[ty] implement typing.NewType

Part of #994. This adds a new field to the Specialization struct to
record when we're dealing with the top or bottom materialization of an
invariant generic. It also implements subtyping and assignability for
these objects.

Next planned steps after this is done are to implement other operations
on top/bottom materializations; probably attribute access is an
important one.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>

.github/workflows/ci.yaml

@@ -441,7 +441,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install cargo-binstall"
-        uses: cargo-bins/cargo-binstall@79e4beb1e02f733a26129a6bf26c37dab4ab3307 # v1.14.4
+        uses: cargo-bins/cargo-binstall@0dca8cf8dfb40cb77a29cece06933ce674674523 # v1.15.1
         with:
           tool: cargo-fuzz@0.11.2
       - name: "Install cargo-fuzz"
@@ -463,7 +463,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         name: Download Ruff binary to test
         id: download-cached-binary
@@ -664,7 +664,7 @@ jobs:
           branch: ${{ github.event.pull_request.base.ref }}
           workflow: "ci.yaml"
           check_artifacts: true
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - name: Fuzz
         env:
           FORCE_COLOR: 1
@@ -694,7 +694,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: cargo-bins/cargo-binstall@79e4beb1e02f733a26129a6bf26c37dab4ab3307 # v1.14.4
+      - uses: cargo-bins/cargo-binstall@0dca8cf8dfb40cb77a29cece06933ce674674523 # v1.15.1
       - run: cargo binstall --no-confirm cargo-shear
       - run: cargo shear
 
@@ -734,7 +734,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
       - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
         with:
@@ -777,7 +777,7 @@ jobs:
       - name: "Install Rust toolchain"
         run: rustup show
       - name: Install uv
-        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - name: "Install Insiders dependencies"
         if: ${{ env.MKDOCS_INSIDERS_SSH_KEY_EXISTS == 'true' }}
         run: uv pip install -r docs/requirements-insiders.txt --system
@@ -909,7 +909,7 @@ jobs:
           persist-credentials: false
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
 
       - name: "Install Rust toolchain"
         run: rustup show
@@ -942,7 +942,7 @@ jobs:
           persist-credentials: false
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
 
       - name: "Install Rust toolchain"
         run: rustup show

.github/workflows/daily_fuzz.yaml

@@ -34,7 +34,7 @@ jobs:
       - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - name: "Install Rust toolchain"
         run: rustup show
       - name: "Install mold"

.github/workflows/mypy_primer.yaml

@@ -39,7 +39,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:
@@ -82,7 +82,7 @@ jobs:
           persist-credentials: false
 
       - name: Install the latest version of uv
-        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:

.github/workflows/publish-pypi.yml

@@ -22,7 +22,7 @@ jobs:
       id-token: write
     steps:
       - name: "Install uv"
-        uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - uses: actions/download-artifact@d3f86a106a0bac45b974a628896c90dbdf5c8093 # v4.3.0
         with:
           pattern: wheels-*

.github/workflows/release.yml

@@ -61,7 +61,7 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      - uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493
         with:
           persist-credentials: false
           submodules: recursive
@@ -124,7 +124,7 @@ jobs:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       BUILD_MANIFEST_NAME: target/distrib/global-dist-manifest.json
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      - uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493
         with:
           persist-credentials: false
           submodules: recursive
@@ -175,7 +175,7 @@ jobs:
     outputs:
       val: ${{ steps.host.outputs.manifest }}
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      - uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493
         with:
           persist-credentials: false
           submodules: recursive
@@ -251,7 +251,7 @@ jobs:
     env:
       GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     steps:
-      - uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8
+      - uses: actions/checkout@ff7abcd0c3c05ccf6adc123a8cd1fd4fb30fb493
         with:
           persist-credentials: false
           submodules: recursive

.github/workflows/sync_typeshed.yaml

@@ -65,7 +65,7 @@ jobs:
         run: |
           git config --global user.name typeshedbot
           git config --global user.email '<>'
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - name: Sync typeshed stubs
         run: |
           rm -rf "ruff/${VENDORED_TYPESHED}"
@@ -117,7 +117,7 @@ jobs:
         with:
           persist-credentials: true
           ref: ${{ env.UPSTREAM_BRANCH}}
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - name: Setup git
         run: |
           git config --global user.name typeshedbot
@@ -155,7 +155,7 @@ jobs:
         with:
           persist-credentials: true
           ref: ${{ env.UPSTREAM_BRANCH}}
-      - uses: astral-sh/setup-uv@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+      - uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
       - name: Setup git
         run: |
           git config --global user.name typeshedbot

.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@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:

.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@e92bafb6253dcd438e0484186d7669ea7a8ca1cc # v6.4.3
+        uses: astral-sh/setup-uv@4959332f0f014c5280e7eac8b70c90cb574c9f9b # v6.6.0
 
       - uses: Swatinem/rust-cache@98c8021b550208e191a6a3145459bfc9fb29c4c0 # v2.8.0
         with:

Cargo.lock

@@ -257,12 +257,9 @@ checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
 [[package]]
 name = "bitflags"
-version = "2.9.2"
+version = "2.9.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6a65b545ab31d687cff52899d4890855fec459eb6afe0da6417b8a18da87aa29"
-dependencies = [
- "serde",
-]
+checksum = "34efbcccd345379ca2868b2b2c9d3782e9cc58ba87bc7d79d5b53d9c9ae6f25d"
 
 [[package]]
 name = "bitvec"
@@ -298,7 +295,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "234113d19d0d7d613b40e86fb654acf958910802bcceab913a4f9e7cda03b1a4"
 dependencies = [
  "memchr",
- "regex-automata 0.4.9",
+ "regex-automata 0.4.10",
  "serde",
 ]
 
@@ -488,7 +485,7 @@ checksum = "85a8ab73a1c02b0c15597b22e09c7dc36e63b2f601f9d1e83ac0c3decd38b1ae"
 dependencies = [
  "nix 0.29.0",
  "terminfo",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "which",
  "windows-sys 0.59.0",
 ]
@@ -958,7 +955,7 @@ dependencies = [
  "libc",
  "option-ext",
  "redox_users",
- "windows-sys 0.60.2",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1031,16 +1028,6 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "877a4ace8713b0bcf2a4e7eec82529c029f1d0619886d18145fea96c3ffe5c0f"
 
-[[package]]
-name = "erased-serde"
-version = "0.4.6"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e004d887f51fcb9fef17317a2f3525c887d8aa3f4f50fed920816a688284a5b7"
-dependencies = [
- "serde",
- "typeid",
-]
-
 [[package]]
 name = "errno"
 version = "0.3.13"
@@ -1048,7 +1035,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "778e2ac28f6c47af28e4907f13ffd1e1ddbd400980a9abd7c8df189bf578a5ad"
 dependencies = [
  "libc",
- "windows-sys 0.60.2",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -1097,14 +1084,14 @@ dependencies = [
 
 [[package]]
 name = "filetime"
-version = "0.2.25"
+version = "0.2.26"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "35c0522e981e68cbfa8c3f978441a5f34b30b96e146b33cd3359176b50fe8586"
+checksum = "bc0505cd1b6fa6580283f6bdf70a73fcf4aba1184038c90902b92b3dd0df63ed"
 dependencies = [
  "cfg-if",
  "libc",
  "libredox",
- "windows-sys 0.59.0",
+ "windows-sys 0.60.2",
 ]
 
 [[package]]
@@ -1131,9 +1118,9 @@ checksum = "d9c4f5dac5e15c24eb999c26181a6ca40b39fe946cbe4c263c7209467bc83af2"
 
 [[package]]
 name = "form_urlencoded"
-version = "1.2.1"
+version = "1.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e13624c2627564efccf4934284bdd98cbaa14e79b0b5a141218e507b3a823456"
+checksum = "cb4cb245038516f5f85277875cdaa4f7d2c9a0fa0468de06ed190163b1581fcf"
 dependencies = [
  "percent-encoding",
 ]
@@ -1244,7 +1231,7 @@ dependencies = [
  "aho-corasick",
  "bstr",
  "log",
- "regex-automata 0.4.9",
+ "regex-automata 0.4.10",
  "regex-syntax 0.8.5",
 ]
 
@@ -1254,7 +1241,7 @@ version = "0.9.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0bf760ebf69878d9fd8f110c89703d90ce35095324d1f1edcb595c63945ee757"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "ignore",
  "walkdir",
 ]
@@ -1443,9 +1430,9 @@ checksum = "b9e0384b61958566e926dc50660321d12159025e767c18e043daf26b70104c39"
 
 [[package]]
 name = "idna"
-version = "1.0.3"
+version = "1.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "686f825264d630750a544639377bae737628043f20d38bbc029e8f29ea968a7e"
+checksum = "3b0875f23caa03898994f6ddc501886a45c7d3d62d04d2d90788d47be1b1e4de"
 dependencies = [
  "idna_adapter",
  "smallvec",
@@ -1472,7 +1459,7 @@ dependencies = [
  "globset",
  "log",
  "memchr",
- "regex-automata 0.4.9",
+ "regex-automata 0.4.10",
  "same-file",
  "walkdir",
  "winapi-util",
@@ -1499,9 +1486,9 @@ dependencies = [
 
 [[package]]
 name = "indexmap"
-version = "2.10.0"
+version = "2.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "fe4cd85333e22411419a0bcae1297d25e58c9443848b11dc6a86fefe8c78a661"
+checksum = "f2481980430f9f78649238835720ddccc57e52df14ffce1c6f37391d61b563e9"
 dependencies = [
  "equivalent",
  "hashbrown 0.15.5",
@@ -1534,7 +1521,7 @@ version = "0.11.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f37dccff2791ab604f9babef0ba14fbe0be30bd368dc541e2b08d07c8aa908f3"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "inotify-sys",
  "libc",
 ]
@@ -1793,7 +1780,7 @@ dependencies = [
  "paste",
  "peg",
  "regex",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
 ]
 
 [[package]]
@@ -1822,7 +1809,7 @@ version = "0.1.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "391290121bad3d37fbddad76d8f5d1c1c314cfc646d143d7e07a3086ddff0ce3"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "libc",
  "redox_syscall",
 ]
@@ -2027,7 +2014,7 @@ version = "0.29.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "71e2746dc3a24dd78b3cfcb7be93368c6de9963d30f43a6a73998a9cf4b17b46"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -2039,7 +2026,7 @@ version = "0.30.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "74523f3a35e05aba87a1d978330aef40f67b0304ac79c1c00b294c9830543db6"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "cfg-if",
  "cfg_aliases",
  "libc",
@@ -2067,7 +2054,7 @@ version = "8.2.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4d3d07927151ff8575b7087f245456e549fea62edf0ec4e565a5ee50c8402bc3"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "fsevent-sys",
  "inotify",
  "kqueue",
@@ -2140,9 +2127,9 @@ checksum = "04744f49eae99ab78e0d5c0b603ab218f515ea8cfe5a456d7629ad883a3b6e7d"
 
 [[package]]
 name = "ordermap"
-version = "0.5.8"
+version = "0.5.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "6d6bff06e4a5dc6416bead102d3e63c480dd852ffbb278bf8cfeb4966b329609"
+checksum = "2fd6fedcd996c8c97932075cc3811d83f53280f48d5620e4e3cab7f6a12678c4"
 dependencies = [
  "indexmap",
  "serde",
@@ -2296,9 +2283,9 @@ dependencies = [
 
 [[package]]
 name = "percent-encoding"
-version = "2.3.1"
+version = "2.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e3148f5046208a5d56bcfc03053e3ca6334e51da8dfb19b6cdc8b306fae3283e"
+checksum = "9b4f627cb1b25917193a259e49bdad08f671f8d9708acfd5fe0a8c1455d87220"
 
 [[package]]
 name = "pest"
@@ -2307,7 +2294,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1db05f56d34358a8b1066f67cbb203ee3e7ed2ba674a6263a1d5ec6db2204323"
 dependencies = [
  "memchr",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "ucd-trie",
 ]
 
@@ -2486,9 +2473,9 @@ dependencies = [
 
 [[package]]
 name = "proc-macro2"
-version = "1.0.96"
+version = "1.0.101"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "beef09f85ae72cea1ef96ba6870c51e6382ebfa4f0e85b643459331f3daa5be0"
+checksum = "89ae43fd86e4158d6db51ad8e2b80f313af9cc74f5c0e03ccb87de09998732de"
 dependencies = [
  "unicode-ident",
 ]
@@ -2503,7 +2490,7 @@ dependencies = [
  "pep440_rs",
  "pep508_rs",
  "serde",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "toml 0.8.23",
 ]
 
@@ -2518,7 +2505,7 @@ dependencies = [
  "newtype-uuid",
  "quick-xml",
  "strip-ansi-escapes",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "uuid",
 ]
 
@@ -2679,7 +2666,7 @@ version = "0.5.17"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5407465600fb0548f1442edf71dd20683c6ed326200ace4b1ef0763521bb3b77"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
 ]
 
 [[package]]
@@ -2690,18 +2677,18 @@ checksum = "a4e608c6638b9c18977b00b475ac1f28d14e84b27d8d42f70e0bf1e3dec127ac"
 dependencies = [
  "getrandom 0.2.16",
  "libredox",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
 ]
 
 [[package]]
 name = "regex"
-version = "1.11.1"
+version = "1.11.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b544ef1b4eac5dc2db33ea63606ae9ffcfac26c1416a2806ae0bf5f56b201191"
+checksum = "23d7fd106d8c02486a8d64e778353d1cffe08ce79ac2e82f540c86d0facf6912"
 dependencies = [
  "aho-corasick",
  "memchr",
- "regex-automata 0.4.9",
+ "regex-automata 0.4.10",
  "regex-syntax 0.8.5",
 ]
 
@@ -2716,9 +2703,9 @@ dependencies = [
 
 [[package]]
 name = "regex-automata"
-version = "0.4.9"
+version = "0.4.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "809e8dc61f6de73b46c85f4c96486310fe304c434cfa43669d7b40f711150908"
+checksum = "6b9458fa0bfeeac22b5ca447c63aaf45f28439a709ccd244698632f9aa6394d6"
 dependencies = [
  "aho-corasick",
  "memchr",
@@ -2762,7 +2749,7 @@ dependencies = [
  "argfile",
  "assert_fs",
  "bincode 2.0.1",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "cachedir",
  "clap",
  "clap_complete_command",
@@ -2806,7 +2793,7 @@ dependencies = [
  "strum",
  "tempfile",
  "test-case",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "tikv-jemallocator",
  "toml 0.9.5",
  "tracing",
@@ -2901,7 +2888,7 @@ dependencies = [
  "serde_json",
  "similar",
  "tempfile",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "tracing",
  "tracing-subscriber",
  "ty_static",
@@ -2948,6 +2935,7 @@ dependencies = [
  "tracing-subscriber",
  "ty",
  "ty_project",
+ "ty_python_semantic",
  "ty_static",
  "url",
 ]
@@ -3014,7 +3002,7 @@ version = "0.12.10"
 dependencies = [
  "aho-corasick",
  "anyhow",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "clap",
  "colored 3.0.0",
  "fern",
@@ -3061,7 +3049,7 @@ dependencies = [
  "strum_macros",
  "tempfile",
  "test-case",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "toml 0.9.5",
  "typed-arena",
  "unicode-normalization",
@@ -3104,7 +3092,7 @@ dependencies = [
  "serde_json",
  "serde_with",
  "test-case",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "uuid",
 ]
 
@@ -3120,7 +3108,7 @@ name = "ruff_python_ast"
 version = "0.0.0"
 dependencies = [
  "aho-corasick",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "compact_str",
  "get-size2",
  "is-macro",
@@ -3135,7 +3123,7 @@ dependencies = [
  "salsa",
  "schemars",
  "serde",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
 ]
 
 [[package]]
@@ -3189,7 +3177,7 @@ dependencies = [
  "similar",
  "smallvec",
  "static_assertions",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "tracing",
 ]
 
@@ -3208,7 +3196,7 @@ dependencies = [
 name = "ruff_python_literal"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "itertools 0.14.0",
  "ruff_python_ast",
  "unic-ucd-category",
@@ -3219,7 +3207,7 @@ name = "ruff_python_parser"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "bstr",
  "compact_str",
  "get-size2",
@@ -3244,7 +3232,7 @@ dependencies = [
 name = "ruff_python_semantic"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "insta",
  "is-macro",
  "ruff_cache",
@@ -3265,7 +3253,7 @@ dependencies = [
 name = "ruff_python_stdlib"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "unicode-ident",
 ]
 
@@ -3319,7 +3307,7 @@ dependencies = [
  "serde",
  "serde_json",
  "shellexpand",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "toml 0.9.5",
  "tracing",
  "tracing-log",
@@ -3442,11 +3430,11 @@ version = "1.0.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "11181fbabf243db407ef8df94a6ce0b2f9a733bd8be4ad02b4eda9602296cac8"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "errno",
  "libc",
  "linux-raw-sys",
- "windows-sys 0.60.2",
+ "windows-sys 0.59.0",
 ]
 
 [[package]]
@@ -3464,13 +3452,12 @@ checksum = "28d3b2b1366ec20994f1fd18c3c594f05c5dd4bc44d8bb0c1c632c8d6829481f"
 [[package]]
 name = "salsa"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=a0e7a06#a0e7a0660c93136f23bf08b4f1604eee3d1f6b11"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=a3ffa22cb26756473d56f867aedec3fd907c4dd9#a3ffa22cb26756473d56f867aedec3fd907c4dd9"
 dependencies = [
  "boxcar",
  "compact_str",
  "crossbeam-queue",
  "crossbeam-utils",
- "erased-serde",
  "hashbrown 0.15.5",
  "hashlink",
  "indexmap",
@@ -3481,7 +3468,6 @@ dependencies = [
  "rustc-hash",
  "salsa-macro-rules",
  "salsa-macros",
- "serde",
  "smallvec",
  "thin-vec",
  "tracing",
@@ -3490,12 +3476,12 @@ dependencies = [
 [[package]]
 name = "salsa-macro-rules"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=a0e7a06#a0e7a0660c93136f23bf08b4f1604eee3d1f6b11"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=a3ffa22cb26756473d56f867aedec3fd907c4dd9#a3ffa22cb26756473d56f867aedec3fd907c4dd9"
 
 [[package]]
 name = "salsa-macros"
 version = "0.23.0"
-source = "git+https://github.com/salsa-rs/salsa.git?rev=a0e7a06#a0e7a0660c93136f23bf08b4f1604eee3d1f6b11"
+source = "git+https://github.com/salsa-rs/salsa.git?rev=a3ffa22cb26756473d56f867aedec3fd907c4dd9#a3ffa22cb26756473d56f867aedec3fd907c4dd9"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3592,9 +3578,9 @@ dependencies = [
 
 [[package]]
 name = "serde_json"
-version = "1.0.142"
+version = "1.0.143"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "030fedb782600dcbd6f02d479bf0d817ac3bb40d644745b769d6a96bc3afc5a7"
+checksum = "d401abef1d108fbd9cbaebc3e46611f4b1021f714a0597a71f41ee463f5f4a5a"
 dependencies = [
  "itoa",
  "memchr",
@@ -3715,9 +3701,6 @@ name = "smallvec"
 version = "1.15.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "67b1b7a3b5fe4f1376887184045fcf45c69e92af734b7aaddc05fb777b6fbd03"
-dependencies = [
- "serde",
-]
 
 [[package]]
 name = "snapbox"
@@ -3808,9 +3791,9 @@ dependencies = [
 
 [[package]]
 name = "syn"
-version = "2.0.104"
+version = "2.0.106"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "17b6f705963418cdb9927482fa304bc562ece2fdd4f616084c50b7023b435a40"
+checksum = "ede7c438028d4436d71104916910f5bb611972c5cfd7f89b8300a8186e6fada6"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -3922,9 +3905,6 @@ name = "thin-vec"
 version = "0.2.14"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "144f754d318415ac792f9d69fc87abbbfc043ce2ef041c60f16ad828f638717d"
-dependencies = [
- "serde",
-]
 
 [[package]]
 name = "thiserror"
@@ -3937,11 +3917,11 @@ dependencies = [
 
 [[package]]
 name = "thiserror"
-version = "2.0.12"
+version = "2.0.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "567b8a2dae586314f7be2a752ec7474332959c6460e02bde30d702a66d488708"
+checksum = "3467d614147380f2e4e374161426ff399c91084acd2363eaf549172b3d5e60c0"
 dependencies = [
- "thiserror-impl 2.0.12",
+ "thiserror-impl 2.0.16",
 ]
 
