Revert "Bump version to 0.0.222"

This reverts commit 852aab5758.

.github/workflows/ci.yaml

@@ -27,8 +27,8 @@ jobs:
           toolchain: nightly-2022-11-01
           override: true
       - uses: Swatinem/rust-cache@v1
-      - run: cargo build --all --release
-      - run: ./target/release/ruff_dev generate-all
+      - run: cargo build --all
+      - run: ./target/debug/ruff_dev generate-all
       - run: git diff --quiet README.md || echo "::error file=README.md::This file is outdated. Run 'cargo +nightly dev generate-all'."
       - run: git diff --quiet ruff.schema.json || echo "::error file=ruff.schema.json::This file is outdated. Run 'cargo +nightly dev generate-all'."
       - run: git diff --exit-code -- README.md ruff.schema.json
@@ -60,7 +60,7 @@ jobs:
           target: wasm32-unknown-unknown
       - uses: Swatinem/rust-cache@v1
       - run: cargo clippy --workspace --all-targets --all-features -- -D warnings -W clippy::pedantic
-      - run: cargo clippy --workspace --target wasm32-unknown-unknown --all-features -- -D warnings -W clippy::pedantic
+      - run: cargo clippy -p ruff --target wasm32-unknown-unknown --all-features -- -D warnings -W clippy::pedantic
 
   cargo-test:
     name: "cargo test"
@@ -79,7 +79,7 @@ jobs:
         run: |
           cargo insta test --all --delete-unreferenced-snapshots
           git diff --exit-code
-      - run: cargo test --package ruff --test black_compatibility_test -- --ignored
+      - run: cargo test --package ruff_cli --test black_compatibility_test -- --ignored
 
 # TODO(charlie): Re-enable the `wasm-pack` tests.
 # See: https://github.com/charliermarsh/ruff/issues/1425

.github/workflows/playground.yaml

@@ -31,7 +31,7 @@ jobs:
       - uses: jetli/wasm-pack-action@v0.4.0
       - uses: jetli/wasm-bindgen-action@v0.2.0
       - name: "Run wasm-pack"
-        run: wasm-pack build --target web --out-dir playground/src/pkg
+        run: wasm-pack build --target web --out-dir playground/src/pkg . -- -p ruff
       - name: "Install Node dependencies"
         run: npm ci
         working-directory: playground

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.217
+    rev: v0.0.221
     hooks:
       - id: ruff
 

Cargo.lock

@@ -735,7 +735,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8-to-ruff"
-version = "0.0.217-dev.0"
+version = "0.0.221-dev.0"
 dependencies = [
  "anyhow",
  "clap 4.0.32",
@@ -1874,27 +1874,19 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.217"
+version = "0.0.221"
 dependencies = [
- "annotate-snippets 0.9.1",
  "anyhow",
- "assert_cmd",
- "atty",
- "bincode",
  "bitflags",
- "cachedir",
  "cfg-if 1.0.0",
  "chrono",
  "clap 4.0.32",
- "clap_complete_command",
- "clearscreen",
  "colored",
  "console_error_panic_hook",
  "console_log",
  "criterion",
  "dirs 4.0.0",
  "fern",
- "filetime",
  "getrandom 0.2.8",
  "glob",
  "globset",
@@ -1906,13 +1898,10 @@ dependencies = [
  "log",
  "natord",
  "nohash-hasher",
- "notify",
  "num-bigint",
  "num-traits",
  "once_cell",
  "path-absolutize",
- "quick-junit",
- "rayon",
  "regex",
  "ropey",
  "ruff_macros",
@@ -1924,25 +1913,57 @@ dependencies = [
  "semver",
  "serde",
  "serde-wasm-bindgen",
- "serde_json",
  "shellexpand",
- "similar",
  "strum",
  "strum_macros",
  "test-case",
  "textwrap",
  "titlecase",
  "toml_edit",
- "update-informer",
- "ureq",
- "walkdir",
  "wasm-bindgen",
  "wasm-bindgen-test",
 ]
 
+[[package]]
+name = "ruff_cli"
+version = "0.0.221"
+dependencies = [
+ "annotate-snippets 0.9.1",
+ "anyhow",
+ "assert_cmd",
+ "atty",
+ "bincode",
+ "cachedir",
+ "chrono",
+ "clap 4.0.32",
+ "clap_complete_command",
+ "clearscreen",
+ "colored",
+ "filetime",
+ "glob",
+ "ignore",
+ "itertools",
+ "log",
+ "notify",
+ "path-absolutize",
+ "quick-junit",
+ "rayon",
+ "regex",
+ "ruff",
+ "rustc-hash",
+ "serde",
+ "serde_json",
+ "similar",
+ "strum",
+ "textwrap",
+ "update-informer",
+ "ureq",
+ "walkdir",
+]
+
 [[package]]
 name = "ruff_dev"
-version = "0.0.217"
+version = "0.0.221"
 dependencies = [
  "anyhow",
  "clap 4.0.32",
@@ -1950,6 +1971,7 @@ dependencies = [
  "libcst",
  "once_cell",
  "ruff",
+ "ruff_cli",
  "rustpython-ast",
  "rustpython-common",
  "rustpython-parser",
@@ -1962,7 +1984,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_macros"
-version = "0.0.217"
+version = "0.0.221"
 dependencies = [
  "once_cell",
  "proc-macro2",

Cargo.toml

@@ -2,11 +2,13 @@
 members = [
   "flake8_to_ruff",
   "ruff_dev",
+  "ruff_cli",
 ]
+default-members = [".", "ruff_cli"]
 
