  "is-terminal",
  "itertools 0.10.5",
  "num-traits",
@@ -701,15 +713,15 @@ dependencies = [
 
 [[package]]
 name = "criterion"
-version = "0.6.0"
+version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3bf7af66b0989381bd0be551bd7cc91912a655a58c6918420c9527b1fd8b4679"
+checksum = "e1c047a62b0cc3e145fa84415a3191f628e980b194c2755aa12300a4e6cbd928"
 dependencies = [
  "anes",
  "cast",
  "ciborium",
  "clap",
- "criterion-plot",
+ "criterion-plot 0.6.0",
  "itertools 0.13.0",
  "num-traits",
  "oorandom",
@@ -730,6 +742,16 @@ dependencies = [
  "itertools 0.10.5",
 ]
 
+[[package]]
+name = "criterion-plot"
+version = "0.6.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b1bcc0dc7dfae599d84ad0b1a55f80cde8af3725da8313b528da95ef783e338"
+dependencies = [
+ "cast",
+ "itertools 0.13.0",
+]
+
 [[package]]
 name = "crossbeam"
 version = "0.8.4"
@@ -1121,6 +1143,12 @@ dependencies = [
  "libc",
 ]
 
+[[package]]
+name = "funty"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e6d5a32815ae3f33302d95fdcb2ce17862f8c65363dcfd29360480ba1001fc9c"
+
 [[package]]
 name = "generic-array"
 version = "0.14.7"
@@ -1133,9 +1161,9 @@ dependencies = [
 
 [[package]]
 name = "get-size-derive2"
-version = "0.5.2"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "028f3cfad7c3e3b1d8d04ef0a1c03576f2d62800803fe1301a4cd262849f2dea"
+checksum = "ca171f9f8ed2f416ac044de2dc4acde3e356662a14ac990345639653bdc7fc28"
 dependencies = [
  "attribute-derive",
  "quote",
@@ -1144,9 +1172,9 @@ dependencies = [
 
 [[package]]
 name = "get-size2"
-version = "0.5.2"
+version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "3a09c2043819a3def7bfbb4927e7df96aab0da4cfd8824484b22d0c94e84458e"
+checksum = "965bc5c1c5fe05c5bbd398bb9b3f0f14d750261ebdd1af959f2c8a603fedb5ad"
 dependencies = [
  "compact_str",
  "get-size-derive2",
@@ -1557,6 +1585,15 @@ dependencies = [
  "memoffset",
 ]
 
+[[package]]
+name = "inventory"
+version = "0.3.20"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ab08d7cd2c5897f2c949e5383ea7c7db03fb19130ffcfbf7eda795137ae3cb83"
+dependencies = [
+ "rustversion",
+]
+
 [[package]]
 name = "is-docker"
 version = "0.2.0"
@@ -2123,16 +2160,6 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "b15813163c1d831bf4a13c3610c05c0d03b39feb07f7e09fa234dac9b15aaf39"
 
-[[package]]
-name = "papaya"
-version = "0.2.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f92dd0b07c53a0a0c764db2ace8c541dc47320dad97c2200c2a637ab9dd2328f"
-dependencies = [
- "equivalent",
- "seize",
-]
-
 [[package]]
 name = "parking_lot"
 version = "0.12.3"
@@ -2549,6 +2576,12 @@ version = "5.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74765f6d916ee2faa39bc8e68e4f3ed8949b48cccdac59983d287a7cb71ce9c5"
 
+[[package]]
+name = "radium"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "dc33ff2d4973d518d823d61aa239014831e521c75da58e3df4840d3f47749d09"
+
 [[package]]
 name = "rand"
 version = "0.8.5"
@@ -2562,9 +2595,9 @@ dependencies = [
 
 [[package]]
 name = "rand"
-version = "0.9.1"
+version = "0.9.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "9fbfd9d094a40bf3ae768db9361049ace4c0e04a4fd6b359518bd7b73a73dd97"
+checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
 dependencies = [
  "rand_chacha 0.9.0",
  "rand_core 0.9.3",
@@ -2711,7 +2744,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.5"
 dependencies = [
  "anyhow",
  "argfile",
@@ -2828,7 +2861,6 @@ dependencies = [
  "anstyle",
  "arc-swap",
  "camino",
- "countme",
  "dashmap",
  "dunce",
  "etcetera",
@@ -2839,6 +2871,7 @@ dependencies = [
  "insta",
  "matchit",
  "path-slash",
+ "quick-junit",
  "ruff_annotate_snippets",
  "ruff_cache",
  "ruff_diagnostics",
@@ -2858,6 +2891,7 @@ dependencies = [
  "tracing",
  "tracing-subscriber",
  "ty_static",
+ "unicode-width 0.2.1",
  "web-time",
  "zip",
 ]
@@ -2937,6 +2971,7 @@ version = "0.1.0"
 dependencies = [
  "anyhow",
  "clap",
+ "memchr",
  "ruff_cache",
  "ruff_db",
  "ruff_linter",
@@ -2962,7 +2997,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_linter"
-version = "0.12.4"
+version = "0.12.5"
 dependencies = [
  "aho-corasick",
  "anyhow",
@@ -2987,7 +3022,6 @@ dependencies = [
  "pathdiff",
  "pep440_rs",
  "pyproject-toml",
- "quick-junit",
  "regex",
  "ruff_annotate_snippets",
  "ruff_cache",
@@ -3042,7 +3076,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "itertools 0.14.0",
- "rand 0.9.1",
+ "rand 0.9.2",
  "ruff_diagnostics",
  "ruff_source_file",
  "ruff_text_size",
@@ -3295,7 +3329,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_wasm"
-version = "0.12.4"
+version = "0.12.5"
 dependencies = [
  "console_error_panic_hook",
  "console_log",
@@ -3409,7 +3443,7 @@ checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
 [[package]]
 name = "salsa"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa?rev=fc00eba89e5dcaa5edba51c41aa5f309b5cb126b#fc00eba89e5dcaa5edba51c41aa5f309b5cb126b"
+source = "git+https://github.com/salsa-rs/salsa?rev=dba66f1a37acca014c2402f231ed5b361bd7d8fe#dba66f1a37acca014c2402f231ed5b361bd7d8fe"
 dependencies = [
  "boxcar",
  "compact_str",
@@ -3419,7 +3453,7 @@ dependencies = [
  "hashlink",
  "indexmap",
  "intrusive-collections",
- "papaya",
+ "inventory",
  "parking_lot",
  "portable-atomic",
  "rayon",
@@ -3434,12 +3468,12 @@ dependencies = [
 [[package]]
 name = "salsa-macro-rules"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa?rev=fc00eba89e5dcaa5edba51c41aa5f309b5cb126b#fc00eba89e5dcaa5edba51c41aa5f309b5cb126b"
+source = "git+https://github.com/salsa-rs/salsa?rev=dba66f1a37acca014c2402f231ed5b361bd7d8fe#dba66f1a37acca014c2402f231ed5b361bd7d8fe"
 
 [[package]]
 name = "salsa-macros"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa?rev=fc00eba89e5dcaa5edba51c41aa5f309b5cb126b#fc00eba89e5dcaa5edba51c41aa5f309b5cb126b"
+source = "git+https://github.com/salsa-rs/salsa?rev=dba66f1a37acca014c2402f231ed5b361bd7d8fe#dba66f1a37acca014c2402f231ed5b361bd7d8fe"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3492,16 +3526,6 @@ version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1c107b6f4780854c8b126e228ea8869f4d7b71260f962fefb57b996b8959ba6b"
 
-[[package]]
-name = "seize"
-version = "0.5.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e4b8d813387d566f627f3ea1b914c068aac94c40ae27ec43f5f33bde65abefe7"
-dependencies = [
- "libc",
- "windows-sys 0.52.0",
-]
-
 [[package]]
 name = "serde"
 version = "1.0.219"
@@ -3546,9 +3570,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.140"
+version = "1.0.141"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "20068b6e96dc6c9bd23e01df8827e6c7e1f2fddd43c21810382803c136b99373"
+checksum = "30b9eff21ebe718216c6ec64e1d9ac57087aad11efc64e32002bce4a0d4c03d3"
 dependencies = [
  "itoa",
  "memchr",
@@ -3738,23 +3762,22 @@ checksum = "7da8b5736845d9f2fcb837ea5d9e2628564b3b043a70948a3f0b778838c5fb4f"
 
 [[package]]
 name = "strum"
-version = "0.27.1"
+version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f64def088c51c9510a8579e3c5d67c65349dcf755e5479ad3d010aa6454e2c32"
+checksum = "af23d6f6c1a224baef9d3f61e287d2761385a5b88fdab4eb4c6f11aeb54c4bcf"
 dependencies = [
  "strum_macros",
 ]
 
 [[package]]
 name = "strum_macros"
-version = "0.27.1"
+version = "0.27.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "c77a8c5abcaf0f9ce05d62342b7d298c346515365c36b673df4ebe3ced01fde8"
+checksum = "7695ce3845ea4b33927c055a39dc438a45b059f7c1b3d91d38d10355fb8cbca7"
 dependencies = [
  "heck",
  "proc-macro2",
  "quote",
- "rustversion",
  "syn",
 ]
 
@@ -3780,6 +3803,12 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "tap"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "55937e1799185b12863d447f42597ed69d9928686b8d88a1df17376a097d8369"
+
 [[package]]
 name = "tempfile"
 version = "3.20.0"
@@ -4194,6 +4223,7 @@ version = "0.0.0"
 dependencies = [
  "bitflags 2.9.1",
  "insta",
+ "itertools 0.14.0",
  "regex",
  "ruff_db",
  "ruff_python_ast",
@@ -4202,11 +4232,10 @@ dependencies = [
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
- "salsa",
  "smallvec",
  "tracing",
+ "ty_project",
  "ty_python_semantic",
- "ty_vendored",
 ]
 
 [[package]]
@@ -4240,7 +4269,6 @@ dependencies = [
  "thiserror 2.0.12",
  "toml 0.9.2",
  "tracing",
- "ty_ide",
  "ty_python_semantic",
  "ty_vendored",
 ]
@@ -4251,6 +4279,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "bitflags 2.9.1",
+ "bitvec",
  "camino",
  "colored 3.0.0",
  "compact_str",
@@ -4302,10 +4331,13 @@ dependencies = [
  "anyhow",
  "bitflags 2.9.1",
  "crossbeam",
+ "dunce",
+ "insta",
  "jod-thread",
  "libc",
  "lsp-server",
  "lsp-types",
+ "regex",
  "ruff_db",
  "ruff_notebook",
  "ruff_python_ast",
@@ -4316,6 +4348,7 @@ dependencies = [
  "serde",
  "serde_json",
  "shellexpand",
+ "tempfile",
  "thiserror 2.0.12",
  "tracing",
  "tracing-subscriber",
@@ -4575,7 +4608,7 @@ checksum = "3cf4199d1e5d15ddd86a694e4d0dffa9c323ce759fea589f00fef9d81cc1931d"
 dependencies = [
  "getrandom 0.3.3",
  "js-sys",
- "rand 0.9.1",
+ "rand 0.9.2",
  "uuid-macro-internal",
  "wasm-bindgen",
 ]
@@ -5104,6 +5137,15 @@ version = "0.6.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ea2f10b9bb0928dfb1b42b65e1f9e36f7f54dbdf08457afefb38afcdec4fa2bb"
 
+[[package]]
+name = "wyz"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "05f360fc0b24296329c78fda852a1e9ae82de9cf7b27dae4b7f62f118f77b9ed"
+dependencies = [
+ "tap",
+]
+
 [[package]]
 name = "yansi"
 version = "1.0.1"

Cargo.toml

@@ -57,6 +57,9 @@ assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
 bincode = { version = "2.0.0" }
 bitflags = { version = "2.5.0" }
+bitvec = { version = "1.0.1", default-features = false, features = [
+    "alloc",
+] }
 bstr = { version = "1.9.1" }
 cachedir = { version = "0.3.1" }
 camino = { version = "1.1.7" }
@@ -70,7 +73,7 @@ console_error_panic_hook = { version = "0.1.7" }
 console_log = { version = "1.0.0" }
 countme = { version = "3.0.1" }
 compact_str = "0.9.0"
-criterion = { version = "0.6.0", default-features = false }
+criterion = { version = "0.7.0", default-features = false }
 crossbeam = { version = "0.8.4" }
 dashmap = { version = "6.0.1" }
 dir-test = { version = "0.4.0" }
@@ -80,7 +83,7 @@ etcetera = { version = "0.10.0" }
 fern = { version = "0.7.0" }
 filetime = { version = "0.2.23" }
 getrandom = { version = "0.3.1" }
-get-size2 = { version = "0.5.0", features = [
+get-size2 = { version = "0.6.0", features = [
     "derive",
     "smallvec",
     "hashbrown",
@@ -138,7 +141,7 @@ regex-automata = { version = "0.4.9" }
 rustc-hash = { version = "2.0.0" }
 rustc-stable-hash = { version = "0.1.2" }
 # When updating salsa, make sure to also update the revision in `fuzz/Cargo.toml`
-salsa = { git = "https://github.com/salsa-rs/salsa", rev = "fc00eba89e5dcaa5edba51c41aa5f309b5cb126b" }
+salsa = { git = "https://github.com/salsa-rs/salsa", rev = "dba66f1a37acca014c2402f231ed5b361bd7d8fe" }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
 serde = { version = "1.0.197", features = ["derive"] }
@@ -150,7 +153,7 @@ serde_with = { version = "3.6.0", default-features = false, features = [
 ] }
 shellexpand = { version = "3.0.0" }
 similar = { version = "2.4.0", features = ["inline"] }
-smallvec = { version = "1.13.2" }
+smallvec = { version = "1.13.2", features = ["union", "const_generics", "const_new"] }
 snapbox = { version = "0.6.0", features = [
     "diff",
     "term-svg",

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/0.12.4/install.sh | sh
-powershell -c "irm https://astral.sh/ruff/0.12.4/install.ps1 | iex"
+curl -LsSf https://astral.sh/ruff/0.12.5/install.sh | sh
+powershell -c "irm https://astral.sh/ruff/0.12.5/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: v0.12.4
+  rev: v0.12.5
   hooks:
     # Run the linter.
     - id: ruff-check

crates/ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff"
-version = "0.12.4"
+version = "0.12.5"
 publish = true
 authors = { workspace = true }
 edition = { workspace = true }

crates/ruff/src/args.rs

@@ -169,6 +169,9 @@ pub struct AnalyzeGraphCommand {
     /// Attempt to detect imports from string literals.
     #[clap(long)]
     detect_string_imports: bool,
+    /// The minimum number of dots in a string import to consider it a valid import.
+    #[clap(long)]
+    min_dots: Option<usize>,
     /// Enable preview mode. Use `--no-preview` to disable.
     #[arg(long, overrides_with("no_preview"))]
     preview: bool,
@@ -808,6 +811,7 @@ impl AnalyzeGraphCommand {
             } else {
                 None
             },
+            string_imports_min_dots: self.min_dots,
             preview: resolve_bool_arg(self.preview, self.no_preview).map(PreviewMode::from),
             target_version: self.target_version.map(ast::PythonVersion::from),
             ..ExplicitConfigOverrides::default()
@@ -1305,6 +1309,7 @@ struct ExplicitConfigOverrides {
     show_fixes: Option<bool>,
     extension: Option<Vec<ExtensionPair>>,
     detect_string_imports: Option<bool>,
+    string_imports_min_dots: Option<usize>,
 }
 
 impl ConfigurationTransformer for ExplicitConfigOverrides {
@@ -1392,6 +1397,9 @@ impl ConfigurationTransformer for ExplicitConfigOverrides {
         if let Some(detect_string_imports) = &self.detect_string_imports {
             config.analyze.detect_string_imports = Some(*detect_string_imports);
         }
+        if let Some(string_imports_min_dots) = &self.string_imports_min_dots {
+            config.analyze.string_imports_min_dots = Some(*string_imports_min_dots);
+        }
 
         config
     }

crates/ruff/src/cache.rs

@@ -454,7 +454,7 @@ impl LintCacheData {
                 CacheMessage {
                     rule,
                     body: msg.body().to_string(),
-                    suggestion: msg.suggestion().map(ToString::to_string),
+                    suggestion: msg.first_help_text().map(ToString::to_string),
                     range: msg.expect_range(),
                     parent: msg.parent(),
                     fix: msg.fix().cloned(),

crates/ruff/src/commands/analyze_graph.rs

@@ -102,7 +102,7 @@ pub(crate) fn analyze_graph(
 
                 // Resolve the per-file settings.
                 let settings = resolver.resolve(path);
-                let string_imports = settings.analyze.detect_string_imports;
+                let string_imports = settings.analyze.string_imports;
                 let include_dependencies = settings.analyze.include_dependencies.get(path).cloned();
 
                 // Skip excluded files.

crates/ruff/src/commands/check.rs

@@ -279,6 +279,7 @@ mod test {
 
         TextEmitter::default()
             .with_show_fix_status(true)
+            .with_color(false)
             .emit(
                 &mut output,
                 &diagnostics.inner,

crates/ruff/src/printer.rs

@@ -15,8 +15,8 @@ use ruff_db::diagnostic::{
 use ruff_linter::fs::relativize_path;
 use ruff_linter::logging::LogLevel;
 use ruff_linter::message::{
-    Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter, JunitEmitter,
-    SarifEmitter, TextEmitter,
+    Emitter, EmitterContext, GithubEmitter, GitlabEmitter, GroupedEmitter, SarifEmitter,
+    TextEmitter,
 };
 use ruff_linter::notify_user;
 use ruff_linter::settings::flags::{self};
@@ -252,7 +252,11 @@ impl Printer {
                 write!(writer, "{value}")?;
             }
             OutputFormat::Junit => {
-                JunitEmitter.emit(writer, &diagnostics.inner, &context)?;
+                let config = DisplayDiagnosticConfig::default()
+                    .format(DiagnosticFormat::Junit)
+                    .preview(preview);
+                let value = DisplayDiagnostics::new(&context, &config, &diagnostics.inner);
+                write!(writer, "{value}")?;
             }
             OutputFormat::Concise | OutputFormat::Full => {
                 TextEmitter::default()
@@ -260,6 +264,7 @@ impl Printer {
                     .with_show_fix_diff(self.flags.intersects(Flags::SHOW_FIX_DIFF))
                     .with_show_source(self.format == OutputFormat::Full)
                     .with_unsafe_fixes(self.unsafe_fixes)
+                    .with_preview(preview)
                     .emit(writer, &diagnostics.inner, &context)?;
 
                 if self.flags.intersects(Flags::SHOW_FIX_SUMMARY) {

crates/ruff/tests/analyze_graph.rs

@@ -57,33 +57,40 @@ fn dependencies() -> Result<()> {
         .write_str(indoc::indoc! {r#"
         def f(): pass
     "#})?;
+    root.child("ruff")
+        .child("e.pyi")
+        .write_str(indoc::indoc! {r#"
+        def f() -> None: ...
+    "#})?;
 
     insta::with_settings!({
         filters => INSTA_FILTERS.to_vec(),
     }, {
-        assert_cmd_snapshot!(command().current_dir(&root), @r###"
-            success: true
-            exit_code: 0
-            ----- stdout -----
-            {
-              "ruff/__init__.py": [],
-              "ruff/a.py": [
-                "ruff/b.py"
-              ],
-              "ruff/b.py": [
-                "ruff/c.py"
-              ],
-              "ruff/c.py": [
-                "ruff/d.py"
-              ],
-              "ruff/d.py": [
-                "ruff/e.py"
-              ],
-              "ruff/e.py": []
-            }
+        assert_cmd_snapshot!(command().current_dir(&root), @r#"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [
+            "ruff/c.py"
+          ],
+          "ruff/c.py": [
+            "ruff/d.py"
+          ],
+          "ruff/d.py": [
+            "ruff/e.py",
+            "ruff/e.pyi"
+          ],
+          "ruff/e.py": [],
+          "ruff/e.pyi": []
+        }
 