 [[package]]
@@ -3957,9 +3937,9 @@ dependencies = [
 
 [[package]]
 name = "thiserror-impl"
-version = "2.0.12"
+version = "2.0.16"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7f7cf42b4507d8ea322120659672cf1b9dbb93f8f2d4ecfd6e51350ff5b17a1d"
+checksum = "6c5e1be1c48b9172ee610da68fd9cd2770e7a4056cb3fc98710ee6906f0c7960"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -4158,9 +4138,9 @@ dependencies = [
 
 [[package]]
 name = "tracing-indicatif"
-version = "0.3.12"
+version = "0.3.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "e1983afead46ff13a3c93581e0cec31d20b29efdd22cbdaa8b9f850eccf2c352"
+checksum = "04d4e11e0e27acef25a47f27e9435355fecdc488867fa2bc90e75b0700d2823d"
 dependencies = [
  "indicatif",
  "tracing",
@@ -4260,17 +4240,22 @@ dependencies = [
 name = "ty_ide"
 version = "0.0.0"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
+ "get-size2",
  "insta",
  "itertools 0.14.0",
+ "rayon",
  "regex",
  "ruff_db",
+ "ruff_index",
+ "ruff_memory_usage",
  "ruff_python_ast",
  "ruff_python_parser",
  "ruff_python_trivia",
  "ruff_source_file",
  "ruff_text_size",
  "rustc-hash",
+ "salsa",
  "smallvec",
  "tracing",
  "ty_project",
@@ -4282,7 +4267,6 @@ name = "ty_project"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bincode 2.0.1",
  "camino",
  "colored 3.0.0",
  "crossbeam",
@@ -4294,7 +4278,7 @@ dependencies = [
  "pep440_rs",
  "rayon",
  "regex",
- "regex-automata 0.4.9",
+ "regex-automata 0.4.10",
  "ruff_cache",
  "ruff_db",
  "ruff_macros",
@@ -4307,12 +4291,11 @@ dependencies = [
  "salsa",
  "schemars",
  "serde",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "toml 0.9.5",
  "tracing",
  "ty_combine",
  "ty_python_semantic",
- "ty_static",
  "ty_vendored",
 ]
 
@@ -4321,7 +4304,7 @@ name = "ty_python_semantic"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "bitvec",
  "camino",
  "colored 3.0.0",
@@ -4361,7 +4344,7 @@ dependencies = [
  "strum_macros",
  "tempfile",
  "test-case",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "tracing",
  "ty_python_semantic",
  "ty_static",
@@ -4374,7 +4357,7 @@ name = "ty_server"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "crossbeam",
  "dunce",
  "insta",
@@ -4395,7 +4378,7 @@ dependencies = [
  "serde_json",
  "shellexpand",
  "tempfile",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "tracing",
  "tracing-subscriber",
  "ty_combine",
@@ -4417,7 +4400,7 @@ name = "ty_test"
 version = "0.0.0"
 dependencies = [
  "anyhow",
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
  "camino",
  "colored 3.0.0",
  "insta",
@@ -4436,7 +4419,7 @@ dependencies = [
  "serde",
  "smallvec",
  "tempfile",
- "thiserror 2.0.12",
+ "thiserror 2.0.16",
  "toml 0.9.5",
  "tracing",
  "ty_python_semantic",
@@ -4484,12 +4467,6 @@ version = "2.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6af6ae20167a9ece4bcb41af5b80f8a1f1df981f6391189ce00fd257af04126a"
 
-[[package]]
-name = "typeid"
-version = "1.0.3"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "bc7d623258602320d5c55d1bc22793b57daff0ec7efc270ea7d55ce1d5f5471c"
-
 [[package]]
 name = "typenum"
 version = "1.18.0"
@@ -4619,9 +4596,9 @@ checksum = "6d49784317cd0d1ee7ec5c716dd598ec5b4483ea832a2dced265471cc0f690ae"
 
 [[package]]
 name = "url"
-version = "2.5.4"
+version = "2.5.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "32f8b686cadd1473f4bd0117a5d28d36b1ade384ea9b5069a1c40aefed7fda60"
+checksum = "08bc136a29a3d1758e07a9cca267be308aeebf5cfd5a10f3f67ab2097683ef5b"
 dependencies = [
  "form_urlencoded",
  "idna",
@@ -5173,7 +5150,7 @@ version = "0.39.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6f42320e61fe2cfd34354ecb597f86f413484a798ba44a8ca1165c58d42da6c1"
 dependencies = [
- "bitflags 2.9.2",
+ "bitflags 2.9.3",
 ]
 
 [[package]]

Cargo.toml

@@ -57,8 +57,8 @@ anyhow = { version = "1.0.80" }
 arc-swap = { version = "1.7.1" }
 assert_fs = { version = "1.1.0" }
 argfile = { version = "0.2.0" }
-bincode = { version = "2.0.0", features = ["serde"] }
-bitflags = { version = "2.5.0", features = ["serde"] }
+bincode = { version = "2.0.0" }
+bitflags = { version = "2.5.0" }
 bitvec = { version = "1.0.1", default-features = false, features = [
     "alloc",
 ] }
@@ -126,7 +126,7 @@ memchr = { version = "2.7.1" }
 mimalloc = { version = "0.1.39" }
 natord = { version = "1.0.9" }
 notify = { version = "8.0.0" }
-ordermap = { version = "0.5.0", features = ["serde"] }
+ordermap = { version = "0.5.0" }
 path-absolutize = { version = "3.1.1" }
 path-slash = { version = "0.2.1" }
 pathdiff = { version = "0.2.1" }
@@ -143,25 +143,24 @@ 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.git", rev = "a0e7a06", default-features = false, features = [
+salsa = { git = "https://github.com/salsa-rs/salsa.git", rev = "a3ffa22cb26756473d56f867aedec3fd907c4dd9", default-features = false, features = [
     "compact_str",
     "macros",
     "salsa_unstable",
     "inventory",
-    "persistence",
 ] }
 schemars = { version = "0.8.16" }
 seahash = { version = "4.1.0" }
-serde = { version = "1.0.197", features = ["derive", "rc"] }
+serde = { version = "1.0.197", features = ["derive"] }
 serde-wasm-bindgen = { version = "0.6.4" }
-serde_json = { version = "1.0.142" }
+serde_json = { version = "1.0.113" }
 serde_test = { version = "1.0.152" }
 serde_with = { version = "3.6.0", default-features = false, features = [
     "macros",
 ] }
 shellexpand = { version = "3.0.0" }
 similar = { version = "2.4.0", features = ["inline"] }
-smallvec = { version = "1.13.2", features = ["union", "const_generics", "const_new", "serde"] }
+smallvec = { version = "1.13.2", features = ["union", "const_generics", "const_new"] }
 snapbox = { version = "0.6.0", features = [
     "diff",
     "term-svg",

crates/ruff/Cargo.toml

@@ -31,7 +31,7 @@ ruff_workspace = { workspace = true }
 
 anyhow = { workspace = true }
 argfile = { workspace = true }
-bincode = { workspace = true }
+bincode = { workspace = true, features = ["serde"] }
 bitflags = { workspace = true }
 cachedir = { workspace = true }
 clap = { workspace = true, features = ["derive", "env", "wrap_help"] }

crates/ruff_db/src/diagnostic/mod.rs

@@ -22,7 +22,6 @@ mod stylesheet;
 /// a characteristic is a deficiency. An example of a characteristic that is
 /// _not_ a deficiency is the `reveal_type` diagnostic for our type checker.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Diagnostic {
     /// The actual diagnostic.
     ///
@@ -326,6 +325,11 @@ impl Diagnostic {
         self.inner.fix.as_ref()
     }
 
+    #[cfg(test)]
+    pub(crate) fn fix_mut(&mut self) -> Option<&mut Fix> {
+        Arc::make_mut(&mut self.inner).fix.as_mut()
+    }
+
     /// Set the fix for this diagnostic.
     pub fn set_fix(&mut self, fix: Fix) {
         debug_assert!(
@@ -501,7 +505,6 @@ impl Diagnostic {
 }
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct DiagnosticInner {
     id: DiagnosticId,
     severity: Severity,
@@ -578,7 +581,6 @@ impl Eq for RenderingSortKey<'_> {}
 /// another (for a single parent diagnostic) is the order in which they were
 /// attached to the diagnostic.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct SubDiagnostic {
     /// Like with `Diagnostic`, we box the `SubDiagnostic` to make it
     /// pointer-sized.
@@ -688,7 +690,6 @@ impl SubDiagnostic {
 }
 
 #[derive(Debug, Clone, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 struct SubDiagnosticInner {
     severity: SubDiagnosticSeverity,
     message: DiagnosticMessage,
@@ -717,7 +718,6 @@ struct SubDiagnosticInner {
 /// Messages attached to annotations should also be as brief and specific as
 /// possible. Long messages could negative impact the quality of rendering.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Annotation {
     /// The span of this annotation, corresponding to some subsequence of the
     /// user's input that we want to highlight.
@@ -860,7 +860,6 @@ impl Annotation {
 /// These tags are used to provide additional information about the annotation.
 /// and are passed through to the language server protocol.
 #[derive(Debug, Clone, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum DiagnosticTag {
     /// Unused or unnecessary code. Used for unused parameters, unreachable code, etc.
     Unnecessary,
@@ -875,7 +874,6 @@ pub enum DiagnosticTag {
 ///
 /// Rules use kebab case, e.g. `no-foo`.
 #[derive(Debug, Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Serialize), serde(transparent))]
 pub struct LintName(&'static str);
 
 impl LintName {
@@ -888,66 +886,6 @@ impl LintName {
     }
 }
 
-#[cfg(feature = "serde")]
-pub use lint_name_serde::LintRegistryGuard;
-
-#[cfg(feature = "serde")]
-mod lint_name_serde {
-    use super::LintName;
-
-    use std::cell::RefCell;
-
-    thread_local! {
-        /// Serde doesn't provide any easy means to pass a value to a [`Deserialize`] implementation,
-        /// but we need a way to retrieve static [`LintName`]s from the lint registry when deserializing.
-        ///
-        /// Use the [`LintRegistryGuard`] to initialize the thread local before calling into any
-        /// deserialization code. It ensures that the thread local variable gets cleaned up
-        /// once deserialization is done (once the guard gets dropped).
-        static LINT_REGISTRY: RefCell<Option<LintRegistry>> = const { RefCell::new(None) };
-    }
-
-    type LintRegistry = fn(&str) -> Option<LintName>;
-
-    /// Guard to safely change the lint registry for the current thread.
-    #[must_use]
-    pub struct LintRegistryGuard {
-        prev_value: Option<LintRegistry>,
-    }
-
-    impl LintRegistryGuard {
-        pub fn new(registry: LintRegistry) -> Self {
-            let prev = LINT_REGISTRY.replace(Some(registry));
-            Self { prev_value: prev }
-        }
-    }
-
-    impl Drop for LintRegistryGuard {
-        fn drop(&mut self) {
-            LINT_REGISTRY.set(self.prev_value.take());
-        }
-    }
-
-    #[cfg(feature = "serde")]
-    impl<'de> serde::Deserialize<'de> for LintName {
-        fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-        where
-            D: serde::Deserializer<'de>,
-        {
-            let name: &str = serde::Deserialize::deserialize(deserializer)?;
-
-            LINT_REGISTRY.with_borrow(|registry| {
-                let registry = registry
-                    .expect("must set the `LintRegistryGuard` when deserializing a `LintName`");
-
-                registry(name).ok_or(serde::de::Error::custom(format!(
-                    "invalid `LintName` {name}"
-                )))
-            })
-        }
-    }
-}
-
 impl std::ops::Deref for LintName {
     type Target = str;
 
@@ -976,7 +914,6 @@ impl PartialEq<&str> for LintName {
 
 /// Uniquely identifies the kind of a diagnostic.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, PartialOrd, Ord, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum DiagnosticId {
     Panic,
 
@@ -1165,30 +1102,6 @@ impl UnifiedFile {
     }
 }
 
-#[cfg(feature = "serde")]
-impl serde::Serialize for UnifiedFile {
-    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
-    where
-        S: serde::Serializer,
-    {
-        match self {
-            UnifiedFile::Ty(file) => serde::Serialize::serialize(file, serializer),
-            // Persistent caching is only used in ty.
-            UnifiedFile::Ruff(..) => panic!("Ruff files are not persistable"),
-        }
-    }
-}
-
-#[cfg(feature = "serde")]
-impl<'de> serde::Deserialize<'de> for UnifiedFile {
-    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
-    where
-        D: serde::Deserializer<'de>,
-    {
-        serde::Deserialize::deserialize(deserializer).map(UnifiedFile::Ty)
-    }
-}
-
 /// A unified wrapper for types that can be converted to a [`SourceCode`].
 ///
 /// As with [`UnifiedFile`], ruff and ty use slightly different representations for source code.
@@ -1220,7 +1133,6 @@ impl DiagnosticSource {
 /// range isn't present, it semantically implies that the diagnostic refers to
 /// the entire file. For example, when the file should be executable but isn't.
 #[derive(Debug, Clone, PartialEq, Eq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct Span {
     file: UnifiedFile,
     range: Option<TextRange>,
@@ -1299,7 +1211,6 @@ impl From<crate::files::FileRange> for Span {
 }
 
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Ord, PartialOrd, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum Severity {
     Info,
     Warning,
@@ -1335,7 +1246,6 @@ impl Severity {
 /// 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, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub enum SubDiagnosticSeverity {
     Help,
     Info,
@@ -1584,7 +1494,6 @@ impl std::fmt::Display for ConciseMessage<'_> {
 /// a blanket trait implementation for `IntoDiagnosticMessage` for
 /// anything that implements `std::fmt::Display`.
 #[derive(Clone, Debug, Eq, PartialEq, Hash, get_size2::GetSize)]
-#[cfg_attr(feature = "serde", derive(serde::Deserialize, serde::Serialize))]
 pub struct DiagnosticMessage(Box<str>);
 
 impl DiagnosticMessage {
@@ -1648,11 +1557,7 @@ impl<T: std::fmt::Display> IntoDiagnosticMessage for T {
 ///
 /// For Ruff rules this means the noqa code.
 #[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Default, Hash, get_size2::GetSize)]
-#[cfg_attr(
-    feature = "serde",
-    derive(serde::Serialize, serde::Deserialize),
-    serde(transparent)
-)]
+#[cfg_attr(feature = "serde", derive(serde::Serialize), serde(transparent))]
 pub struct SecondaryCode(String);
 
 impl SecondaryCode {

crates/ruff_db/src/diagnostic/render.rs

@@ -2622,6 +2622,13 @@ watermelon
             self.config = config;
         }
 
+        /// Show a diff for the fix when rendering.
+        pub(super) fn show_fix_diff(&mut self, yes: bool) {
+            let mut config = std::mem::take(&mut self.config);
+            config = config.show_fix_diff(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);

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

@@ -2,12 +2,13 @@ use std::borrow::Cow;
 use std::num::NonZeroUsize;
 
 use anstyle::Style;
+use ruff_notebook::NotebookIndex;
 use similar::{ChangeTag, TextDiff};
 
 use ruff_annotate_snippets::Renderer as AnnotateRenderer;
 use ruff_diagnostics::{Applicability, Fix};
 use ruff_source_file::OneIndexed;
-use ruff_text_size::{Ranged, TextRange, TextSize};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 
 use crate::diagnostic::render::{FileResolver, Resolved};
 use crate::diagnostic::stylesheet::{DiagnosticStylesheet, fmt_styled};
@@ -81,6 +82,7 @@ impl<'a> FullRenderer<'a> {
 struct Diff<'a> {
     fix: &'a Fix,
     diagnostic_source: DiagnosticSource,
+    notebook_index: Option<NotebookIndex>,
     stylesheet: &'a DiagnosticStylesheet,
 }
 
@@ -90,12 +92,11 @@ impl<'a> Diff<'a> {
         stylesheet: &'a DiagnosticStylesheet,
         resolver: &'a dyn FileResolver,
     ) -> Option<Diff<'a>> {
+        let file = &diagnostic.primary_span_ref()?.file;
         Some(Diff {
             fix: diagnostic.fix()?,
-            diagnostic_source: diagnostic
-                .primary_span_ref()?
-                .file
-                .diagnostic_source(resolver),
+            diagnostic_source: file.diagnostic_source(resolver),
+            notebook_index: resolver.notebook_index(file),
             stylesheet,
         })
     }
@@ -106,19 +107,24 @@ impl std::fmt::Display for Diff<'_> {
         let source_code = self.diagnostic_source.as_source_code();
         let source_text = source_code.text();
 
-        // TODO(dhruvmanila): Add support for Notebook cells once it's user-facing
-        let mut output = String::with_capacity(source_text.len());
-        let mut last_end = TextSize::default();
-
-        for edit in self.fix.edits() {
-            output.push_str(source_code.slice(TextRange::new(last_end, edit.start())));
-            output.push_str(edit.content().unwrap_or_default());
-            last_end = edit.end();
-        }
-
-        output.push_str(&source_text[usize::from(last_end)..]);
-
-        let diff = TextDiff::from_lines(source_text, &output);
+        // Partition the source code into end offsets for each cell. If `self.notebook_index` is
+        // `None`, indicating a regular script file, all the lines will be in one "cell" under the
+        // `None` key.
+        let cells = if let Some(notebook_index) = &self.notebook_index {
+            let mut last_cell = OneIndexed::MIN;
+            let mut cells: Vec<(Option<OneIndexed>, TextSize)> = Vec::new();
+            for (row, cell) in notebook_index.iter() {
+                if cell != last_cell {
+                    let offset = source_code.line_start(row);
+                    cells.push((Some(last_cell), offset));
+                    last_cell = cell;
+                }
+            }
+            cells.push((Some(last_cell), source_text.text_len()));
+            cells
+        } else {
+            vec![(None, source_text.text_len())]
+        };
 
         let message = match self.fix.applicability() {
             // TODO(zanieb): Adjust this messaging once it's user-facing
@@ -133,59 +139,97 @@ impl std::fmt::Display for Diff<'_> {
         // tests, which is the only place these are currently used.
         writeln!(f, "ℹ {}", fmt_styled(message, self.stylesheet.separator))?;
 
-        let (largest_old, largest_new) = diff
-            .ops()
-            .last()
-            .map(|op| (op.old_range().start, op.new_range().start))
-            .unwrap_or_default();
+        let mut last_end = TextSize::ZERO;
+        for (cell, offset) in cells {
+            let range = TextRange::new(last_end, offset);
+            last_end = offset;
+            let input = source_code.slice(range);
 
-        let digit_with = OneIndexed::from_zero_indexed(largest_new.max(largest_old)).digits();
+            let mut output = String::with_capacity(input.len());
+            let mut last_end = range.start();
 
-        for (idx, group) in diff.grouped_ops(3).iter().enumerate() {
-            if idx > 0 {
-                writeln!(f, "{:-^1$}", "-", 80)?;
+            let mut applied = 0;
+            for edit in self.fix.edits() {
+                if range.contains_range(edit.range()) {
+                    output.push_str(source_code.slice(TextRange::new(last_end, edit.start())));
+                    output.push_str(edit.content().unwrap_or_default());
+                    last_end = edit.end();
+                    applied += 1;
+                }
             }
-            for op in group {
-                for change in diff.iter_inline_changes(op) {
-                    let sign = match change.tag() {
-                        ChangeTag::Delete => "-",
-                        ChangeTag::Insert => "+",
-                        ChangeTag::Equal => " ",
-                    };
 
-                    let line_style = LineStyle::from(change.tag(), self.stylesheet);
+            // No edits were applied, so there's no need to diff.
+            if applied == 0 {
+                continue;
+            }
 
-                    let old_index = change.old_index().map(OneIndexed::from_zero_indexed);
-                    let new_index = change.new_index().map(OneIndexed::from_zero_indexed);
+            output.push_str(&source_text[usize::from(last_end)..usize::from(range.end())]);
 