 [package]
 name = "ruff"
-version = "0.0.217"
+version = "0.0.221"
 authors = ["Charlie Marsh <charlie.r.marsh@gmail.com>"]
 edition = "2021"
 rust-version = "1.65.0"
@@ -19,22 +21,17 @@ license = "MIT"
 [lib]
 name = "ruff"
 crate-type = ["cdylib", "rlib"]
+doctest = false
 
 [dependencies]
-annotate-snippets = { version = "0.9.1", features = ["color"] }
 anyhow = { version = "1.0.66" }
-atty = { version = "0.2.14" }
-bincode = { version = "1.3.3" }
 bitflags = { version = "1.3.2" }
-cachedir = { version = "0.3.0" }
 cfg-if = { version = "1.0.0" }
 chrono = { version = "0.4.21", default-features = false, features = ["clock"] }
 clap = { version = "4.0.1", features = ["derive", "env"] }
-clap_complete_command = { version = "0.4.0" }
 colored = { version = "2.0.0" }
 dirs = { version = "4.0.0" }
 fern = { version = "0.6.1" }
-filetime = { version = "0.2.17" }
 glob = { version = "0.3.0" }
 globset = { version = "0.4.9" }
 ignore = { version = "0.4.18" }
@@ -43,15 +40,13 @@ libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a87
 log = { version = "0.4.17" }
 natord = { version = "1.0.9" }
 nohash-hasher = { version = "0.2.0" }
-notify = { version = "5.0.0" }
 num-bigint = { version = "0.4.3" }
 num-traits = "0.2.15"
 once_cell = { version = "1.16.0" }
 path-absolutize = { version = "3.0.14", features = ["once_cell_cache", "use_unix_paths_on_wasm"] }
-quick-junit = { version = "0.3.2" }
 regex = { version = "1.6.0" }
 ropey = { version = "1.5.0", features = ["cr_lines", "simd"], default-features = false }
-ruff_macros = { version = "0.0.217", path = "ruff_macros" }
+ruff_macros = { version = "0.0.221", path = "ruff_macros" }
 rustc-hash = { version = "1.1.0" }
 rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
 rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
@@ -59,20 +54,12 @@ rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPyth
 schemars = { version = "0.8.11" }
 semver = { version = "1.0.16" }
 serde = { version = "1.0.147", features = ["derive"] }
-serde_json = { version = "1.0.87" }
 shellexpand = { version = "3.0.0" }
-similar = { version = "2.2.1" }
 strum = { version = "0.24.1", features = ["strum_macros"] }
 strum_macros = { version = "0.24.3" }
 textwrap = { version = "0.16.0" }
 titlecase = { version = "2.2.1" }
 toml_edit = { version = "0.17.1", features = ["easy"] }
-walkdir = { version = "2.3.2" }
-
-[target.'cfg(not(target_family = "wasm"))'.dependencies]
-clearscreen = { version = "2.0.0" }
-rayon = { version = "1.5.3" }
-update-informer = { version = "0.6.0", default-features = false, features = ["pypi"], optional = true }
 
 # https://docs.rs/getrandom/0.2.7/getrandom/#webassembly-support
 # For (future) wasm-pack support
@@ -87,17 +74,11 @@ wasm-bindgen = { version = "0.2.83" }
 [dev-dependencies]
 insta = { version = "1.19.1", features = ["yaml"] }
 test-case = { version = "2.2.2" }
-ureq = { version = "2.5.0", features = [] }
 wasm-bindgen-test = { version = "0.3.33" }
 
 [target.'cfg(not(target_family = "wasm"))'.dev-dependencies]
-assert_cmd = { version = "2.0.4" }
 criterion = { version = "0.4.0" }
 
-[features]
-default = ["update-informer"]
-update-informer = ["dep:update-informer"]
-
 [profile.release]
 panic = "abort"
 lto = "thin"

README.md

@@ -46,7 +46,9 @@ imports, and more.
 
 Ruff is extremely actively developed and used in major open-source projects like:
 
+- [pandas](https://github.com/pandas-dev/pandas)
 - [FastAPI](https://github.com/tiangolo/fastapi)
+- [Apache Airflow](https://github.com/apache/airflow)
 - [Bokeh](https://github.com/bokeh/bokeh)
 - [Zulip](https://github.com/zulip/zulip)
 - [Pydantic](https://github.com/pydantic/pydantic)
@@ -139,8 +141,6 @@ Ruff is available as [`ruff`](https://pypi.org/project/ruff/) on PyPI:
 pip install ruff
 ```
 
-[![Packaging status](https://repology.org/badge/vertical-allrepos/ruff-python-linter.svg?exclude_unsupported=1)](https://repology.org/project/ruff-python-linter/versions)
-
 For **macOS Homebrew** and **Linuxbrew** users, Ruff is also available as [`ruff`](https://formulae.brew.sh/formula/ruff) on Homebrew:
 