-            ----- stderr -----
-            "###);
+        ----- stderr -----
+        "#);
     });
 
     Ok(())
@@ -197,23 +204,43 @@ fn string_detection() -> Result<()> {
     insta::with_settings!({
         filters => INSTA_FILTERS.to_vec(),
     }, {
-        assert_cmd_snapshot!(command().arg("--detect-string-imports").current_dir(&root), @r###"
-            success: true
-            exit_code: 0
-            ----- stdout -----
-            {
-              "ruff/__init__.py": [],
-              "ruff/a.py": [
-                "ruff/b.py"
-              ],
-              "ruff/b.py": [
-                "ruff/c.py"
-              ],
-              "ruff/c.py": []
-            }
+        assert_cmd_snapshot!(command().arg("--detect-string-imports").current_dir(&root), @r#"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [],
+          "ruff/c.py": []
+        }
 
-            ----- stderr -----
-            "###);
+        ----- stderr -----
+        "#);
+    });
+
+    insta::with_settings!({
+        filters => INSTA_FILTERS.to_vec(),
+    }, {
+        assert_cmd_snapshot!(command().arg("--detect-string-imports").arg("--min-dots").arg("1").current_dir(&root), @r#"
+        success: true
+        exit_code: 0
+        ----- stdout -----
+        {
+          "ruff/__init__.py": [],
+          "ruff/a.py": [
+            "ruff/b.py"
+          ],
+          "ruff/b.py": [
+            "ruff/c.py"
+          ],
+          "ruff/c.py": []
+        }
+
+        ----- stderr -----
+        "#);
     });
 
     Ok(())

crates/ruff/tests/lint.rs

@@ -2422,7 +2422,7 @@ requires-python = ">= 3.11"
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.11
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -2734,7 +2734,7 @@ requires-python = ">= 3.11"
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.10
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -3098,7 +3098,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.11
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -3478,7 +3478,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.11
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -3806,7 +3806,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.10
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -4134,7 +4134,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.9
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -4419,7 +4419,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.9
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 
@@ -4757,7 +4757,7 @@ from typing import Union;foo: Union[int, str] = 1
         analyze.exclude = []
         analyze.preview = disabled
         analyze.target_version = 3.10
-        analyze.detect_string_imports = false
+        analyze.string_imports = disabled
         analyze.extension = ExtensionMapping({})
         analyze.include_dependencies = {}
 

crates/ruff/tests/snapshots/lint__output_format_junit.snap

@@ -25,7 +25,7 @@ exit_code: 1
         <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">
+        <testcase name="org.ruff.invalid-syntax" classname="[TMP]/input" line="3" column="1">
             <failure message="SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)">line 3, col 1, SyntaxError: Cannot use `match` statement on Python 3.9 (syntax was added in Python 3.10)</failure>
         </testcase>
     </testsuite>

crates/ruff/tests/snapshots/show_settings__display_default_settings.snap

@@ -392,7 +392,7 @@ formatter.docstring_code_line_width = dynamic
 analyze.exclude = []
 analyze.preview = disabled
 analyze.target_version = 3.7
-analyze.detect_string_imports = false
+analyze.string_imports = disabled
 analyze.extension = ExtensionMapping({})
 analyze.include_dependencies = {}
 

crates/ruff_benchmark/benches/ty.rs

@@ -18,7 +18,7 @@ use ruff_python_ast::PythonVersion;
 use ty_project::metadata::options::{EnvironmentOptions, Options};
 use ty_project::metadata::value::{RangedValue, RelativePathBuf};
 use ty_project::watch::{ChangeEvent, ChangedKind};
-use ty_project::{Db, ProjectDatabase, ProjectMetadata};
+use ty_project::{CheckMode, Db, ProjectDatabase, ProjectMetadata};
 
 struct Case {
     db: ProjectDatabase,
@@ -102,6 +102,7 @@ fn setup_tomllib_case() -> Case {
 
     let re = re.unwrap();
 
+    db.set_check_mode(CheckMode::OpenFiles);
     db.project().set_open_files(&mut db, tomllib_files);
 
     let re_path = re.path(&db).as_system_path().unwrap().to_owned();
@@ -237,6 +238,7 @@ fn setup_micro_case(code: &str) -> Case {
     let mut db = ProjectDatabase::new(metadata, system).unwrap();
     let file = system_path_to_file(&db, SystemPathBuf::from(file_path)).unwrap();
 
+    db.set_check_mode(CheckMode::OpenFiles);
     db.project()
         .set_open_files(&mut db, FxHashSet::from_iter([file]));
 
@@ -525,14 +527,21 @@ impl<'a> ProjectBenchmark<'a> {
 
 #[track_caller]
 fn bench_project(benchmark: &ProjectBenchmark, criterion: &mut Criterion) {
-    fn check_project(db: &mut ProjectDatabase, max_diagnostics: usize) {
+    fn check_project(db: &mut ProjectDatabase, project_name: &str, max_diagnostics: usize) {
         let result = db.check();
         let diagnostics = result.len();
 
-        assert!(
-            diagnostics <= max_diagnostics,
-            "Expected <={max_diagnostics} diagnostics but got {diagnostics}"
-        );
+        if diagnostics > max_diagnostics {
+            let details = result
+                .into_iter()
+                .map(|diagnostic| diagnostic.concise_message().to_string())
+                .collect::<Vec<_>>()
+                .join("\n  ");
+            assert!(
+                diagnostics <= max_diagnostics,
+                "{project_name}: Expected <={max_diagnostics} diagnostics but got {diagnostics}:\n  {details}",
+            );
+        }
     }
 
     setup_rayon();
@@ -542,7 +551,7 @@ fn bench_project(benchmark: &ProjectBenchmark, criterion: &mut Criterion) {
     group.bench_function(benchmark.project.config.name, |b| {
         b.iter_batched_ref(
             || benchmark.setup_iteration(),
-            |db| check_project(db, benchmark.max_diagnostics),
+            |db| check_project(db, benchmark.project.config.name, benchmark.max_diagnostics),
             BatchSize::SmallInput,
         );
     });
@@ -610,7 +619,7 @@ fn datetype(criterion: &mut Criterion) {
             max_dep_date: "2025-07-04",
             python_version: PythonVersion::PY313,
         },
-        0,
+        2,
     );
 
     bench_project(&benchmark, criterion);

crates/ruff_db/Cargo.toml

@@ -25,7 +25,6 @@ ty_static = { workspace = true }
 anstyle = { workspace = true }
 arc-swap = { workspace = true }
 camino = { workspace = true }
-countme = { workspace = true }
 dashmap = { workspace = true }
 dunce = { workspace = true }
 filetime = { workspace = true }
@@ -34,6 +33,7 @@ glob = { workspace = true }
 ignore = { workspace = true, optional = true }
 matchit = { workspace = true }
 path-slash = { workspace = true }
+quick-junit = { workspace = true, optional = true }
 rustc-hash = { workspace = true }
 salsa = { workspace = true }
 schemars = { workspace = true, optional = true }
@@ -42,6 +42,7 @@ serde_json = { workspace = true, optional = true }
 thiserror = { workspace = true }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true, optional = true }
+unicode-width = { workspace = true }
 zip = { workspace = true }
 
 [target.'cfg(target_arch="wasm32")'.dependencies]
@@ -56,7 +57,13 @@ tempfile = { workspace = true }
 
 [features]
 cache = ["ruff_cache"]
+junit = ["dep:quick-junit"]
 os = ["ignore", "dep:etcetera"]
-serde = ["camino/serde1", "dep:serde", "dep:serde_json", "ruff_diagnostics/serde"]
+serde = [
+    "camino/serde1",
+    "dep:serde",
+    "dep:serde_json",
+    "ruff_diagnostics/serde",
+]
 # Exposes testing utilities.
 testing = ["tracing-subscriber"]

crates/ruff_db/src/diagnostic/mod.rs

@@ -1,12 +1,14 @@
 use std::{fmt::Formatter, path::Path, sync::Arc};
 
-use ruff_diagnostics::Fix;
+use ruff_diagnostics::{Applicability, 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, DisplayDiagnostics, FileResolver, Input};
+pub use self::render::{
+    DisplayDiagnostic, DisplayDiagnostics, FileResolver, Input, ceil_char_boundary,
+};
 use crate::{Db, files::File};
 
 mod render;
@@ -122,7 +124,14 @@ impl Diagnostic {
     /// directly. If callers want or need to avoid cloning the diagnostic
     /// message, then they can also pass a `DiagnosticMessage` directly.
     pub fn info<'a>(&mut self, message: impl IntoDiagnosticMessage + 'a) {
-        self.sub(SubDiagnostic::new(Severity::Info, message));
+        self.sub(SubDiagnostic::new(SubDiagnosticSeverity::Info, message));
+    }
+
+    /// Adds a "help" sub-diagnostic with the given message.
+    ///
+    /// See the closely related [`Diagnostic::info`] method for more details.
+    pub fn help<'a>(&mut self, message: impl IntoDiagnosticMessage + 'a) {
+        self.sub(SubDiagnostic::new(SubDiagnosticSeverity::Help, message));
     }
 
     /// Adds a "sub" diagnostic to this diagnostic.
@@ -377,9 +386,15 @@ impl Diagnostic {
         self.primary_message()
     }
 
-    /// Returns the fix suggestion for the violation.
-    pub fn suggestion(&self) -> Option<&str> {
-        self.primary_annotation()?.get_message()
+    /// Returns the message of the first sub-diagnostic with a `Help` severity.
+    ///
+    /// Note that this is used as the fix title/suggestion for some of Ruff's output formats, but in
+    /// general this is not the guaranteed meaning of such a message.
+    pub fn first_help_text(&self) -> Option<&str> {
+        self.sub_diagnostics()
+            .iter()
+            .find(|sub| matches!(sub.inner.severity, SubDiagnosticSeverity::Help))
+            .map(|sub| sub.inner.message.as_str())
     }
 
     /// Returns the URL for the rule documentation, if it exists.
@@ -565,7 +580,10 @@ impl SubDiagnostic {
     /// Callers can pass anything that implements `std::fmt::Display`
     /// directly. If callers want or need to avoid cloning the diagnostic
     /// message, then they can also pass a `DiagnosticMessage` directly.
-    pub fn new<'a>(severity: Severity, message: impl IntoDiagnosticMessage + 'a) -> SubDiagnostic {
+    pub fn new<'a>(
+        severity: SubDiagnosticSeverity,
+        message: impl IntoDiagnosticMessage + 'a,
+    ) -> SubDiagnostic {
         let inner = Box::new(SubDiagnosticInner {
             severity,
             message: message.into_diagnostic_message(),
@@ -643,7 +661,7 @@ impl SubDiagnostic {
 
 #[derive(Debug, Clone, Eq, PartialEq, get_size2::GetSize)]
 struct SubDiagnosticInner {
-    severity: Severity,
+    severity: SubDiagnosticSeverity,
     message: DiagnosticMessage,
     annotations: Vec<Annotation>,
 }
@@ -1170,6 +1188,32 @@ impl Severity {
     }
 }
 
+/// Like [`Severity`] but exclusively for sub-diagnostics.
+///
+/// This type only exists to add an additional `Help` severity that isn't present in `Severity` or
+/// used for main diagnostics. If we want to add `Severity::Help` in the future, this type could be
+/// deleted and the two combined again.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, get_size2::GetSize)]
+pub enum SubDiagnosticSeverity {
+    Help,
+    Info,
+    Warning,
+    Error,
+    Fatal,
+}
+
+impl SubDiagnosticSeverity {
+    fn to_annotate(self) -> AnnotateLevel {
+        match self {
+            SubDiagnosticSeverity::Help => AnnotateLevel::Help,
+            SubDiagnosticSeverity::Info => AnnotateLevel::Info,
+            SubDiagnosticSeverity::Warning => AnnotateLevel::Warning,
+            SubDiagnosticSeverity::Error => AnnotateLevel::Error,
+            SubDiagnosticSeverity::Fatal => AnnotateLevel::Error,
+        }
+    }
+}
+
 /// Configuration for rendering diagnostics.
 #[derive(Clone, Debug)]
 pub struct DisplayDiagnosticConfig {
@@ -1196,6 +1240,15 @@ pub struct DisplayDiagnosticConfig {
         reason = "This is currently only used for JSON but will be needed soon for other formats"
     )]
     preview: bool,
+    /// Whether to hide the real `Severity` of diagnostics.
+    ///
+    /// This is intended for temporary use by Ruff, which only has a single `error` severity at the
+    /// moment. We should be able to remove this option when Ruff gets more severities.
+    hide_severity: bool,
+    /// Whether to show the availability of a fix in a diagnostic.
+    show_fix_status: bool,
+    /// The lowest applicability that should be shown when reporting diagnostics.
+    fix_applicability: Applicability,
 }
 
 impl DisplayDiagnosticConfig {
@@ -1224,6 +1277,35 @@ impl DisplayDiagnosticConfig {
             ..self
         }
     }
+
+    /// Whether to hide a diagnostic's severity or not.
+    pub fn hide_severity(self, yes: bool) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            hide_severity: yes,
+            ..self
+        }
+    }
+
+    /// Whether to show a fix's availability or not.
+    pub fn show_fix_status(self, yes: bool) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            show_fix_status: yes,
+            ..self
+        }
+    }
+
+    /// Set the lowest fix applicability that should be shown.
+    ///
+    /// In other words, an applicability of `Safe` (the default) would suppress showing fixes or fix
+    /// availability for unsafe or display-only fixes.
+    ///
+    /// Note that this option is currently ignored when `hide_severity` is false.
+    pub fn fix_applicability(self, applicability: Applicability) -> DisplayDiagnosticConfig {
+        DisplayDiagnosticConfig {
+            fix_applicability: applicability,
+            ..self
+        }
+    }
 }
 
 impl Default for DisplayDiagnosticConfig {
@@ -1233,6 +1315,9 @@ impl Default for DisplayDiagnosticConfig {
             color: false,
             context: 2,
             preview: false,
+            hide_severity: false,
+            show_fix_status: false,
+            fix_applicability: Applicability::Safe,
         }
     }
 }
@@ -1282,6 +1367,9 @@ pub enum DiagnosticFormat {
     Rdjson,
     /// Print diagnostics in the format emitted by Pylint.
     Pylint,
+    /// Print diagnostics in the format expected by JUnit.
+    #[cfg(feature = "junit")]
+    Junit,
 }
 
 /// A representation of the kinds of messages inside a diagnostic.

crates/ruff_db/src/diagnostic/render.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::collections::BTreeMap;
 use std::path::Path;
 
@@ -7,9 +8,9 @@ use ruff_annotate_snippets::{
 };
 use ruff_notebook::{Notebook, NotebookIndex};
 use ruff_source_file::{LineIndex, OneIndexed, SourceCode};
-use ruff_text_size::{TextRange, TextSize};
+use ruff_text_size::{TextLen, TextRange, TextSize};
 
-use crate::diagnostic::stylesheet::{DiagnosticStylesheet, fmt_styled};
+use crate::diagnostic::stylesheet::DiagnosticStylesheet;
 use crate::{
     Db,
     files::File,
@@ -18,18 +19,23 @@ use crate::{
 };
 
 use super::{
-    Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig, Severity,
+    Annotation, Diagnostic, DiagnosticFormat, DiagnosticSource, DisplayDiagnosticConfig,
     SubDiagnostic, UnifiedFile,
 };
 
 use azure::AzureRenderer;
+use concise::ConciseRenderer;
 use pylint::PylintRenderer;
 
 mod azure;
+mod concise;
+mod full;
 #[cfg(feature = "serde")]
 mod json;
 #[cfg(feature = "serde")]
 mod json_lines;
+#[cfg(feature = "junit")]
+mod junit;
 mod pylint;
 #[cfg(feature = "serde")]
 mod rdjson;
@@ -102,48 +108,7 @@ 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,
-                        "{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())?;
-                }
+                ConciseRenderer::new(self.resolver, self.config).render(f, self.diagnostics)?;
             }
             DiagnosticFormat::Full => {
                 let stylesheet = if self.config.color {
@@ -156,7 +121,8 @@ impl std::fmt::Display for DisplayDiagnostics<'_> {
                     AnnotateRenderer::styled()
                 } else {
                     AnnotateRenderer::plain()
-                };
+                }
+                .cut_indicator("…");
 
                 renderer = renderer
                     .error(stylesheet.error)
@@ -196,6 +162,10 @@ impl std::fmt::Display for DisplayDiagnostics<'_> {
             DiagnosticFormat::Pylint => {
                 PylintRenderer::new(self.resolver).render(f, self.diagnostics)?;
             }
+            #[cfg(feature = "junit")]
+            DiagnosticFormat::Junit => {
+                junit::JunitRenderer::new(self.resolver).render(f, self.diagnostics)?;
+            }
         }
 
         Ok(())
@@ -249,7 +219,7 @@ impl<'a> Resolved<'a> {
 /// both.)
 #[derive(Debug)]
 struct ResolvedDiagnostic<'a> {
-    severity: Severity,
+    level: AnnotateLevel,
     id: Option<String>,
     message: String,
     annotations: Vec<ResolvedAnnotation<'a>>,
@@ -274,7 +244,7 @@ impl<'a> ResolvedDiagnostic<'a> {
         let id = Some(diag.inner.id.to_string());
         let message = diag.inner.message.as_str().to_string();
         ResolvedDiagnostic {
-            severity: diag.inner.severity,
+            level: diag.inner.severity.to_annotate(),
             id,
             message,
             annotations,
@@ -297,7 +267,7 @@ impl<'a> ResolvedDiagnostic<'a> {
             })
             .collect();
         ResolvedDiagnostic {
-            severity: diag.inner.severity,
+            level: diag.inner.severity.to_annotate(),
             id: None,
             message: diag.inner.message.as_str().to_string(),
             annotations,
@@ -364,7 +334,7 @@ impl<'a> ResolvedDiagnostic<'a> {
         snippets_by_input
             .sort_by(|snips1, snips2| snips1.has_primary.cmp(&snips2.has_primary).reverse());
         RenderableDiagnostic {
-            severity: self.severity,
+            level: self.level,
             id: self.id.as_deref(),
             message: &self.message,
             snippets_by_input,
@@ -452,7 +422,7 @@ struct Renderable<'r> {
 #[derive(Debug)]
 struct RenderableDiagnostic<'r> {
     /// The severity of the diagnostic.
-    severity: Severity,
+    level: AnnotateLevel,
     /// The ID of the diagnostic. The ID can usually be used on the CLI or in a
     /// config file to change the severity of a lint.
     ///
@@ -471,7 +441,6 @@ struct RenderableDiagnostic<'r> {
 impl RenderableDiagnostic<'_> {
     /// Convert this to an "annotate" snippet.
     fn to_annotate(&self) -> AnnotateMessage<'_> {
-        let level = self.severity.to_annotate();
         let snippets = self.snippets_by_input.iter().flat_map(|snippets| {
             let path = snippets.path;
             snippets
@@ -479,7 +448,7 @@ impl RenderableDiagnostic<'_> {
                 .iter()
                 .map(|snippet| snippet.to_annotate(path))
         });
-        let mut message = level.title(self.message);
+        let mut message = self.level.title(self.message);
         if let Some(id) = self.id {
             message = message.id(id);
         }
@@ -552,7 +521,7 @@ impl<'r> RenderableSnippets<'r> {
 #[derive(Debug)]
 struct RenderableSnippet<'r> {
     /// The actual snippet text.
-    snippet: &'r str,
+    snippet: Cow<'r, str>,
     /// The absolute line number corresponding to where this
     /// snippet begins.
     line_start: OneIndexed,
@@ -612,6 +581,13 @@ impl<'r> RenderableSnippet<'r> {
             .iter()
             .map(|ann| RenderableAnnotation::new(snippet_start, ann))
             .collect();
+
+        let EscapedSourceCode {
+            text: snippet,
+            annotations,
+        } = replace_whitespace_and_unprintable(snippet, annotations)
+            .fix_up_empty_spans_after_line_terminator();
+
         RenderableSnippet {
             snippet,
             line_start,
@@ -622,7 +598,7 @@ impl<'r> RenderableSnippet<'r> {
 