-                    write!(
-                        f,
-                        "{} {} |{}",
-                        Line {
-                            index: old_index,
-                            width: digit_with
-                        },
-                        Line {
-                            index: new_index,
-                            width: digit_with
-                        },
-                        fmt_styled(line_style.apply_to(sign), self.stylesheet.emphasis),
-                    )?;
+            let diff = TextDiff::from_lines(input, &output);
 
-                    for (emphasized, value) in change.iter_strings_lossy() {
-                        let value = show_nonprinting(&value);
-                        if emphasized {
-                            write!(
-                                f,
-                                "{}",
-                                fmt_styled(line_style.apply_to(&value), self.stylesheet.underline)
-                            )?;
-                        } else {
-                            write!(f, "{}", line_style.apply_to(&value))?;
+            let (largest_old, largest_new) = diff
+                .ops()
+                .last()
+                .map(|op| (op.old_range().start, op.new_range().start))
+                .unwrap_or_default();
+
+            let digit_with = OneIndexed::from_zero_indexed(largest_new.max(largest_old)).digits();
+
+            if let Some(cell) = cell {
+                // Room for 2 digits, 2 x 1 space before each digit, 1 space, and 1 `|`. This
+                // centers the three colons on the pipe.
+                writeln!(f, "{:>1$} cell {cell}", ":::", 2 * digit_with.get() + 4)?;
+            }
+
+            for (idx, group) in diff.grouped_ops(3).iter().enumerate() {
+                if idx > 0 {
+                    writeln!(f, "{:-^1$}", "-", 80)?;
+                }
+                for op in group {
+                    for change in diff.iter_inline_changes(op) {
+                        let sign = match change.tag() {
+                            ChangeTag::Delete => "-",
+                            ChangeTag::Insert => "+",
+                            ChangeTag::Equal => " ",
+                        };
+
+                        let line_style = LineStyle::from(change.tag(), self.stylesheet);
+
+                        let old_index = change.old_index().map(OneIndexed::from_zero_indexed);
+                        let new_index = change.new_index().map(OneIndexed::from_zero_indexed);
+
+                        write!(
+                            f,
+                            "{} {} |{}",
+                            Line {
+                                index: old_index,
+                                width: digit_with,
+                            },
+                            Line {
+                                index: new_index,
+                                width: digit_with,
+                            },
+                            fmt_styled(line_style.apply_to(sign), self.stylesheet.emphasis),
+                        )?;
+
+                        for (emphasized, value) in change.iter_strings_lossy() {
+                            let value = show_nonprinting(&value);
+                            if emphasized {
+                                write!(
+                                    f,
+                                    "{}",
+                                    fmt_styled(
+                                        line_style.apply_to(&value),
+                                        self.stylesheet.underline
+                                    )
+                                )?;
+                            } else {
+                                write!(f, "{}", line_style.apply_to(&value))?;
+                            }
+                        }
+                        if change.missing_newline() {
+                            writeln!(f)?;
                         }
-                    }
-                    if change.missing_newline() {
-                        writeln!(f)?;
                     }
                 }
             }
@@ -253,7 +297,7 @@ fn show_nonprinting(s: &str) -> Cow<'_, str> {
 
 #[cfg(test)]
 mod tests {
-    use ruff_diagnostics::Applicability;
+    use ruff_diagnostics::{Applicability, Fix};
     use ruff_text_size::{TextLen, TextRange, TextSize};
 
     use crate::diagnostic::{
@@ -654,6 +698,107 @@ print()
         ");
     }
 
+    /// Test that we remap notebook cell line numbers in the diff as well as the main diagnostic.
+    #[test]
+    fn notebook_output_with_diff() {
+        let (mut env, diagnostics) = create_notebook_diagnostics(DiagnosticFormat::Full);
+        env.show_fix_diff(true);
+        insta::assert_snapshot!(env.render_diagnostics(&diagnostics), @r"
+        error[unused-import][*]: `os` imported but unused
+         --> notebook.ipynb:cell 1:2:8
+          |
+        1 | # cell 1
+        2 | import os
+          |        ^^
+          |
+        help: Remove unused import: `os`
+
+        ℹ Safe fix
+           ::: cell 1
+        1 1 | # cell 1
+        2   |-import os
+
+        error[unused-import][*]: `math` imported but unused
+         --> notebook.ipynb:cell 2:2:8
+          |
+        1 | # cell 2
+        2 | import math
+          |        ^^^^
+        3 |
+        4 | print('hello world')
+          |
+        help: Remove unused import: `math`
+
+        ℹ Safe fix
+           ::: cell 2
+        1 1 | # cell 2
+        2   |-import math
+        3 2 | 
+        4 3 | print('hello world')
+
+        error[unused-variable]: Local variable `x` is assigned to but never used
+         --> notebook.ipynb:cell 3:4:5
+          |
+        2 | def foo():
+        3 |     print()
+        4 |     x = 1
+          |     ^
+          |
+        help: Remove assignment to unused variable `x`
+
+        ℹ Unsafe fix
+           ::: cell 3
+        1 1 | # cell 3
+        2 2 | def foo():
+        3 3 |     print()
+        4   |-    x = 1
+        5 4 |
+        ");
+    }
+
+    #[test]
+    fn notebook_output_with_diff_spanning_cells() {
+        let (mut env, mut diagnostics) = create_notebook_diagnostics(DiagnosticFormat::Full);
+        env.show_fix_diff(true);
+
+        // Move all of the edits from the later diagnostics to the first diagnostic to simulate a
+        // single diagnostic with edits in different cells.
+        let mut diagnostic = diagnostics.swap_remove(0);
+        let fix = diagnostic.fix_mut().unwrap();
+        let mut edits = fix.edits().to_vec();
+        for diag in diagnostics {
+            edits.extend_from_slice(diag.fix().unwrap().edits());
+        }
+        *fix = Fix::unsafe_edits(edits.remove(0), edits);
+
+        insta::assert_snapshot!(env.render(&diagnostic), @r"
+        error[unused-import]: `os` imported but unused
+         --> notebook.ipynb:cell 1:2:8
+          |
+        1 | # cell 1
+        2 | import os
+          |        ^^
+          |
+        help: Remove unused import: `os`
+
+        ℹ Unsafe fix
+           ::: cell 1
+        1 1 | # cell 1
+        2   |-import os
+           ::: cell 2
+        1 1 | # cell 2
+        2   |-import math
+        3 2 | 
+        4 3 | print('hello world')
+           ::: cell 3
+        1 1 | # cell 3
+        2 2 | def foo():
+        3 3 |     print()
+        4   |-    x = 1
+        5 4 |
+        ");
+    }
+
     /// Carriage return (`\r`) is a valid line-ending in Python, so we should normalize this to a
     /// line feed (`\n`) for rendering. Otherwise we report a single long line for this case.
     #[test]

crates/ruff_db/src/file_revision.rs

@@ -9,17 +9,7 @@ use crate::system::file_time_now;
 /// * The last modification time of the file.
 /// * The hash of the file's content.
 /// * The revision as it comes from an external system, for example the LSP.
-#[derive(
-    Copy,
-    Clone,
-    Debug,
-    Eq,
-    PartialEq,
-    Default,
-    get_size2::GetSize,
-    serde::Serialize,
-    serde::Deserialize,
-)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Default, get_size2::GetSize)]
 pub struct FileRevision(u128);
 
 impl FileRevision {

crates/ruff_db/src/files.rs

@@ -14,7 +14,7 @@ use crate::diagnostic::{Span, UnifiedFile};
 use crate::file_revision::FileRevision;
 use crate::files::file_root::FileRoots;
 use crate::files::private::FileStatus;
-use crate::system::{FileType, SystemPath, SystemPathBuf, SystemVirtualPath, SystemVirtualPathBuf};
+use crate::system::{SystemPath, SystemPathBuf, SystemVirtualPath, SystemVirtualPathBuf};
 use crate::vendored::{VendoredPath, VendoredPathBuf};
 use crate::{Db, FxDashMap, vendored};
 
@@ -139,7 +139,6 @@ impl Files {
                 };
 
                 tracing::trace!("Adding vendored file `{}`", path);
-
                 let file = File::builder(FilePath::Vendored(path.to_path_buf()))
                     .permissions(Some(0o444))
                     .revision(metadata.revision())
@@ -201,15 +200,7 @@ impl Files {
         let mut roots = self.inner.roots.write().unwrap();
 
         let absolute = SystemPath::absolute(path, db.system().current_directory());
-
-        let (Ok(root) | Err(root)) = roots.try_add(db, absolute, |absolute| {
-            FileRoot::builder(absolute, kind, FileRevision::now())
-                .durability(Durability::HIGH)
-                .revision_durability(kind.durability())
-                .new(db)
-        });
-
-        root
+        roots.try_add(db, absolute, kind)
     }
 
     /// Updates the revision of the root for `path`.
@@ -268,51 +259,6 @@ impl Files {
             root.set_revision(db).to(FileRevision::now());
         }
     }
-
-    /// Seed the files with an existing [`File`] instance.
-    pub fn seed(&self, file: File, db: &dyn Db) {
-        let seeded = match file.path(db) {
-            FilePath::System(path) => self
-                .inner
-                .system_by_path
-                .insert(path.clone(), file)
-                .is_none(),
-            FilePath::SystemVirtual(path) => self
-                .inner
-                .system_virtual_by_path
-                .insert(path.clone(), VirtualFile(file))
-                .is_none(),
-            FilePath::Vendored(path) => self
-                .inner
-                .vendored_by_path
-                .insert(path.clone(), file)
-                .is_none(),
-        };
-
-        // Recreating a `File` input means the persisted queries depending on that file
-        // will be invalidated.
-        assert!(
-            seeded,
-            "unexpected `File` input recreated for path `{}`",
-            file.path(db)
-        );
-    }
-
-    /// Seed the files with an existing [`FileRoot`] instance.
-    pub fn seed_root(&self, root: FileRoot, db: &dyn Db) {
-        let mut roots = self.inner.roots.write().unwrap();
-        let seeded = roots
-            .try_add(db, root.path(db).to_path_buf(), |_| root)
-            .is_ok();
-
-        // Recreating a `FileRoot` input means the persisted queries depending on that file
-        // root will be invalidated.
-        assert!(
-            seeded,
-            "unexpected `FileRoot` input recreated for path `{}`",
-            root.path(db)
-        );
-    }
 }
 
 impl fmt::Debug for Files {
@@ -344,7 +290,7 @@ impl std::panic::RefUnwindSafe for Files {}
 /// # Ordering
 /// Ordering is based on the file's salsa-assigned id and not on its values.
 /// The id may change between runs.
-#[salsa::input(persist, heap_size=ruff_memory_usage::heap_size)]
+#[salsa::input(heap_size=ruff_memory_usage::heap_size)]
 #[derive(PartialOrd, Ord)]
 pub struct File {
     /// The path of the file (immutable).
@@ -468,15 +414,6 @@ impl File {
         }
     }
 
-    /// Loads all existing [`File`]s in the database.
-    pub fn load_all(db: &dyn Db) -> Vec<File> {
-        // TODO: Prune deleted paths.
-        File::ingredient(db)
-            .entries(db.zalsa())
-            .map(|entry| entry.as_struct())
-            .collect()
-    }
-
     /// Private method providing the implementation for [`Self::sync_path`] and [`Self::sync`] for
     /// system paths.
     fn sync_system_path(db: &mut dyn Db, path: &SystemPath, file: Option<File>) {
@@ -585,17 +522,7 @@ impl VirtualFile {
 // The types in here need to be public because they're salsa ingredients but we
 // don't want them to be publicly accessible. That's why we put them into a private module.
 mod private {
-    #[derive(
-        Copy,
-        Clone,
-        Debug,
-        Eq,
-        PartialEq,
-        Default,
-        get_size2::GetSize,
-        serde::Serialize,
-        serde::Deserialize,
-    )]
+    #[derive(Copy, Clone, Debug, Eq, PartialEq, Default, get_size2::GetSize)]
     pub enum FileStatus {
         /// The file exists.
         #[default]
@@ -609,16 +536,6 @@ mod private {
     }
 }
 
-impl From<FileType> for FileStatus {
-    fn from(value: FileType) -> Self {
-        match value {
-            FileType::File => FileStatus::Exists,
-            FileType::Symlink => FileStatus::Exists,
-            FileType::Directory => FileStatus::IsADirectory,
-        }
-    }
-}
-
 #[derive(Copy, Clone, Debug, Eq, PartialEq)]
 pub enum FileError {
     IsADirectory,

crates/ruff_db/src/files/file_root.rs

@@ -16,7 +16,7 @@ use crate::system::{SystemPath, SystemPathBuf};
 /// The main usage of file roots is to determine a file's durability. But it can also be used
 /// to make a salsa query dependent on whether a file in a root has changed without writing any
 /// manual invalidation logic.
-#[salsa::input(persist, debug, heap_size=ruff_memory_usage::heap_size)]
+#[salsa::input(debug, heap_size=ruff_memory_usage::heap_size)]
 pub struct FileRoot {
     /// The path of a root is guaranteed to never change.
     #[returns(deref)]
@@ -35,20 +35,9 @@ impl FileRoot {
     pub fn durability(self, db: &dyn Db) -> salsa::Durability {
         self.kind_at_time_of_creation(db).durability()
     }
-
-    /// Loads all existing [`FileRoot`]s in the database.
-    pub fn load_all(db: &dyn Db) -> Vec<FileRoot> {
-        // TODO: Prune deleted paths.
-        FileRoot::ingredient(db)
-            .entries(db.zalsa())
-            .map(|entry| entry.as_struct())
-            .collect()
-    }
 }
 
-#[derive(
-    Copy, Clone, Debug, Eq, PartialEq, get_size2::GetSize, serde::Serialize, serde::Deserialize,
-)]
+#[derive(Copy, Clone, Debug, Eq, PartialEq, get_size2::GetSize)]
 pub enum FileRootKind {
     /// The root of a project.
     Project,
@@ -58,7 +47,7 @@ pub enum FileRootKind {
 }
 
 impl FileRootKind {
-    pub const fn durability(self) -> Durability {
+    const fn durability(self) -> Durability {
         match self {
             FileRootKind::Project => Durability::LOW,
             FileRootKind::LibrarySearchPath => Durability::HIGH,
@@ -73,34 +62,34 @@ pub(super) struct FileRoots {
 }
 
 impl FileRoots {
-    /// Tries to add a new root for `path`.
+    /// Tries to add a new root for `path` and returns the root.
     ///
     /// The root isn't added nor is the file root's kind updated if a root for `path` already exists.
-    ///
-    /// Returns `Ok(root)` if the `FileRoot` was successfully added, and returns `Err(root)` with
-    /// the previous root if one already existed at that path.
     pub(super) fn try_add(
         &mut self,
         db: &dyn Db,
         path: SystemPathBuf,
-        create_root: impl FnOnce(SystemPathBuf) -> FileRoot,
-    ) -> Result<FileRoot, FileRoot> {
+        kind: FileRootKind,
+    ) -> FileRoot {
         // SAFETY: Guaranteed to succeed because `path` is a UTF-8 that only contains Unicode characters.
         let normalized_path = path.as_std_path().to_slash().unwrap();
 
         if let Ok(existing) = self.by_path.at(&normalized_path) {
             // Only if it is an exact match
             if existing.value.path(db) == &*path {
-                return Err(*existing.value);
+                return *existing.value;
             }
         }
 
-        // Normalize the path to use `/` separators and escape the '{' and '}' characters,
-        // which `matchit` uses for routing parameters.
+        // normalize the path to use `/` separators and escape the '{' and '}' characters,
+        // which matchit uses for routing parameters
         let mut route = normalized_path.replace('{', "{{").replace('}', "}}");
 
         // Insert a new source root
-        let root = create_root(path);
+        let root = FileRoot::builder(path, kind, FileRevision::now())
+            .durability(Durability::HIGH)
+            .revision_durability(kind.durability())
+            .new(db);
 
         // Insert a path that matches the root itself
         self.by_path.insert(route.clone(), root).unwrap();
@@ -111,7 +100,7 @@ impl FileRoots {
         self.by_path.insert(route, root).unwrap();
         self.roots.push(root);
 
-        Ok(root)
+        root
     }
 
     /// Returns the closest root for `path` or `None` if no root contains `path`.

crates/ruff_db/src/files/path.rs

@@ -11,9 +11,7 @@ use std::fmt::{Display, Formatter};
 /// * a file stored on the [host system](crate::system::System).
 /// * a virtual file stored on the [host system](crate::system::System).
 /// * a vendored file stored in the [vendored file system](crate::vendored::VendoredFileSystem).
-#[derive(
-    Clone, Debug, Eq, PartialEq, Hash, get_size2::GetSize, serde::Serialize, serde::Deserialize,
-)]
+#[derive(Clone, Debug, Eq, PartialEq, Hash, get_size2::GetSize)]
 pub enum FilePath {
     /// Path to a file on the [host system](crate::system::System).
     System(SystemPathBuf),

crates/ruff_db/src/source.rs

@@ -148,16 +148,7 @@ impl From<Notebook> for SourceTextKind {
     }
 }
 
-#[derive(
-    Debug,
-    thiserror::Error,
-    PartialEq,
-    Eq,
-    Clone,
-    get_size2::GetSize,
-    serde::Serialize,
-    serde::Deserialize,
-)]
+#[derive(Debug, thiserror::Error, PartialEq, Eq, Clone, get_size2::GetSize)]
 pub enum SourceTextError {
     #[error("Failed to read notebook: {0}`")]
     FailedToReadNotebook(String),

crates/ruff_db/src/system.rs

@@ -66,9 +66,6 @@ pub trait System: Debug + Sync + Send {
     /// See [dunce::canonicalize] for more information.
     fn canonicalize_path(&self, path: &SystemPath) -> Result<SystemPathBuf>;
 
-    /// Reads the content of the file at `path` into a bytes buffer.
-    fn read_to_end(&self, path: &SystemPath) -> Result<Vec<u8>>;
-
     /// Reads the content of the file at `path` into a [`String`].
     fn read_to_string(&self, path: &SystemPath) -> Result<String>;
 
@@ -245,7 +242,7 @@ pub trait WritableSystem: System {
     fn create_new_file(&self, path: &SystemPath) -> Result<()>;
 
     /// Writes the given content to the file at the given path.
-    fn write_file(&self, path: &SystemPath, content: &[u8]) -> Result<()>;
+    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()>;
 
     /// Creates a directory at `path` as well as any intermediate directories.
     fn create_directory_all(&self, path: &SystemPath) -> Result<()>;
@@ -281,7 +278,7 @@ pub trait WritableSystem: System {
         // ensures that only one thread/process ever attempts to write to it to avoid corrupting
         // the cache.
         self.create_new_file(&cache_path)?;
-        self.write_file(&cache_path, contents.as_bytes())?;
+        self.write_file(&cache_path, &contents)?;
 
         Ok(Some(cache_path))
     }

crates/ruff_db/src/system/memory_fs.rs

@@ -114,8 +114,8 @@ impl MemoryFileSystem {
         matches!(by_path.get(&normalized), Some(Entry::Directory(_)))
     }
 
-    pub fn read_to_end(&self, path: impl AsRef<SystemPath>) -> Result<Vec<u8>> {
-        fn read_to_end(fs: &MemoryFileSystem, path: &SystemPath) -> Result<Vec<u8>> {
+    pub fn read_to_string(&self, path: impl AsRef<SystemPath>) -> Result<String> {
+        fn read_to_string(fs: &MemoryFileSystem, path: &SystemPath) -> Result<String> {
             let by_path = fs.inner.by_path.read().unwrap();
             let normalized = fs.normalize_path(path);
 