 ```shell
@@ -159,6 +159,8 @@ For **Arch Linux** users, Ruff is also available as [`ruff`](https://archlinux.o
 pacman -S ruff
 ```
 
+[![Packaging status](https://repology.org/badge/vertical-allrepos/ruff-python-linter.svg?exclude_unsupported=1)](https://repology.org/project/ruff-python-linter/versions)
+
 ### Usage
 
 To run Ruff, try any of the following:
@@ -180,7 +182,7 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 - repo: https://github.com/charliermarsh/ruff-pre-commit
   # Ruff version.
-  rev: 'v0.0.217'
+  rev: 'v0.0.221'
   hooks:
     - id: ruff
       # Respect `exclude` and `extend-exclude` settings.
@@ -343,21 +345,21 @@ Options:
           Disable cache reads
       --isolated
           Ignore all configuration files
-      --select <SELECT>
+      --select <RULE_CODE>
           Comma-separated list of rule codes to enable (or ALL, to enable all rules)
-      --extend-select <EXTEND_SELECT>
+      --extend-select <RULE_CODE>
           Like --select, but adds additional rule codes on top of the selected ones
-      --ignore <IGNORE>
+      --ignore <RULE_CODE>
           Comma-separated list of rule codes to disable
-      --extend-ignore <EXTEND_IGNORE>
+      --extend-ignore <RULE_CODE>
           Like --ignore, but adds additional rule codes on top of the ignored ones
-      --exclude <EXCLUDE>
+      --exclude <FILE_PATTERN>
           List of paths, used to omit files and/or directories from analysis
-      --extend-exclude <EXTEND_EXCLUDE>
+      --extend-exclude <FILE_PATTERN>
           Like --exclude, but adds additional files and directories on top of those already excluded
-      --fixable <FIXABLE>
+      --fixable <RULE_CODE>
           List of rule codes to treat as eligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
-      --unfixable <UNFIXABLE>
+      --unfixable <RULE_CODE>
           List of rule codes to treat as ineligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
       --per-file-ignores <PER_FILE_IGNORES>
           List of mappings from file pattern to code to exclude
@@ -597,6 +599,7 @@ For more, see [pycodestyle](https://pypi.org/project/pycodestyle/2.9.1/) on PyPI
 | E902 | IOError | IOError: `...` |  |
 | E999 | SyntaxError | SyntaxError: `...` |  |
 | W292 | NoNewLineAtEndOfFile | No newline at end of file | 🛠 |
+| W505 | DocLineTooLong | Doc line too long (89 > 88 characters) |  |
 | W605 | InvalidEscapeSequence | Invalid escape sequence: '\c' | 🛠 |
 
 ### mccabe (C90)
@@ -614,6 +617,7 @@ For more, see [isort](https://pypi.org/project/isort/5.10.1/) on PyPI.
 | Code | Name | Message | Fix |
 | ---- | ---- | ------- | --- |
 | I001 | UnsortedImports | Import block is un-sorted or un-formatted | 🛠 |
+| I002 | MissingRequiredImport | Missing required import: `from __future__ import ...` | 🛠 |
 
 ### pydocstyle (D)
 
@@ -701,6 +705,7 @@ For more, see [pyupgrade](https://pypi.org/project/pyupgrade/3.2.0/) on PyPI.
 | UP027 | RewriteListComprehension | Replace unpacked list comprehension with a generator expression | 🛠 |
 | UP028 | RewriteYieldFrom | Replace `yield` over `for` loop with `yield from` | 🛠 |
 | UP029 | UnnecessaryBuiltinImport | Unnecessary builtin import: `...` | 🛠 |
+| UP030 | FormatLiterals | Use implicit references for positional format fields | 🛠 |
 
 ### pep8-naming (N)
 
@@ -777,6 +782,9 @@ For more, see [flake8-bandit](https://pypi.org/project/flake8-bandit/4.1.1/) on
 | S324 | HashlibInsecureHashFunction | Probable use of insecure hash functions in `hashlib`: "..." |  |
 | S501 | RequestWithNoCertValidation | Probable use of `...` call with `verify=False` disabling SSL certificate checks |  |
 | S506 | UnsafeYAMLLoad | Probable use of unsafe `yaml.load`. Allows instantiation of arbitrary objects. Consider `yaml.safe_load`. |  |
+| S508 | SnmpInsecureVersion | The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able. |  |
+| S509 | SnmpWeakCryptography | You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure. |  |
+| S701 | Jinja2AutoescapeFalse | By default, jinja2 sets `autoescape` to `False`. Consider using `autoescape=True` or the `select_autoescape` function to mitigate XSS vulnerabilities. |  |
 
 ### flake8-blind-except (BLE)
 
@@ -916,8 +924,8 @@ For more, see [flake8-pytest-style](https://pypi.org/project/flake8-pytest-style
 | PT001 | IncorrectFixtureParenthesesStyle | Use `@pytest.fixture()` over `@pytest.fixture` | 🛠 |