     /// Convert this to an "annotate" snippet.
     fn to_annotate<'a>(&'a self, path: &'a str) -> AnnotateSnippet<'a> {
-        AnnotateSnippet::source(self.snippet)
+        AnnotateSnippet::source(&self.snippet)
             .origin(path)
             .line_start(self.line_start.get())
             .annotations(
@@ -852,12 +828,239 @@ fn relativize_path<'p>(cwd: &SystemPath, path: &'p str) -> &'p str {
     path
 }
 
+/// Given some source code and annotation ranges, this routine replaces tabs
+/// with ASCII whitespace, and unprintable characters with printable
+/// representations of them.
+///
+/// The source code and annotations returned are updated to reflect changes made
+/// to the source code (if any).
+fn replace_whitespace_and_unprintable<'r>(
+    source: &'r str,
+    mut annotations: Vec<RenderableAnnotation<'r>>,
+) -> EscapedSourceCode<'r> {
+    // Updates the annotation ranges given by the caller whenever a single byte (at `index` in
+    // `source`) is replaced with `len` bytes.
+    //
+    // When the index occurs before the start of the range, the range is
+    // offset by `len`. When the range occurs after or at the start but before
+    // the end, then the end of the range only is offset by `len`.
+    let mut update_ranges = |index: usize, len: u32| {
+        for ann in &mut annotations {
+            if index < usize::from(ann.range.start()) {
+                ann.range += TextSize::new(len - 1);
+            } else if index < usize::from(ann.range.end()) {
+                ann.range = ann.range.add_end(TextSize::new(len - 1));
+            }
+        }
+    };
+
+    // If `c` is an unprintable character, then this returns a printable
+    // representation of it (using a fancier Unicode codepoint).
+    let unprintable_replacement = |c: char| -> Option<char> {
+        match c {
+            '\x07' => Some('␇'),
+            '\x08' => Some('␈'),
+            '\x1b' => Some('␛'),
+            '\x7f' => Some('␡'),
+            _ => None,
+        }
+    };
+
+    const TAB_SIZE: usize = 4;
+    let mut width = 0;
+    let mut column = 0;
+    let mut last_end = 0;
+    let mut result = String::new();
+    for (index, c) in source.char_indices() {
+        let old_width = width;
+        match c {
+            '\n' | '\r' => {
+                width = 0;
+                column = 0;
+            }
+            '\t' => {
+                let tab_offset = TAB_SIZE - (column % TAB_SIZE);
+                width += tab_offset;
+                column += tab_offset;
+
+                let tab_width =
+                    u32::try_from(width - old_width).expect("small width because of tab size");
+                result.push_str(&source[last_end..index]);
+
+                update_ranges(result.text_len().to_usize(), tab_width);
+
+                for _ in 0..tab_width {
+                    result.push(' ');
+                }
+                last_end = index + 1;
+            }
+            _ => {
+                width += unicode_width::UnicodeWidthChar::width(c).unwrap_or(0);
+                column += 1;
+
+                if let Some(printable) = unprintable_replacement(c) {
+                    result.push_str(&source[last_end..index]);
+
+                    let len = printable.text_len().to_u32();
+                    update_ranges(result.text_len().to_usize(), len);
+
+                    result.push(printable);
+                    last_end = index + 1;
+                }
+            }
+        }
+    }
+
+    // No tabs or unprintable chars
+    if result.is_empty() {
+        EscapedSourceCode {
+            annotations,
+            text: Cow::Borrowed(source),
+        }
+    } else {
+        result.push_str(&source[last_end..]);
+        EscapedSourceCode {
+            annotations,
+            text: Cow::Owned(result),
+        }
+    }
+}
+
+struct EscapedSourceCode<'r> {
+    text: Cow<'r, str>,
+    annotations: Vec<RenderableAnnotation<'r>>,
+}
+
+impl<'r> EscapedSourceCode<'r> {
+    // This attempts to "fix up" the spans on each annotation  in the case where
+    // it's an empty span immediately following a line terminator.
+    //
+    // At present, `annotate-snippets` (both upstream and our vendored copy)
+    // will render annotations of such spans to point to the space immediately
+    // following the previous line. But ideally, this should point to the space
+    // immediately preceding the next line.
+    //
+    // After attempting to fix `annotate-snippets` and giving up after a couple
+    // hours, this routine takes a different tact: it adjusts the span to be
+    // non-empty and it will cover the first codepoint of the following line.
+    // This forces `annotate-snippets` to point to the right place.
+    //
+    // See also: <https://github.com/astral-sh/ruff/issues/15509> and
+    // `ruff_linter::message::text::SourceCode::fix_up_empty_spans_after_line_terminator`,
+    // from which this was adapted.
+    fn fix_up_empty_spans_after_line_terminator(mut self) -> EscapedSourceCode<'r> {
+        for ann in &mut self.annotations {
+            let range = ann.range;
+            if !range.is_empty()
+                || range.start() == TextSize::from(0)
+                || range.start() >= self.text.text_len()
+            {
+                continue;
+            }
+            if !matches!(
+                self.text.as_bytes()[range.start().to_usize() - 1],
+                b'\n' | b'\r'
+            ) {
+                continue;
+            }
+            let start = range.start();
+            let end = ceil_char_boundary(&self.text, start + TextSize::from(1));
+            ann.range = TextRange::new(start, end);
+        }
+
+        self
+    }
+}
+
+/// Finds the closest [`TextSize`] not less than the offset given for which
+/// `is_char_boundary` is `true`. Unless the offset given is greater than
+/// the length of the underlying contents, in which case, the length of the
+/// contents is returned.
+///
+/// Can be replaced with `str::ceil_char_boundary` once it's stable.
+///
+/// # Examples
+///
+/// From `std`:
+///
+/// ```
+/// use ruff_db::diagnostic::ceil_char_boundary;
+/// use ruff_text_size::{Ranged, TextLen, TextSize};
+///
+/// let source = "❤️🧡💛💚💙💜";
+/// assert_eq!(source.text_len(), TextSize::from(26));
+/// assert!(!source.is_char_boundary(13));
+///
+/// let closest = ceil_char_boundary(source, TextSize::from(13));
+/// assert_eq!(closest, TextSize::from(14));
+/// assert_eq!(&source[..closest.to_usize()], "❤️🧡💛");
+/// ```
+///
+/// Additional examples:
+///
+/// ```
+/// use ruff_db::diagnostic::ceil_char_boundary;
+/// use ruff_text_size::{Ranged, TextRange, TextSize};
+///
+/// let source = "Hello";
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(0)),
+///     TextSize::from(0)
+/// );
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(5)),
+///     TextSize::from(5)
+/// );
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(6)),
+///     TextSize::from(5)
+/// );
+///
+/// let source = "α";
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(0)),
+///     TextSize::from(0)
+/// );
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(1)),
+///     TextSize::from(2)
+/// );
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(2)),
+///     TextSize::from(2)
+/// );
+///
+/// assert_eq!(
+///     ceil_char_boundary(source, TextSize::from(3)),
+///     TextSize::from(2)
+/// );
+/// ```
+pub fn ceil_char_boundary(text: &str, offset: TextSize) -> TextSize {
+    let upper_bound = offset
+        .to_u32()
+        .saturating_add(4)
+        .min(text.text_len().to_u32());
+    (offset.to_u32()..upper_bound)
+        .map(TextSize::from)
+        .find(|offset| text.is_char_boundary(offset.to_usize()))
+        .unwrap_or_else(|| TextSize::from(upper_bound))
+}
+
 #[cfg(test)]
 mod tests {
 
-    use ruff_diagnostics::{Edit, Fix};
+    use ruff_diagnostics::{Applicability, Edit, Fix};
 
-    use crate::diagnostic::{Annotation, DiagnosticId, SecondaryCode, Severity, Span};
+    use crate::diagnostic::{
+        Annotation, DiagnosticId, IntoDiagnosticMessage, SecondaryCode, Severity, Span,
+        SubDiagnosticSeverity,
+    };
     use crate::files::system_path_to_file;
     use crate::system::{DbWithWritableSystem, SystemPath};
     use crate::tests::TestDb;
@@ -1541,7 +1744,7 @@ watermelon
 
         let mut diag = env.err().primary("animals", "3", "3", "").build();
         diag.sub(
-            env.sub_builder(Severity::Info, "this is a helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "this is a helpful note")
                 .build(),
         );
         insta::assert_snapshot!(
@@ -1570,15 +1773,15 @@ watermelon
 
         let mut diag = env.err().primary("animals", "3", "3", "").build();
         diag.sub(
-            env.sub_builder(Severity::Info, "this is a helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "this is a helpful note")
                 .build(),
         );
         diag.sub(
-            env.sub_builder(Severity::Info, "another helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "another helpful note")
                 .build(),
         );
         diag.sub(
-            env.sub_builder(Severity::Info, "and another helpful note")
+            env.sub_builder(SubDiagnosticSeverity::Info, "and another helpful note")
                 .build(),
         );
         insta::assert_snapshot!(
@@ -2300,6 +2503,27 @@ watermelon
             self.config = config;
         }
 
+        /// Hide diagnostic severity when rendering.
+        pub(super) fn hide_severity(&mut self, yes: bool) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.hide_severity(yes);
+            self.config = config;
+        }
+
+        /// Show fix availability when rendering.
+        pub(super) fn show_fix_status(&mut self, yes: bool) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.show_fix_status(yes);
+            self.config = config;
+        }
+
+        /// The lowest fix applicability to show when rendering.
+        pub(super) fn fix_applicability(&mut self, applicability: Applicability) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.fix_applicability(applicability);
+            self.config = config;
+        }
+
         /// Add a file with the given path and contents to this environment.
         pub(super) fn add(&mut self, path: &str, contents: &str) {
             let path = SystemPath::new(path);
@@ -2363,11 +2587,11 @@ watermelon
         /// sub-diagnostic with "error" severity and canned values for
         /// its identifier and message.
         fn sub_warn(&mut self) -> SubDiagnosticBuilder<'_> {
-            self.sub_builder(Severity::Warning, "sub-diagnostic message")
+            self.sub_builder(SubDiagnosticSeverity::Warning, "sub-diagnostic message")
         }
 
         /// Returns a builder for tersely constructing diagnostics.
-        fn builder(
+        pub(super) fn builder(
             &mut self,
             identifier: &'static str,
             severity: Severity,
@@ -2384,7 +2608,11 @@ watermelon
         }
 
         /// Returns a builder for tersely constructing sub-diagnostics.
-        fn sub_builder(&mut self, severity: Severity, message: &str) -> SubDiagnosticBuilder<'_> {
+        fn sub_builder(
+            &mut self,
+            severity: SubDiagnosticSeverity,
+            message: &str,
+        ) -> SubDiagnosticBuilder<'_> {
             let subdiag = SubDiagnostic::new(severity, message);
             SubDiagnosticBuilder { env: self, subdiag }
         }
@@ -2430,7 +2658,7 @@ watermelon
         ///
         /// See the docs on `TestEnvironment::span` for the meaning of
         /// `path`, `line_offset_start` and `line_offset_end`.
-        fn primary(
+        pub(super) fn primary(
             mut self,
             path: &str,
             line_offset_start: &str,
@@ -2487,6 +2715,12 @@ watermelon
             self.diag.set_noqa_offset(noqa_offset);
             self
         }
+
+        /// Adds a "help" sub-diagnostic with the given message.
+        fn help(mut self, message: impl IntoDiagnosticMessage) -> DiagnosticBuilder<'e> {
+            self.diag.help(message);
+            self
+        }
     }
 
     /// A helper builder for tersely populating a `SubDiagnostic`.
@@ -2593,7 +2827,8 @@ def fibonacci(n):
 
         let diagnostics = vec![
             env.builder("unused-import", Severity::Error, "`os` imported but unused")
-                .primary("fib.py", "1:7", "1:9", "Remove unused import: `os`")
+                .primary("fib.py", "1:7", "1:9", "")
+                .help("Remove unused import: `os`")
                 .secondary_code("F401")
                 .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
                     TextSize::from(0),
@@ -2606,12 +2841,8 @@ def fibonacci(n):
                 Severity::Error,
                 "Local variable `x` is assigned to but never used",
             )
-            .primary(
-                "fib.py",
-                "6:4",
-                "6:5",
-                "Remove assignment to unused variable `x`",
-            )
+            .primary("fib.py", "6:4", "6:5", "")
+            .help("Remove assignment to unused variable `x`")
             .secondary_code("F841")
             .fix(Fix::unsafe_edit(Edit::deletion(
                 TextSize::from(94),
@@ -2658,6 +2889,25 @@ if call(foo
     }
 
     /// Create Ruff-style diagnostics for testing the various output formats for a notebook.
+    ///
+    /// The concatenated cells look like this:
+    ///
+    /// ```python
+    /// # cell 1
+    /// import os
+    /// # cell 2
+    /// import math
+    ///
+    /// print('hello world')
+    /// # cell 3
+    /// def foo():
+    ///     print()
+    ///     x = 1
+    /// ```
+    ///
+    /// The first diagnostic is on the unused `os` import with location cell 1, row 2, column 8
+    /// (`cell 1:2:8`). The second diagnostic is the unused `math` import at `cell 2:2:8`, and the
+    /// third diagnostic is an unfixable unused variable at `cell 3:4:5`.
     #[allow(
         dead_code,
         reason = "This is currently only used for JSON but will be needed soon for other formats"
@@ -2713,7 +2963,8 @@ if call(foo
 
         let diagnostics = vec![
             env.builder("unused-import", Severity::Error, "`os` imported but unused")
-                .primary("notebook.ipynb", "2:7", "2:9", "Remove unused import: `os`")
+                .primary("notebook.ipynb", "2:7", "2:9", "")
+                .help("Remove unused import: `os`")
                 .secondary_code("F401")
                 .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
                     TextSize::from(9),
@@ -2726,12 +2977,8 @@ if call(foo
                 Severity::Error,
                 "`math` imported but unused",
             )
-            .primary(
-                "notebook.ipynb",
-                "4:7",
-                "4:11",
-                "Remove unused import: `math`",
-            )
+            .primary("notebook.ipynb", "4:7", "4:11", "")
+            .help("Remove unused import: `math`")
             .secondary_code("F401")
             .fix(Fix::safe_edit(Edit::range_deletion(TextRange::new(
                 TextSize::from(28),
@@ -2744,12 +2991,8 @@ if call(foo
                 Severity::Error,
                 "Local variable `x` is assigned to but never used",
             )
-            .primary(
-                "notebook.ipynb",
-                "10:4",
-                "10:5",
-                "Remove assignment to unused variable `x`",
-            )
+            .primary("notebook.ipynb", "10:4", "10:5", "")
+            .help("Remove assignment to unused variable `x`")
             .secondary_code("F841")
             .fix(Fix::unsafe_edit(Edit::range_deletion(TextRange::new(
                 TextSize::from(94),

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

@@ -0,0 +1,195 @@
+use crate::diagnostic::{
+    Diagnostic, DisplayDiagnosticConfig, Severity,
+    stylesheet::{DiagnosticStylesheet, fmt_styled},
+};
+
+use super::FileResolver;
+
+pub(super) struct ConciseRenderer<'a> {
+    resolver: &'a dyn FileResolver,
+    config: &'a DisplayDiagnosticConfig,
+}
+
+impl<'a> ConciseRenderer<'a> {
+    pub(super) fn new(resolver: &'a dyn FileResolver, config: &'a DisplayDiagnosticConfig) -> Self {
+        Self { resolver, config }
+    }
+
+    pub(super) fn render(
+        &self,
+        f: &mut std::fmt::Formatter,
+        diagnostics: &[Diagnostic],
+    ) -> std::fmt::Result {
+        let stylesheet = if self.config.color {
+            DiagnosticStylesheet::styled()
+        } else {
+            DiagnosticStylesheet::plain()
+        };
+
+        let sep = fmt_styled(":", stylesheet.separator);
+        for diag in diagnostics {
+            if let Some(span) = diag.primary_span() {
+                write!(
+                    f,
+                    "{path}",
+                    path = fmt_styled(
+                        span.file().relative_path(self.resolver).to_string_lossy(),
+                        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());
+
+                    if let Some(notebook_index) = self.resolver.notebook_index(span.file()) {
+                        write!(
+                            f,
+                            "{sep}cell {cell}{sep}{line}{sep}{col}",
+                            cell = notebook_index.cell(start.line).unwrap_or_default(),
+                            line = notebook_index.cell_row(start.line).unwrap_or_default(),
+                            col = start.column,
+                        )?;
+                    } else {
+                        write!(
+                            f,
+                            "{sep}{line}{sep}{col}",
+                            line = start.line,
+                            col = start.column,
+                        )?;
+                    }
+                }
+                write!(f, "{sep} ")?;
+            }
+            if self.config.hide_severity {
+                if let Some(code) = diag.secondary_code() {
+                    write!(
+                        f,
+                        "{code} ",
+                        code = fmt_styled(code, stylesheet.secondary_code)
+                    )?;
+                }
+                if self.config.show_fix_status {
+                    if let Some(fix) = diag.fix() {
+                        // Do not display an indicator for inapplicable fixes
+                        if fix.applies(self.config.fix_applicability) {
+                            write!(f, "[{fix}] ", fix = fmt_styled("*", stylesheet.separator))?;
+                        }
+                    }
+                }
+            } else {
+                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,
+                    "{severity}[{id}] ",
+                    severity = fmt_styled(severity, severity_style),
+                    id = fmt_styled(diag.id(), stylesheet.emphasis)
+                )?;
+            }
+
+            writeln!(f, "{message}", message = diag.concise_message())?;
+        }
+
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use ruff_diagnostics::Applicability;
+
+    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::Concise);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        fib.py:1:8: error[unused-import] `os` imported but unused
+        fib.py:6:5: error[unused-variable] Local variable `x` is assigned to but never used
+        undef.py:1:4: error[undefined-name] Undefined name `a`
+        ");
+    }
+
+    #[test]
+    fn show_fixes() {
+        let (mut env, diagnostics) = create_diagnostics(DiagnosticFormat::Concise);
+        env.hide_severity(true);
+        env.show_fix_status(true);
+        env.fix_applicability(Applicability::DisplayOnly);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        fib.py:1:8: F401 [*] `os` imported but unused
+        fib.py:6:5: F841 [*] Local variable `x` is assigned to but never used
+        undef.py:1:4: F821 Undefined name `a`
+        ");
+    }
+
+    #[test]
+    fn show_fixes_preview() {
+        let (mut env, diagnostics) = create_diagnostics(DiagnosticFormat::Concise);
+        env.hide_severity(true);
+        env.show_fix_status(true);
+        env.fix_applicability(Applicability::DisplayOnly);
+        env.preview(true);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        fib.py:1:8: F401 [*] `os` imported but unused
+        fib.py:6:5: F841 [*] Local variable `x` is assigned to but never used
+        undef.py:1:4: F821 Undefined name `a`
+        ");
+    }
+
+    #[test]
+    fn show_fixes_syntax_errors() {
+        let (mut env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Concise);
+        env.hide_severity(true);
+        env.show_fix_status(true);
+        env.fix_applicability(Applicability::DisplayOnly);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        syntax_errors.py:1:15: SyntaxError: Expected one or more symbol names after import
+        syntax_errors.py:3:12: SyntaxError: Expected ')', found newline
+        ");
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Concise);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        syntax_errors.py:1:15: error[invalid-syntax] SyntaxError: Expected one or more symbol names after import
+        syntax_errors.py:3:12: error[invalid-syntax] SyntaxError: Expected ')', found newline
+        ");
+    }
+
+    #[test]
+    fn notebook_output() {
+        let (env, diagnostics) = create_notebook_diagnostics(DiagnosticFormat::Concise);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        notebook.ipynb:cell 1:2:8: error[unused-import] `os` imported but unused
+        notebook.ipynb:cell 2:2:8: error[unused-import] `math` imported but unused
+        notebook.ipynb:cell 3:4:5: error[unused-variable] Local variable `x` is assigned to but never used
+        ");
+    }
+
+    #[test]
+    fn missing_file() {
+        let mut env = TestEnvironment::new();
+        env.format(DiagnosticFormat::Concise);
+
+        let diag = env.err().build();
+
+        insta::assert_snapshot!(
+            env.render(&diag),
+            @"error[test-diagnostic] main diagnostic message",
+        );
+    }
+}