@@ -127,32 +127,19 @@ impl MemoryFileSystem {
             }
         }
 
-        read_to_end(self, path.as_ref())
-    }
-
-    pub fn read_to_string(&self, path: impl AsRef<SystemPath>) -> Result<String> {
-        self.read_to_end(path)
-            .and_then(|bytes| String::from_utf8(bytes).map_err(io::Error::other))
-    }
-
-    pub(crate) fn read_virtual_path_to_end(
-        &self,
-        path: impl AsRef<SystemVirtualPath>,
-    ) -> Result<Vec<u8>> {
-        let virtual_files = self.inner.virtual_files.read().unwrap();
-        let file = virtual_files
-            .get(&path.as_ref().to_path_buf())
-            .ok_or_else(not_found)?;
-
-        Ok(file.content.clone())
+        read_to_string(self, path.as_ref())
     }
 
     pub(crate) fn read_virtual_path_to_string(
         &self,
         path: impl AsRef<SystemVirtualPath>,
     ) -> Result<String> {
-        self.read_virtual_path_to_end(path)
-            .and_then(|bytes| String::from_utf8(bytes).map_err(io::Error::other))
+        let virtual_files = self.inner.virtual_files.read().unwrap();
+        let file = virtual_files
+            .get(&path.as_ref().to_path_buf())
+            .ok_or_else(not_found)?;
+
+        Ok(file.content.clone())
     }
 
     pub fn exists(&self, path: &SystemPath) -> bool {
@@ -174,7 +161,7 @@ impl MemoryFileSystem {
         match by_path.entry(normalized) {
             btree_map::Entry::Vacant(entry) => {
                 entry.insert(Entry::File(File {
-                    content: Vec::new(),
+                    content: String::new(),
                     last_modified: file_time_now(),
                 }));
 
@@ -190,17 +177,13 @@ impl MemoryFileSystem {
     /// Stores a new file in the file system.
     ///
     /// The operation overrides the content for an existing file with the same normalized `path`.
-    pub fn write_file(
-        &self,
-        path: impl AsRef<SystemPath>,
-        content: impl Into<Vec<u8>>,
-    ) -> Result<()> {
+    pub fn write_file(&self, path: impl AsRef<SystemPath>, content: impl ToString) -> Result<()> {
         let mut by_path = self.inner.by_path.write().unwrap();
 
         let normalized = self.normalize_path(path.as_ref());
 
         let file = get_or_create_file(&mut by_path, &normalized)?;
-        file.content = content.into();
+        file.content = content.to_string();
         file.last_modified = file_time_now();
 
         Ok(())
@@ -231,7 +214,7 @@ impl MemoryFileSystem {
     pub fn write_file_all(
         &self,
         path: impl AsRef<SystemPath>,
-        content: impl Into<Vec<u8>>,
+        content: impl ToString,
     ) -> Result<()> {
         let path = path.as_ref();
 
@@ -245,23 +228,19 @@ impl MemoryFileSystem {
     /// Stores a new virtual file in the file system.
     ///
     /// The operation overrides the content for an existing virtual file with the same `path`.
-    pub fn write_virtual_file(
-        &self,
-        path: impl AsRef<SystemVirtualPath>,
-        content: impl Into<Vec<u8>>,
-    ) {
+    pub fn write_virtual_file(&self, path: impl AsRef<SystemVirtualPath>, content: impl ToString) {
         let path = path.as_ref();
         let mut virtual_files = self.inner.virtual_files.write().unwrap();
 
         match virtual_files.entry(path.to_path_buf()) {
             std::collections::hash_map::Entry::Vacant(entry) => {
                 entry.insert(File {
-                    content: content.into(),
+                    content: content.to_string(),
                     last_modified: file_time_now(),
                 });
             }
             std::collections::hash_map::Entry::Occupied(mut entry) => {
-                entry.get_mut().content = content.into();
+                entry.get_mut().content = content.to_string();
             }
         }
     }
@@ -489,7 +468,7 @@ impl Entry {
 
 #[derive(Debug)]
 struct File {
-    content: Vec<u8>,
+    content: String,
     last_modified: FileTime,
 }
 
@@ -554,7 +533,7 @@ fn get_or_create_file<'a>(
 
     let entry = paths.entry(normalized.to_path_buf()).or_insert_with(|| {
         Entry::File(File {
-            content: Vec::new(),
+            content: String::new(),
             last_modified: file_time_now(),
         })
     });

crates/ruff_db/src/system/os.rs

@@ -93,10 +93,6 @@ impl System for OsSystem {
         })
     }
 
-    fn read_to_end(&self, path: &SystemPath) -> Result<Vec<u8>> {
-        std::fs::read(path.as_std_path())
-    }
-
     fn read_to_string(&self, path: &SystemPath) -> Result<String> {
         std::fs::read_to_string(path.as_std_path())
     }
@@ -361,7 +357,7 @@ impl WritableSystem for OsSystem {
         std::fs::File::create_new(path).map(drop)
     }
 
-    fn write_file(&self, path: &SystemPath, content: &[u8]) -> Result<()> {
+    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
         std::fs::write(path.as_std_path(), content)
     }
 

crates/ruff_db/src/system/path.rs

@@ -762,17 +762,7 @@ impl SystemVirtualPath {
 }
 
 /// An owned, virtual path on [`System`](`super::System`) (akin to [`String`]).
-#[derive(
-    Eq,
-    PartialEq,
-    Clone,
-    Hash,
-    PartialOrd,
-    Ord,
-    get_size2::GetSize,
-    serde::Serialize,
-    serde::Deserialize,
-)]
+#[derive(Eq, PartialEq, Clone, Hash, PartialOrd, Ord, get_size2::GetSize)]
 pub struct SystemVirtualPathBuf(String);
 
 impl SystemVirtualPathBuf {

crates/ruff_db/src/system/test.rs

@@ -75,10 +75,6 @@ impl System for TestSystem {
         self.system().canonicalize_path(path)
     }
 
-    fn read_to_end(&self, path: &SystemPath) -> Result<Vec<u8>> {
-        self.system().read_to_end(path)
-    }
-
     fn read_to_string(&self, path: &SystemPath) -> Result<String> {
         self.system().read_to_string(path)
     }
@@ -169,7 +165,7 @@ impl WritableSystem for TestSystem {
         self.system().create_new_file(path)
     }
 
-    fn write_file(&self, path: &SystemPath, content: &[u8]) -> Result<()> {
+    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
         self.system().write_file(path, content)
     }
 
@@ -189,9 +185,7 @@ pub trait DbWithWritableSystem: Db + Sized {
     /// Writes the content of the given file and notifies the Db about the change.
     fn write_file(&mut self, path: impl AsRef<SystemPath>, content: impl AsRef<str>) -> Result<()> {
         let path = path.as_ref();
-        let content = content.as_ref();
-
-        match self.writable_system().write_file(path, content.as_bytes()) {
+        match self.writable_system().write_file(path, content.as_ref()) {
             Ok(()) => {
                 File::sync_path(self, path);
                 Ok(())
@@ -204,8 +198,7 @@ pub trait DbWithWritableSystem: Db + Sized {
                         File::sync_path(self, ancestor);
                     }
 
-                    self.writable_system()
-                        .write_file(path, content.as_bytes())?;
+                    self.writable_system().write_file(path, content.as_ref())?;
                     File::sync_path(self, path);
 
                     Ok(())
@@ -250,14 +243,8 @@ pub trait DbWithTestSystem: Db + Sized {
     ///
     /// ## Panics
     /// If the db isn't using the [`InMemorySystem`].
-    fn write_virtual_file(
-        &mut self,
-        path: impl AsRef<SystemVirtualPath>,
-        content: impl Into<Vec<u8>>,
-    ) {
+    fn write_virtual_file(&mut self, path: impl AsRef<SystemVirtualPath>, content: impl ToString) {
         let path = path.as_ref();
-        let content = content.into();
-
         self.test_system()
             .memory_file_system()
             .write_virtual_file(path, content);
@@ -335,10 +322,6 @@ impl System for InMemorySystem {
         self.memory_fs.canonicalize(path)
     }
 
-    fn read_to_end(&self, path: &SystemPath) -> Result<Vec<u8>> {
-        self.memory_fs.read_to_end(path)
-    }
-
     fn read_to_string(&self, path: &SystemPath) -> Result<String> {
         self.memory_fs.read_to_string(path)
     }
@@ -429,7 +412,7 @@ impl WritableSystem for InMemorySystem {
         self.memory_fs.create_new_file(path)
     }
 
-    fn write_file(&self, path: &SystemPath, content: &[u8]) -> Result<()> {
+    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
         self.memory_fs.write_file(path, content)
     }
 

crates/ruff_db/src/vendored/path.rs

@@ -88,7 +88,7 @@ impl ToOwned for VendoredPath {
 }
 
 #[repr(transparent)]
-#[derive(Debug, Eq, PartialEq, Clone, Hash, serde::Serialize, serde::Deserialize)]
+#[derive(Debug, Eq, PartialEq, Clone, Hash)]
 pub struct VendoredPathBuf(Utf8PathBuf);
 
 impl get_size2::GetSize for VendoredPathBuf {

crates/ruff_dev/Cargo.toml

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

crates/ruff_dev/src/generate_ty_rules.rs

@@ -52,7 +52,7 @@ pub(crate) fn main(args: &Args) -> Result<()> {
 }
 
 fn generate_markdown() -> String {
-    let registry = &*ty_project::DEFAULT_LINT_REGISTRY;
+    let registry = ty_python_semantic::default_lint_registry();
 
     let mut output = String::new();
 

crates/ruff_linter/resources/test/fixtures/airflow/AIR311_names.py

@@ -34,7 +34,7 @@ task_group()
 setup()
 from airflow.decorators import teardown
 from airflow.io.path import ObjectStoragePath
-from airflow.io.storage import attach
+from airflow.io.store import attach
 from airflow.models import DAG as DAGFromModel
 from airflow.models import (
     Connection,
@@ -74,3 +74,36 @@ DatasetOrTimeSchedule()
 
 # airflow.utils.dag_parsing_context
 get_parsing_context()
+
+from airflow.decorators.base import (
+    DecoratedMappedOperator,
+    DecoratedOperator,
+    TaskDecorator,
+    get_unique_task_id,
+    task_decorator_factory,
+)
+
+# airflow.decorators.base
+DecoratedMappedOperator()
+DecoratedOperator()
+TaskDecorator()
+get_unique_task_id()
+task_decorator_factory()
+
+
+from airflow.models import Param
+
+# airflow.models
+Param()
+
+
+from airflow.sensors.base import (
+    BaseSensorOperator,
+    PokeReturnValue,
+    poke_mode_only,
+)
+
+# airflow.sensors.base
+BaseSensorOperator()
+PokeReturnValue()
+poke_mode_only()

crates/ruff_linter/resources/test/fixtures/airflow/AIR312.py

@@ -9,7 +9,6 @@ from airflow.operators.empty import EmptyOperator
 from airflow.operators.latest_only import LatestOnlyOperator
 from airflow.operators.trigger_dagrun import TriggerDagRunOperator
 from airflow.operators.weekday import BranchDayOfWeekOperator
-from airflow.sensors.date_time import DateTimeSensor
 
 FSHook()
 PackageIndexHook()
@@ -22,7 +21,6 @@ EmptyOperator()
 
 LatestOnlyOperator()
 BranchDayOfWeekOperator()
-DateTimeSensor()
 
 from airflow.operators.python import (
     BranchPythonOperator,
@@ -30,16 +28,23 @@ from airflow.operators.python import (
     PythonVirtualenvOperator,
     ShortCircuitOperator,
 )
+from airflow.sensors.bash import BashSensor
+from airflow.sensors.date_time import DateTimeSensor
+
+BranchPythonOperator()
+PythonOperator()
+PythonVirtualenvOperator()
+ShortCircuitOperator()
+
+BashSensor()
+DateTimeSensor()
 from airflow.sensors.date_time import DateTimeSensorAsync
 from airflow.sensors.external_task import (
     ExternalTaskMarker,
     ExternalTaskSensor,
 )
-from airflow.sensors.time_sensor import (
-    TimeSensor,
-    TimeSensorAsync,
-)
 from airflow.sensors.filesystem import FileSensor
+from airflow.sensors.python import PythonSensor
 
 BranchPythonOperator()
 PythonOperator()
@@ -49,6 +54,13 @@ DateTimeSensorAsync()
 ExternalTaskMarker()
 ExternalTaskSensor()
 FileSensor()
+PythonSensor()
+
+from airflow.sensors.time_sensor import (
+    TimeSensor,
+    TimeSensorAsync,
+)
+
 TimeSensor()
 TimeSensorAsync()
 

crates/ruff_linter/resources/test/fixtures/flake8_async/ASYNC212.py

@@ -0,0 +1,75 @@
+from typing import Optional
+
+import httpx
+
+
+def foo():
+    client = httpx.Client()
+    client.close()  # Ok
+    client.delete()  # Ok
+    client.get()  # Ok
+    client.head()  # Ok
+    client.options()  # Ok
+    client.patch()  # Ok
+    client.post()  # Ok
+    client.put()  # Ok
+    client.request()  # Ok
+    client.send()  # Ok
+    client.stream()  # Ok
+
+    client.anything()  # Ok
+    client.build_request()  # Ok
+    client.is_closed  # Ok
+
+
+async def foo():
+    client = httpx.Client()
+    client.close()  # ASYNC212
+    client.delete()  # ASYNC212
+    client.get()  # ASYNC212
+    client.head()  # ASYNC212
+    client.options()  # ASYNC212
+    client.patch()  # ASYNC212
+    client.post()  # ASYNC212
+    client.put()  # ASYNC212
+    client.request()  # ASYNC212
+    client.send()  # ASYNC212
+    client.stream()  # ASYNC212
+
+    client.anything()  # Ok
+    client.build_request()  # Ok
+    client.is_closed  # Ok
+
+
+async def foo(client: httpx.Client):
+    client.request()  # ASYNC212
+    client.anything()  # Ok
+
+
+async def foo(client: httpx.Client | None):
+    client.request()  # ASYNC212
+    client.anything()  # Ok
+
+
+async def foo(client: Optional[httpx.Client]):
+    client.request()  # ASYNC212
+    client.anything()  # Ok
+
+
+async def foo():
+    client: httpx.Client = ...
+    client.request()  # ASYNC212
+    client.anything()  # Ok
+
+
+global_client = httpx.Client()
+
+
+async def foo():
+    global_client.request()  # ASYNC212
+    global_client.anything()  # Ok
+
+
+async def foo():
+    async with httpx.AsyncClient() as client:
+        await client.get()  # Ok

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

@@ -17,3 +17,50 @@ info(f"{__name__}")
 # Don't trigger for t-strings
 info(t"{name}")
 info(t"{__name__}")
+
+count = 5
+total = 9
+directory_path = "/home/hamir/ruff/crates/ruff_linter/resources/test/"
+logging.info(f"{count} out of {total} files in {directory_path} checked")
+
+
+
+x = 99
+fmt = "08d"
+logger.info(f"{x:{'08d'}}")
+logger.info(f"{x:>10} {x:{fmt}}")
+
+logging.info(f"")
+logging.info(f"This message doesn't have any variables.")
+
+obj = {"key": "value"}
+logging.info(f"Object: {obj!r}")
+
+items_count = 3
+logging.warning(f"Items: {items_count:d}")
+
+data = {"status": "active"}
+logging.info(f"Processing {len(data)} items")
+logging.info(f"Status: {data.get('status', 'unknown').upper()}")
+
+
+result = 123
+logging.info(f"Calculated result: {result + 100}")
+
+temperature = 123
+logging.info(f"Temperature: {temperature:.1f}°C")
+
+class FilePath:
+    def __init__(self, name: str):
+        self.name = name
+
+logging.info(f"No changes made to {file_path.name}.")
+
+user = "tron"
+balance = 123.45
+logging.error(f"Error {404}: User {user} has insufficient balance ${balance:.2f}")
+
+import logging
+
+x = 1
+logging.error(f"{x} -> %s", x)

crates/ruff_linter/resources/test/fixtures/flake8_logging_format/G004_arg_order.py

@@ -0,0 +1,10 @@
+"""Test f-string argument order."""
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+X = 1
+Y = 2
+logger.error(f"{X} -> %s", Y)
+logger.error(f"{Y} -> %s", X)

crates/ruff_linter/resources/test/fixtures/pyflakes/F841_0.py

@@ -151,3 +151,39 @@ def f():
         pass
     except Exception as _:
         pass
+
+
+# OK, `__class__` in this case is not the special `__class__` cell, so we don't
+# emit a diagnostic. (It has its own special semantics -- see
+# https://github.com/astral-sh/ruff/pull/20048#discussion_r2298338048 -- but
+# those aren't relevant here.)
+class A:
+    __class__ = 1
+
+
+# The following three cases are flagged because they declare local `__class__`
+# variables that don't refer to the special `__class__` cell.
+class A:
+    def set_class(self, cls):
+        __class__ = cls  # F841
+
+
+class A:
+    class B:
+        def set_class(self, cls):
+            __class__ = cls  # F841
+
+
+class A:
+    def foo():
+        class B:
+            print(__class__)
+            def set_class(self, cls):
+                __class__ = cls  # F841
+
+
+# OK, the `__class__` cell is nonlocal and declared as such.
+class NonlocalDunderClass:
+    def foo():
+        nonlocal __class__
+        __class__ = 1

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

@@ -44,3 +44,8 @@ def f():
     def g():
         nonlocal x
         x = 2
+
+# OK
+class A:
+    def method(self):
+        nonlocal __class__

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

@@ -124,3 +124,19 @@ def fun_with_python_syntax():
             ...
 
     return Foo
+
+
+@dataclass
+class C:
+    def __post_init__(self, x: tuple[int, ...] = (
+        1,
+        2,
+    )) -> None:
+        self.x = x
+
+
+@dataclass
+class D:
+    def __post_init__(self, x: int = """
+    """) -> None:
+        self.x = x

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

@@ -660,6 +660,9 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
             if checker.is_rule_enabled(Rule::BlockingHttpCallInAsyncFunction) {
                 flake8_async::rules::blocking_http_call(checker, call);
             }
+            if checker.is_rule_enabled(Rule::BlockingHttpCallHttpxInAsyncFunction) {
+                flake8_async::rules::blocking_http_call_httpx(checker, call);
+            }
             if checker.is_rule_enabled(Rule::BlockingOpenCallInAsyncFunction) {
                 flake8_async::rules::blocking_open_call(checker, call);
             }
@@ -1046,7 +1049,6 @@ pub(crate) fn expression(expr: &Expr, checker: &Checker) {
                 Rule::PyPath,
                 Rule::Glob,
                 Rule::OsListdir,
-                Rule::OsSymlink,
             ]) {
                 flake8_use_pathlib::rules::replaceable_by_pathlib(checker, call);
             }

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

@@ -703,7 +703,10 @@ impl SemanticSyntaxContext for Checker<'_> {
             match scope.kind {
                 ScopeKind::Class(_) | ScopeKind::Lambda(_) => return false,
                 ScopeKind::Function(ast::StmtFunctionDef { is_async, .. }) => return *is_async,
-                ScopeKind::Generator { .. } | ScopeKind::Module | ScopeKind::Type => {}
+                ScopeKind::Generator { .. }
+                | ScopeKind::Module
+                | ScopeKind::Type
+                | ScopeKind::DunderClassCell => {}
             }
         }
         false
@@ -714,7 +717,10 @@ impl SemanticSyntaxContext for Checker<'_> {
             match scope.kind {
                 ScopeKind::Class(_) => return false,
                 ScopeKind::Function(_) | ScopeKind::Lambda(_) => return true,
-                ScopeKind::Generator { .. } | ScopeKind::Module | ScopeKind::Type => {}
+                ScopeKind::Generator { .. }
+                | ScopeKind::Module
+                | ScopeKind::Type
+                | ScopeKind::DunderClassCell => {}
             }
         }
         false
@@ -725,7 +731,7 @@ impl SemanticSyntaxContext for Checker<'_> {
             match scope.kind {
                 ScopeKind::Class(_) | ScopeKind::Generator { .. } => return false,
                 ScopeKind::Function(_) | ScopeKind::Lambda(_) => return true,
-                ScopeKind::Module | ScopeKind::Type => {}
+                ScopeKind::Module | ScopeKind::Type | ScopeKind::DunderClassCell => {}
             }
         }
         false
@@ -1092,6 +1098,24 @@ impl<'a> Visitor<'a> for Checker<'a> {
                     }
                 }
 