 | PT002 | FixturePositionalArgs | Configuration for fixture `...` specified via positional args, use kwargs |  |
 | PT003 | ExtraneousScopeFunction | `scope='function'` is implied in `@pytest.fixture()` |  |
-| PT004 | MissingFixtureNameUnderscore | Fixture `...` does not return anything, add leading underscore | 🛠 |
-| PT005 | IncorrectFixtureNameUnderscore | Fixture `...` returns a value, remove leading underscore | 🛠 |
+| PT004 | MissingFixtureNameUnderscore | Fixture `...` does not return anything, add leading underscore |  |
+| PT005 | IncorrectFixtureNameUnderscore | Fixture `...` returns a value, remove leading underscore |  |
 | PT006 | ParametrizeNamesWrongType | Wrong name(s) type in `@pytest.mark.parametrize`, expected `tuple` | 🛠 |
 | PT007 | ParametrizeValuesWrongType | Wrong values type in `@pytest.mark.parametrize` expected `list` of `tuple` |  |
 | PT008 | PatchWithLambda | Use `return_value=` instead of patching with `lambda` |  |
@@ -945,10 +953,10 @@ For more, see [flake8-quotes](https://pypi.org/project/flake8-quotes/3.3.1/) on
 
 | Code | Name | Message | Fix |
 | ---- | ---- | ------- | --- |
-| Q000 | BadQuotesInlineString | Single quotes found but double quotes preferred |  |
-| Q001 | BadQuotesMultilineString | Single quote multiline found but double quotes preferred |  |
-| Q002 | BadQuotesDocstring | Single quote docstring found but double quotes preferred |  |
-| Q003 | AvoidQuoteEscape | Change outer quotes to avoid escaping inner quotes |  |
+| Q000 | BadQuotesInlineString | Single quotes found but double quotes preferred | 🛠 |
+| Q001 | BadQuotesMultilineString | Single quote multiline found but double quotes preferred | 🛠 |
+| Q002 | BadQuotesDocstring | Single quote docstring found but double quotes preferred | 🛠 |
+| Q003 | AvoidQuoteEscape | Change outer quotes to avoid escaping inner quotes | 🛠 |
 
 ### flake8-return (RET)
 
@@ -971,6 +979,7 @@ For more, see [flake8-simplify](https://pypi.org/project/flake8-simplify/0.19.3/
 
 | Code | Name | Message | Fix |
 | ---- | ---- | ------- | --- |
+| SIM115 | OpenFileWithContextHandler | Use context handler for opening files |  |
 | SIM101 | DuplicateIsinstanceCall | Multiple `isinstance` calls for `...`, merge into a single call | 🛠 |
 | SIM102 | NestedIfStatements | Use a single `if` statement instead of nested `if` statements |  |
 | SIM103 | ReturnBoolConditionDirectly | Return the condition `...` directly | 🛠 |
@@ -980,6 +989,7 @@ For more, see [flake8-simplify](https://pypi.org/project/flake8-simplify/0.19.3/
 | SIM109 | CompareWithTuple | Use `value in (..., ...)` instead of `value == ... or value == ...` | 🛠 |
 | SIM110 | ConvertLoopToAny | Use `return any(x for x in y)` instead of `for` loop | 🛠 |
 | SIM111 | ConvertLoopToAll | Use `return all(x for x in y)` instead of `for` loop | 🛠 |
+| SIM112 | UseCapitalEnvironmentVariables | Use capitalized environment variable `...` instead of `...` | 🛠 |
 | SIM117 | MultipleWithStatements | Use a single `with` statement with multiple contexts instead of nested `with` statements |  |
 | SIM118 | KeyInDict | Use `key in dict` instead of `key in dict.keys()` | 🛠 |
 | SIM201 | NegateEqualOp | Use `left != right` instead of `not left == right` | 🛠 |
@@ -993,6 +1003,7 @@ For more, see [flake8-simplify](https://pypi.org/project/flake8-simplify/0.19.3/
 | SIM222 | OrTrue | Use `True` instead of `... or True` | 🛠 |
 | SIM223 | AndFalse | Use `False` instead of `... and False` | 🛠 |
 | SIM300 | YodaConditions | Yoda conditions are discouraged, use `left == right` instead | 🛠 |
+| SIM401 | DictGetWithDefault | Use `var = dict.get(key, "default")` instead of an `if` block | 🛠 |
 
 ### flake8-tidy-imports (TID)
 
@@ -1083,8 +1094,10 @@ For more, see [Pylint](https://pypi.org/project/pylint/2.15.7/) on PyPI.
 | PLE1142 | AwaitOutsideAsync | `await` should be used within an async function |  |
 | PLR0206 | PropertyWithParameters | Cannot have defined parameters for properties |  |
 | PLR0402 | ConsiderUsingFromImport | Use `from ... import ...` in lieu of alias |  |
+| PLR0133 | ConstantComparison | Two constants compared in a comparison, consider replacing `0 == 0` |  |
 | PLR1701 | ConsiderMergingIsinstance | Merge these isinstance calls: `isinstance(..., (...))` |  |
 | PLR1722 | UseSysExit | Use `sys.exit()` instead of `exit` | 🛠 |