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

@@ -0,0 +1,180 @@
+#[cfg(test)]
+mod tests {
+    use crate::diagnostic::{
+        DiagnosticFormat, Severity,
+        render::tests::{TestEnvironment, create_diagnostics, create_syntax_error_diagnostics},
+    };
+
+    #[test]
+    fn output() {
+        let (env, diagnostics) = create_diagnostics(DiagnosticFormat::Full);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r#"
+        error[unused-import]: `os` imported but unused
+         --> fib.py:1:8
+          |
+        1 | import os
+          |        ^^
+          |
+        help: Remove unused import: `os`
+
+        error[unused-variable]: Local variable `x` is assigned to but never used
+         --> fib.py:6:5
+          |
+        4 | def fibonacci(n):
+        5 |     """Compute the nth number in the Fibonacci sequence."""
+        6 |     x = 1
+          |     ^
+        7 |     if n == 0:
+        8 |         return 0
+          |
+        help: Remove assignment to unused variable `x`
+
+        error[undefined-name]: Undefined name `a`
+         --> undef.py:1:4
+          |
+        1 | if a == 1: pass
+          |    ^
+          |
+        "#);
+    }
+
+    #[test]
+    fn syntax_errors() {
+        let (env, diagnostics) = create_syntax_error_diagnostics(DiagnosticFormat::Full);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        error[invalid-syntax]: SyntaxError: Expected one or more symbol names after import
+         --> syntax_errors.py:1:15
+          |
+        1 | from os import
+          |               ^
+        2 |
+        3 | if call(foo
+          |
+
+        error[invalid-syntax]: SyntaxError: Expected ')', found newline
+         --> syntax_errors.py:3:12
+          |
+        1 | from os import
+        2 |
+        3 | if call(foo
+          |            ^
+        4 |     def bar():
+        5 |         pass
+          |
+        ");
+    }
+
+    /// Check that the new `full` rendering code in `ruff_db` handles cases fixed by commit c9b99e4.
+    ///
+    /// For example, without the fix, we get diagnostics like this:
+    ///
+    /// ```
+    /// error[no-indented-block]: Expected an indented block
+    ///  --> example.py:3:1
+    ///   |
+    /// 2 | if False:
+    ///   |          ^
+    /// 3 | print()
+    ///   |
+    ///  ```
+    ///
+    /// where the caret points to the end of the previous line instead of the start of the next.
+    #[test]
+    fn empty_span_after_line_terminator() {
+        let mut env = TestEnvironment::new();
+        env.add(
+            "example.py",
+            r#"
+if False:
+print()
+"#,
+        );
+        env.format(DiagnosticFormat::Full);
+
+        let diagnostic = env
+            .builder(
+                "no-indented-block",
+                Severity::Error,
+                "Expected an indented block",
+            )
+            .primary("example.py", "3:0", "3:0", "")
+            .build();
+
+        insta::assert_snapshot!(env.render(&diagnostic), @r"
+        error[no-indented-block]: Expected an indented block
+         --> example.py:3:1
+          |
+        2 | if False:
+        3 | print()
+          | ^
+          |
+        ");
+    }
+
+    /// Check that the new `full` rendering code in `ruff_db` handles cases fixed by commit 2922490.
+    ///
+    /// For example, without the fix, we get diagnostics like this:
+    ///
+    /// ```
+    /// error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+    ///  --> example.py:1:25
+    ///   |
+    /// 1 | nested_fstrings = f'␈{f'{f'␛'}'}'
+    ///   |                       ^
+    ///   |
+    ///  ```
+    ///
+    /// where the caret points to the `f` in the f-string instead of the start of the invalid
+    /// character (`^Z`).
+    #[test]
+    fn unprintable_characters() {
+        let mut env = TestEnvironment::new();
+        env.add("example.py", "nested_fstrings = f'{f'{f''}'}'");
+        env.format(DiagnosticFormat::Full);
+
+        let diagnostic = env
+            .builder(
+                "invalid-character-sub",
+                Severity::Error,
+                r#"Invalid unescaped character SUB, use "\x1A" instead"#,
+            )
+            .primary("example.py", "1:24", "1:24", "")
+            .build();
+
+        insta::assert_snapshot!(env.render(&diagnostic), @r#"
+        error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+         --> example.py:1:25
+          |
+        1 | nested_fstrings = f'␈{f'{f'␛'}'}'
+          |                         ^
+          |
+        "#);
+    }
+
+    #[test]
+    fn multiple_unprintable_characters() -> std::io::Result<()> {
+        let mut env = TestEnvironment::new();
+        env.add("example.py", "");
+        env.format(DiagnosticFormat::Full);
+
+        let diagnostic = env
+            .builder(
+                "invalid-character-sub",
+                Severity::Error,
+                r#"Invalid unescaped character SUB, use "\x1A" instead"#,
+            )
+            .primary("example.py", "1:1", "1:1", "")
+            .build();
+
+        insta::assert_snapshot!(env.render(&diagnostic), @r#"
+        error[invalid-character-sub]: Invalid unescaped character SUB, use "\x1A" instead
+         --> example.py:1:2
+          |
+        1 | ␈␛
+          |  ^
+          |
+        "#);
+
+        Ok(())
+    }
+}

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

@@ -87,7 +87,7 @@ pub(super) fn diagnostic_to_json<'a>(
 
     let fix = diagnostic.fix().map(|fix| JsonFix {
         applicability: fix.applicability(),
-        message: diagnostic.suggestion(),
+        message: diagnostic.first_help_text(),
         edits: ExpandedEdits {
             edits: fix.edits(),
             notebook_index,

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

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

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

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

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

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

crates/ruff_db/src/diagnostic/stylesheet.rs

@@ -41,6 +41,8 @@ pub struct DiagnosticStylesheet {
     pub(crate) line_no: Style,
     pub(crate) emphasis: Style,
     pub(crate) none: Style,
+    pub(crate) separator: Style,
+    pub(crate) secondary_code: Style,
 }
 
 impl Default for DiagnosticStylesheet {
@@ -62,6 +64,8 @@ impl DiagnosticStylesheet {
             line_no: bright_blue.effects(Effects::BOLD),
             emphasis: Style::new().effects(Effects::BOLD),
             none: Style::new(),
+            separator: AnsiColor::Cyan.on_default(),
+            secondary_code: AnsiColor::Red.on_default().effects(Effects::BOLD),
         }
     }
 
@@ -75,6 +79,8 @@ impl DiagnosticStylesheet {
             line_no: Style::new(),
             emphasis: Style::new(),
             none: Style::new(),
+            separator: Style::new(),
+            secondary_code: Style::new(),
         }
     }
 }

crates/ruff_db/src/files.rs

@@ -1,7 +1,6 @@
 use std::fmt;
 use std::sync::Arc;
 
-use countme::Count;
 use dashmap::mapref::entry::Entry;
 pub use file_root::{FileRoot, FileRootKind};
 pub use path::FilePath;
@@ -232,7 +231,7 @@ impl Files {
         let roots = inner.roots.read().unwrap();
 
         for root in roots.all() {
-            if root.path(db).starts_with(&path) {
+            if path.starts_with(root.path(db)) {
                 root.set_revision(db).to(FileRevision::now());
             }
         }
@@ -312,11 +311,6 @@ pub struct File {
     /// the file has been deleted is to change the status to `Deleted`.
     #[default]
     status: FileStatus,
-
-    /// Counter that counts the number of created file instances and active file instances.
-    /// Only enabled in debug builds.
-    #[default]
-    count: Count<File>,
 }
 
 // The Salsa heap is tracked separately.
@@ -375,12 +369,25 @@ impl File {
     }
 
     /// Refreshes the file metadata by querying the file system if needed.
+    ///
+    /// This also "touches" the file root associated with the given path.
+    /// This means that any Salsa queries that depend on the corresponding
+    /// root's revision will become invalidated.
     pub fn sync_path(db: &mut dyn Db, path: &SystemPath) {
         let absolute = SystemPath::absolute(path, db.system().current_directory());
         Files::touch_root(db, &absolute);
         Self::sync_system_path(db, &absolute, None);
     }
 
+    /// Refreshes *only* the file metadata by querying the file system if needed.
+    ///
+    /// This specifically does not touch any file root associated with the
+    /// given file path.
+    pub fn sync_path_only(db: &mut dyn Db, path: &SystemPath) {
+        let absolute = SystemPath::absolute(path, db.system().current_directory());
+        Self::sync_system_path(db, &absolute, None);
+    }
+
     /// Increments the revision for the virtual file at `path`.
     pub fn sync_virtual_path(db: &mut dyn Db, path: &SystemVirtualPath) {
         if let Some(virtual_file) = db.files().try_virtual_file(path) {
@@ -486,7 +493,7 @@ impl fmt::Debug for File {
 ///
 /// This is a wrapper around a [`File`] that provides additional methods to interact with a virtual
 /// file.
-#[derive(Copy, Clone)]
+#[derive(Copy, Clone, Debug)]
 pub struct VirtualFile(File);
 
 impl VirtualFile {

crates/ruff_db/src/files/file_root.rs

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

crates/ruff_db/src/source.rs

@@ -1,8 +1,6 @@
 use std::ops::Deref;
 use std::sync::Arc;
 
-use countme::Count;
-
 use ruff_notebook::Notebook;
 use ruff_python_ast::PySourceType;
 use ruff_source_file::LineIndex;
@@ -38,11 +36,7 @@ pub fn source_text(db: &dyn Db, file: File) -> SourceText {
     };
 
     SourceText {
-        inner: Arc::new(SourceTextInner {
-            kind,
-            read_error,
-            count: Count::new(),
-        }),
+        inner: Arc::new(SourceTextInner { kind, read_error }),
     }
 }
 
@@ -125,8 +119,6 @@ impl std::fmt::Debug for SourceText {
 
 #[derive(Eq, PartialEq, get_size2::GetSize)]
 struct SourceTextInner {
-    #[get_size(ignore)]
-    count: Count<SourceText>,
     kind: SourceTextKind,
     read_error: Option<SourceTextError>,
 }

crates/ruff_graph/Cargo.toml

@@ -20,6 +20,7 @@ ty_python_semantic = { workspace = true }
 
 anyhow = { workspace = true }
 clap = { workspace = true, optional = true }
+memchr = { workspace = true }
 salsa = { workspace = true }
 schemars = { workspace = true, optional = true }
 serde = { workspace = true, optional = true }

crates/ruff_graph/src/collector.rs

@@ -1,3 +1,4 @@
+use crate::StringImports;
 use ruff_python_ast::visitor::source_order::{
     SourceOrderVisitor, walk_expr, walk_module, walk_stmt,
 };
@@ -10,13 +11,13 @@ pub(crate) struct Collector<'a> {
     /// The path to the current module.
     module_path: Option<&'a [String]>,
     /// Whether to detect imports from string literals.
-    string_imports: bool,
+    string_imports: StringImports,
     /// The collected imports from the Python AST.
     imports: Vec<CollectedImport>,
 }
 
 impl<'a> Collector<'a> {
-    pub(crate) fn new(module_path: Option<&'a [String]>, string_imports: bool) -> Self {
+    pub(crate) fn new(module_path: Option<&'a [String]>, string_imports: StringImports) -> Self {
         Self {
             module_path,
             string_imports,
@@ -118,7 +119,7 @@ impl<'ast> SourceOrderVisitor<'ast> for Collector<'_> {
             | Stmt::Continue(_)
             | Stmt::IpyEscapeCommand(_) => {
                 // Only traverse simple statements when string imports is enabled.
-                if self.string_imports {
+                if self.string_imports.enabled {
                     walk_stmt(self, stmt);
                 }
             }
@@ -126,20 +127,26 @@ impl<'ast> SourceOrderVisitor<'ast> for Collector<'_> {
     }
 
     fn visit_expr(&mut self, expr: &'ast Expr) {
-        if self.string_imports {
+        if self.string_imports.enabled {
             if let Expr::StringLiteral(ast::ExprStringLiteral {
                 value,
                 range: _,
                 node_index: _,
             }) = expr
             {
-                // Determine whether the string literal "looks like" an import statement: contains
-                // a dot, and consists solely of valid Python identifiers.
                 let value = value.to_str();
-                if let Some(module_name) = ModuleName::new(value) {
-                    self.imports.push(CollectedImport::Import(module_name));
+                // Determine whether the string literal "looks like" an import statement: contains
+                // the requisite number of dots, and consists solely of valid Python identifiers.
+                if self.string_imports.min_dots == 0
+                    || memchr::memchr_iter(b'.', value.as_bytes()).count()
+                        >= self.string_imports.min_dots
+                {
+                    if let Some(module_name) = ModuleName::new(value) {
+                        self.imports.push(CollectedImport::Import(module_name));
+                    }
                 }
             }
+
             walk_expr(self, expr);
         }
     }

crates/ruff_graph/src/db.rs

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

crates/ruff_graph/src/lib.rs

@@ -9,7 +9,7 @@ use ruff_python_parser::{Mode, ParseOptions, parse};
 use crate::collector::Collector;
 pub use crate::db::ModuleDb;
 use crate::resolver::Resolver;
-pub use crate::settings::{AnalyzeSettings, Direction};
+pub use crate::settings::{AnalyzeSettings, Direction, StringImports};
 
 mod collector;
 mod db;
@@ -26,7 +26,7 @@ impl ModuleImports {
         db: &ModuleDb,
         path: &SystemPath,
         package: Option<&SystemPath>,
-        string_imports: bool,
+        string_imports: StringImports,
     ) -> Result<Self> {
         // Read and parse the source code.
         let source = std::fs::read_to_string(path)?;
@@ -42,13 +42,11 @@ impl ModuleImports {
         // Resolve the imports.
         let mut resolved_imports = ModuleImports::default();
         for import in imports {
-            let Some(resolved) = Resolver::new(db).resolve(import) else {
-                continue;
-            };
-            let Some(path) = resolved.as_system_path() else {
-                continue;
-            };
-            resolved_imports.insert(path.to_path_buf());
+            for resolved in Resolver::new(db).resolve(import) {
+                if let Some(path) = resolved.as_system_path() {
+                    resolved_imports.insert(path.to_path_buf());
+                }
+            }
         }
 
         Ok(resolved_imports)

crates/ruff_graph/src/resolver.rs

@@ -1,5 +1,5 @@
 use ruff_db::files::FilePath;
-use ty_python_semantic::resolve_module;
+use ty_python_semantic::{ModuleName, resolve_module, resolve_real_module};
 
 use crate::ModuleDb;
 use crate::collector::CollectedImport;
@@ -16,24 +16,67 @@ impl<'a> Resolver<'a> {
     }
 
     /// Resolve the [`CollectedImport`] into a [`FilePath`].
-    pub(crate) fn resolve(&self, import: CollectedImport) -> Option<&'a FilePath> {
+    pub(crate) fn resolve(&self, import: CollectedImport) -> impl Iterator<Item = &'a FilePath> {
         match import {
             CollectedImport::Import(import) => {
-                let module = resolve_module(self.db, &import)?;
-                Some(module.file()?.path(self.db))
+                // Attempt to resolve the module (e.g., given `import foo`, look for `foo`).
+                let file = self.resolve_module(&import);
+
+                // If the file is a stub, look for the corresponding source file.
+                let source_file = file
+                    .is_some_and(|file| file.extension() == Some("pyi"))
+                    .then(|| self.resolve_real_module(&import))
+                    .flatten();
+
+                std::iter::once(file)
+                    .chain(std::iter::once(source_file))
+                    .flatten()
             }
             CollectedImport::ImportFrom(import) => {
                 // Attempt to resolve the member (e.g., given `from foo import bar`, look for `foo.bar`).
+                if let Some(file) = self.resolve_module(&import) {
+                    // If the file is a stub, look for the corresponding source file.
+                    let source_file = (file.extension() == Some("pyi"))
+                        .then(|| self.resolve_real_module(&import))
+                        .flatten();
+
+                    return std::iter::once(Some(file))
+                        .chain(std::iter::once(source_file))
+                        .flatten();
+                }
+
+                // Attempt to resolve the module (e.g., given `from foo import bar`, look for `foo`).
                 let parent = import.parent();
+                let file = parent
+                    .as_ref()
+                    .and_then(|parent| self.resolve_module(parent));
 
-                let module = resolve_module(self.db, &import).or_else(|| {
-                    // Attempt to resolve the module (e.g., given `from foo import bar`, look for `foo`).
+                // If the file is a stub, look for the corresponding source file.
+                let source_file = file
+                    .is_some_and(|file| file.extension() == Some("pyi"))
+                    .then(|| {
+                        parent
+                            .as_ref()
+                            .and_then(|parent| self.resolve_real_module(parent))
+                    })
+                    .flatten();
 