+                // Here we add the implicit scope surrounding a method which allows code in the
+                // method to access `__class__` at runtime. See the `ScopeKind::DunderClassCell`
+                // docs for more information.
+                let added_dunder_class_scope = if self.semantic.current_scope().kind.is_class() {
+                    self.semantic.push_scope(ScopeKind::DunderClassCell);
+                    let binding_id = self.semantic.push_binding(
+                        TextRange::default(),
+                        BindingKind::DunderClassCell,
+                        BindingFlags::empty(),
+                    );
+                    self.semantic
+                        .current_scope_mut()
+                        .add("__class__", binding_id);
+                    true
+                } else {
+                    false
+                };
+
                 self.semantic.push_scope(ScopeKind::Type);
 
                 if let Some(type_params) = type_params {
@@ -1155,6 +1179,9 @@ impl<'a> Visitor<'a> for Checker<'a> {
                 self.semantic.pop_scope(); // Function scope
                 self.semantic.pop_definition();
                 self.semantic.pop_scope(); // Type parameter scope
+                if added_dunder_class_scope {
+                    self.semantic.pop_scope(); // `__class__` cell closure scope
+                }
                 self.add_binding(
                     name,
                     stmt.identifier(),

crates/ruff_linter/src/codes.rs

@@ -336,6 +336,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Flake8Async, "115") => (RuleGroup::Stable, rules::flake8_async::rules::AsyncZeroSleep),
         (Flake8Async, "116") => (RuleGroup::Preview, rules::flake8_async::rules::LongSleepNotForever),
         (Flake8Async, "210") => (RuleGroup::Stable, rules::flake8_async::rules::BlockingHttpCallInAsyncFunction),
+        (Flake8Async, "212") => (RuleGroup::Preview, rules::flake8_async::rules::BlockingHttpCallHttpxInAsyncFunction),
         (Flake8Async, "220") => (RuleGroup::Stable, rules::flake8_async::rules::CreateSubprocessInAsyncFunction),
         (Flake8Async, "221") => (RuleGroup::Stable, rules::flake8_async::rules::RunProcessInAsyncFunction),
         (Flake8Async, "222") => (RuleGroup::Stable, rules::flake8_async::rules::WaitForProcessInAsyncFunction),

crates/ruff_linter/src/preview.rs

@@ -40,6 +40,11 @@ pub(crate) const fn is_bad_version_info_in_non_stub_enabled(settings: &LinterSet
     settings.preview.is_enabled()
 }
 
+/// <https://github.com/astral-sh/ruff/pull/19303>
+pub(crate) const fn is_fix_f_string_logging_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}
+
 // https://github.com/astral-sh/ruff/pull/16719
 pub(crate) const fn is_fix_manual_dict_comprehension_enabled(settings: &LinterSettings) -> bool {
     settings.preview.is_enabled()

crates/ruff_linter/src/renamer.rs

@@ -354,7 +354,10 @@ impl Renamer {
                 ))
             }
             // Avoid renaming builtins and other "special" bindings.
-            BindingKind::FutureImport | BindingKind::Builtin | BindingKind::Export(_) => None,
+            BindingKind::FutureImport
+            | BindingKind::Builtin
+            | BindingKind::Export(_)
+            | BindingKind::DunderClassCell => None,
             // By default, replace the binding's name with the target name.
             BindingKind::Annotation
             | BindingKind::Argument

crates/ruff_linter/src/rules/airflow/rules/suggested_to_move_to_provider_in_3.rs

@@ -215,6 +215,12 @@ fn check_names_moved_to_provider(checker: &Checker, expr: &Expr, ranged: TextRan
                 version: "0.0.1",
             }
         }
+        ["airflow", "sensors", "bash", "BashSensor"] => ProviderReplacement::AutoImport {
+            module: "airflow.providers.standard.sensor.bash",
+            name: "BashSensor",
+            provider: "standard",
+            version: "0.0.1",
+        },
         [
             "airflow",
             "sensors",
@@ -243,6 +249,12 @@ fn check_names_moved_to_provider(checker: &Checker, expr: &Expr, ranged: TextRan
             provider: "standard",
             version: "0.0.2",
         },
+        ["airflow", "sensors", "python", "PythonSensor"] => ProviderReplacement::AutoImport {
+            module: "airflow.providers.standard.sensors.python",
+            name: "PythonSensor",
+            provider: "standard",
+            version: "0.0.1",
+        },
         [
             "airflow",
             "sensors",

crates/ruff_linter/src/rules/airflow/rules/suggested_to_update_3_0.rs

@@ -227,13 +227,26 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
             module: "airflow.sdk",
             name: (*rest).to_string(),
         },
+        [
+            "airflow",
+            "decorators",
+            "base",
+            rest @ ("DecoratedMappedOperator"
+            | "DecoratedOperator"
+            | "TaskDecorator"
+            | "get_unique_task_id"
+            | "task_decorator_factory"),
+        ] => Replacement::SourceModuleMoved {
+            module: "airflow.sdk.bases.decorator",
+            name: (*rest).to_string(),
+        },
 
         // airflow.io
         ["airflow", "io", "path", "ObjectStoragePath"] => Replacement::SourceModuleMoved {
             module: "airflow.sdk",
             name: "ObjectStoragePath".to_string(),
         },
-        ["airflow", "io", "storage", "attach"] => Replacement::SourceModuleMoved {
+        ["airflow", "io", "store", "attach"] => Replacement::SourceModuleMoved {
             module: "airflow.sdk.io",
             name: "attach".to_string(),
         },
@@ -245,6 +258,10 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
                 name: (*rest).to_string(),
             }
         }
+        ["airflow", "models", "Param"] => Replacement::AutoImport {
+            module: "airflow.sdk.definitions.param",
+            name: "Param",
+        },
 
         // airflow.models.baseoperator
         [
@@ -260,16 +277,30 @@ fn check_name(checker: &Checker, expr: &Expr, range: TextRange) {
             module: "airflow.sdk",
             name: "BaseOperatorLink",
         },
+
         // airflow.model..DAG
         ["airflow", "models", .., "DAG"] => Replacement::SourceModuleMoved {
             module: "airflow.sdk",
             name: "DAG".to_string(),
         },
+
+        // airflow.sensors.base
+        [
+            "airflow",
+            "sensors",
+            "base",
+            rest @ ("BaseSensorOperator" | "PokeReturnValue" | "poke_mode_only"),
+        ] => Replacement::SourceModuleMoved {
+            module: "airflow.sdk",
+            name: (*rest).to_string(),
+        },
+
         // airflow.timetables
         ["airflow", "timetables", "datasets", "DatasetOrTimeSchedule"] => Replacement::AutoImport {
             module: "airflow.timetables.assets",
             name: "AssetOrTimeSchedule",
         },
+
         // airflow.utils
         [
             "airflow",

crates/ruff_linter/src/rules/airflow/snapshots/ruff_linter__rules__airflow__tests__AIR311_AIR311_names.py.snap

@@ -312,7 +312,7 @@ help: Use `teardown` from `airflow.sdk` instead.
 34 34 | setup()
 35    |-from airflow.decorators import teardown
 36 35 | from airflow.io.path import ObjectStoragePath
-37 36 | from airflow.io.storage import attach
+37 36 | from airflow.io.store import attach
 38 37 | from airflow.models import DAG as DAGFromModel
 --------------------------------------------------------------------------------
 43 42 | from airflow.models.baseoperator import chain, chain_linear, cross_downstream
@@ -338,7 +338,7 @@ help: Use `ObjectStoragePath` from `airflow.sdk` instead.
 34 34 | setup()
 35 35 | from airflow.decorators import teardown
 36    |-from airflow.io.path import ObjectStoragePath
-37 36 | from airflow.io.storage import attach
+37 36 | from airflow.io.store import attach
 38 37 | from airflow.models import DAG as DAGFromModel
 39 38 | from airflow.models import (
 --------------------------------------------------------------------------------
@@ -350,7 +350,7 @@ help: Use `ObjectStoragePath` from `airflow.sdk` instead.
 47 47 | # airflow.decorators
 48 48 | teardown()
 
-AIR311 [*] `airflow.io.storage.attach` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+AIR311 [*] `airflow.io.store.attach` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
   --> AIR311_names.py:52:1
    |
 50 | # # airflow.io
@@ -366,7 +366,7 @@ help: Use `attach` from `airflow.sdk.io` instead.
 34 34 | setup()
 35 35 | from airflow.decorators import teardown
 36 36 | from airflow.io.path import ObjectStoragePath
-37    |-from airflow.io.storage import attach
+37    |-from airflow.io.store import attach
 38 37 | from airflow.models import DAG as DAGFromModel
 39 38 | from airflow.models import (
 40 39 |     Connection,
@@ -391,7 +391,7 @@ AIR311 [*] `airflow.models.Connection` is removed in Airflow 3.0; It still works
 help: Use `Connection` from `airflow.sdk` instead.
 
 ℹ Unsafe fix
-37 37 | from airflow.io.storage import attach
+37 37 | from airflow.io.store import attach
 38 38 | from airflow.models import DAG as DAGFromModel
 39 39 | from airflow.models import (
 40    |-    Connection,
@@ -614,6 +614,8 @@ AIR311 [*] `airflow.utils.dag_parsing_context.get_parsing_context` is removed in
 75 | # airflow.utils.dag_parsing_context
 76 | get_parsing_context()
    | ^^^^^^^^^^^^^^^^^^^
+77 |
+78 | from airflow.decorators.base import (
    |
 help: Use `get_parsing_context` from `airflow.sdk` instead.
 
@@ -626,3 +628,211 @@ help: Use `get_parsing_context` from `airflow.sdk` instead.
 71 71 | 
 72 72 | # airflow.timetables.datasets
 73 73 | DatasetOrTimeSchedule()
+
+AIR311 [*] `airflow.decorators.base.DecoratedMappedOperator` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+  --> AIR311_names.py:87:1
+   |
+86 | # airflow.decorators.base
+87 | DecoratedMappedOperator()
+   | ^^^^^^^^^^^^^^^^^^^^^^^
+88 | DecoratedOperator()
+89 | TaskDecorator()
+   |
+help: Use `DecoratedMappedOperator` from `airflow.sdk.bases.decorator` instead.
+
+ℹ Unsafe fix
+76 76 | get_parsing_context()
+77 77 | 
+78 78 | from airflow.decorators.base import (
+79    |-    DecoratedMappedOperator,
+80 79 |     DecoratedOperator,
+81 80 |     TaskDecorator,
+82 81 |     get_unique_task_id,
+83 82 |     task_decorator_factory,
+84 83 | )
+   84 |+from airflow.sdk.bases.decorator import DecoratedMappedOperator
+85 85 | 
+86 86 | # airflow.decorators.base
+87 87 | DecoratedMappedOperator()
+
+AIR311 [*] `airflow.decorators.base.DecoratedOperator` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+  --> AIR311_names.py:88:1
+   |
+86 | # airflow.decorators.base
+87 | DecoratedMappedOperator()
+88 | DecoratedOperator()
+   | ^^^^^^^^^^^^^^^^^
+89 | TaskDecorator()
+90 | get_unique_task_id()
+   |
+help: Use `DecoratedOperator` from `airflow.sdk.bases.decorator` instead.
+
+ℹ Unsafe fix
+77 77 | 
+78 78 | from airflow.decorators.base import (
+79 79 |     DecoratedMappedOperator,
+80    |-    DecoratedOperator,
+81 80 |     TaskDecorator,
+82 81 |     get_unique_task_id,
+83 82 |     task_decorator_factory,
+84 83 | )
+   84 |+from airflow.sdk.bases.decorator import DecoratedOperator
+85 85 | 
+86 86 | # airflow.decorators.base
+87 87 | DecoratedMappedOperator()
+
+AIR311 [*] `airflow.decorators.base.TaskDecorator` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+  --> AIR311_names.py:89:1
+   |
+87 | DecoratedMappedOperator()
+88 | DecoratedOperator()
+89 | TaskDecorator()
+   | ^^^^^^^^^^^^^
+90 | get_unique_task_id()
+91 | task_decorator_factory()
+   |
+help: Use `TaskDecorator` from `airflow.sdk.bases.decorator` instead.
+
+ℹ Unsafe fix
+78 78 | from airflow.decorators.base import (
+79 79 |     DecoratedMappedOperator,
+80 80 |     DecoratedOperator,
+81    |-    TaskDecorator,
+82 81 |     get_unique_task_id,
+83 82 |     task_decorator_factory,
+84 83 | )
+   84 |+from airflow.sdk.bases.decorator import TaskDecorator
+85 85 | 
+86 86 | # airflow.decorators.base
+87 87 | DecoratedMappedOperator()
+
+AIR311 [*] `airflow.decorators.base.get_unique_task_id` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+  --> AIR311_names.py:90:1
+   |
+88 | DecoratedOperator()
+89 | TaskDecorator()
+90 | get_unique_task_id()
+   | ^^^^^^^^^^^^^^^^^^
+91 | task_decorator_factory()
+   |
+help: Use `get_unique_task_id` from `airflow.sdk.bases.decorator` instead.
+
+ℹ Unsafe fix
+79 79 |     DecoratedMappedOperator,
+80 80 |     DecoratedOperator,
+81 81 |     TaskDecorator,
+82    |-    get_unique_task_id,
+83 82 |     task_decorator_factory,
+84 83 | )
+   84 |+from airflow.sdk.bases.decorator import get_unique_task_id
+85 85 | 
+86 86 | # airflow.decorators.base
+87 87 | DecoratedMappedOperator()
+
+AIR311 [*] `airflow.decorators.base.task_decorator_factory` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+  --> AIR311_names.py:91:1
+   |
+89 | TaskDecorator()
+90 | get_unique_task_id()
+91 | task_decorator_factory()
+   | ^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: Use `task_decorator_factory` from `airflow.sdk.bases.decorator` instead.
+
+ℹ Unsafe fix
+80 80 |     DecoratedOperator,
+81 81 |     TaskDecorator,
+82 82 |     get_unique_task_id,
+83    |-    task_decorator_factory,
+84 83 | )
+   84 |+from airflow.sdk.bases.decorator import task_decorator_factory
+85 85 | 
+86 86 | # airflow.decorators.base
+87 87 | DecoratedMappedOperator()
+
+AIR311 [*] `airflow.models.Param` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+  --> AIR311_names.py:97:1
+   |
+96 | # airflow.models
+97 | Param()
+   | ^^^^^
+   |
+help: Use `Param` from `airflow.sdk.definitions.param` instead.
+
+ℹ Unsafe fix
+91 91 | task_decorator_factory()
+92 92 | 
+93 93 | 
+94    |-from airflow.models import Param
+   94 |+from airflow.sdk.definitions.param import Param
+95 95 | 
+96 96 | # airflow.models
+97 97 | Param()
+
+AIR311 [*] `airflow.sensors.base.BaseSensorOperator` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+   --> AIR311_names.py:107:1
+    |
+106 | # airflow.sensors.base
+107 | BaseSensorOperator()
+    | ^^^^^^^^^^^^^^^^^^
+108 | PokeReturnValue()
+109 | poke_mode_only()
+    |
+help: Use `BaseSensorOperator` from `airflow.sdk` instead.
+
+ℹ Unsafe fix
+98  98  | 
+99  99  | 
+100 100 | from airflow.sensors.base import (
+101     |-    BaseSensorOperator,
+102 101 |     PokeReturnValue,
+103 102 |     poke_mode_only,
+104 103 | )
+    104 |+from airflow.sdk import BaseSensorOperator
+105 105 | 
+106 106 | # airflow.sensors.base
+107 107 | BaseSensorOperator()
+
+AIR311 [*] `airflow.sensors.base.PokeReturnValue` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+   --> AIR311_names.py:108:1
+    |
+106 | # airflow.sensors.base
+107 | BaseSensorOperator()
+108 | PokeReturnValue()
+    | ^^^^^^^^^^^^^^^
+109 | poke_mode_only()
+    |
+help: Use `PokeReturnValue` from `airflow.sdk` instead.
+
+ℹ Unsafe fix
+99  99  | 
+100 100 | from airflow.sensors.base import (
+101 101 |     BaseSensorOperator,
+102     |-    PokeReturnValue,
+103 102 |     poke_mode_only,
+104 103 | )
+    104 |+from airflow.sdk import PokeReturnValue
+105 105 | 
+106 106 | # airflow.sensors.base
+107 107 | BaseSensorOperator()
+
+AIR311 [*] `airflow.sensors.base.poke_mode_only` is removed in Airflow 3.0; It still works in Airflow 3.0 but is expected to be removed in a future version.
+   --> AIR311_names.py:109:1
+    |
+107 | BaseSensorOperator()
+108 | PokeReturnValue()
+109 | poke_mode_only()
+    | ^^^^^^^^^^^^^^
+    |
+help: Use `poke_mode_only` from `airflow.sdk` instead.
+
+ℹ Unsafe fix
+100 100 | from airflow.sensors.base import (
+101 101 |     BaseSensorOperator,
+102 102 |     PokeReturnValue,
+103     |-    poke_mode_only,
+104 103 | )
+    104 |+from airflow.sdk import poke_mode_only
+105 105 | 
+106 106 | # airflow.sensors.base
+107 107 | BaseSensorOperator()

crates/ruff_linter/src/rules/flake8_async/mod.rs

@@ -23,6 +23,7 @@ mod tests {
     #[test_case(Rule::AsyncZeroSleep, Path::new("ASYNC115.py"))]
     #[test_case(Rule::LongSleepNotForever, Path::new("ASYNC116.py"))]
     #[test_case(Rule::BlockingHttpCallInAsyncFunction, Path::new("ASYNC210.py"))]
+    #[test_case(Rule::BlockingHttpCallHttpxInAsyncFunction, Path::new("ASYNC212.py"))]
     #[test_case(Rule::CreateSubprocessInAsyncFunction, Path::new("ASYNC22x.py"))]
     #[test_case(Rule::RunProcessInAsyncFunction, Path::new("ASYNC22x.py"))]
     #[test_case(Rule::WaitForProcessInAsyncFunction, Path::new("ASYNC22x.py"))]

crates/ruff_linter/src/rules/flake8_async/rules/blocking_http_call_httpx.rs

@@ -0,0 +1,145 @@
+use ruff_python_ast::{self as ast, Expr, ExprCall};
+
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_semantic::analyze::typing::{TypeChecker, check_type, traverse_union_and_optional};
+use ruff_text_size::Ranged;
+
+use crate::Violation;
+use crate::checkers::ast::Checker;
+
+/// ## What it does
+/// Checks that async functions do not use blocking httpx clients.
+///
+/// ## Why is this bad?
+/// Blocking an async function via a blocking HTTP call will block the entire
+/// event loop, preventing it from executing other tasks while waiting for the
+/// HTTP response, negating the benefits of asynchronous programming.
+///
+/// Instead of using the blocking `httpx` client, use the asynchronous client.
+///
+/// ## Example
+/// ```python
+/// import httpx
+///
+///
+/// async def fetch():
+///     client = httpx.Client()
+///     response = client.get(...)
+/// ```
+///
+/// Use instead:
+/// ```python
+/// import httpx
+///
+///
+/// async def fetch():
+///     async with httpx.AsyncClient() as client:
+///         response = await client.get(...)
+/// ```
+#[derive(ViolationMetadata)]
+pub(crate) struct BlockingHttpCallHttpxInAsyncFunction {
+    name: String,
+    call: String,
+}
+
+impl Violation for BlockingHttpCallHttpxInAsyncFunction {
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        format!(
+            "Blocking httpx method {name}.{call}() in async context, use httpx.AsyncClient",
+            name = self.name,
+            call = self.call,
+        )
+    }
+}
+
+struct HttpxClientChecker;
+
+impl TypeChecker for HttpxClientChecker {
+    fn match_annotation(
+        annotation: &ruff_python_ast::Expr,
+        semantic: &ruff_python_semantic::SemanticModel,
+    ) -> bool {
+        // match base annotation directly
+        if semantic
+            .resolve_qualified_name(annotation)
+            .is_some_and(|qualified_name| matches!(qualified_name.segments(), ["httpx", "Client"]))
+        {
+            return true;
+        }
+
+        // otherwise traverse any union or optional annotation
+        let mut found = false;
+        traverse_union_and_optional(
+            &mut |inner_expr, _| {
+                if semantic
+                    .resolve_qualified_name(inner_expr)
+                    .is_some_and(|qualified_name| {
+                        matches!(qualified_name.segments(), ["httpx", "Client"])
+                    })
+                {
+                    found = true;
+                }
+            },
+            semantic,
+            annotation,
+        );
+        found
+    }
+
+    fn match_initializer(
+        initializer: &ruff_python_ast::Expr,
+        semantic: &ruff_python_semantic::SemanticModel,
+    ) -> bool {
+        let Expr::Call(ExprCall { func, .. }) = initializer else {
+            return false;
+        };
+
+        semantic
+            .resolve_qualified_name(func)
+            .is_some_and(|qualified_name| matches!(qualified_name.segments(), ["httpx", "Client"]))
+    }
+}
+
+/// ASYNC212
+pub(crate) fn blocking_http_call_httpx(checker: &Checker, call: &ExprCall) {
+    let semantic = checker.semantic();
+    if !semantic.in_async_context() {
+        return;
+    }
+
+    let Some(ast::ExprAttribute { value, attr, .. }) = call.func.as_attribute_expr() else {
+        return;
+    };
+    let Some(name) = value.as_name_expr() else {
+        return;
+    };
+    let Some(binding) = semantic.only_binding(name).map(|id| semantic.binding(id)) else {
+        return;
+    };
+
+    if check_type::<HttpxClientChecker>(binding, semantic) {
+        if matches!(
+            attr.id.as_str(),
+            "close"
+                | "delete"
+                | "get"
+                | "head"
+                | "options"
+                | "patch"
+                | "post"
+                | "put"
+                | "request"
+                | "send"
+                | "stream"
+        ) {
+            checker.report_diagnostic(
+                BlockingHttpCallHttpxInAsyncFunction {
+                    name: name.id.to_string(),
+                    call: attr.id.to_string(),
+                },
+                call.func.range(),
+            );
+        }
+    }
+}

crates/ruff_linter/src/rules/flake8_async/rules/mod.rs

@@ -2,6 +2,7 @@ pub(crate) use async_busy_wait::*;
 pub(crate) use async_function_with_timeout::*;
 pub(crate) use async_zero_sleep::*;
 pub(crate) use blocking_http_call::*;
+pub(crate) use blocking_http_call_httpx::*;
 pub(crate) use blocking_open_call::*;
 pub(crate) use blocking_process_invocation::*;
 pub(crate) use blocking_sleep::*;
@@ -13,6 +14,7 @@ mod async_busy_wait;
 mod async_function_with_timeout;
 mod async_zero_sleep;
 mod blocking_http_call;
+mod blocking_http_call_httpx;
 mod blocking_open_call;
 mod blocking_process_invocation;
 mod blocking_sleep;

crates/ruff_linter/src/rules/flake8_async/snapshots/ruff_linter__rules__flake8_async__tests__ASYNC212_ASYNC212.py.snap