+| PLR2004 | MagicValueComparison | Magic number used in comparison, consider replacing magic with a constant variable |  |
 | PLW0120 | UselessElseOnLoop | Else clause on loop without a break statement, remove the else and de-indent all the code inside it |  |
 | PLW0602 | GlobalVariableNotAssigned | Using global for `...` but no assignment is done |  |
 
@@ -1243,6 +1256,18 @@ officially supported LSP server for Ruff.
 However, Ruff is also available as part of the [coc-pyright](https://github.com/fannheyward/coc-pyright)
 extension for `coc.nvim`.
 
+<details>
+<summary>With the <a href="https://github.com/dense-analysis/ale">ALE</a> plugin for (Neo)Vim.</summary>
+
+```vim
+let g:ale_linters = { "python": ["ruff"] }
+let g:ale_fixers = {
+\       "python": ["black", "ruff"],
+\}
+```
+
+</details>
+
 <details>
 <summary>Ruff can also be integrated via <a href="https://github.com/neovim/nvim-lspconfig/blob/master/doc/server_configurations.md#efm"><code>efm</code></a> in just a <a href="https://github.com/JafarAbdi/myconfigs/blob/6f0b6b2450e92ec8fc50422928cd22005b919110/efm-langserver/config.yaml#L14-L20">few lines</a>.</summary>
 <br>
@@ -1407,7 +1432,7 @@ Beyond the rule set, Ruff suffers from the following limitations vis-à-vis Flak
 
 There are a few other minor incompatibilities between Ruff and the originating Flake8 plugins:
 
-- Ruff doesn't implement the "opinionated" lint rules from `flake8-bugbear`.
+- Ruff doesn't implement all the "opinionated" lint rules from `flake8-bugbear`.
 - Depending on your project structure, Ruff and `isort` can differ in their detection of first-party
   code. (This is often solved by modifying the `src` property, e.g., to `src = ["src"]`, if your
   code is nested in a `src` directory.)
@@ -1817,6 +1842,8 @@ Exclusions are based on globs, and can be either:
   `directory`). Note that these paths are relative to the project root
   (e.g., the directory containing your `pyproject.toml`).
 
+For more information on the glob syntax, refer to the [`globset` documentation](https://docs.rs/globset/latest/globset/#syntax).
+
 Note that you'll typically want to use
 [`extend-exclude`](#extend-exclude) to modify the excluded paths.
 
@@ -1864,6 +1891,18 @@ line-length = 100
 A list of file patterns to omit from linting, in addition to those
 specified by `exclude`.
 
+Exclusions are based on globs, and can be either:
+
+- Single-path patterns, like `.mypy_cache` (to exclude any directory
+  named `.mypy_cache` in the tree), `foo.py` (to exclude any file named
+  `foo.py`), or `foo_*.py` (to exclude any file matching `foo_*.py` ).
+- Relative patterns, like `directory/foo.py` (to exclude that specific
+  file) or `directory/*.py` (to exclude any Python files in
+  `directory`). Note that these paths are relative to the project root
+  (e.g., the directory containing your `pyproject.toml`).
+
+For more information on the glob syntax, refer to the [`globset` documentation](https://docs.rs/globset/latest/globset/#syntax).
+
 **Default value**: `[]`
 
 **Type**: `Vec<FilePattern>`
@@ -1883,6 +1922,12 @@ extend-exclude = ["tests", "src/bad.py"]
 A list of rule codes or prefixes to ignore, in addition to those
 specified by `ignore`.
 
+Note that `extend-ignore` is applied after resolving rules from
+`ignore`/`select` and a less specific rule in `extend-ignore`
+would overwrite a more specific rule in `select`. It is
+recommended to only use `extend-ignore` when extending a
+`pyproject.toml` file via `extend`.
+
 **Default value**: `[]`
 
 **Type**: `Vec<RuleCodePrefix>`
@@ -1902,6 +1947,12 @@ extend-ignore = ["F841"]
 A list of rule codes or prefixes to enable, in addition to those
 specified by `select`.
 
+Note that `extend-select` is applied after resolving rules from
+`ignore`/`select` and a less specific rule in `extend-select`
+would overwrite a more specific rule in `ignore`. It is
+recommended to only use `extend-select` when extending a
+`pyproject.toml` file via `extend`.
+
 **Default value**: `[]`
 
 **Type**: `Vec<RuleCodePrefix>`
@@ -2335,7 +2386,7 @@ unfixable = ["F401"]
 Enable or disable automatic update checks (overridden by the
 `--update-check` and `--no-update-check` command-line flags).
 
-**Default value**: `true`
+**Default value**: `false`
 
 **Type**: `bool`
 
@@ -2343,7 +2394,7 @@ Enable or disable automatic update checks (overridden by the
 