-                    resolve_module(self.db, &parent?)
-                })?;
-
-                Some(module.file()?.path(self.db))
+                std::iter::once(file)
+                    .chain(std::iter::once(source_file))
+                    .flatten()
             }
         }
     }
+
+    /// Resolves a module name to a module.
+    fn resolve_module(&self, module_name: &ModuleName) -> Option<&'a FilePath> {
+        let module = resolve_module(self.db, module_name)?;
+        Some(module.file(self.db)?.path(self.db))
+    }
+
+    /// Resolves a module name to a module (stubs not allowed).
+    fn resolve_real_module(&self, module_name: &ModuleName) -> Option<&'a FilePath> {
+        let module = resolve_real_module(self.db, module_name)?;
+        Some(module.file(self.db)?.path(self.db))
+    }
 }

crates/ruff_graph/src/settings.rs

@@ -11,7 +11,7 @@ pub struct AnalyzeSettings {
     pub exclude: FilePatternSet,
     pub preview: PreviewMode,
     pub target_version: PythonVersion,
-    pub detect_string_imports: bool,
+    pub string_imports: StringImports,
     pub include_dependencies: BTreeMap<PathBuf, (PathBuf, Vec<String>)>,
     pub extension: ExtensionMapping,
 }
@@ -26,7 +26,7 @@ impl fmt::Display for AnalyzeSettings {
                 self.exclude,
                 self.preview,
                 self.target_version,
-                self.detect_string_imports,
+                self.string_imports,
                 self.extension | debug,
                 self.include_dependencies | debug,
             ]
@@ -35,6 +35,31 @@ impl fmt::Display for AnalyzeSettings {
     }
 }
 
+#[derive(Debug, Copy, Clone, CacheKey)]
+pub struct StringImports {
+    pub enabled: bool,
+    pub min_dots: usize,
+}
+
+impl Default for StringImports {
+    fn default() -> Self {
+        Self {
+            enabled: false,
+            min_dots: 2,
+        }
+    }
+}
+
+impl fmt::Display for StringImports {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        if self.enabled {
+            write!(f, "enabled (min_dots: {})", self.min_dots)
+        } else {
+            write!(f, "disabled")
+        }
+    }
+}
+
 #[derive(Default, Debug, Copy, Clone, PartialEq, Eq, CacheKey)]
 #[cfg_attr(
     feature = "serde",

crates/ruff_linter/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_linter"
-version = "0.12.4"
+version = "0.12.5"
 publish = false
 authors = { workspace = true }
 edition = { workspace = true }
@@ -15,7 +15,7 @@ license = { workspace = true }
 [dependencies]
 ruff_annotate_snippets = { workspace = true }
 ruff_cache = { workspace = true }
-ruff_db = { workspace = true, features = ["serde"] }
+ruff_db = { workspace = true, features = ["junit", "serde"] }
 ruff_diagnostics = { workspace = true, features = ["serde"] }
 ruff_notebook = { workspace = true }
 ruff_macros = { workspace = true }
@@ -55,7 +55,6 @@ path-absolutize = { workspace = true, features = [
 pathdiff = { workspace = true }
 pep440_rs = { workspace = true }
 pyproject-toml = { workspace = true }
-quick-junit = { workspace = true }
 regex = { workspace = true }
 rustc-hash = { workspace = true }
 schemars = { workspace = true, optional = true }

crates/ruff_linter/resources/test/fixtures/flake8_bandit/S104.py

@@ -25,5 +25,5 @@ def my_func():
 
 # t-strings - all ok
 t"0.0.0.0"
-"0.0.0.0" t"0.0.0.0{expr}0.0.0.0"
-"0.0.0.0" f"0.0.0.0{expr}0.0.0.0" t"0.0.0.0{expr}0.0.0.0"
+t"0.0.0.0" t"0.0.0.0{expr}0.0.0.0"
+t"0.0.0.0" t"0.0.0.0{expr}0.0.0.0" t"0.0.0.0{expr}0.0.0.0"

crates/ruff_linter/resources/test/fixtures/flake8_blind_except/BLE.py

@@ -94,7 +94,7 @@ except Exception:
     logging.error("...", exc_info=True)
 
 
-from logging import error, exception
+from logging import critical, error, exception
 
 try:
     pass
@@ -114,6 +114,23 @@ except Exception:
     error("...", exc_info=None)
 
 
+try:
+    pass
+except Exception:
+    critical("...")
+
+
+try:
+    pass
+except Exception:
+    critical("...", exc_info=False)
+
+
+try:
+    pass
+except Exception:
+    critical("...", exc_info=None)
+
 try:
     pass
 except Exception:
@@ -125,6 +142,13 @@ try:
 except Exception:
     error("...", exc_info=True)
 
+
+try:
+    pass
+except Exception:
+    critical("...", exc_info=True)
+
+
 try:
     ...
 except Exception as e:

crates/ruff_linter/resources/test/fixtures/flake8_commas/COM81.py

@@ -650,3 +650,17 @@ f"""This is a test. {
     if True else
     "Don't add a trailing comma here ->"
 }"""
+
+type X[
+    T
+] = T
+def f[
+    T
+](): pass
+class C[
+    T
+]: pass
+
+type X[T,] = T
+def f[T,](): pass
+class C[T,]: pass

crates/ruff_linter/resources/test/fixtures/flake8_pyi/PYI016.py

@@ -142,3 +142,7 @@ field47: typing.Optional[int] | typing.Optional[dict]
 # avoid reporting twice
 field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 field49: typing.Optional[complex | complex] | complex
+
+# Regression test for https://github.com/astral-sh/ruff/issues/19403
+# Should throw duplicate union member but not fix
+isinstance(None, typing.Union[None, None])

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

@@ -47,3 +47,19 @@ def _():
     from builtin import open
 
     with open(p) as _: ...  # No error
+
+file = "file_1.py"
+
+rename(file, "file_2.py")
+
+rename(
+    # commment 1
+    file, # comment 2
+    "file_2.py"
+    ,
+    # comment 3
+)
+
+rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+
+rename(file, "file_2.py", src_dir_fd=1)

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

@@ -84,3 +84,25 @@ class MyRequestHandler(BaseHTTPRequestHandler):
     def dont_GET(self):
         pass
 
+
+from http.server import CGIHTTPRequestHandler
+
+
+class MyCGIRequestHandler(CGIHTTPRequestHandler):
+    def do_OPTIONS(self):
+        pass
+
+    def dont_OPTIONS(self):
+        pass
+
+
+from http.server import SimpleHTTPRequestHandler
+
+
+class MySimpleRequestHandler(SimpleHTTPRequestHandler):
+    def do_OPTIONS(self):
+        pass
+
+    def dont_OPTIONS(self):
+        pass
+

crates/ruff_linter/resources/test/fixtures/perflint/PERF401.py

@@ -278,3 +278,30 @@ def f():
     for i in src:
         if lambda: 0:
             dst.append(i)
+
+def f():
+    i = "xyz"
+    result = []
+    for i in range(3):
+        result.append(x for x in [i])
+
+def f():
+    i = "xyz"
+    result = []
+    for i in range(3):
+        result.append((x for x in [i]))
+
+G_INDEX = None
+def f():
+    global G_INDEX
+    result = []
+    for G_INDEX in range(3):
+        result.append(G_INDEX)
+
+def f():
+    NL_INDEX = None
+    def x():
+        nonlocal NL_INDEX
+        result = []
+        for NL_INDEX in range(3):
+            result.append(NL_INDEX)

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

@@ -0,0 +1,5 @@
+#
+x = 0 \
+#
++1
+print(x)

crates/ruff_linter/resources/test/fixtures/refurb/FURB118.py

@@ -143,3 +143,23 @@ class NotAMethodButHardToDetect:
     # without risking false positives elsewhere or introducing complex heuristics
     # that users would find surprising and confusing
     FOO = sorted([x for x in BAR], key=lambda x: x.baz)
+
+# https://github.com/astral-sh/ruff/issues/19305
+import pytest
+
+@pytest.fixture
+def my_fixture_with_param(request):
+    return request.param
+
+@pytest.fixture()
+def my_fixture_with_param2(request):
+    return request.param
+
+
+# Decorated function (should be ignored)
+def custom_decorator(func):
+    return func
+
+@custom_decorator
+def add(x, y):
+    return x + y

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

@@ -55,3 +55,12 @@ _ = Decimal(0.1)
 _ = Decimal(-0.5)
 _ = Decimal(5.0)
 _ = decimal.Decimal(4.2)
+
+# Cases with int and bool - should produce safe fixes
+_ = Decimal.from_float(1)
+_ = Decimal.from_float(True)
+
+# Cases with non-finite floats - should produce safe fixes
+_ = Decimal.from_float(float("-nan"))
+_ = Decimal.from_float(float("\x2dnan"))
+_ = Decimal.from_float(float("\N{HYPHEN-MINUS}nan"))

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

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

crates/ruff_linter/resources/test/fixtures/ruff/RUF033.py

@@ -65,3 +65,62 @@ class Foo:
     bar = "should've used attrs"
 
     def __post_init__(self, bar: str = "ahhh", baz: str = "hmm") -> None: ...
+
+
+# https://github.com/astral-sh/ruff/issues/18950
+@dataclass
+class Foo:
+    def __post_init__(self, bar: int = (x := 1)) -> None:
+        pass
+
+
+@dataclass
+class Foo:
+    def __post_init__(
+        self,
+        bar: int = (x := 1)  #  comment
+        ,
+        baz: int = (y := 2),  # comment
+        foo = (a := 1)  #  comment
+        ,
+        faz = (b := 2),  # comment
+    ) -> None:
+        pass
+
+
+@dataclass
+class Foo:
+    def __post_init__(
+        self,
+        bar: int = 1,  # comment
+        baz: int = 2,  # comment
+    ) -> None:
+        pass
+
+
+@dataclass
+class Foo:
+    def __post_init__(
+        self,
+        arg1: int = (1)  # comment
+        ,
+        arg2: int = ((1))  # comment
+        ,
+        arg2: int = (i for i in range(10))  # comment
+        ,
+    ) -> None:
+        pass
+
+
+# makes little sense, but is valid syntax
+def fun_with_python_syntax():
+    @dataclass
+    class Foo:
+        def __post_init__(
+            self,
+            bar: (int) = (yield from range(5))  # comment
+            ,
+        ) -> None:
+            ...
+
+    return Foo

crates/ruff_linter/resources/test/fixtures/ruff/RUF039.py

@@ -53,3 +53,16 @@ regex.subn(br"""eak your machine with rm -""", rf"""/""")
 regex.splititer(both, non_literal)
 regex.subf(f, lambda _: r'means', '"format"')
 regex.subfn(fn, f'''a$1n't''', lambda: "'function'")
+
+
+# https://github.com/astral-sh/ruff/issues/16713
+re.compile("\a\f\n\r\t\u27F2\U0001F0A1\v\x41")  # with unsafe fix
+re.compile("\b")  # without fix
+re.compile("\"")  # without fix
+re.compile("\'")  # without fix
+re.compile('\"')  # without fix
+re.compile('\'')  # without fix
+re.compile("\\")  # without fix
+re.compile("\101")  # without fix
+re.compile("a\
+b")  # without fix

crates/ruff_linter/resources/test/fixtures/ruff/RUF039_concat.py

@@ -91,3 +91,20 @@ regex.subf(
     br''br""br''
 )
 regex.subfn(br'I\s\nee*d\s[O0o]me\x20\Qoffe\E, ' br'b')
+
+
+# https://github.com/astral-sh/ruff/issues/16713
+re.compile(
+    "["
+    "\U0001F600-\U0001F64F"  # emoticons
+    "\U0001F300-\U0001F5FF"  # symbols & pictographs
+    "\U0001F680-\U0001F6FF"  # transport & map symbols
+    "\U0001F1E0-\U0001F1FF"  # flags (iOS)
+    "\U00002702-\U000027B0"
+    "\U000024C2-\U0001F251"
+    "\u200d"  # zero width joiner
+    "\u200c"  # zero width non-joiner
+    "\\u200c" # must not be escaped in a raw string
+    "]+",
+    flags=re.UNICODE,
+)

crates/ruff_linter/resources/test/fixtures/ruff/RUF039_py_version_sensitive.py

@@ -0,0 +1,3 @@
+import re
+
+re.compile("\N{Partial Differential}")  # with unsafe fix if python target is 3.8 or higher, else without fix

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

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

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

@@ -1039,14 +1039,10 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 flake8_simplify::rules::zip_dict_keys_and_values(checker, call);
             }
             if checker.any_rule_enabled(&[
-                Rule::OsChmod,
                 Rule::OsMkdir,
                 Rule::OsMakedirs,
-                Rule::OsRename,
-                Rule::OsReplace,
                 Rule::OsStat,
                 Rule::OsPathJoin,
-                Rule::OsPathSamefile,
                 Rule::OsPathSplitext,
                 Rule::BuiltinOpen,
                 Rule::PyPath,
@@ -1112,6 +1108,18 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 if checker.is_rule_enabled(Rule::OsGetcwd) {
                     flake8_use_pathlib::rules::os_getcwd(checker, call, segments);
                 }
+                if checker.is_rule_enabled(Rule::OsChmod) {
+                    flake8_use_pathlib::rules::os_chmod(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsRename) {
+                    flake8_use_pathlib::rules::os_rename(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsReplace) {
+                    flake8_use_pathlib::rules::os_replace(checker, call, segments);
+                }
+                if checker.is_rule_enabled(Rule::OsPathSamefile) {
+                    flake8_use_pathlib::rules::os_path_samefile(checker, call, segments);
+                }
                 if checker.is_rule_enabled(Rule::PathConstructorCurrentDirectory) {
                     flake8_use_pathlib::rules::path_constructor_current_directory(
                         checker, call, segments,

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

@@ -3216,6 +3216,11 @@ impl<'a> LintContext<'a> {
     pub(crate) fn iter(&mut self) -> impl Iterator<Item = &Diagnostic> {
         self.diagnostics.get_mut().iter()
     }
+
+    /// The [`LinterSettings`] for the current analysis, including the enabled rules.
+    pub(crate) const fn settings(&self) -> &LinterSettings {
+        self.settings
+    }
 }
 
 /// An abstraction for mutating a diagnostic.

crates/ruff_linter/src/checkers/tokens.rs

@@ -16,7 +16,6 @@ use crate::rules::{
     eradicate, flake8_commas, flake8_executable, flake8_fixme, flake8_implicit_str_concat,
     flake8_pyi, flake8_todos, pycodestyle, pygrep_hooks, pylint, pyupgrade, ruff,
 };
-use crate::settings::LinterSettings;
 
 use super::ast::LintContext;
 
@@ -27,7 +26,6 @@ pub(crate) fn check_tokens(
     locator: &Locator,
     indexer: &Indexer,
     stylist: &Stylist,
-    settings: &LinterSettings,
     source_type: PySourceType,
     cell_offsets: Option<&CellOffsets>,
     context: &mut LintContext,
@@ -42,15 +40,8 @@ pub(crate) fn check_tokens(
         Rule::BlankLinesAfterFunctionOrClass,
         Rule::BlankLinesBeforeNestedDefinition,
     ]) {
-        BlankLinesChecker::new(
-            locator,
-            stylist,
-            settings,
-            source_type,
-            cell_offsets,
-            context,
-        )
-        .check_lines(tokens);
+        BlankLinesChecker::new(locator, stylist, source_type, cell_offsets, context)
+            .check_lines(tokens);
     }
 
     if context.is_rule_enabled(Rule::BlanketTypeIgnore) {
@@ -58,17 +49,17 @@ pub(crate) fn check_tokens(
     }
 
     if context.is_rule_enabled(Rule::EmptyComment) {
-        pylint::rules::empty_comments(context, comment_ranges, locator);
+        pylint::rules::empty_comments(context, comment_ranges, locator, indexer);
     }
 
     if context.is_rule_enabled(Rule::AmbiguousUnicodeCharacterComment) {
         for range in comment_ranges {
-            ruff::rules::ambiguous_unicode_character_comment(context, locator, range, settings);
+            ruff::rules::ambiguous_unicode_character_comment(context, locator, range);
         }
     }
 
     if context.is_rule_enabled(Rule::CommentedOutCode) {
-        eradicate::rules::commented_out_code(context, locator, comment_ranges, settings);
+        eradicate::rules::commented_out_code(context, locator, comment_ranges);
     }
 
     if context.is_rule_enabled(Rule::UTF8EncodingDeclaration) {
@@ -110,7 +101,7 @@ pub(crate) fn check_tokens(
         Rule::SingleLineImplicitStringConcatenation,
         Rule::MultiLineImplicitStringConcatenation,
     ]) {
-        flake8_implicit_str_concat::rules::implicit(context, tokens, locator, indexer, settings);
+        flake8_implicit_str_concat::rules::implicit(context, tokens, locator, indexer);
     }
 
     if context.any_rule_enabled(&[

crates/ruff_linter/src/codes.rs

@@ -920,11 +920,11 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
 
         // flake8-use-pathlib
         (Flake8UsePathlib, "100") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathAbspath),
-        (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsChmod),
+        (Flake8UsePathlib, "101") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::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, "104") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsRename),
+        (Flake8UsePathlib, "105") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsReplace),
         (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),
@@ -940,7 +940,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8UsePathlib, "118") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathJoin),
         (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, "121") => (RuleGroup::Stable, rules::flake8_use_pathlib::rules::OsPathSamefile),
         (Flake8UsePathlib, "122") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::OsPathSplitext),
         (Flake8UsePathlib, "123") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::BuiltinOpen),
         (Flake8UsePathlib, "124") => (RuleGroup::Stable, rules::flake8_use_pathlib::violations::PyPath),

crates/ruff_linter/src/linter.rs

@@ -188,7 +188,6 @@ pub fn check_path(
             locator,
             indexer,
             stylist,
-            settings,
             source_type,
             source_kind.as_ipy_notebook().map(Notebook::cell_offsets),
             &mut context,
@@ -473,7 +472,7 @@ pub fn lint_only(
         && !is_py314_support_enabled(settings)
     {
         warn_user_once!(
-            "Support for Python 3.14 is under development and may be unstable. Enable `preview` to remove this warning."
+            "Support for Python 3.14 is in preview and may undergo breaking changes. Enable `preview` to remove this warning."
         );
     }
 