@@ -0,0 +1,168 @@
+---
+source: crates/ruff_linter/src/rules/flake8_async/mod.rs
+---
+ASYNC212 Blocking httpx method client.close() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:27:5
+   |
+25 | async def foo():
+26 |     client = httpx.Client()
+27 |     client.close()  # ASYNC212
+   |     ^^^^^^^^^^^^
+28 |     client.delete()  # ASYNC212
+29 |     client.get()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.delete() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:28:5
+   |
+26 |     client = httpx.Client()
+27 |     client.close()  # ASYNC212
+28 |     client.delete()  # ASYNC212
+   |     ^^^^^^^^^^^^^
+29 |     client.get()  # ASYNC212
+30 |     client.head()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.get() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:29:5
+   |
+27 |     client.close()  # ASYNC212
+28 |     client.delete()  # ASYNC212
+29 |     client.get()  # ASYNC212
+   |     ^^^^^^^^^^
+30 |     client.head()  # ASYNC212
+31 |     client.options()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.head() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:30:5
+   |
+28 |     client.delete()  # ASYNC212
+29 |     client.get()  # ASYNC212
+30 |     client.head()  # ASYNC212
+   |     ^^^^^^^^^^^
+31 |     client.options()  # ASYNC212
+32 |     client.patch()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.options() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:31:5
+   |
+29 |     client.get()  # ASYNC212
+30 |     client.head()  # ASYNC212
+31 |     client.options()  # ASYNC212
+   |     ^^^^^^^^^^^^^^
+32 |     client.patch()  # ASYNC212
+33 |     client.post()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.patch() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:32:5
+   |
+30 |     client.head()  # ASYNC212
+31 |     client.options()  # ASYNC212
+32 |     client.patch()  # ASYNC212
+   |     ^^^^^^^^^^^^
+33 |     client.post()  # ASYNC212
+34 |     client.put()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.post() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:33:5
+   |
+31 |     client.options()  # ASYNC212
+32 |     client.patch()  # ASYNC212
+33 |     client.post()  # ASYNC212
+   |     ^^^^^^^^^^^
+34 |     client.put()  # ASYNC212
+35 |     client.request()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.put() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:34:5
+   |
+32 |     client.patch()  # ASYNC212
+33 |     client.post()  # ASYNC212
+34 |     client.put()  # ASYNC212
+   |     ^^^^^^^^^^
+35 |     client.request()  # ASYNC212
+36 |     client.send()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.request() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:35:5
+   |
+33 |     client.post()  # ASYNC212
+34 |     client.put()  # ASYNC212
+35 |     client.request()  # ASYNC212
+   |     ^^^^^^^^^^^^^^
+36 |     client.send()  # ASYNC212
+37 |     client.stream()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.send() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:36:5
+   |
+34 |     client.put()  # ASYNC212
+35 |     client.request()  # ASYNC212
+36 |     client.send()  # ASYNC212
+   |     ^^^^^^^^^^^
+37 |     client.stream()  # ASYNC212
+   |
+
+ASYNC212 Blocking httpx method client.stream() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:37:5
+   |
+35 |     client.request()  # ASYNC212
+36 |     client.send()  # ASYNC212
+37 |     client.stream()  # ASYNC212
+   |     ^^^^^^^^^^^^^
+38 |
+39 |     client.anything()  # Ok
+   |
+
+ASYNC212 Blocking httpx method client.request() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:45:5
+   |
+44 | async def foo(client: httpx.Client):
+45 |     client.request()  # ASYNC212
+   |     ^^^^^^^^^^^^^^
+46 |     client.anything()  # Ok
+   |
+
+ASYNC212 Blocking httpx method client.request() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:50:5
+   |
+49 | async def foo(client: httpx.Client | None):
+50 |     client.request()  # ASYNC212
+   |     ^^^^^^^^^^^^^^
+51 |     client.anything()  # Ok
+   |
+
+ASYNC212 Blocking httpx method client.request() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:55:5
+   |
+54 | async def foo(client: Optional[httpx.Client]):
+55 |     client.request()  # ASYNC212
+   |     ^^^^^^^^^^^^^^
+56 |     client.anything()  # Ok
+   |
+
+ASYNC212 Blocking httpx method client.request() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:61:5
+   |
+59 | async def foo():
+60 |     client: httpx.Client = ...
+61 |     client.request()  # ASYNC212
+   |     ^^^^^^^^^^^^^^
+62 |     client.anything()  # Ok
+   |
+
+ASYNC212 Blocking httpx method global_client.request() in async context, use httpx.AsyncClient
+  --> ASYNC212.py:69:5
+   |
+68 | async def foo():
+69 |     global_client.request()  # ASYNC212
+   |     ^^^^^^^^^^^^^^^^^^^^^
+70 |     global_client.anything()  # Ok
+   |

crates/ruff_linter/src/rules/flake8_logging_format/mod.rs

@@ -22,6 +22,7 @@ mod tests {
     #[test_case(Path::new("G002.py"))]
     #[test_case(Path::new("G003.py"))]
     #[test_case(Path::new("G004.py"))]
+    #[test_case(Path::new("G004_arg_order.py"))]
     #[test_case(Path::new("G010.py"))]
     #[test_case(Path::new("G101_1.py"))]
     #[test_case(Path::new("G101_2.py"))]
@@ -48,4 +49,24 @@ mod tests {
         assert_diagnostics!(snapshot, diagnostics);
         Ok(())
     }
+
+    #[test_case(Rule::LoggingFString, Path::new("G004.py"))]
+    #[test_case(Rule::LoggingFString, Path::new("G004_arg_order.py"))]
+    fn preview_rules(rule_code: Rule, path: &Path) -> Result<()> {
+        let snapshot = format!(
+            "preview__{}_{}",
+            rule_code.noqa_code(),
+            path.to_string_lossy()
+        );
+        let diagnostics = test_path(
+            Path::new("flake8_logging_format").join(path).as_path(),
+            &settings::LinterSettings {
+                logger_objects: vec!["logging_setup.logger".to_string()],
+                preview: settings::types::PreviewMode::Enabled,
+                ..settings::LinterSettings::for_rule(rule_code)
+            },
+        )?;
+        assert_diagnostics!(snapshot, diagnostics);
+        Ok(())
+    }
 }

crates/ruff_linter/src/rules/flake8_logging_format/rules/logging_call.rs

@@ -1,9 +1,11 @@
-use ruff_python_ast::{self as ast, Arguments, Expr, Keyword, Operator};
+use ruff_python_ast::InterpolatedStringElement;
+use ruff_python_ast::{self as ast, Arguments, Expr, Keyword, Operator, StringFlags};
 use ruff_python_semantic::analyze::logging;
 use ruff_python_stdlib::logging::LoggingLevel;
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
+use crate::preview::is_fix_f_string_logging_enabled;
 use crate::registry::Rule;
 use crate::rules::flake8_logging_format::violations::{
     LoggingExcInfo, LoggingExtraAttrClash, LoggingFString, LoggingPercentFormat,
@@ -11,6 +13,87 @@ use crate::rules::flake8_logging_format::violations::{
 };
 use crate::{Edit, Fix};
 
+fn logging_f_string(
+    checker: &Checker,
+    msg: &Expr,
+    f_string: &ast::ExprFString,
+    arguments: &Arguments,
+    msg_pos: usize,
+) {
+    // Report the diagnostic up-front so we can attach a fix later only when preview is enabled.
+    let mut diagnostic = checker.report_diagnostic(LoggingFString, msg.range());
+
+    // Preview gate for the automatic fix.
+    if !is_fix_f_string_logging_enabled(checker.settings()) {
+        return;
+    }
+
+    // If there are existing positional arguments after the message, bail out.
+    // This could indicate a mistake or complex usage we shouldn't try to fix.
+    if arguments.args.len() > msg_pos + 1 {
+        return;
+    }
+
+    let mut format_string = String::new();
+    let mut args: Vec<&str> = Vec::new();
+
+    // Try to reuse the first part's quote style when building the replacement.
+    // Default to double quotes if we can't determine it.
+    let quote_str = f_string
+        .value
+        .f_strings()
+        .next()
+        .map(|f| f.flags.quote_str())
+        .unwrap_or("\"");
+
+    for f in f_string.value.f_strings() {
+        for element in &f.elements {
+            match element {
+                InterpolatedStringElement::Literal(lit) => {
+                    // If the literal text contains a '%' placeholder, bail out: mixing
+                    // f-string interpolation with '%' placeholders is ambiguous for our
+                    // automatic conversion, so don't offer a fix for this case.
+                    if lit.value.as_ref().contains('%') {
+                        return;
+                    }
+                    format_string.push_str(lit.value.as_ref());
+                }
+                InterpolatedStringElement::Interpolation(interpolated) => {
+                    if interpolated.format_spec.is_some()
+                        || !matches!(
+                            interpolated.conversion,
+                            ruff_python_ast::ConversionFlag::None
+                        )
+                    {
+                        return;
+                    }
+                    match interpolated.expression.as_ref() {
+                        Expr::Name(name) => {
+                            format_string.push_str("%s");
+                            args.push(name.id.as_str());
+                        }
+                        _ => return,
+                    }
+                }
+            }
+        }
+    }
+
+    if args.is_empty() {
+        return;
+    }
+
+    let replacement = format!(
+        "{q}{format_string}{q}, {args}",
+        q = quote_str,
+        format_string = format_string,
+        args = args.join(", ")
+    );
+
+    let fix = Fix::safe_edit(Edit::range_replacement(replacement, msg.range()));
+    diagnostic.set_fix(fix);
+}
+
 /// Returns `true` if the attribute is a reserved attribute on the `logging` module's `LogRecord`
 /// class.
 fn is_reserved_attr(attr: &str) -> bool {
@@ -42,7 +125,7 @@ fn is_reserved_attr(attr: &str) -> bool {
 }
 
 /// Check logging messages for violations.
-fn check_msg(checker: &Checker, msg: &Expr) {
+fn check_msg(checker: &Checker, msg: &Expr, arguments: &Arguments, msg_pos: usize) {
     match msg {
         // Check for string concatenation and percent format.
         Expr::BinOp(ast::ExprBinOp { op, .. }) => match op {
@@ -55,8 +138,10 @@ fn check_msg(checker: &Checker, msg: &Expr) {
             _ => {}
         },
         // Check for f-strings.
-        Expr::FString(_) => {
-            checker.report_diagnostic_if_enabled(LoggingFString, msg.range());
+        Expr::FString(f_string) => {
+            if checker.is_rule_enabled(Rule::LoggingFString) {
+                logging_f_string(checker, msg, f_string, arguments, msg_pos);
+            }
         }
         // Check for .format() calls.
         Expr::Call(ast::ExprCall { func, .. }) => {
@@ -168,7 +253,7 @@ pub(crate) fn logging_call(checker: &Checker, call: &ast::ExprCall) {
     // G001, G002, G003, G004
     let msg_pos = usize::from(matches!(logging_call_type, LoggingCallType::LogCall));
     if let Some(format_arg) = call.arguments.find_argument_value("msg", msg_pos) {
-        check_msg(checker, format_arg);
+        check_msg(checker, format_arg, &call.arguments, msg_pos);
     }
 
     // G010

crates/ruff_linter/src/rules/flake8_logging_format/snapshots/ruff_linter__rules__flake8_logging_format__tests__G004.py.snap

@@ -9,6 +9,7 @@ G004 Logging statement uses f-string
   |              ^^^^^^^^^^^^^^^
 5 | logging.log(logging.INFO, f"Hello {name}")
   |
+help: Convert to lazy `%` formatting
 
 G004 Logging statement uses f-string
  --> G004.py:5:27
@@ -20,6 +21,7 @@ G004 Logging statement uses f-string
 6 |
 7 | _LOGGER = logging.getLogger()
   |
+help: Convert to lazy `%` formatting
 
 G004 Logging statement uses f-string
   --> G004.py:8:14
@@ -30,6 +32,7 @@ G004 Logging statement uses f-string
  9 |
 10 | logging.getLogger().info(f"{name}")
    |
+help: Convert to lazy `%` formatting
 
 G004 Logging statement uses f-string
   --> G004.py:10:26
@@ -41,6 +44,7 @@ G004 Logging statement uses f-string
 11 |
 12 | from logging import info
    |
+help: Convert to lazy `%` formatting
 
 G004 Logging statement uses f-string
   --> G004.py:14:6
@@ -51,6 +55,7 @@ G004 Logging statement uses f-string
    |      ^^^^^^^^^
 15 | info(f"{__name__}")
    |
+help: Convert to lazy `%` formatting
 
 G004 Logging statement uses f-string
   --> G004.py:15:6
@@ -61,3 +66,156 @@ G004 Logging statement uses f-string
 16 |
 17 | # Don't trigger for t-strings
    |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:24:14
+   |
+22 | total = 9
+23 | directory_path = "/home/hamir/ruff/crates/ruff_linter/resources/test/"
+24 | logging.info(f"{count} out of {total} files in {directory_path} checked")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:30:13
+   |
+28 | x = 99
+29 | fmt = "08d"
+30 | logger.info(f"{x:{'08d'}}")
+   |             ^^^^^^^^^^^^^^
+31 | logger.info(f"{x:>10} {x:{fmt}}")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:31:13
+   |
+29 | fmt = "08d"
+30 | logger.info(f"{x:{'08d'}}")
+31 | logger.info(f"{x:>10} {x:{fmt}}")
+   |             ^^^^^^^^^^^^^^^^^^^^
+32 |
+33 | logging.info(f"")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:33:14
+   |
+31 | logger.info(f"{x:>10} {x:{fmt}}")
+32 |
+33 | logging.info(f"")
+   |              ^^^
+34 | logging.info(f"This message doesn't have any variables.")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:34:14
+   |
+33 | logging.info(f"")
+34 | logging.info(f"This message doesn't have any variables.")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+35 |
+36 | obj = {"key": "value"}
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:37:14
+   |
+36 | obj = {"key": "value"}
+37 | logging.info(f"Object: {obj!r}")
+   |              ^^^^^^^^^^^^^^^^^^
+38 |
+39 | items_count = 3
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:40:17
+   |
+39 | items_count = 3
+40 | logging.warning(f"Items: {items_count:d}")
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^
+41 |
+42 | data = {"status": "active"}
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:43:14
+   |
+42 | data = {"status": "active"}
+43 | logging.info(f"Processing {len(data)} items")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+44 | logging.info(f"Status: {data.get('status', 'unknown').upper()}")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:44:14
+   |
+42 | data = {"status": "active"}
+43 | logging.info(f"Processing {len(data)} items")
+44 | logging.info(f"Status: {data.get('status', 'unknown').upper()}")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:48:14
+   |
+47 | result = 123
+48 | logging.info(f"Calculated result: {result + 100}")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+49 |
+50 | temperature = 123
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:51:14
+   |
+50 | temperature = 123
+51 | logging.info(f"Temperature: {temperature:.1f}°C")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+52 |
+53 | class FilePath:
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:57:14
+   |
+55 |         self.name = name
+56 |
+57 | logging.info(f"No changes made to {file_path.name}.")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+58 |
+59 | user = "tron"
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:61:15
+   |
+59 | user = "tron"
+60 | balance = 123.45
+61 | logging.error(f"Error {404}: User {user} has insufficient balance ${balance:.2f}")
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+62 |
+63 | import logging
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:66:15
+   |
+65 | x = 1
+66 | logging.error(f"{x} -> %s", x)
+   |               ^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting

crates/ruff_linter/src/rules/flake8_logging_format/snapshots/ruff_linter__rules__flake8_logging_format__tests__G004_arg_order.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/flake8_logging_format/mod.rs
+---
+G004 Logging statement uses f-string
+  --> G004_arg_order.py:9:14
+   |
+ 7 | X = 1
+ 8 | Y = 2
+ 9 | logger.error(f"{X} -> %s", Y)
+   |              ^^^^^^^^^^^^
+10 | logger.error(f"{Y} -> %s", X)
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004_arg_order.py:10:14
+   |
+ 8 | Y = 2
+ 9 | logger.error(f"{X} -> %s", Y)
+10 | logger.error(f"{Y} -> %s", X)
+   |              ^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting

crates/ruff_linter/src/rules/flake8_logging_format/snapshots/ruff_linter__rules__flake8_logging_format__tests__preview__G004_G004.py.snap