 ```toml
 [tool.ruff]
-update-check = false
+update-check = true
 ```
 
 ---
@@ -2839,6 +2890,24 @@ ignore-variadic-names = true
 
 ### `isort`
 
+#### [`classes`](#classes)
+
+An override list of tokens to always recognize as a Class for
+`order-by-type` regardless of casing.
+
+**Default value**: `[]`
+
+**Type**: `Vec<String>`
+
+**Example usage**:
+
+```toml
+[tool.ruff.isort]
+classes = ["SVC"]
+```
+
+---
+
 #### [`combine-as-imports`](#combine-as-imports)
 
 Combines as imports on the same line. See isort's [`combine-as-imports`](https://pycqa.github.io/isort/docs/configuration/options.html#combine-as-imports)
@@ -2998,6 +3067,47 @@ order-by-type = true
 
 ---
 
+#### [`relative-imports-order`](#relative-imports-order)
+
+Whether to place "closer" imports (fewer `.` characters, most local)
+before "further" imports (more `.` characters, least local), or vice
+versa.
+
+The default ("furthest-to-closest") is equivalent to isort's
+`reverse-relative` default (`reverse-relative = false`); setting
+this to "closest-to-furthest" is equivalent to isort's `reverse-relative
+= true`.
+
+**Default value**: `furthest-to-closest`
+
+**Type**: `RelatveImportsOrder`
+
+**Example usage**:
+
+```toml
+[tool.ruff.isort]
+relative-imports-order = "closest-to-furthest"
+```
+
+---
+
+#### [`required-imports`](#required-imports)
+
+Add the specified import line to all files.
+
+**Default value**: `[]`
+
+**Type**: `Vec<String>`
+
+**Example usage**:
+
+```toml
+[tool.ruff.isort]
+required-imports = ["from __future__ import annotations"]
+```
+
+---
+
 #### [`single-line-exclusions`](#single-line-exclusions)
 
 One or more modules to exclude from the single line rule.
@@ -3137,6 +3247,24 @@ ignore-overlong-task-comments = true
 
 ---
 
+#### [`max-doc-length`](#max-doc-length)
+
+The maximum line length to allow for line-length violations within
+documentation (`W505`), including standalone comments.
+
+**Default value**: `None`
+
+**Type**: `usize`
+
+**Example usage**:
+
+```toml
+[tool.ruff.pycodestyle]
+max-doc-length = 88
+```
+
+---
+
 ### `pydocstyle`
 
 #### [`convention`](#convention)
@@ -3191,4 +3319,4 @@ MIT
 ## Contributing
 
 Contributions are welcome and hugely appreciated. To get started, check out the
-[contributing guidelines](https://github.com/charliermarsh/ruff/blob/main/.github/CONTRIBUTING.md).
+[contributing guidelines](https://github.com/charliermarsh/ruff/blob/main/CONTRIBUTING.md).

flake8_to_ruff/Cargo.lock

@@ -771,7 +771,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8_to_ruff"
-version = "0.0.217"
+version = "0.0.221"
 dependencies = [
  "anyhow",
  "clap",
@@ -1975,7 +1975,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.217"
+version = "0.0.221"
 dependencies = [
  "anyhow",
  "bincode",

flake8_to_ruff/Cargo.toml

@@ -1,10 +1,11 @@
 [package]
 name = "flake8-to-ruff"
-version = "0.0.217-dev.0"
+version = "0.0.221-dev.0"
 edition = "2021"
 
 [lib]
 name = "flake8_to_ruff"
+doctest = false
 
 [dependencies]
 anyhow = { version = "1.0.66" }

pyproject.toml

@@ -1,10 +1,13 @@
 [build-system]
-requires = ["maturin>=0.14,<0.15"]
+requires = ["maturin>=0.14.10,<0.15"]
+# We depend on >=0.14.10 because we specify name in
+# [package.metadata.maturin] in ruff_cli/Cargo.toml.
+
 build-backend = "maturin"
 
 [project]
 name = "ruff"
-version = "0.0.217"
+version = "0.0.221"
 description = "An extremely fast Python linter, written in Rust."
 authors = [
   { name = "Charlie Marsh", email = "charlie.r.marsh@gmail.com" },
@@ -35,6 +38,8 @@ urls = { repository = "https://github.com/charliermarsh/ruff" }
 
 [tool.maturin]
 bindings = "bin"
+manifest-path = "ruff_cli/Cargo.toml"
+python-source = "python"
 strip = true
 
 [tool.setuptools]

resources/test/fixtures/flake8_annotations/allow_nested_overload.py

@@ -0,0 +1,9 @@
+class C:
+    from typing import overload
+
+    @overload
+    def f(self, x: int, y: int) -> None:
+        ...
+
+    def f(self, x, y):
+        pass

resources/test/fixtures/flake8_bandit/S508.py

@@ -0,0 +1,6 @@
+from pysnmp.hlapi import CommunityData
+
+CommunityData("public", mpModel=0)  # S508
+CommunityData("public", mpModel=1)  # S508
+
+CommunityData("public", mpModel=2)  # OK

resources/test/fixtures/flake8_bandit/S509.py

@@ -0,0 +1,7 @@
+from pysnmp.hlapi import UsmUserData
+
+
+insecure = UsmUserData("securityName")  # S509
+auth_no_priv = UsmUserData("securityName", "authName")  # S509
+
+less_insecure = UsmUserData("securityName", "authName", "privName")  # OK

resources/test/fixtures/flake8_bandit/S701.py

@@ -0,0 +1,29 @@
+import jinja2
+from jinja2 import Environment, select_autoescape
+templateLoader = jinja2.FileSystemLoader( searchpath="/" )
+something = ''
+
+Environment(loader=templateLoader, load=templateLoader, autoescape=True)
+templateEnv = jinja2.Environment(autoescape=True,
+        loader=templateLoader )
+Environment(loader=templateLoader, load=templateLoader, autoescape=something)  # S701
+templateEnv = jinja2.Environment(autoescape=False, loader=templateLoader )  # S701
+Environment(loader=templateLoader,
+            load=templateLoader,
+            autoescape=False)  # S701
+
+Environment(loader=templateLoader,  # S701
+            load=templateLoader)
+
+Environment(loader=templateLoader, autoescape=select_autoescape())
+
+Environment(loader=templateLoader,
+            autoescape=select_autoescape(['html', 'htm', 'xml']))
+
+Environment(loader=templateLoader,