@@ -584,7 +583,7 @@ pub fn lint_fix<'a>(
         && !is_py314_support_enabled(settings)
     {
         warn_user_once!(
-            "Support for Python 3.14 is under development and may be unstable. Enable `preview` to remove this warning."
+            "Support for Python 3.14 is in preview and may undergo breaking changes. Enable `preview` to remove this warning."
         );
     }
 

crates/ruff_linter/src/locator.rs

@@ -118,86 +118,6 @@ impl<'a> Locator<'a> {
         }
     }
 
-    /// Finds the closest [`TextSize`] not less than the offset given for which
-    /// `is_char_boundary` is `true`. Unless the offset given is greater than
-    /// the length of the underlying contents, in which case, the length of the
-    /// contents is returned.
-    ///
-    /// Can be replaced with `str::ceil_char_boundary` once it's stable.
-    ///
-    /// # Examples
-    ///
-    /// From `std`:
-    ///
-    /// ```
-    /// use ruff_text_size::{Ranged, TextSize};
-    /// use ruff_linter::Locator;
-    ///
-    /// let locator = Locator::new("❤️🧡💛💚💙💜");
-    /// assert_eq!(locator.text_len(), TextSize::from(26));
-    /// assert!(!locator.contents().is_char_boundary(13));
-    ///
-    /// let closest = locator.ceil_char_boundary(TextSize::from(13));
-    /// assert_eq!(closest, TextSize::from(14));
-    /// assert_eq!(&locator.contents()[..closest.to_usize()], "❤️🧡💛");
-    /// ```
-    ///
-    /// Additional examples:
-    ///
-    /// ```
-    /// use ruff_text_size::{Ranged, TextRange, TextSize};
-    /// use ruff_linter::Locator;
-    ///
-    /// let locator = Locator::new("Hello");
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(0)),
-    ///     TextSize::from(0)
-    /// );
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(5)),
-    ///     TextSize::from(5)
-    /// );
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(6)),
-    ///     TextSize::from(5)
-    /// );
-    ///
-    /// let locator = Locator::new("α");
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(0)),
-    ///     TextSize::from(0)
-    /// );
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(1)),
-    ///     TextSize::from(2)
-    /// );
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(2)),
-    ///     TextSize::from(2)
-    /// );
-    ///
-    /// assert_eq!(
-    ///     locator.ceil_char_boundary(TextSize::from(3)),
-    ///     TextSize::from(2)
-    /// );
-    /// ```
-    pub fn ceil_char_boundary(&self, offset: TextSize) -> TextSize {
-        let upper_bound = offset
-            .to_u32()
-            .saturating_add(4)
-            .min(self.text_len().to_u32());
-        (offset.to_u32()..upper_bound)
-            .map(TextSize::from)
-            .find(|offset| self.contents.is_char_boundary(offset.to_usize()))
-            .unwrap_or_else(|| TextSize::from(upper_bound))
-    }
-
     /// Take the source code between the given [`TextRange`].
     #[inline]
     pub fn slice<T: Ranged>(&self, ranged: T) -> &'a str {

crates/ruff_linter/src/message/junit.rs

@@ -1,117 +0,0 @@
-use std::io::Write;
-use std::path::Path;
-
-use quick_junit::{NonSuccessKind, Report, TestCase, TestCaseStatus, TestSuite, XmlString};
-
-use ruff_db::diagnostic::Diagnostic;
-use ruff_source_file::LineColumn;
-
-use crate::message::{Emitter, EmitterContext, MessageWithLocation, group_diagnostics_by_filename};
-
-#[derive(Default)]
-pub struct JunitEmitter;
-
-impl Emitter for JunitEmitter {
-    fn emit(
-        &mut self,
-        writer: &mut dyn Write,
-        diagnostics: &[Diagnostic],
-        context: &EmitterContext,
-    ) -> anyhow::Result<()> {
-        let mut report = Report::new("ruff");
-
-        if diagnostics.is_empty() {
-            let mut test_suite = TestSuite::new("ruff");
-            test_suite
-                .extra
-                .insert(XmlString::new("package"), XmlString::new("org.ruff"));
-            let mut case = TestCase::new("No errors found", TestCaseStatus::success());
-            case.set_classname("ruff");
-            test_suite.add_test_case(case);
-            report.add_test_suite(test_suite);
-        } else {
-            for (filename, messages) in group_diagnostics_by_filename(diagnostics) {
-                let mut test_suite = TestSuite::new(&filename);
-                test_suite
-                    .extra
-                    .insert(XmlString::new("package"), XmlString::new("org.ruff"));
-
-                for message in messages {
-                    let MessageWithLocation {
-                        message,
-                        start_location,
-                    } = message;
-                    let mut status = TestCaseStatus::non_success(NonSuccessKind::Failure);
-                    status.set_message(message.body());
-                    let location = if context.is_notebook(&message.expect_ruff_filename()) {
-                        // We can't give a reasonable location for the structured formats,
-                        // so we show one that's clearly a fallback
-                        LineColumn::default()
-                    } else {
-                        start_location
-                    };
-
-                    status.set_description(format!(
-                        "line {row}, col {col}, {body}",
-                        row = location.line,
-                        col = location.column,
-                        body = message.body()
-                    ));
-                    let mut case = TestCase::new(
-                        if let Some(code) = message.secondary_code() {
-                            format!("org.ruff.{code}")
-                        } else {
-                            "org.ruff".to_string()
-                        },
-                        status,
-                    );
-                    let file_path = Path::new(&*filename);
-                    let file_stem = file_path.file_stem().unwrap().to_str().unwrap();
-                    let classname = file_path.parent().unwrap().join(file_stem);
-                    case.set_classname(classname.to_str().unwrap());
-                    case.extra.insert(
-                        XmlString::new("line"),
-                        XmlString::new(location.line.to_string()),
-                    );
-                    case.extra.insert(
-                        XmlString::new("column"),
-                        XmlString::new(location.column.to_string()),
-                    );
-
-                    test_suite.add_test_case(case);
-                }
-                report.add_test_suite(test_suite);
-            }
-        }
-
-        report.serialize(writer)?;
-
-        Ok(())
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use insta::assert_snapshot;
-
-    use crate::message::JunitEmitter;
-    use crate::message::tests::{
-        capture_emitter_output, create_diagnostics, create_syntax_error_diagnostics,
-    };
-
-    #[test]
-    fn output() {
-        let mut emitter = JunitEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_diagnostics());
-
-        assert_snapshot!(content);
-    }
-
-    #[test]
-    fn syntax_errors() {
-        let mut emitter = JunitEmitter;
-        let content = capture_emitter_output(&mut emitter, &create_syntax_error_diagnostics());
-
-        assert_snapshot!(content);
-    }
-}

crates/ruff_linter/src/message/mod.rs

@@ -14,7 +14,6 @@ use ruff_db::files::File;
 pub use github::GithubEmitter;
 pub use gitlab::GitlabEmitter;
 pub use grouped::GroupedEmitter;
-pub use junit::JunitEmitter;
 use ruff_notebook::NotebookIndex;
 use ruff_source_file::{LineColumn, SourceFile};
 use ruff_text_size::{Ranged, TextRange, TextSize};
@@ -28,7 +27,6 @@ mod diff;
 mod github;
 mod gitlab;
 mod grouped;
-mod junit;
 mod sarif;
 mod text;
 
@@ -77,12 +75,13 @@ where
     );
 
     let span = Span::from(file).with_range(range);
-    let mut annotation = Annotation::primary(span);
-    if let Some(suggestion) = suggestion {
-        annotation = annotation.message(suggestion);
-    }
+    let annotation = Annotation::primary(span);
     diagnostic.annotate(annotation);
 
+    if let Some(suggestion) = suggestion {
+        diagnostic.help(suggestion);
+    }
+
     if let Some(fix) = fix {
         diagnostic.set_fix(fix);
     }

crates/ruff_linter/src/message/text.rs

@@ -6,13 +6,13 @@ use bitflags::bitflags;
 use colored::Colorize;
 use ruff_annotate_snippets::{Level, Renderer, Snippet};
 
-use ruff_db::diagnostic::{Diagnostic, SecondaryCode};
+use ruff_db::diagnostic::{
+    Diagnostic, DiagnosticFormat, DisplayDiagnosticConfig, SecondaryCode, ceil_char_boundary,
+};
 use ruff_notebook::NotebookIndex;
-use ruff_source_file::{LineColumn, OneIndexed};
+use ruff_source_file::OneIndexed;
 use ruff_text_size::{TextLen, TextRange, TextSize};
 
-use crate::Locator;
-use crate::fs::relativize_path;
 use crate::line_width::{IndentWidth, LineWidthBuilder};
 use crate::message::diff::Diff;
 use crate::message::{Emitter, EmitterContext};
@@ -21,8 +21,6 @@ use crate::settings::types::UnsafeFixes;
 bitflags! {
     #[derive(Default)]
     struct EmitterFlags: u8 {
-        /// Whether to show the fix status of a diagnostic.
-        const SHOW_FIX_STATUS   = 1 << 0;
         /// Whether to show the diff of a fix, for diagnostics that have a fix.
         const SHOW_FIX_DIFF     = 1 << 1;
         /// Whether to show the source code of a diagnostic.
@@ -30,17 +28,27 @@ bitflags! {
     }
 }
 
-#[derive(Default)]
 pub struct TextEmitter {
     flags: EmitterFlags,
-    unsafe_fixes: UnsafeFixes,
+    config: DisplayDiagnosticConfig,
+}
+
+impl Default for TextEmitter {
+    fn default() -> Self {
+        Self {
+            flags: EmitterFlags::default(),
+            config: DisplayDiagnosticConfig::default()
+                .format(DiagnosticFormat::Concise)
+                .hide_severity(true)
+                .color(!cfg!(test) && colored::control::SHOULD_COLORIZE.should_colorize()),
+        }
+    }
 }
 
 impl TextEmitter {
     #[must_use]
     pub fn with_show_fix_status(mut self, show_fix_status: bool) -> Self {
-        self.flags
-            .set(EmitterFlags::SHOW_FIX_STATUS, show_fix_status);
+        self.config = self.config.show_fix_status(show_fix_status);
         self
     }
 
@@ -58,7 +66,21 @@ impl TextEmitter {
 
     #[must_use]
     pub fn with_unsafe_fixes(mut self, unsafe_fixes: UnsafeFixes) -> Self {
-        self.unsafe_fixes = unsafe_fixes;
+        self.config = self
+            .config
+            .fix_applicability(unsafe_fixes.required_applicability());
+        self
+    }
+
+    #[must_use]
+    pub fn with_preview(mut self, preview: bool) -> Self {
+        self.config = self.config.preview(preview);
+        self
+    }
+
+    #[must_use]
+    pub fn with_color(mut self, color: bool) -> Self {
+        self.config = self.config.color(color);
         self
     }
 }
@@ -71,51 +93,10 @@ impl Emitter for TextEmitter {
         context: &EmitterContext,
     ) -> anyhow::Result<()> {
         for message in diagnostics {
+            write!(writer, "{}", message.display(context, &self.config))?;
+
             let filename = message.expect_ruff_filename();
-            write!(
-                writer,
-                "{path}{sep}",
-                path = relativize_path(&filename).bold(),
-                sep = ":".cyan(),
-            )?;
-
-            let start_location = message.expect_ruff_start_location();
             let notebook_index = context.notebook_index(&filename);
-
-            // Check if we're working on a jupyter notebook and translate positions with cell accordingly
-            let diagnostic_location = if let Some(notebook_index) = notebook_index {
-                write!(
-                    writer,
-                    "cell {cell}{sep}",
-                    cell = notebook_index
-                        .cell(start_location.line)
-                        .unwrap_or(OneIndexed::MIN),
-                    sep = ":".cyan(),
-                )?;
-
-                LineColumn {
-                    line: notebook_index
-                        .cell_row(start_location.line)
-                        .unwrap_or(OneIndexed::MIN),
-                    column: start_location.column,
-                }
-            } else {
-                start_location
-            };
-
-            writeln!(
-                writer,
-                "{row}{sep}{col}{sep} {code_and_body}",
-                row = diagnostic_location.line,
-                col = diagnostic_location.column,
-                sep = ":".cyan(),
-                code_and_body = RuleCodeAndBody {
-                    message,
-                    show_fix_status: self.flags.intersects(EmitterFlags::SHOW_FIX_STATUS),
-                    unsafe_fixes: self.unsafe_fixes,
-                }
-            )?;
-
             if self.flags.intersects(EmitterFlags::SHOW_SOURCE) {
                 // The `0..0` range is used to highlight file-level diagnostics.
                 if message.expect_range() != TextRange::default() {
@@ -186,7 +167,7 @@ pub(super) struct MessageCodeFrame<'a> {
 
 impl Display for MessageCodeFrame<'_> {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
-        let suggestion = self.message.suggestion();
+        let suggestion = self.message.first_help_text();
         let footers = if let Some(suggestion) = suggestion {
             vec![Level::Help.title(suggestion)]
         } else {
@@ -396,9 +377,8 @@ impl<'a> SourceCode<'a> {
         if self.text.as_bytes()[self.annotation_range.start().to_usize() - 1] != b'\n' {
             return self;
         }
-        let locator = Locator::new(&self.text);
         let start = self.annotation_range.start();
-        let end = locator.ceil_char_boundary(start + TextSize::from(1));
+        let end = ceil_char_boundary(&self.text, start + TextSize::from(1));
         SourceCode {
             annotation_range: TextRange::new(start, end),
             ..self

crates/ruff_linter/src/preview.rs

@@ -134,6 +134,26 @@ pub(crate) const fn is_fix_os_path_dirname_enabled(settings: &LinterSettings) ->
     settings.preview.is_enabled()
 }
 
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_chmod_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_rename_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_replace_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
+// https://github.com/astral-sh/ruff/pull/19404
+pub(crate) const fn is_fix_os_path_samefile_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
 // https://github.com/astral-sh/ruff/pull/19245
 pub(crate) const fn is_fix_os_getcwd_enabled(settings: &LinterSettings) -> bool {
     settings.preview.is_enabled()
@@ -205,3 +225,8 @@ pub(crate) const fn is_assert_raises_exception_call_enabled(settings: &LinterSet
 pub(crate) const fn is_add_future_annotations_imports_enabled(settings: &LinterSettings) -> bool {
     settings.preview.is_enabled()
 }
+
+// https://github.com/astral-sh/ruff/pull/19390
+pub(crate) const fn is_trailing_comma_type_params_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}

crates/ruff_linter/src/rules/eradicate/rules/commented_out_code.rs

@@ -5,7 +5,6 @@ use ruff_text_size::TextRange;
 
 use crate::Locator;
 use crate::checkers::ast::LintContext;
-use crate::settings::LinterSettings;
 use crate::{Edit, Fix, FixAvailability, Violation};
 
 use crate::rules::eradicate::detection::comment_contains_code;
@@ -51,7 +50,6 @@ pub(crate) fn commented_out_code(
     context: &LintContext,
     locator: &Locator,
     comment_ranges: &CommentRanges,
-    settings: &LinterSettings,
 ) {
     let mut comments = comment_ranges.into_iter().peekable();
     // Iterate over all comments in the document.
@@ -65,7 +63,9 @@ pub(crate) fn commented_out_code(
         }
 
         // Verify that the comment is on its own line, and that it contains code.
-        if is_own_line_comment(line) && comment_contains_code(line, &settings.task_tags[..]) {
+        if is_own_line_comment(line)
+            && comment_contains_code(line, &context.settings().task_tags[..])
+        {
             if let Some(mut diagnostic) =
                 context.report_diagnostic_if_enabled(CommentedOutCode, range)
             {

crates/ruff_linter/src/rules/flake8_blind_except/rules/blind_except.rs

@@ -47,9 +47,10 @@ use crate::checkers::ast::Checker;
 ///     raise
 /// ```
 ///
-/// Exceptions that are logged via `logging.exception()` or `logging.error()`
-/// with `exc_info` enabled will _not_ be flagged, as this is a common pattern
-/// for propagating exception traces:
+/// Exceptions that are logged via `logging.exception()` or are logged via
+/// `logging.error()` or `logging.critical()` with `exc_info` enabled will
+/// _not_ be flagged, as this is a common pattern for propagating exception
+/// traces:
 /// ```python
 /// try:
 ///     foo()
@@ -201,7 +202,7 @@ impl<'a> StatementVisitor<'a> for LogExceptionVisitor<'a> {
                             ) {
                                 if match attr.as_str() {
                                     "exception" => true,
-                                    "error" => arguments
+                                    "error" | "critical" => arguments
                                         .find_keyword("exc_info")
                                         .is_some_and(|keyword| is_const_true(&keyword.value)),
                                     _ => false,
@@ -214,7 +215,7 @@ impl<'a> StatementVisitor<'a> for LogExceptionVisitor<'a> {
                             if self.semantic.resolve_qualified_name(func).is_some_and(
                                 |qualified_name| match qualified_name.segments() {
                                     ["logging", "exception"] => true,
-                                    ["logging", "error"] => arguments
+                                    ["logging", "error" | "critical"] => arguments
                                         .find_keyword("exc_info")
                                         .is_some_and(|keyword| is_const_true(&keyword.value)),
                                     _ => false,

crates/ruff_linter/src/rules/flake8_blind_except/snapshots/ruff_linter__rules__flake8_blind_except__tests__BLE001_BLE.py.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_blind_except/mod.rs
-snapshot_kind: text
 ---
 BLE.py:25:8: BLE001 Do not catch blind exception: `BaseException`
    |
@@ -121,3 +120,30 @@ BLE.py:113:8: BLE001 Do not catch blind exception: `Exception`
     |        ^^^^^^^^^ BLE001
 114 |     error("...", exc_info=None)
     |
+
+BLE.py:119:8: BLE001 Do not catch blind exception: `Exception`
+    |
+117 | try:
+118 |     pass
+119 | except Exception:
+    |        ^^^^^^^^^ BLE001
+120 |     critical("...")
+    |
+
+BLE.py:125:8: BLE001 Do not catch blind exception: `Exception`
+    |
+123 | try:
+124 |     pass
+125 | except Exception:
+    |        ^^^^^^^^^ BLE001
+126 |     critical("...", exc_info=False)
+    |
+
+BLE.py:131:8: BLE001 Do not catch blind exception: `Exception`
+    |
+129 | try:
+130 |     pass
+131 | except Exception:
+    |        ^^^^^^^^^ BLE001
+132 |     critical("...", exc_info=None)
+    |

crates/ruff_linter/src/rules/flake8_commas/mod.rs

@@ -27,4 +27,23 @@ mod tests {
         assert_diagnostics!(snapshot, diagnostics);
         Ok(())
     }
+
+    #[test_case(Path::new("COM81.py"))]
+    #[test_case(Path::new("COM81_syntax_error.py"))]
+    fn preview_rules(path: &Path) -> Result<()> {
+        let snapshot = format!("preview__{}", path.to_string_lossy());
+        let diagnostics = test_path(
+            Path::new("flake8_commas").join(path).as_path(),
+            &settings::LinterSettings {
+                preview: crate::settings::types::PreviewMode::Enabled,
+                ..settings::LinterSettings::for_rules(vec![
+                    Rule::MissingTrailingComma,
+                    Rule::TrailingCommaOnBareTuple,
+                    Rule::ProhibitedTrailingComma,
+                ])
+            },
+        )?;
+        assert_diagnostics!(snapshot, diagnostics);
+        Ok(())
+    }
 }

crates/ruff_linter/src/rules/flake8_commas/rules/trailing_commas.rs

@@ -5,6 +5,8 @@ use ruff_text_size::{Ranged, TextRange};
 
 use crate::Locator;
 use crate::checkers::ast::LintContext;
+use crate::preview::is_trailing_comma_type_params_enabled;
+use crate::settings::LinterSettings;
 use crate::{AlwaysFixableViolation, Violation};
 use crate::{Edit, Fix};
 
@@ -24,6 +26,8 @@ enum TokenType {
     Def,
     For,
     Lambda,
+    Class,
+    Type,
     Irrelevant,
 }
 