@@ -0,0 +1,291 @@
+---
+source: crates/ruff_linter/src/rules/flake8_logging_format/mod.rs
+---
+G004 [*] Logging statement uses f-string
+ --> G004.py:4:14
+  |
+3 | name = "world"
+4 | logging.info(f"Hello {name}")
+  |              ^^^^^^^^^^^^^^^
+5 | logging.log(logging.INFO, f"Hello {name}")
+  |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+1 1 | import logging
+2 2 | 
+3 3 | name = "world"
+4   |-logging.info(f"Hello {name}")
+  4 |+logging.info("Hello %s", name)
+5 5 | logging.log(logging.INFO, f"Hello {name}")
+6 6 | 
+7 7 | _LOGGER = logging.getLogger()
+
+G004 [*] Logging statement uses f-string
+ --> G004.py:5:27
+  |
+3 | name = "world"
+4 | logging.info(f"Hello {name}")
+5 | logging.log(logging.INFO, f"Hello {name}")
+  |                           ^^^^^^^^^^^^^^^
+6 |
+7 | _LOGGER = logging.getLogger()
+  |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+2 2 | 
+3 3 | name = "world"
+4 4 | logging.info(f"Hello {name}")
+5   |-logging.log(logging.INFO, f"Hello {name}")
+  5 |+logging.log(logging.INFO, "Hello %s", name)
+6 6 | 
+7 7 | _LOGGER = logging.getLogger()
+8 8 | _LOGGER.info(f"{__name__}")
+
+G004 [*] Logging statement uses f-string
+  --> G004.py:8:14
+   |
+ 7 | _LOGGER = logging.getLogger()
+ 8 | _LOGGER.info(f"{__name__}")
+   |              ^^^^^^^^^^^^^
+ 9 |
+10 | logging.getLogger().info(f"{name}")
+   |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+5 5 | logging.log(logging.INFO, f"Hello {name}")
+6 6 | 
+7 7 | _LOGGER = logging.getLogger()
+8   |-_LOGGER.info(f"{__name__}")
+  8 |+_LOGGER.info("%s", __name__)
+9 9 | 
+10 10 | logging.getLogger().info(f"{name}")
+11 11 | 
+
+G004 [*] Logging statement uses f-string
+  --> G004.py:10:26
+   |
+ 8 | _LOGGER.info(f"{__name__}")
+ 9 |
+10 | logging.getLogger().info(f"{name}")
+   |                          ^^^^^^^^^
+11 |
+12 | from logging import info
+   |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+7  7  | _LOGGER = logging.getLogger()
+8  8  | _LOGGER.info(f"{__name__}")
+9  9  | 
+10    |-logging.getLogger().info(f"{name}")
+   10 |+logging.getLogger().info("%s", name)
+11 11 | 
+12 12 | from logging import info
+13 13 | 
+
+G004 [*] Logging statement uses f-string
+  --> G004.py:14:6
+   |
+12 | from logging import info
+13 |
+14 | info(f"{name}")
+   |      ^^^^^^^^^
+15 | info(f"{__name__}")
+   |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+11 11 | 
+12 12 | from logging import info
+13 13 | 
+14    |-info(f"{name}")
+   14 |+info("%s", name)
+15 15 | info(f"{__name__}")
+16 16 | 
+17 17 | # Don't trigger for t-strings
+
+G004 [*] Logging statement uses f-string
+  --> G004.py:15:6
+   |
+14 | info(f"{name}")
+15 | info(f"{__name__}")
+   |      ^^^^^^^^^^^^^
+16 |
+17 | # Don't trigger for t-strings
+   |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+12 12 | from logging import info
+13 13 | 
+14 14 | info(f"{name}")
+15    |-info(f"{__name__}")
+   15 |+info("%s", __name__)
+16 16 | 
+17 17 | # Don't trigger for t-strings
+18 18 | info(t"{name}")
+
+G004 [*] Logging statement uses f-string
+  --> G004.py:24:14
+   |
+22 | total = 9
+23 | directory_path = "/home/hamir/ruff/crates/ruff_linter/resources/test/"
+24 | logging.info(f"{count} out of {total} files in {directory_path} checked")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting
+
+ℹ Safe fix
+21 21 | count = 5
+22 22 | total = 9
+23 23 | directory_path = "/home/hamir/ruff/crates/ruff_linter/resources/test/"
+24    |-logging.info(f"{count} out of {total} files in {directory_path} checked")
+   24 |+logging.info("%s out of %s files in %s checked", count, total, directory_path)
+25 25 | 
+26 26 | 
+27 27 | 
+
+G004 Logging statement uses f-string
+  --> G004.py:30:13
+   |
+28 | x = 99
+29 | fmt = "08d"
+30 | logger.info(f"{x:{'08d'}}")
+   |             ^^^^^^^^^^^^^^
+31 | logger.info(f"{x:>10} {x:{fmt}}")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:31:13
+   |
+29 | fmt = "08d"
+30 | logger.info(f"{x:{'08d'}}")
+31 | logger.info(f"{x:>10} {x:{fmt}}")
+   |             ^^^^^^^^^^^^^^^^^^^^
+32 |
+33 | logging.info(f"")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:33:14
+   |
+31 | logger.info(f"{x:>10} {x:{fmt}}")
+32 |
+33 | logging.info(f"")
+   |              ^^^
+34 | logging.info(f"This message doesn't have any variables.")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:34:14
+   |
+33 | logging.info(f"")
+34 | logging.info(f"This message doesn't have any variables.")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+35 |
+36 | obj = {"key": "value"}
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:37:14
+   |
+36 | obj = {"key": "value"}
+37 | logging.info(f"Object: {obj!r}")
+   |              ^^^^^^^^^^^^^^^^^^
+38 |
+39 | items_count = 3
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:40:17
+   |
+39 | items_count = 3
+40 | logging.warning(f"Items: {items_count:d}")
+   |                 ^^^^^^^^^^^^^^^^^^^^^^^^^
+41 |
+42 | data = {"status": "active"}
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:43:14
+   |
+42 | data = {"status": "active"}
+43 | logging.info(f"Processing {len(data)} items")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+44 | logging.info(f"Status: {data.get('status', 'unknown').upper()}")
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:44:14
+   |
+42 | data = {"status": "active"}
+43 | logging.info(f"Processing {len(data)} items")
+44 | logging.info(f"Status: {data.get('status', 'unknown').upper()}")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:48:14
+   |
+47 | result = 123
+48 | logging.info(f"Calculated result: {result + 100}")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+49 |
+50 | temperature = 123
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:51:14
+   |
+50 | temperature = 123
+51 | logging.info(f"Temperature: {temperature:.1f}°C")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+52 |
+53 | class FilePath:
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:57:14
+   |
+55 |         self.name = name
+56 |
+57 | logging.info(f"No changes made to {file_path.name}.")
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+58 |
+59 | user = "tron"
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:61:15
+   |
+59 | user = "tron"
+60 | balance = 123.45
+61 | logging.error(f"Error {404}: User {user} has insufficient balance ${balance:.2f}")
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+62 |
+63 | import logging
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004.py:66:15
+   |
+65 | x = 1
+66 | logging.error(f"{x} -> %s", x)
+   |               ^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting

crates/ruff_linter/src/rules/flake8_logging_format/snapshots/ruff_linter__rules__flake8_logging_format__tests__preview__G004_G004_arg_order.py.snap

@@ -0,0 +1,23 @@
+---
+source: crates/ruff_linter/src/rules/flake8_logging_format/mod.rs
+---
+G004 Logging statement uses f-string
+  --> G004_arg_order.py:9:14
+   |
+ 7 | X = 1
+ 8 | Y = 2
+ 9 | logger.error(f"{X} -> %s", Y)
+   |              ^^^^^^^^^^^^
+10 | logger.error(f"{Y} -> %s", X)
+   |
+help: Convert to lazy `%` formatting
+
+G004 Logging statement uses f-string
+  --> G004_arg_order.py:10:14
+   |
+ 8 | Y = 2
+ 9 | logger.error(f"{X} -> %s", Y)
+10 | logger.error(f"{Y} -> %s", X)
+   |              ^^^^^^^^^^^^
+   |
+help: Convert to lazy `%` formatting

crates/ruff_linter/src/rules/flake8_logging_format/violations.rs

@@ -327,10 +327,16 @@ impl Violation for LoggingStringConcat {
 pub(crate) struct LoggingFString;
 
 impl Violation for LoggingFString {
+    const FIX_AVAILABILITY: crate::FixAvailability = crate::FixAvailability::Sometimes;
+
     #[derive_message_formats]
     fn message(&self) -> String {
         "Logging statement uses f-string".to_string()
     }
+
+    fn fix_title(&self) -> Option<String> {
+        Some("Convert to lazy `%` formatting".to_string())
+    }
 }
 
 /// ## What it does

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -43,7 +43,7 @@ use ruff_text_size::Ranged;
 /// - [Python documentation: `os.getcwd`](https://docs.python.org/3/library/os.html#os.getcwd)
 /// - [Python documentation: `os.getcwdb`](https://docs.python.org/3/library/os.html#os.getcwdb)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -46,7 +46,7 @@ use crate::{FixAvailability, Violation};
 /// - [Python documentation: `Path.mkdir`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.mkdir)
 /// - [Python documentation: `os.makedirs`](https://docs.python.org/3/library/os.html#os.makedirs)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -47,7 +47,7 @@ use crate::{FixAvailability, Violation};
 /// - [Python documentation: `Path.mkdir`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.mkdir)
 /// - [Python documentation: `os.mkdir`](https://docs.python.org/3/library/os.html#os.mkdir)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -1,9 +1,15 @@
-use crate::checkers::ast::Checker;
-use crate::preview::is_fix_os_path_abspath_enabled;
-use crate::rules::flake8_use_pathlib::helpers::check_os_pathlib_single_arg_calls;
-use crate::{FixAvailability, Violation};
+use ruff_diagnostics::{Edit, Fix};
 use ruff_macros::{ViolationMetadata, derive_message_formats};
 use ruff_python_ast::ExprCall;
+use ruff_text_size::Ranged;
+
+use crate::checkers::ast::Checker;
+use crate::importer::ImportRequest;
+use crate::preview::is_fix_os_path_abspath_enabled;
+use crate::rules::flake8_use_pathlib::helpers::{
+    has_unknown_keywords_or_starred_expr, is_pathlib_path_call,
+};
+use crate::{FixAvailability, Violation};
 
 /// ## What it does
 /// Checks for uses of `os.path.abspath`.
@@ -34,13 +40,18 @@ use ruff_python_ast::ExprCall;
 /// 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.
+/// This rule's fix is always marked as unsafe because `Path.resolve()` resolves symlinks, while
+/// `os.path.abspath()` does not. If resolving symlinks is important, you may need to use
+/// `Path.absolute()`. However, `Path.absolute()` also does not remove any `..` components in a
+/// path, unlike `os.path.abspath()` and `Path.resolve()`, so if that specific combination of
+/// behaviors is required, there's no existing `pathlib` alternative. See CPython issue
+/// [#69200](https://github.com/python/cpython/issues/69200).
 ///
 /// ## References
 /// - [Python documentation: `Path.resolve`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.resolve)
 /// - [Python documentation: `os.path.abspath`](https://docs.python.org/3/library/os.path.html#os.path.abspath)
 /// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]
@@ -63,12 +74,44 @@ pub(crate) fn os_path_abspath(checker: &Checker, call: &ExprCall, segments: &[&s
     if segments != ["os", "path", "abspath"] {
         return;
     }
-    check_os_pathlib_single_arg_calls(
-        checker,
-        call,
-        "resolve()",
-        "path",
-        is_fix_os_path_abspath_enabled(checker.settings()),
-        OsPathAbspath,
-    );
+
+    if call.arguments.len() != 1 {
+        return;
+    }
+
+    let Some(arg) = call.arguments.find_argument_value("path", 0) else {
+        return;
+    };
+
+    let arg_code = checker.locator().slice(arg.range());
+    let range = call.range();
+
+    let mut diagnostic = checker.report_diagnostic(OsPathAbspath, call.func.range());
+
+    if has_unknown_keywords_or_starred_expr(&call.arguments, &["path"]) {
+        return;
+    }
+
+    if !is_fix_os_path_abspath_enabled(checker.settings()) {
+        return;
+    }
+
+    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, arg) {
+            format!("{arg_code}.resolve()")
+        } else {
+            format!("{binding}({arg_code}).resolve()")
+        };
+
+        Ok(Fix::unsafe_edits(
+            Edit::range_replacement(replacement, range),
+            [import_edit],
+        ))
+    });
 }

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `PurePath.name`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.name)
 /// - [Python documentation: `os.path.basename`](https://docs.python.org/3/library/os.path.html#os.path.basename)
 /// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `PurePath.parent`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.parent)
 /// - [Python documentation: `os.path.dirname`](https://docs.python.org/3/library/os.path.html#os.path.dirname)
 /// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.exists`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.exists)
 /// - [Python documentation: `os.path.exists`](https://docs.python.org/3/library/os.path.html#os.path.exists)
 /// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.expanduser`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.expanduser)
 /// - [Python documentation: `os.path.expanduser`](https://docs.python.org/3/library/os.path.html#os.path.expanduser)
 /// - [PEP 428 – The pathlib module – object-oriented filesystem paths](https://peps.python.org/pep-0428/)
-/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#correspondence-to-tools-in-the-os-module)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
 /// - [Python documentation: `os.path.getatime`](https://docs.python.org/3/library/os.path.html#os.path.getatime)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
 /// - [Python documentation: `os.path.getctime`](https://docs.python.org/3/library/os.path.html#os.path.getctime)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
 /// - [Python documentation: `os.path.getmtime`](https://docs.python.org/3/library/os.path.html#os.path.getmtime)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.stat`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.stat)
 /// - [Python documentation: `os.path.getsize`](https://docs.python.org/3/library/os.path.html#os.path.getsize)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -39,7 +39,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `PurePath.is_absolute`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.is_absolute)
 /// - [Python documentation: `os.path.isabs`](https://docs.python.org/3/library/os.path.html#os.path.isabs)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.is_dir`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_dir)
 /// - [Python documentation: `os.path.isdir`](https://docs.python.org/3/library/os.path.html#os.path.isdir)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.is_file`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_file)
 /// - [Python documentation: `os.path.isfile`](https://docs.python.org/3/library/os.path.html#os.path.isfile)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.is_symlink`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.is_symlink)
 /// - [Python documentation: `os.path.islink`](https://docs.python.org/3/library/os.path.html#os.path.islink)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -40,7 +40,7 @@ use ruff_python_ast::ExprCall;
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::{ExprCall, PythonVersion};
 /// - [Python documentation: `Path.readlink`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.readline)
 /// - [Python documentation: `os.readlink`](https://docs.python.org/3/library/os.html#os.readlink)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.unlink`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.unlink)
 /// - [Python documentation: `os.remove`](https://docs.python.org/3/library/os.html#os.remove)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -45,7 +45,7 @@ use ruff_python_ast::ExprCall;
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.rmdir`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.rmdir)
 /// - [Python documentation: `os.rmdir`](https://docs.python.org/3/library/os.html#os.rmdir)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -44,7 +44,7 @@ use crate::{FixAvailability, Violation};
 /// ## References
 /// - [Python documentation: `Path.symlink_to`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.symlink_to)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -42,7 +42,7 @@ use ruff_python_ast::ExprCall;
 /// - [Python documentation: `Path.unlink`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.unlink)
 /// - [Python documentation: `os.unlink`](https://docs.python.org/3/library/os.html#os.unlink)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -13,7 +13,7 @@ PTH100 [*] `os.path.abspath()` should be replaced by `Path.resolve()`
   |
 help: Replace with `Path(...).resolve()`
 
-ℹ Safe fix
+ℹ Unsafe fix
 1 1 | import os
 2 2 | import os.path
   3 |+import pathlib

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

@@ -13,7 +13,7 @@ PTH100 [*] `os.path.abspath()` should be replaced by `Path.resolve()`
   |
 help: Replace with `Path(...).resolve()`
 
-ℹ Safe fix
+ℹ Unsafe fix
 1 1 | import os as foo
 2 2 | import os.path as foo_p
   3 |+import pathlib

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

@@ -13,7 +13,7 @@ PTH100 [*] `os.path.abspath()` should be replaced by `Path.resolve()`
    |
 help: Replace with `Path(...).resolve()`
 
-ℹ Safe fix
+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

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

@@ -13,7 +13,7 @@ PTH100 [*] `os.path.abspath()` should be replaced by `Path.resolve()`
    |
 help: Replace with `Path(...).resolve()`
 
-ℹ Safe fix
+ℹ Unsafe fix
 7  7  | from os.path import isfile as xisfile, islink as xislink, isabs as xisabs
 8  8  | from os.path import join as xjoin, basename as xbasename, dirname as xdirname
 9  9  | from os.path import samefile as xsamefile, splitext as xsplitext

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

@@ -43,7 +43,7 @@ use crate::Violation;
 /// - [Python documentation: `Path.owner`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.owner)
 /// - [Python documentation: `os.stat`](https://docs.python.org/3/library/os.html#os.stat)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]
@@ -89,7 +89,7 @@ impl Violation for OsStat {
 /// - [Python documentation: `PurePath.joinpath`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.joinpath)
 /// - [Python documentation: `os.path.join`](https://docs.python.org/3/library/os.path.html#os.path.join)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]
@@ -160,7 +160,7 @@ pub(crate) enum Joiner {
 /// - [Python documentation: `Path.suffixes`](https://docs.python.org/3/library/pathlib.html#pathlib.PurePath.suffixes)
 /// - [Python documentation: `os.path.splitext`](https://docs.python.org/3/library/os.path.html#os.path.splitext)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]
@@ -205,7 +205,7 @@ impl Violation for OsPathSplitext {
 /// - [Python documentation: `Path.open`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.open)
 /// - [Python documentation: `open`](https://docs.python.org/3/library/functions.html#open)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]
@@ -298,7 +298,7 @@ impl Violation for PyPath {
 /// - [Python documentation: `Path.iterdir`](https://docs.python.org/3/library/pathlib.html#pathlib.Path.iterdir)
 /// - [Python documentation: `os.listdir`](https://docs.python.org/3/library/os.html#os.listdir)
 /// - [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)
+/// - [Correspondence between `os` and `pathlib`](https://docs.python.org/3/library/pathlib.html#corresponding-tools)
 /// - [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)]

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

@@ -737,6 +737,7 @@ mod tests {
 
     /// A re-implementation of the Pyflakes test runner.
     /// Note that all tests marked with `#[ignore]` should be considered TODOs.
+    #[track_caller]
     fn flakes(contents: &str, expected: &[Rule]) {
         let contents = dedent(contents);
         let source_type = PySourceType::default();

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F841_F841_0.py.snap

@@ -251,3 +251,63 @@ F841 Local variable `value` is assigned to but never used
 128 |         print(key)
     |
 help: Remove assignment to unused variable `value`
+
+F841 [*] Local variable `__class__` is assigned to but never used
+   --> F841_0.py:168:9
+    |
+166 | class A:
+167 |     def set_class(self, cls):
+168 |         __class__ = cls  # F841
+    |         ^^^^^^^^^
+    |
+help: Remove assignment to unused variable `__class__`
+
+ℹ Unsafe fix
+165 165 | # variables that don't refer to the special `__class__` cell.
+166 166 | class A:
+167 167 |     def set_class(self, cls):
+168     |-        __class__ = cls  # F841
+    168 |+        pass  # F841
+169 169 | 
+170 170 | 
+171 171 | class A:
+
+F841 [*] Local variable `__class__` is assigned to but never used
+   --> F841_0.py:174:13
+    |
+172 |     class B:
+173 |         def set_class(self, cls):
+174 |             __class__ = cls  # F841
+    |             ^^^^^^^^^
+    |
+help: Remove assignment to unused variable `__class__`
+
+ℹ Unsafe fix
+171 171 | class A:
+172 172 |     class B:
+173 173 |         def set_class(self, cls):
+174     |-            __class__ = cls  # F841
+    174 |+            pass  # F841
+175 175 | 
+176 176 | 
+177 177 | class A:
+
+F841 [*] Local variable `__class__` is assigned to but never used
+   --> F841_0.py:182:17
+    |
+180 |             print(__class__)
+181 |             def set_class(self, cls):
+182 |                 __class__ = cls  # F841
+    |                 ^^^^^^^^^
+    |
+help: Remove assignment to unused variable `__class__`
+
+ℹ Unsafe fix
+179 179 |         class B:
+180 180 |             print(__class__)
+181 181 |             def set_class(self, cls):
+182     |-                __class__ = cls  # F841
+    182 |+                pass  # F841
+183 183 | 
+184 184 | 
+185 185 | # OK, the `__class__` cell is nonlocal and declared as such.

crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__f841_dummy_variable_rgx.snap

@@ -289,3 +289,65 @@ help: Remove assignment to unused variable `_`
 152     |-    except Exception as _:
     152 |+    except Exception:
 153 153 |         pass
+154 154 | 
+155 155 | 
+
+F841 [*] Local variable `__class__` is assigned to but never used
+   --> F841_0.py:168:9
+    |
+166 | class A:
+167 |     def set_class(self, cls):
+168 |         __class__ = cls  # F841
+    |         ^^^^^^^^^
+    |
+help: Remove assignment to unused variable `__class__`
+
+ℹ Unsafe fix
+165 165 | # variables that don't refer to the special `__class__` cell.
+166 166 | class A:
+167 167 |     def set_class(self, cls):
+168     |-        __class__ = cls  # F841
+    168 |+        pass  # F841
+169 169 | 
+170 170 | 
+171 171 | class A:
+
+F841 [*] Local variable `__class__` is assigned to but never used
+   --> F841_0.py:174:13
+    |
+172 |     class B:
+173 |         def set_class(self, cls):
+174 |             __class__ = cls  # F841
+    |             ^^^^^^^^^
+    |
+help: Remove assignment to unused variable `__class__`
+
+ℹ Unsafe fix
+171 171 | class A:
+172 172 |     class B:
+173 173 |         def set_class(self, cls):
+174     |-            __class__ = cls  # F841
+    174 |+            pass  # F841
+175 175 | 
+176 176 | 
+177 177 | class A:
+
+F841 [*] Local variable `__class__` is assigned to but never used
+   --> F841_0.py:182:17
+    |
+180 |             print(__class__)
+181 |             def set_class(self, cls):
+182 |                 __class__ = cls  # F841
+    |                 ^^^^^^^^^
+    |
+help: Remove assignment to unused variable `__class__`
+
+ℹ Unsafe fix
+179 179 |         class B:
+180 180 |             print(__class__)
+181 181 |             def set_class(self, cls):
+182     |-                __class__ = cls  # F841
+    182 |+                pass  # F841
+183 183 | 
+184 184 | 
+185 185 | # OK, the `__class__` cell is nonlocal and declared as such.