+            autoescape=jinja2.select_autoescape(['html', 'htm', 'xml']))
+
+
+def fake_func():
+    return 'foobar'
+Environment(loader=templateLoader, autoescape=fake_func())  # S701

resources/test/fixtures/flake8_bugbear/B023.py

@@ -25,10 +25,10 @@ for x in range(3):
 
 
 def check_inside_functions_too():
-    ls = [lambda: x for x in range(2)]
-    st = {lambda: x for x in range(2)}
-    gn = (lambda: x for x in range(2))
-    dt = {x: lambda: x for x in range(2)}
+    ls = [lambda: x for x in range(2)]  # error
+    st = {lambda: x for x in range(2)}  # error
+    gn = (lambda: x for x in range(2))  # error
+    dt = {x: lambda: x for x in range(2)}  # error
 
 
 async def pointless_async_iterable():
@@ -37,9 +37,9 @@ async def pointless_async_iterable():
 
 async def container_for_problems():
     async for x in pointless_async_iterable():
-        functions.append(lambda: x)
+        functions.append(lambda: x)  # error
 
-    [lambda: x async for x in pointless_async_iterable()]
+    [lambda: x async for x in pointless_async_iterable()]  # error
 
 
 a = 10
@@ -47,10 +47,10 @@ b = 0
 while True:
     a = a_ = a - 1
     b += 1
-    functions.append(lambda: a)
-    functions.append(lambda: a_)
-    functions.append(lambda: b)
-    functions.append(lambda: c)  # not a name error because of late binding!
+    functions.append(lambda: a)  # error
+    functions.append(lambda: a_)  # error
+    functions.append(lambda: b)  # error
+    functions.append(lambda: c)  # error, but not a name error due to late binding
     c: bool = a > 3
     if not c:
         break
@@ -58,7 +58,7 @@ while True:
 # Nested loops should not duplicate reports
 for j in range(2):
     for k in range(3):
-        lambda: j * k
+        lambda: j * k  # error
 
 
 for j, k, l in [(1, 2, 3)]:
@@ -80,3 +80,95 @@ for var in range(2):
 
 for i in range(3):
     lambda: f"{i}"
+
+
+# `query` is defined in the function, so also defining it in the loop should be OK.
+for name in ["a", "b"]:
+    query = name
+
+    def myfunc(x):
+        query = x
+        query_post = x
+        _ = query
+        _ = query_post
+
+    query_post = name  # in case iteration order matters
+
+
+# Bug here because two dict comprehensions reference `name`, one of which is inside
+# the lambda.  This should be totally fine, of course.
+_ = {
+    k: v
+    for k, v in reduce(
+        lambda data, event: merge_mappings(
+            [data, {name: f(caches, data, event) for name, f in xx}]
+        ),
+        events,
+        {name: getattr(group, name) for name in yy},
+    ).items()
+    if k in backfill_fields
+}
+
+
+# OK to define lambdas if they're immediately consumed, typically as the `key=`
+# argument or in a consumed `filter()` (even if a comprehension is better style)
+for x in range(2):
+    # It's not a complete get-out-of-linting-free construct - these should fail:
+    min([None, lambda: x], key=repr)
+    sorted([None, lambda: x], key=repr)
+    any(filter(bool, [None, lambda: x]))
+    list(filter(bool, [None, lambda: x]))
+    all(reduce(bool, [None, lambda: x]))
+
+    # But all these should be OK:
+    min(range(3), key=lambda y: x * y)
+    max(range(3), key=lambda y: x * y)
+    sorted(range(3), key=lambda y: x * y)
+
+    any(map(lambda y: x < y, range(3)))
+    all(map(lambda y: x < y, range(3)))
+    set(map(lambda y: x < y, range(3)))
+    list(map(lambda y: x < y, range(3)))
+    tuple(map(lambda y: x < y, range(3)))
+    sorted(map(lambda y: x < y, range(3)))
+    frozenset(map(lambda y: x < y, range(3)))
+
+    any(filter(lambda y: x < y, range(3)))
+    all(filter(lambda y: x < y, range(3)))
+    set(filter(lambda y: x < y, range(3)))
+    list(filter(lambda y: x < y, range(3)))
+    tuple(filter(lambda y: x < y, range(3)))
+    sorted(filter(lambda y: x < y, range(3)))
+    frozenset(filter(lambda y: x < y, range(3)))
+
+    any(reduce(lambda y: x | y, range(3)))
+    all(reduce(lambda y: x | y, range(3)))
+    set(reduce(lambda y: x | y, range(3)))
+    list(reduce(lambda y: x | y, range(3)))
+    tuple(reduce(lambda y: x | y, range(3)))
+    sorted(reduce(lambda y: x | y, range(3)))
+    frozenset(reduce(lambda y: x | y, range(3)))
+
+    import functools
+
+    any(functools.reduce(lambda y: x | y, range(3)))
+    all(functools.reduce(lambda y: x | y, range(3)))
+    set(functools.reduce(lambda y: x | y, range(3)))
+    list(functools.reduce(lambda y: x | y, range(3)))
+    tuple(functools.reduce(lambda y: x | y, range(3)))
+    sorted(functools.reduce(lambda y: x | y, range(3)))
+    frozenset(functools.reduce(lambda y: x | y, range(3)))
+
+# OK because the lambda which references a loop variable is defined in a `return`
+# statement, and after we return the loop variable can't be redefined.
+# In principle we could do something fancy with `break`, but it's not worth it.
+def iter_f(names):
+    for name in names:
+        if exists(name):
+            return lambda: name if exists(name) else None
+
+        if foo(name):
+            return [lambda: name]  # known false alarm
+
+        if False:
+            return [lambda: i for i in range(3)]  # error

resources/test/fixtures/flake8_bugbear/B024.py

@@ -1,15 +1,16 @@
 """
 Should emit:
-B024 - on lines 17, 34, 52, 58, 69, 74, 79, 84, 89
+B024 - on lines 18, 71, 82, 87, 92, 141
 """
 
 import abc
 import abc as notabc
 from abc import ABC, ABCMeta
-from abc import abstractmethod
+from abc import abstractmethod, abstractproperty