@@ -69,6 +73,8 @@ impl From<(TokenKind, TextRange)> for SimpleToken {
             TokenKind::Lbrace => TokenType::OpeningCurlyBracket,
             TokenKind::Rbrace => TokenType::ClosingBracket,
             TokenKind::Def => TokenType::Def,
+            TokenKind::Class => TokenType::Class,
+            TokenKind::Type => TokenType::Type,
             TokenKind::For => TokenType::For,
             TokenKind::Lambda => TokenType::Lambda,
             // Import treated like a function.
@@ -98,6 +104,8 @@ enum ContextType {
     Dict,
     /// Lambda parameter list, e.g. `lambda a, b`.
     LambdaParameters,
+    /// Type parameter list, e.g. `def foo[T, U](): ...`
+    TypeParameters,
 }
 
 /// Comma context - described a comma-delimited "situation".
@@ -290,7 +298,7 @@ pub(crate) fn trailing_commas(
         }
 
         // Update the comma context stack.
-        let context = update_context(token, prev, prev_prev, &mut stack);
+        let context = update_context(token, prev, prev_prev, &mut stack, lint_context.settings());
 
         check_token(token, prev, prev_prev, context, locator, lint_context);
 
@@ -326,6 +334,7 @@ fn check_token(
             ContextType::No => false,
             ContextType::FunctionParameters => true,
             ContextType::CallArguments => true,
+            ContextType::TypeParameters => true,
             // `(1)` is not equivalent to `(1,)`.
             ContextType::Tuple => context.num_commas != 0,
             // `x[1]` is not equivalent to `x[1,]`.
@@ -408,6 +417,7 @@ fn update_context(
     prev: SimpleToken,
     prev_prev: SimpleToken,
     stack: &mut Vec<Context>,
+    settings: &LinterSettings,
 ) -> Context {
     let new_context = match token.ty {
         TokenType::OpeningBracket => match (prev.ty, prev_prev.ty) {
@@ -417,6 +427,17 @@ fn update_context(
             }
             _ => Context::new(ContextType::Tuple),
         },
+        TokenType::OpeningSquareBracket if is_trailing_comma_type_params_enabled(settings) => {
+            match (prev.ty, prev_prev.ty) {
+                (TokenType::Named, TokenType::Def | TokenType::Class | TokenType::Type) => {
+                    Context::new(ContextType::TypeParameters)
+                }
+                (TokenType::ClosingBracket | TokenType::Named | TokenType::String, _) => {
+                    Context::new(ContextType::Subscript)
+                }
+                _ => Context::new(ContextType::List),
+            }
+        }
         TokenType::OpeningSquareBracket => match prev.ty {
             TokenType::ClosingBracket | TokenType::Named | TokenType::String => {
                 Context::new(ContextType::Subscript)

crates/ruff_linter/src/rules/flake8_commas/snapshots/ruff_linter__rules__flake8_commas__tests__preview__COM81_syntax_error.py.snap

@@ -0,0 +1,30 @@
+---
+source: crates/ruff_linter/src/rules/flake8_commas/mod.rs
+---
+COM81_syntax_error.py:3:5: SyntaxError: Starred expression cannot be used here
+  |
+1 | # Check for `flake8-commas` violation for a file containing syntax errors.
+2 | (
+3 |     *args
+  |     ^^^^^
+4 | )
+  |
+
+COM81_syntax_error.py:6:9: SyntaxError: Type parameter list cannot be empty
+  |
+4 | )
+5 |
+6 | def foo[(param1='test', param2='test',):
+  |         ^
+7 |     pass
+  |
+
+COM81_syntax_error.py:6:38: COM819 Trailing comma prohibited
+  |
+4 | )
+5 |
+6 | def foo[(param1='test', param2='test',):
+  |                                      ^ COM819
+7 |     pass
+  |
+  = help: Remove trailing comma

crates/ruff_linter/src/rules/flake8_implicit_str_concat/rules/implicit.rs

@@ -11,7 +11,6 @@ use ruff_text_size::{Ranged, TextRange};
 
 use crate::Locator;
 use crate::checkers::ast::LintContext;
-use crate::settings::LinterSettings;
 use crate::{Edit, Fix, FixAvailability, Violation};
 
 /// ## What it does
@@ -108,13 +107,15 @@ pub(crate) fn implicit(
     tokens: &Tokens,
     locator: &Locator,
     indexer: &Indexer,
-    settings: &LinterSettings,
 ) {
     for (a_token, b_token) in tokens
         .iter()
         .filter(|token| {
             token.kind() != TokenKind::Comment
-                && (settings.flake8_implicit_str_concat.allow_multiline
+                && (context
+                    .settings()
+                    .flake8_implicit_str_concat
+                    .allow_multiline
                     || token.kind() != TokenKind::NonLogicalNewline)
         })
         .tuple_windows()

crates/ruff_linter/src/rules/flake8_pyi/rules/duplicate_union_member.rs

@@ -64,6 +64,7 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
     let mut diagnostics = Vec::new();
 
     let mut union_type = UnionKind::TypingUnion;
+    let mut optional_present = false;
     // Adds a member to `literal_exprs` if it is a `Literal` annotation
     let mut check_for_duplicate_members = |expr: &'a Expr, parent: &'a Expr| {
         if matches!(parent, Expr::BinOp(_)) {
@@ -74,6 +75,7 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
             && is_optional_type(checker, expr)
         {
             // If the union member is an `Optional`, add a virtual `None` literal.
+            optional_present = true;
             &VIRTUAL_NONE_LITERAL
         } else {
             expr
@@ -87,7 +89,7 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
                 DuplicateUnionMember {
                     duplicate_name: checker.generator().expr(virtual_expr),
                 },
-                // Use the real expression's range for diagnostics,
+                // Use the real expression's range for diagnostics.
                 expr.range(),
             ));
         }
@@ -104,6 +106,13 @@ pub(crate) fn duplicate_union_member<'a>(checker: &Checker, expr: &'a Expr) {
         return;
     }
 
+    // Do not reduce `Union[None, ... None]` to avoid introducing a `TypeError` unintentionally
+    // e.g. `isinstance(None, Union[None, None])`, if reduced to `isinstance(None, None)`, causes
+    // `TypeError: isinstance() arg 2 must be a type, a tuple of types, or a union` to throw.
+    if unique_nodes.iter().all(|expr| expr.is_none_literal_expr()) && !optional_present {
+        return;
+    }
+
     // Mark [`Fix`] as unsafe when comments are in range.
     let applicability = if checker.comment_ranges().intersects(expr.range()) {
         Applicability::Unsafe

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__PYI016_PYI016.py.snap

@@ -974,6 +974,8 @@ PYI016.py:143:61: PYI016 [*] Duplicate union member `complex`
 143     |-field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
     143 |+field48: typing.Union[typing.Optional[complex], complex]
 144 144 | field49: typing.Optional[complex | complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
 
 PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
     |
@@ -981,6 +983,8 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144 | field49: typing.Optional[complex | complex] | complex
     |                                    ^^^^^^^ PYI016
+145 |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
     |
     = help: Remove duplicate union member `complex`
 
@@ -990,3 +994,15 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144     |-field49: typing.Optional[complex | complex] | complex
     144 |+field49: typing.Optional[complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 147 | # Should throw duplicate union member but not fix
+
+PYI016.py:148:37: PYI016 Duplicate union member `None`
+    |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 | # Should throw duplicate union member but not fix
+148 | isinstance(None, typing.Union[None, None])
+    |                                     ^^^^ PYI016
+    |
+    = help: Remove duplicate union member `None`

crates/ruff_linter/src/rules/flake8_pyi/snapshots/ruff_linter__rules__flake8_pyi__tests__preview__PYI016_PYI016.py.snap

@@ -1162,6 +1162,8 @@ PYI016.py:143:61: PYI016 [*] Duplicate union member `complex`
 143     |-field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
     143 |+field48: typing.Union[None, complex]
 144 144 | field49: typing.Optional[complex | complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
 
 PYI016.py:143:72: PYI016 [*] Duplicate union member `complex`
     |
@@ -1179,6 +1181,8 @@ PYI016.py:143:72: PYI016 [*] Duplicate union member `complex`
 143     |-field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
     143 |+field48: typing.Union[None, complex]
 144 144 | field49: typing.Optional[complex | complex] | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
 
 PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
     |
@@ -1186,6 +1190,8 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144 | field49: typing.Optional[complex | complex] | complex
     |                                    ^^^^^^^ PYI016
+145 |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
     |
     = help: Remove duplicate union member `complex`
 
@@ -1195,6 +1201,9 @@ PYI016.py:144:36: PYI016 [*] Duplicate union member `complex`
 143 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144     |-field49: typing.Optional[complex | complex] | complex
     144 |+field49: None | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 147 | # Should throw duplicate union member but not fix
 
 PYI016.py:144:47: PYI016 [*] Duplicate union member `complex`
     |
@@ -1202,6 +1211,8 @@ PYI016.py:144:47: PYI016 [*] Duplicate union member `complex`
 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144 | field49: typing.Optional[complex | complex] | complex
     |                                               ^^^^^^^ PYI016
+145 |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
     |
     = help: Remove duplicate union member `complex`
 
@@ -1211,3 +1222,15 @@ PYI016.py:144:47: PYI016 [*] Duplicate union member `complex`
 143 143 | field48: typing.Union[typing.Optional[typing.Union[complex, complex]], complex]
 144     |-field49: typing.Optional[complex | complex] | complex
     144 |+field49: None | complex
+145 145 | 
+146 146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 147 | # Should throw duplicate union member but not fix
+
+PYI016.py:148:37: PYI016 Duplicate union member `None`
+    |
+146 | # Regression test for https://github.com/astral-sh/ruff/issues/19403
+147 | # Should throw duplicate union member but not fix
+148 | isinstance(None, typing.Union[None, None])
+    |                                     ^^^^ PYI016
+    |
+    = help: Remove duplicate union member `None`

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

@@ -1,8 +1,8 @@
 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_python_ast::{self as ast, Expr, ExprCall};
+use ruff_python_semantic::{SemanticModel, analyze::typing};
 use ruff_text_size::Ranged;
 
 pub(crate) fn is_keyword_only_argument_non_default(arguments: &ast::Arguments, name: &str) -> bool {
@@ -72,3 +72,85 @@ pub(crate) fn check_os_pathlib_single_arg_calls(
         });
     }
 }
+
+pub(crate) fn get_name_expr(expr: &Expr) -> Option<&ast::ExprName> {
+    match expr {
+        Expr::Name(name) => Some(name),
+        Expr::Call(ExprCall { func, .. }) => get_name_expr(func),
+        _ => None,
+    }
+}
+
+/// Returns `true` if the given expression looks like a file descriptor, i.e., if it is an integer.
+pub(crate) fn is_file_descriptor(expr: &Expr, semantic: &SemanticModel) -> bool {
+    if matches!(
+        expr,
+        Expr::NumberLiteral(ast::ExprNumberLiteral {
+            value: ast::Number::Int(_),
+            ..
+        })
+    ) {
+        return true;
+    }
+
+    let Some(name) = get_name_expr(expr) else {
+        return false;
+    };
+
+    let Some(binding) = semantic.only_binding(name).map(|id| semantic.binding(id)) else {
+        return false;
+    };
+
+    typing::is_int(binding, semantic)
+}
+
+pub(crate) fn check_os_pathlib_two_arg_calls(
+    checker: &Checker,
+    call: &ExprCall,
+    attr: &str,
+    path_arg: &str,
+    second_arg: &str,
+    fix_enabled: bool,
+    violation: impl Violation,
+) {
+    let range = call.range();
+    let mut diagnostic = checker.report_diagnostic(violation, call.func.range());
+
+    let (Some(path_expr), Some(second_expr)) = (
+        call.arguments.find_argument_value(path_arg, 0),
+        call.arguments.find_argument_value(second_arg, 1),
+    ) else {
+        return;
+    };
+
+    let path_code = checker.locator().slice(path_expr.range());
+    let second_code = checker.locator().slice(second_expr.range());
+
+    if fix_enabled {
+        diagnostic.try_set_fix(|| {
+            let (import_edit, binding) = checker.importer().get_or_import_symbol(
+                &ImportRequest::import("pathlib", "Path"),
+                call.start(),
+                checker.semantic(),
+            )?;
+
+            let replacement = if is_pathlib_path_call(checker, path_expr) {
+                format!("{path_code}.{attr}({second_code})")
+            } else {
+                format!("{binding}({path_code}).{attr}({second_code})")
+            };
+
+            let applicability = if checker.comment_ranges().intersects(range) {
+                Applicability::Unsafe
+            } else {
+                Applicability::Safe
+            };
+
+            Ok(Fix::applicable_edits(
+                Edit::range_replacement(replacement, range),
+                [import_edit],
+                applicability,
+            ))
+        });
+    }
+}

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

@@ -1,5 +1,6 @@
 pub(crate) use glob_rule::*;
 pub(crate) use invalid_pathlib_with_suffix::*;
+pub(crate) use os_chmod::*;
 pub(crate) use os_getcwd::*;
 pub(crate) use os_path_abspath::*;
 pub(crate) use os_path_basename::*;
@@ -14,8 +15,11 @@ 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_path_samefile::*;
 pub(crate) use os_readlink::*;
 pub(crate) use os_remove::*;
+pub(crate) use os_rename::*;
+pub(crate) use os_replace::*;
 pub(crate) use os_rmdir::*;
 pub(crate) use os_sep_split::*;
 pub(crate) use os_unlink::*;
@@ -24,6 +28,7 @@ pub(crate) use replaceable_by_pathlib::*;
 
 mod glob_rule;
 mod invalid_pathlib_with_suffix;
+mod os_chmod;
 mod os_getcwd;
 mod os_path_abspath;
 mod os_path_basename;
@@ -38,8 +43,11 @@ mod os_path_isabs;
 mod os_path_isdir;
 mod os_path_isfile;
 mod os_path_islink;
+mod os_path_samefile;
 mod os_readlink;
 mod os_remove;
+mod os_rename;
+mod os_replace;
 mod os_rmdir;
 mod os_sep_split;
 mod os_unlink;

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

@@ -0,0 +1,94 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_chmod_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    check_os_pathlib_two_arg_calls, is_file_descriptor, is_keyword_only_argument_non_default,
+};
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.chmod`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.chmod()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.chmod()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.chmod("file.py", 0o444)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("file.py").chmod(0o444)
+/// ```
+///
+/// ## 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.chmod`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.chmod)
+/// - [Python documentation: `os.chmod`](https://docs.python.org/3/library/os.html#os.chmod)
+/// - [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 OsChmod;
+
+impl Violation for OsChmod {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.chmod()` should be replaced by `Path.chmod()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).chmod(...)`".to_string())
+    }
+}
+
+/// PTH101
+pub(crate) fn os_chmod(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "chmod"] {
+        return;
+    }
+
+    // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.
+    // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.chmod)
+    // ```text
+    //           0     1          2               3
+    // os.chmod(path, mode, *, dir_fd=None, follow_symlinks=True)
+    // ```
+    if call
+        .arguments
+        .find_argument_value("path", 0)
+        .is_some_and(|expr| is_file_descriptor(expr, checker.semantic()))
+        || is_keyword_only_argument_non_default(&call.arguments, "dir_fd")
+    {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "chmod",
+        "path",
+        "mode",
+        is_fix_os_chmod_enabled(checker.settings()),
+        OsChmod,
+    );
+}

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

@@ -0,0 +1,77 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_path_samefile_enabled;
+use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_two_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.samefile`.
+///
+/// ## 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.samefile()` can improve readability over the `os.path`
+/// module's counterparts (e.g., `os.path.samefile()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.path.samefile("f1.py", "f2.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("f1.py").samefile("f2.py")
+/// ```
+///
+/// ## 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.samefile`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.samefile)
+/// - [Python documentation: `os.path.samefile`](https://docs.python.org/3/library/os.path.html#os.path.samefile)
+/// - [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 OsPathSamefile;
+
+impl Violation for OsPathSamefile {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.path.samefile()` should be replaced by `Path.samefile()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).samefile()`".to_string())
+    }
+}
+
+/// PTH121
+pub(crate) fn os_path_samefile(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "path", "samefile"] {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "samefile",
+        "f1",
+        "f2",
+        is_fix_os_path_samefile_enabled(checker.settings()),
+        OsPathSamefile,
+    );
+}

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

@@ -0,0 +1,91 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_rename_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    check_os_pathlib_two_arg_calls, is_keyword_only_argument_non_default,
+};
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.rename`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.rename()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.rename()`).
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.rename("old.py", "new.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("old.py").rename("new.py")
+/// ```
+///
+/// ## 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.rename`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.rename)
+/// - [Python documentation: `os.rename`](https://docs.python.org/3/library/os.html#os.rename)
+/// - [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 OsRename;
+
+impl Violation for OsRename {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.rename()` should be replaced by `Path.rename()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).rename(...)`".to_string())
+    }
+}
+
+/// PTH104
+pub(crate) fn os_rename(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "rename"] {
+        return;
+    }
+    // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
+    // set to non-default values.
+    // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.rename)
+    // ```text
+    //            0    1           2                  3
+    // os.rename(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
+    // ```
+    if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
+        || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
+    {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "rename",
+        "src",
+        "dst",
+        is_fix_os_rename_enabled(checker.settings()),
+        OsRename,
+    );
+}

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

@@ -0,0 +1,94 @@
+use crate::checkers::ast::Checker;
+use crate::preview::is_fix_os_replace_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    check_os_pathlib_two_arg_calls, is_keyword_only_argument_non_default,
+};
+use crate::{FixAvailability, Violation};
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::ExprCall;
+
+/// ## What it does
+/// Checks for uses of `os.replace`.
+///
+/// ## Why is this bad?
+/// `pathlib` offers a high-level API for path manipulation, as compared to
+/// the lower-level API offered by `os`. When possible, using `Path` object
+/// methods such as `Path.replace()` can improve readability over the `os`
+/// module's counterparts (e.g., `os.replace()`).
+///
+/// Note that `os` functions may be preferable if performance is a concern,
+/// e.g., in hot loops.
+///
+/// ## Examples
+/// ```python
+/// import os
+///
+/// os.replace("old.py", "new.py")
+/// ```
+///
+/// Use instead:
+/// ```python
+/// from pathlib import Path
+///
+/// Path("old.py").replace("new.py")
+/// ```
+///
+/// ## 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.replace`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.replace)
+/// - [Python documentation: `os.replace`](https://docs.python.org/3/library/os.html#os.replace)
+/// - [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 OsReplace;
+
+impl Violation for OsReplace {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        "`os.replace()` should be replaced by `Path.replace()`".to_string()
+    }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Replace with `Path(...).replace(...)`".to_string())
+    }
+}
+
+/// PTH105
+pub(crate) fn os_replace(checker: &Checker, call: &ExprCall, segments: &[&str]) {
+    if segments != ["os", "replace"] {
+        return;
+    }
+    // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
+    // set to non-default values.
+    // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.replace)
+    // ```text
+    //             0    1           2                3
+    // os.replace(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
+    // ```
+    if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
+        || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
+    {
+        return;
+    }
+
+    check_os_pathlib_two_arg_calls(
+        checker,
+        call,
+        "replace",
+        "src",
+        "dst",
+        is_fix_os_replace_enabled(checker.settings()),
+        OsReplace,
+    );
+}