crates/ruff_linter/src/rules/pylint/rules/non_ascii_name.rs

@@ -73,7 +73,8 @@ pub(crate) fn non_ascii_name(checker: &Checker, binding: &Binding) {
         | BindingKind::SubmoduleImport(_)
         | BindingKind::Deletion
         | BindingKind::ConditionalDeletion(_)
-        | BindingKind::UnboundException(_) => {
+        | BindingKind::UnboundException(_)
+        | BindingKind::DunderClassCell => {
             return;
         }
     };

crates/ruff_linter/src/rules/ruff/rules/post_init_default.rs

@@ -186,7 +186,7 @@ fn use_initvar(
 
     let indentation = indentation_at_offset(post_init_def.start(), checker.source())
         .context("Failed to calculate leading indentation of `__post_init__` method")?;
-    let content = textwrap::indent(&content, indentation);
+    let content = textwrap::indent_first_line(&content, indentation);
 
     let initvar_edit = Edit::insertion(
         content.into_owned(),

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF033_RUF033.py.snap

@@ -455,3 +455,57 @@ help: Use `dataclasses.InitVar` instead
 122 123 |             ,
 123 124 |         ) -> None:
 124 125 |             ...
+
+RUF033 [*] `__post_init__` method with argument defaults
+   --> RUF033.py:131:50
+    |
+129 |   @dataclass
+130 |   class C:
+131 |       def __post_init__(self, x: tuple[int, ...] = (
+    |  __________________________________________________^
+132 | |         1,
+133 | |         2,
+134 | |     )) -> None:
+    | |_____^
+135 |           self.x = x
+    |
+help: Use `dataclasses.InitVar` instead
+
+ℹ Unsafe fix
+128 128 | 
+129 129 | @dataclass
+130 130 | class C:
+131     |-    def __post_init__(self, x: tuple[int, ...] = (
+    131 |+    x: InitVar[tuple[int, ...]] = (
+132 132 |         1,
+133 133 |         2,
+134     |-    )) -> None:
+    134 |+    )
+    135 |+    def __post_init__(self, x: tuple[int, ...]) -> None:
+135 136 |         self.x = x
+136 137 | 
+137 138 | 
+
+RUF033 [*] `__post_init__` method with argument defaults
+   --> RUF033.py:140:38
+    |
+138 |   @dataclass
+139 |   class D:
+140 |       def __post_init__(self, x: int = """
+    |  ______________________________________^
+141 | |     """) -> None:
+    | |_______^
+142 |           self.x = x
+    |
+help: Use `dataclasses.InitVar` instead
+
+ℹ Unsafe fix
+137 137 | 
+138 138 | @dataclass
+139 139 | class D:
+140     |-    def __post_init__(self, x: int = """
+141     |-    """) -> None:
+    140 |+    x: InitVar[int] = """
+    141 |+    """
+    142 |+    def __post_init__(self, x: int) -> None:
+142 143 |         self.x = x

crates/ruff_linter/src/snapshots/ruff_linter__linter__tests__import_sorting.snap

@@ -12,14 +12,12 @@ I001 [*] Import block is un-sorted or un-formatted
 help: Organize imports
 
 ℹ Safe fix
+   ::: cell 1
   1 |+import math
   2 |+import random
 1 3 | from pathlib import Path
 2   |-import random
 3   |-import math
-4 4 | from typing import Any
-5 5 | import collections
-6 6 | # Newline should be added here
 
 I001 [*] Import block is un-sorted or un-formatted
  --> isort.ipynb:cell 2:1:1
@@ -33,17 +31,15 @@ I001 [*] Import block is un-sorted or un-formatted
 help: Organize imports
 
 ℹ Safe fix
-1 1 | from pathlib import Path
-2 2 | import random
-3 3 | import math
-  4 |+import collections
-4 5 | from typing import Any
-5   |-import collections
-  6 |+
-  7 |+
-6 8 | # Newline should be added here
-7 9 | def foo():
-8 10 |     pass
+   ::: cell 2
+  1 |+import collections
+1 2 | from typing import Any
+2   |-import collections
+  3 |+
+  4 |+
+3 5 | # Newline should be added here
+4 6 | def foo():
+5 7 |     pass
 
 I001 [*] Import block is un-sorted or un-formatted
  --> isort.ipynb:cell 3:1:1
@@ -57,15 +53,13 @@ I001 [*] Import block is un-sorted or un-formatted
 help: Organize imports
 
 ℹ Safe fix
-6  6  | # Newline should be added here
-7  7  | def foo():
-8  8  |     pass
-   9  |+import sys
-9  10 | from pathlib import Path
-10    |-import sys
-11 11 | 
-12 12 | %matplotlib \
-13 13 |     --inline
+   ::: cell 3
+  1 |+import sys
+1 2 | from pathlib import Path
+2   |-import sys
+3 3 | 
+4 4 | %matplotlib \
+5 5 |     --inline
 
 I001 [*] Import block is un-sorted or un-formatted
  --> isort.ipynb:cell 3:7:1
@@ -79,9 +73,10 @@ I001 [*] Import block is un-sorted or un-formatted
 help: Organize imports
 
 ℹ Safe fix
-12 12 | %matplotlib \
-13 13 |     --inline
-14 14 | 
-   15 |+import abc
-15 16 | import math
-16    |-import abc
+   ::: cell 3
+4 4 | %matplotlib \
+5 5 |     --inline
+6 6 | 
+  7 |+import abc
+7 8 | import math
+8   |-import abc

crates/ruff_linter/src/snapshots/ruff_linter__linter__tests__ipy_escape_command.snap

@@ -14,13 +14,13 @@ F401 [*] `os` imported but unused
 help: Remove unused import: `os`
 
 ℹ Safe fix
+   ::: cell 1
 2 2 | 
 3 3 | %matplotlib inline
 4 4 | 
 5   |-import os
 6 5 | 
 7 6 | _ = math.pi
-8 7 | %%timeit
 
 F401 [*] `sys` imported but unused
  --> ipy_escape_command.ipynb:cell 2:2:8
@@ -32,7 +32,6 @@ F401 [*] `sys` imported but unused
 help: Remove unused import: `sys`
 
 ℹ Safe fix
-6 6 | 
-7 7 | _ = math.pi
-8 8 | %%timeit
-9   |-import sys
+   ::: cell 2
+1 1 | %%timeit
+2   |-import sys

crates/ruff_linter/src/snapshots/ruff_linter__linter__tests__unused_variable.snap

@@ -12,12 +12,11 @@ F841 [*] Local variable `foo1` is assigned to but never used
 help: Remove assignment to unused variable `foo1`
 
 ℹ Unsafe fix
+   ::: cell 1
 1 1 | def f():
 2   |-    foo1 = %matplotlib --list
   2 |+    %matplotlib --list
 3 3 |     foo2: list[str] = %matplotlib --list
-4 4 | def f():
-5 5 |     bar1 = !pwd
 
 F841 [*] Local variable `foo2` is assigned to but never used
  --> unused_variable.ipynb:cell 1:3:5
@@ -30,13 +29,11 @@ F841 [*] Local variable `foo2` is assigned to but never used
 help: Remove assignment to unused variable `foo2`
 
 ℹ Unsafe fix
+   ::: cell 1
 1 1 | def f():
 2 2 |     foo1 = %matplotlib --list
 3   |-    foo2: list[str] = %matplotlib --list
   3 |+    %matplotlib --list
-4 4 | def f():
-5 5 |     bar1 = !pwd
-6 6 |     bar2: str = !pwd
 
 F841 [*] Local variable `bar1` is assigned to but never used
  --> unused_variable.ipynb:cell 2:2:5
@@ -49,12 +46,11 @@ F841 [*] Local variable `bar1` is assigned to but never used
 help: Remove assignment to unused variable `bar1`
 
 ℹ Unsafe fix
-2 2 |     foo1 = %matplotlib --list
-3 3 |     foo2: list[str] = %matplotlib --list
-4 4 | def f():
-5   |-    bar1 = !pwd
-  5 |+    !pwd
-6 6 |     bar2: str = !pwd
+   ::: cell 2
+1 1 | def f():
+2   |-    bar1 = !pwd
+  2 |+    !pwd
+3 3 |     bar2: str = !pwd
 
 F841 [*] Local variable `bar2` is assigned to but never used
  --> unused_variable.ipynb:cell 2:3:5
@@ -67,8 +63,8 @@ F841 [*] Local variable `bar2` is assigned to but never used
 help: Remove assignment to unused variable `bar2`
 
 ℹ Unsafe fix
-3 3 |     foo2: list[str] = %matplotlib --list
-4 4 | def f():
-5 5 |     bar1 = !pwd
-6   |-    bar2: str = !pwd
-  6 |+    !pwd
+   ::: cell 2
+1 1 | def f():
+2 2 |     bar1 = !pwd
+3   |-    bar2: str = !pwd
+  3 |+    !pwd

crates/ruff_linter/src/snapshots/ruff_linter__linter__tests__vscode_language_id.snap

@@ -12,6 +12,7 @@ F401 [*] `os` imported but unused
 help: Remove unused import: `os`
 
 ℹ Safe fix
+   ::: cell 3
 1   |-import os
 2 1 | 
 3 2 | print("hello world")

crates/ruff_notebook/src/index.rs

@@ -33,6 +33,14 @@ impl NotebookIndex {
         self.row_to_row_in_cell.get(row.to_zero_indexed()).copied()
     }
 
+    /// Returns an iterator over the row:cell-number pairs (both 1-based).
+    pub fn iter(&self) -> impl Iterator<Item = (OneIndexed, OneIndexed)> {
+        self.row_to_cell
+            .iter()
+            .enumerate()
+            .map(|(row, cell)| (OneIndexed::from_zero_indexed(row), *cell))
+    }
+
     /// Translates the given [`LineColumn`] based on the indexing table.
     ///
     /// This will translate the row/column in the concatenated source code

crates/ruff_python_ast/src/node_index.rs

@@ -19,7 +19,6 @@ where
 /// A unique index for a node within an AST.
 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Hash)]
 #[cfg_attr(feature = "get-size", derive(get_size2::GetSize))]
-#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
 pub struct NodeIndex(NonZeroU32);
 
 impl NodeIndex {

crates/ruff_python_semantic/src/binding.rs

@@ -446,7 +446,7 @@ impl Ranged for Binding<'_> {
 /// ID uniquely identifying a [Binding] in a program.
 ///
 /// Using a `u32` to identify [Binding]s should be sufficient because Ruff only supports documents with a
-/// size smaller than or equal to `u32::max`. A document with the size of `u32::max` must have fewer than `u32::max`
+/// size smaller than or equal to `u32::MAX`. A document with the size of `u32::MAX` must have fewer than `u32::MAX`
 /// bindings because bindings must be separated by whitespace (and have an assignment).
 #[newtype_index]
 pub struct BindingId;
@@ -672,6 +672,24 @@ pub enum BindingKind<'a> {
     /// Stores the ID of the binding that was shadowed in the enclosing
     /// scope, if any.
     UnboundException(Option<BindingId>),
+
+    /// A binding to `__class__` in the implicit closure created around every method in a class
+    /// body, if any method refers to either `__class__` or `super`.
+    ///
+    /// ```python
+    /// class C:
+    ///     __class__  # NameError: name '__class__' is not defined
+    ///
+    ///     def f():
+    ///         print(__class__)  # allowed
+    ///
+    ///     def g():
+    ///         nonlocal __class__  # also allowed because the scope is *not* the function scope
+    /// ```
+    ///
+    /// See <https://docs.python.org/3/reference/datamodel.html#creating-the-class-object> for more
+    /// details.
+    DunderClassCell,
 }
 
 bitflags! {

crates/ruff_python_semantic/src/model.rs

@@ -404,22 +404,11 @@ impl<'a> SemanticModel<'a> {
             }
         }
 
-        let mut seen_function = false;
         let mut import_starred = false;
         let mut class_variables_visible = true;
         for (index, scope_id) in self.scopes.ancestor_ids(self.scope_id).enumerate() {
             let scope = &self.scopes[scope_id];
             if scope.kind.is_class() {
-                // Allow usages of `__class__` within methods, e.g.:
-                //
-                // ```python
-                // class Foo:
-                //     def __init__(self):
-                //         print(__class__)
-                // ```
-                if seen_function && matches!(name.id.as_str(), "__class__") {
-                    return ReadResult::ImplicitGlobal;
-                }
                 // Do not allow usages of class symbols unless it is the immediate parent
                 // (excluding type scopes), e.g.:
                 //
@@ -442,7 +431,13 @@ impl<'a> SemanticModel<'a> {
             // Allow class variables to be visible for an additional scope level
             // when a type scope is seen — this covers the type scope present between
             // function and class definitions and their parent class scope.
-            class_variables_visible = scope.kind.is_type() && index == 0;
+            //
+            // Also allow an additional level beyond that to cover the implicit
+            // `__class__` closure created around methods and enclosing the type scope.
+            class_variables_visible = matches!(
+                (scope.kind, index),
+                (ScopeKind::Type, 0) | (ScopeKind::DunderClassCell, 1)
+            );
 
             if let Some(binding_id) = scope.get(name.id.as_str()) {
                 // Mark the binding as used.
@@ -614,7 +609,6 @@ impl<'a> SemanticModel<'a> {
                 }
             }
 
-            seen_function |= scope.kind.is_function();
             import_starred = import_starred || scope.uses_star_imports();
         }
 
@@ -658,21 +652,19 @@ impl<'a> SemanticModel<'a> {
             }
         }
 
-        let mut seen_function = false;
         let mut class_variables_visible = true;
         for (index, scope_id) in self.scopes.ancestor_ids(scope_id).enumerate() {
             let scope = &self.scopes[scope_id];
             if scope.kind.is_class() {
-                if seen_function && matches!(symbol, "__class__") {
-                    return None;
-                }
                 if !class_variables_visible {
                     continue;
                 }
             }
 
-            class_variables_visible = scope.kind.is_type() && index == 0;
-            seen_function |= scope.kind.is_function();
+            class_variables_visible = matches!(
+                (scope.kind, index),
+                (ScopeKind::Type, 0) | (ScopeKind::DunderClassCell, 1)
+            );
 
             if let Some(binding_id) = scope.get(symbol) {
                 match self.bindings[binding_id].kind {
@@ -786,15 +778,15 @@ impl<'a> SemanticModel<'a> {
             }
 
             if scope.kind.is_class() {
-                if seen_function && matches!(symbol, "__class__") {
-                    return None;
-                }
                 if !class_variables_visible {
                     continue;
                 }
             }
 
-            class_variables_visible = scope.kind.is_type() && index == 0;
+            class_variables_visible = matches!(
+                (scope.kind, index),
+                (ScopeKind::Type, 0) | (ScopeKind::DunderClassCell, 1)
+            );
             seen_function |= scope.kind.is_function();
 
             if let Some(binding_id) = scope.get(symbol) {
@@ -1353,11 +1345,12 @@ impl<'a> SemanticModel<'a> {
         self.scopes[scope_id].parent
     }
 
-    /// Returns the first parent of the given [`Scope`] that is not of [`ScopeKind::Type`], if any.
+    /// Returns the first parent of the given [`Scope`] that is not of [`ScopeKind::Type`] or
+    /// [`ScopeKind::DunderClassCell`], if any.
     pub fn first_non_type_parent_scope(&self, scope: &Scope) -> Option<&Scope<'a>> {
         let mut current_scope = scope;
         while let Some(parent) = self.parent_scope(current_scope) {
-            if parent.kind.is_type() {
+            if matches!(parent.kind, ScopeKind::Type | ScopeKind::DunderClassCell) {
                 current_scope = parent;
             } else {
                 return Some(parent);
@@ -1366,11 +1359,15 @@ impl<'a> SemanticModel<'a> {
         None
     }
 
-    /// Returns the first parent of the given [`ScopeId`] that is not of [`ScopeKind::Type`], if any.
+    /// Returns the first parent of the given [`ScopeId`] that is not of [`ScopeKind::Type`] or
+    /// [`ScopeKind::DunderClassCell`], if any.
     pub fn first_non_type_parent_scope_id(&self, scope_id: ScopeId) -> Option<ScopeId> {
         let mut current_scope_id = scope_id;
         while let Some(parent_id) = self.parent_scope_id(current_scope_id) {
-            if self.scopes[parent_id].kind.is_type() {
+            if matches!(
+                self.scopes[parent_id].kind,
+                ScopeKind::Type | ScopeKind::DunderClassCell
+            ) {
                 current_scope_id = parent_id;
             } else {
                 return Some(parent_id);
@@ -2649,16 +2646,16 @@ pub enum ReadResult {
     /// The `x` in `print(x)` is resolved to the binding of `x` in `x = 1`.
     Resolved(BindingId),
 
-    /// The read reference is resolved to a context-specific, implicit global (e.g., `__class__`
+    /// The read reference is resolved to a context-specific, implicit global (e.g., `__qualname__`
     /// within a class scope).
     ///
     /// For example, given:
     /// ```python
     /// class C:
-    ///    print(__class__)
+    ///    print(__qualname__)
     /// ```
     ///
-    /// The `__class__` in `print(__class__)` is resolved to the implicit global `__class__`.
+    /// The `__qualname__` in `print(__qualname__)` is resolved to the implicit global `__qualname__`.
     ImplicitGlobal,
 
     /// The read reference is unresolved, but at least one of the containing scopes contains a

crates/ruff_python_semantic/src/scope.rs

@@ -166,9 +166,49 @@ bitflags! {
     }
 }
 
-#[derive(Debug, is_macro::Is)]
+#[derive(Clone, Copy, Debug, is_macro::Is)]
 pub enum ScopeKind<'a> {
     Class(&'a ast::StmtClassDef),
+    /// The implicit `__class__` scope surrounding a method which allows code in the
+    ///  method to access `__class__` at runtime. The closure sits in between the class
+    ///  scope and the function scope.
+    ///
+    /// Parameter defaults in methods cannot access `__class__`:
+    ///
+    /// ```pycon
+    /// >>> class Bar:
+    /// ...     def method(self, x=__class__): ...
+    /// ...
+    /// Traceback (most recent call last):
+    /// File "<python-input-6>", line 1, in <module>
+    ///     class Bar:
+    ///         def method(self, x=__class__): ...
+    /// File "<python-input-6>", line 2, in Bar
+    ///     def method(self, x=__class__): ...
+    ///                     ^^^^^^^^^
+    /// NameError: name '__class__' is not defined
+    /// ```
+    ///
+    /// However, type parameters in methods *can* access `__class__`:
+    ///
+    /// ```pycon
+    /// >>> class Foo:
+    /// ...     def bar[T: __class__](): ...
+    /// ...
+    /// >>> Foo.bar.__type_params__[0].__bound__
+    /// <class '__main__.Foo'>
+    /// ```
+    ///
+    /// Note that this is still not 100% accurate! At runtime, the implicit `__class__`
+    /// closure is only added if the name `super` (has to be a name -- `builtins.super`
+    /// and similar don't count!) or the name `__class__` is used in any method of the
+    /// class. However, accurately emulating that would be both complex and probably
+    /// quite expensive unless we moved to a double-traversal of each scope similar to
+    /// ty. It would also only matter in extreme and unlikely edge cases. So we ignore
+    /// that subtlety for now.
+    ///
+    /// See <https://docs.python.org/3/reference/datamodel.html#creating-the-class-object>.
+    DunderClassCell,
     Function(&'a ast::StmtFunctionDef),
     Generator {
         kind: GeneratorKind,