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

@@ -1,14 +1,16 @@
 use ruff_python_ast::{self as ast, Expr, ExprBooleanLiteral, ExprCall};
-use ruff_python_semantic::SemanticModel;
-use ruff_python_semantic::analyze::typing;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
-use crate::rules::flake8_use_pathlib::helpers::is_keyword_only_argument_non_default;
-use crate::rules::flake8_use_pathlib::rules::Glob;
-use crate::rules::flake8_use_pathlib::violations::{
-    BuiltinOpen, Joiner, OsChmod, OsListdir, OsMakedirs, OsMkdir, OsPathJoin, OsPathSamefile,
-    OsPathSplitext, OsRename, OsReplace, OsStat, OsSymlink, PyPath,
+use crate::rules::flake8_use_pathlib::helpers::{
+    is_file_descriptor, is_keyword_only_argument_non_default,
+};
+use crate::rules::flake8_use_pathlib::{
+    rules::Glob,
+    violations::{
+        BuiltinOpen, Joiner, OsListdir, OsMakedirs, OsMkdir, OsPathJoin, OsPathSplitext, OsStat,
+        OsSymlink, PyPath,
+    },
 };
 
 pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
@@ -18,24 +20,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
 
     let range = call.func.range();
     match qualified_name.segments() {
-        // PTH101
-        ["os", "chmod"] => {
-            // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.
-            // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.chmod)
-            // ```text
-            //           0     1          2               3
-            // os.chmod(path, mode, *, dir_fd=None, follow_symlinks=True)
-            // ```
-            if call
-                .arguments
-                .find_argument_value("path", 0)
-                .is_some_and(|expr| is_file_descriptor(expr, checker.semantic()))
-                || is_keyword_only_argument_non_default(&call.arguments, "dir_fd")
-            {
-                return;
-            }
-            checker.report_diagnostic_if_enabled(OsChmod, range)
-        }
         // PTH102
         ["os", "makedirs"] => checker.report_diagnostic_if_enabled(OsMakedirs, range),
         // PTH103
@@ -51,38 +35,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
             }
             checker.report_diagnostic_if_enabled(OsMkdir, range)
         }
-        // PTH104
-        ["os", "rename"] => {
-            // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
-            // set to non-default values.
-            // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.rename)
-            // ```text
-            //           0    1       2                3
-            // os.rename(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
-            // ```
-            if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
-                || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
-            {
-                return;
-            }
-            checker.report_diagnostic_if_enabled(OsRename, range)
-        }
-        // PTH105
-        ["os", "replace"] => {
-            // `src_dir_fd` and `dst_dir_fd` are not supported by pathlib, so check if they are
-            // set to non-default values.
-            // Signature as of Python 3.13 (https://docs.python.org/3/library/os.html#os.replace)
-            // ```text
-            //              0    1       2                3
-            // os.replace(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
-            // ```
-            if is_keyword_only_argument_non_default(&call.arguments, "src_dir_fd")
-                || is_keyword_only_argument_non_default(&call.arguments, "dst_dir_fd")
-            {
-                return;
-            }
-            checker.report_diagnostic_if_enabled(OsReplace, range)
-        }
         // PTH116
         ["os", "stat"] => {
             // `dir_fd` is not supported by pathlib, so check if it's set to non-default values.
@@ -124,8 +76,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
             },
             range,
         ),
-        // PTH121
-        ["os", "path", "samefile"] => checker.report_diagnostic_if_enabled(OsPathSamefile, range),
         // PTH122
         ["os", "path", "splitext"] => checker.report_diagnostic_if_enabled(OsPathSplitext, range),
         // PTH211
@@ -234,37 +184,6 @@ pub(crate) fn replaceable_by_pathlib(checker: &Checker, call: &ExprCall) {
     };
 }
 
-/// Returns `true` if the given expression looks like a file descriptor, i.e., if it is an integer.
-fn is_file_descriptor(expr: &Expr, semantic: &SemanticModel) -> bool {
-    if matches!(
-        expr,
-        Expr::NumberLiteral(ast::ExprNumberLiteral {
-            value: ast::Number::Int(_),
-            ..
-        })
-    ) {
-        return true;
-    }
-
-    let Some(name) = get_name_expr(expr) else {
-        return false;
-    };
-
-    let Some(binding) = semantic.only_binding(name).map(|id| semantic.binding(id)) else {
-        return false;
-    };
-
-    typing::is_int(binding, semantic)
-}
-
-fn get_name_expr(expr: &Expr) -> Option<&ast::ExprName> {
-    match expr {
-        Expr::Name(name) => Some(name),
-        Expr::Call(ExprCall { func, .. }) => get_name_expr(func),
-        _ => None,
-    }
-}
-
 /// Returns `true` if argument `name` is set to a non-default `None` value.
 fn is_argument_non_default(arguments: &ast::Arguments, name: &str, position: usize) -> bool {
     arguments

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__full_name.py.snap

@@ -20,6 +20,7 @@ full_name.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = os.mkdir(p)
 10 | os.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 full_name.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ full_name.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | os.replace(p)
 13 | os.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | os.rmdir(p)
 14 | os.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 full_name.py:13:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -253,6 +256,7 @@ full_name.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
 31 | os.path.splitext(p)
 32 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 full_name.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_as.py.snap

@@ -20,6 +20,7 @@ import_as.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = foo.mkdir(p)
 10 | foo.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_as.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ import_as.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | foo.replace(p)
 13 | foo.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | foo.rmdir(p)
 14 | foo.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_as.py:13:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -252,6 +255,7 @@ import_as.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
    | ^^^^^^^^^^^^^^ PTH121
 31 | foo_p.splitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_as.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_from.py.snap

@@ -20,6 +20,7 @@ import_from.py:10:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 11 | aaa = mkdir(p)
 12 | makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from.py:11:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ import_from.py:13:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 14 | replace(p)
 15 | rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()
 15 | rmdir(p)
 16 | remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from.py:15:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -253,6 +256,7 @@ import_from.py:32:1: PTH121 `os.path.samefile()` should be replaced by `Path.sam
 33 | splitext(p)
 34 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from.py:33:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |
@@ -289,3 +293,36 @@ import_from.py:43:10: PTH123 `open()` should be replaced by `Path.open()`
 43 |     with open(p) as _: ...  # Error
    |          ^^^^ PTH123
    |
+
+import_from.py:53:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
+   |
+51 | file = "file_1.py"
+52 |
+53 | rename(file, "file_2.py")
+   | ^^^^^^ PTH104
+54 |
+55 | rename(
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+import_from.py:55:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
+   |
+53 | rename(file, "file_2.py")
+54 |
+55 | rename(
+   | ^^^^^^ PTH104
+56 |     # commment 1
+57 |     file, # comment 2
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+import_from.py:63:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
+   |
+61 | )
+62 |
+63 | rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+   | ^^^^^^ PTH104
+64 |
+65 | rename(file, "file_2.py", src_dir_fd=1)
+   |
+   = help: Replace with `Path(...).rename(...)`

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__import_from_as.py.snap

@@ -20,6 +20,7 @@ import_from_as.py:15:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 16 | aaa = xmkdir(p)
 17 | xmakedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from_as.py:16:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -50,6 +51,7 @@ import_from_as.py:18:1: PTH104 `os.rename()` should be replaced by `Path.rename(
 19 | xreplace(p)
 20 | xrmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -60,6 +62,7 @@ import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replac
 20 | xrmdir(p)
 21 | xremove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from_as.py:20:1: PTH106 `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -252,6 +255,7 @@ import_from_as.py:37:1: PTH121 `os.path.samefile()` should be replaced by `Path.
    | ^^^^^^^^^ PTH121
 38 | xsplitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from_as.py:38:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_full_name.py.snap

@@ -34,6 +34,7 @@ full_name.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = os.mkdir(p)
 10 | os.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 full_name.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -64,6 +65,7 @@ full_name.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | os.replace(p)
 13 | os.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -74,6 +76,7 @@ full_name.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | os.rmdir(p)
 14 | os.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 full_name.py:13:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -471,6 +474,7 @@ full_name.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
 31 | os.path.splitext(p)
 32 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 full_name.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_as.py.snap

@@ -34,6 +34,7 @@ import_as.py:8:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
  9 | aaa = foo.mkdir(p)
 10 | foo.makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_as.py:9:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -64,6 +65,7 @@ import_as.py:11:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 12 | foo.replace(p)
 13 | foo.rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -74,6 +76,7 @@ import_as.py:12:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
 13 | foo.rmdir(p)
 14 | foo.remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_as.py:13:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -469,6 +472,7 @@ import_as.py:30:1: PTH121 `os.path.samefile()` should be replaced by `Path.samef
    | ^^^^^^^^^^^^^^ PTH121
 31 | foo_p.splitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_as.py:31:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_from.py.snap

@@ -35,6 +35,7 @@ import_from.py:10:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 11 | aaa = mkdir(p)
 12 | makedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from.py:11:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -65,6 +66,7 @@ import_from.py:13:1: PTH104 `os.rename()` should be replaced by `Path.rename()`
 14 | replace(p)
 15 | rmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -75,6 +77,7 @@ import_from.py:14:1: PTH105 `os.replace()` should be replaced by `Path.replace()
 15 | rmdir(p)
 16 | remove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from.py:15:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -484,6 +487,7 @@ import_from.py:32:1: PTH121 `os.path.samefile()` should be replaced by `Path.sam
 33 | splitext(p)
 34 | with open(p) as fp:
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from.py:33:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |
@@ -520,3 +524,95 @@ import_from.py:43:10: PTH123 `open()` should be replaced by `Path.open()`
 43 |     with open(p) as _: ...  # Error
    |          ^^^^ PTH123
    |
+
+import_from.py:53:1: PTH104 [*] `os.rename()` should be replaced by `Path.rename()`
+   |
+51 | file = "file_1.py"
+52 |
+53 | rename(file, "file_2.py")
+   | ^^^^^^ PTH104
+54 |
+55 | rename(
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+ℹ Safe fix
+2  2  | from os import remove, unlink, getcwd, readlink, stat
+3  3  | from os.path import abspath, exists, expanduser, isdir, isfile, islink
+4  4  | from os.path import isabs, join, basename, dirname, samefile, splitext
+   5  |+import pathlib
+5  6  | 
+6  7  | p = "/foo"
+7  8  | q = "bar"
+--------------------------------------------------------------------------------
+50 51 | 
+51 52 | file = "file_1.py"
+52 53 | 
+53    |-rename(file, "file_2.py")
+   54 |+pathlib.Path(file).rename("file_2.py")
+54 55 | 
+55 56 | rename(
+56 57 |     # commment 1
+
+import_from.py:55:1: PTH104 [*] `os.rename()` should be replaced by `Path.rename()`
+   |
+53 | rename(file, "file_2.py")
+54 |
+55 | rename(
+   | ^^^^^^ PTH104
+56 |     # commment 1
+57 |     file, # comment 2
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+ℹ Unsafe fix
+2  2  | from os import remove, unlink, getcwd, readlink, stat
+3  3  | from os.path import abspath, exists, expanduser, isdir, isfile, islink
+4  4  | from os.path import isabs, join, basename, dirname, samefile, splitext
+   5  |+import pathlib
+5  6  | 
+6  7  | p = "/foo"
+7  8  | q = "bar"
+--------------------------------------------------------------------------------
+52 53 | 
+53 54 | rename(file, "file_2.py")
+54 55 | 
+55    |-rename(
+56    |-    # commment 1
+57    |-    file, # comment 2
+58    |-    "file_2.py"
+59    |-    ,
+60    |-    # comment 3
+61    |-)
+   56 |+pathlib.Path(file).rename("file_2.py")
+62 57 | 
+63 58 | rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+64 59 | 
+
+import_from.py:63:1: PTH104 [*] `os.rename()` should be replaced by `Path.rename()`
+   |
+61 | )
+62 |
+63 | rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+   | ^^^^^^ PTH104
+64 |
+65 | rename(file, "file_2.py", src_dir_fd=1)
+   |
+   = help: Replace with `Path(...).rename(...)`
+
+ℹ Safe fix
+2  2  | from os import remove, unlink, getcwd, readlink, stat
+3  3  | from os.path import abspath, exists, expanduser, isdir, isfile, islink
+4  4  | from os.path import isabs, join, basename, dirname, samefile, splitext
+   5  |+import pathlib
+5  6  | 
+6  7  | p = "/foo"
+7  8  | q = "bar"
+--------------------------------------------------------------------------------
+60 61 |     # comment 3
+61 62 | )
+62 63 | 
+63    |-rename(file, "file_2.py", src_dir_fd=None, dst_dir_fd=None)
+   64 |+pathlib.Path(file).rename("file_2.py")
+64 65 | 
+65 66 | rename(file, "file_2.py", src_dir_fd=1)

crates/ruff_linter/src/rules/flake8_use_pathlib/snapshots/ruff_linter__rules__flake8_use_pathlib__tests__preview_import_from_as.py.snap

@@ -35,6 +35,7 @@ import_from_as.py:15:6: PTH101 `os.chmod()` should be replaced by `Path.chmod()`
 16 | aaa = xmkdir(p)
 17 | xmakedirs(p)
    |
+   = help: Replace with `Path(...).chmod(...)`
 
 import_from_as.py:16:7: PTH102 `os.mkdir()` should be replaced by `Path.mkdir()`
    |
@@ -65,6 +66,7 @@ import_from_as.py:18:1: PTH104 `os.rename()` should be replaced by `Path.rename(
 19 | xreplace(p)
 20 | xrmdir(p)
    |
+   = help: Replace with `Path(...).rename(...)`
 
 import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replace()`
    |
@@ -75,6 +77,7 @@ import_from_as.py:19:1: PTH105 `os.replace()` should be replaced by `Path.replac
 20 | xrmdir(p)
 21 | xremove(p)
    |
+   = help: Replace with `Path(...).replace(...)`
 
 import_from_as.py:20:1: PTH106 [*] `os.rmdir()` should be replaced by `Path.rmdir()`
    |
@@ -482,6 +485,7 @@ import_from_as.py:37:1: PTH121 `os.path.samefile()` should be replaced by `Path.
    | ^^^^^^^^^ PTH121
 38 | xsplitext(p)
    |
+   = help: Replace with `Path(...).samefile()`
 
 import_from_as.py:38:1: PTH122 `os.path.splitext()` should be replaced by `Path.suffix`, `Path.stem`, and `Path.parent`
    |

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

@@ -2,51 +2,6 @@ use ruff_macros::{ViolationMetadata, derive_message_formats};
 
 use crate::Violation;
 
-/// ## What it does
-/// Checks for uses of `os.chmod`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.chmod()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.chmod()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.chmod("file.py", 0o444)
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("file.py").chmod(0o444)
-/// ```
-///
-/// ## 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: `Path.chmod`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.chmod)
-/// - [Python documentation: `os.chmod`](https://docs.python.org/3/library/os.html#os.chmod)
-/// - [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 OsChmod;
-
-impl Violation for OsChmod {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.chmod()` should be replaced by `Path.chmod()`".to_string()
-    }
-}
-
 /// ## What it does
 /// Checks for uses of `os.makedirs`.
 ///
@@ -137,99 +92,6 @@ impl Violation for OsMkdir {
     }
 }
 
-/// ## What it does
-/// Checks for uses of `os.rename`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.rename()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.rename()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.rename("old.py", "new.py")
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("old.py").rename("new.py")
-/// ```
-///
-/// ## 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: `Path.rename`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.rename)
-/// - [Python documentation: `os.rename`](https://docs.python.org/3/library/os.html#os.rename)
-/// - [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 OsRename;
-
-impl Violation for OsRename {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.rename()` should be replaced by `Path.rename()`".to_string()
-    }
-}
-
-/// ## What it does
-/// Checks for uses of `os.replace`.
-///
-/// ## Why is this bad?
-/// `pathlib` offers a high-level API for path manipulation, as compared to
-/// the lower-level API offered by `os`. When possible, using `Path` object
-/// methods such as `Path.replace()` can improve readability over the `os`
-/// module's counterparts (e.g., `os.replace()`).
-///
-/// Note that `os` functions may be preferable if performance is a concern,
-/// e.g., in hot loops.
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.replace("old.py", "new.py")
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("old.py").replace("new.py")
-/// ```
-///
-/// ## 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: `Path.replace`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.replace)
-/// - [Python documentation: `os.replace`](https://docs.python.org/3/library/os.html#os.replace)
-/// - [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 OsReplace;
-
-impl Violation for OsReplace {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.replace()` should be replaced by `Path.replace()`".to_string()
-    }
-}
-
 /// ## What it does
 /// Checks for uses of `os.stat`.
 ///
@@ -347,51 +209,6 @@ pub(crate) enum Joiner {
     Joinpath,
 }
 
-/// ## What it does
-/// Checks for uses of `os.path.samefile`.
-///
-/// ## 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.samefile()` can improve readability over the `os.path`
-/// module's counterparts (e.g., `os.path.samefile()`).
-///
-/// ## Examples
-/// ```python
-/// import os
-///
-/// os.path.samefile("f1.py", "f2.py")
-/// ```
-///
-/// Use instead:
-/// ```python
-/// from pathlib import Path
-///
-/// Path("f1.py").samefile("f2.py")
-/// ```
-///
-/// ## 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: `Path.samefile`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.samefile)
-/// - [Python documentation: `os.path.samefile`](https://docs.python.org/3/library/os.path.html#os.path.samefile)
-/// - [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 OsPathSamefile;
-
-impl Violation for OsPathSamefile {
-    #[derive_message_formats]
-    fn message(&self) -> String {
-        "`os.path.samefile()` should be replaced by `Path.samefile()`".to_string()
-    }
-}
-
 /// ## What it does
 /// Checks for uses of `os.path.splitext`.
 ///

crates/ruff_linter/src/rules/pep8_naming/rules/invalid_function_name.rs

@@ -100,7 +100,7 @@ pub(crate) fn invalid_function_name(
         return;
     }
 
-    // Ignore the do_* methods of the http.server.BaseHTTPRequestHandler class
+    // Ignore the do_* methods of the http.server.BaseHTTPRequestHandler class and its subclasses
     if name.starts_with("do_")
         && parent_class.is_some_and(|class| {
             any_base_class(class, semantic, &mut |superclass| {
@@ -108,7 +108,13 @@ pub(crate) fn invalid_function_name(
                 qualified.is_some_and(|name| {
                     matches!(
                         name.segments(),
-                        ["http", "server", "BaseHTTPRequestHandler"]
+                        [
+                            "http",
+                            "server",
+                            "BaseHTTPRequestHandler"
+                                | "CGIHTTPRequestHandler"
+                                | "SimpleHTTPRequestHandler"
+                        ]
                     )
                 })
             })

crates/ruff_linter/src/rules/pep8_naming/snapshots/ruff_linter__rules__pep8_naming__tests__N802_N802.py.snap

@@ -55,3 +55,21 @@ N802.py:84:9: N802 Function name `dont_GET` should be lowercase
    |         ^^^^^^^^ N802
 85 |         pass
    |
+
+N802.py:95:9: N802 Function name `dont_OPTIONS` should be lowercase
+   |
+93 |         pass
+94 |
+95 |     def dont_OPTIONS(self):
+   |         ^^^^^^^^^^^^ N802
+96 |         pass
+   |
+
+N802.py:106:9: N802 Function name `dont_OPTIONS` should be lowercase
+    |
+104 |         pass
+105 |
+106 |     def dont_OPTIONS(self):
+    |         ^^^^^^^^^^^^ N802
+107 |         pass
+    |