 from abc import abstractmethod as abstract
 from abc import abstractmethod as abstractaoeuaoeuaoeu
 from abc import abstractmethod as notabstract
+from abc import abstractproperty as notabstract_property
 
 import foo
 
@@ -49,12 +50,24 @@ class Base_6(ABC):
         foo()
 
 
-class Base_7(ABC):  # error
+class Base_7(ABC):
     @notabstract
     def method(self):
         foo()
 
 
+class Base_8(ABC):
+    @notabstract_property
+    def method(self):
+        foo()
+
+
+class Base_9(ABC):
+    @abstractproperty
+    def method(self):
+        foo()
+
+
 class MetaBase_1(metaclass=ABCMeta):  # error
     def method(self):
         foo()

resources/test/fixtures/flake8_bugbear/B027.py

@@ -1,11 +1,12 @@
 """
 Should emit:
-B027 - on lines 12, 15, 18, 22, 30
+B027 - on lines 13, 16, 19, 23
 """
 import abc
 from abc import ABC
-from abc import abstractmethod
+from abc import abstractmethod, abstractproperty
 from abc import abstractmethod as notabstract
+from abc import abstractproperty as notabstract_property
 
 
 class AbstractClass(ABC):
@@ -42,6 +43,18 @@ class AbstractClass(ABC):
     def abstract_3(self):
         ...
 
+    @abc.abstractproperty
+    def abstract_4(self):
+        ...
+
+    @abstractproperty
+    def abstract_5(self):
+        ...
+
+    @notabstract_property
+    def abstract_6(self):
+        ...
+
     def body_1(self):
         print("foo")
         ...

resources/test/fixtures/flake8_comprehensions/C400.py

@@ -2,3 +2,10 @@ x = list(x for x in range(3))
 x = list(
     x for x in range(3)
 )
+
+
+def list(*args, **kwargs):
+    return None
+
+
+list(x for x in range(3))

resources/test/fixtures/flake8_comprehensions/C401.py

@@ -2,3 +2,10 @@ x = set(x for x in range(3))
 x = set(
     x for x in range(3)
 )
+
+
+def set(*args, **kwargs):
+    return None
+
+
+set(x for x in range(3))

resources/test/fixtures/flake8_comprehensions/C405.py

@@ -1,5 +1,18 @@
-s1 = set([1, 2])
-s2 = set((1, 2))
-s3 = set([])
-s4 = set(())
-s5 = set()
+set([1, 2])
+set((1, 2))
+set([])
+set(())
+set()
+set((1,))
+set((
+    1,
+))
+set([
+    1,
+])
+set(
+    (1,)
+)
+set(
+    [1,]
+)

resources/test/fixtures/flake8_comprehensions/C408.py

@@ -3,3 +3,10 @@ l = list()
 d1 = dict()
 d2 = dict(a=1)
 d3 = dict(**d2)
+
+
+def list():
+    return [1, 2, 3]
+
+
+a = list()

resources/test/fixtures/flake8_comprehensions/C413.py

@@ -4,3 +4,10 @@ list(sorted(x))
 reversed(sorted(x))
 reversed(sorted(x, key=lambda e: e))
 reversed(sorted(x, reverse=True))
+
+
+def reversed(*args, **kwargs):
+    return None
+
+
+reversed(sorted(x, reverse=True))

resources/test/fixtures/flake8_pie/PIE794.py

@@ -31,3 +31,10 @@ class User(BaseModel):
     @buzz.setter
     def buzz(self, value: str | int) -> None:
         ...
+
+
+class User:
+    bar: str = StringField()
+    foo: bool = BooleanField()
+    # ...
+    bar = StringField()  # PIE794

resources/test/fixtures/flake8_quotes/docstring_doubles_function.py

@@ -17,6 +17,15 @@ def fun_with_params_no_docstring(a, b="""
 """ """docstring"""):
     pass
 
+
 def fun_with_params_no_docstring2(a, b=c[foo():], c=\
     """ not a docstring """):
     pass
+
+
+def function_with_single_docstring(a):
+    "Single line docstring"
+
+
+def double_inside_single(a):
+    'Double inside "single "'

resources/test/fixtures/flake8_quotes/docstring_singles_function.py

@@ -13,11 +13,19 @@ def foo2():
 
 
 def fun_with_params_no_docstring(a, b='''
-    not a 
+    not a
 ''' '''docstring'''):
     pass
 
+
 def fun_with_params_no_docstring2(a, b=c[foo():], c=\
     ''' not a docstring '''):
     pass
 
+
+def function_with_single_docstring(a):
+    'Single line docstring'
+
+
+def double_inside_single(a):
+    "Double inside 'single '"

resources/test/fixtures/flake8_quotes/doubles_escaped.py

@@ -1,4 +1,5 @@
 this_should_raise_Q003 = 'This is a \'string\''
+this_should_raise_Q003 = 'This is \\ a \\\'string\''
 this_is_fine = '"This" is a \'string\''
 this_is_fine = "This is a 'string'"
 this_is_fine = "\"This\" is a 'string'"

resources/test/fixtures/flake8_simplify/SIM108.py

@@ -1,13 +1,13 @@
-# Bad
+# SIM108
 if a:
     b = c
 else:
     b = d
 
-# Good
+# OK
 b = c if a else d
 
-# https://github.com/MartinThoma/flake8-simplify/issues/115
+# OK
 if a:
     b = c
 elif c:
@@ -15,6 +15,7 @@ elif c:
 else:
     b = d
 
+# OK
 if True:
     pass
 elif a:
@@ -22,6 +23,7 @@ elif a:
 else:
     b = 2
 
+# OK (false negative)
 if True:
     pass
 else:
@@ -30,19 +32,62 @@ else:
     else:
         b = 2
 
+
 import sys
 
+# OK
 if sys.version_info >= (3, 9):
     randbytes = random.randbytes
 else:
     randbytes = _get_random_bytes
 
+# OK
 if sys.platform == "darwin":
     randbytes = random.randbytes
 else:
     randbytes = _get_random_bytes
 
+# OK
 if sys.platform.startswith("linux"):
     randbytes = random.randbytes
 else:
     randbytes = _get_random_bytes
+
+
+# OK (includes comments)
+if x > 0:
+    # test test
+    abc = x
+else:
+    # test test test
+    abc = -x
+
+
+# OK (too long)
+if parser.errno == BAD_FIRST_LINE:
+    req = wrappers.Request(sock, server=self._server)
+else:
+    req = wrappers.Request(
+        sock,
+        parser.get_method(),
+        parser.get_scheme() or _scheme,
+        parser.get_path(),
+        parser.get_version(),
+        parser.get_query_string(),
+        server=self._server,
+    )
+
+
+# SIM108
+if a:
+    b = cccccccccccccccccccccccccccccccccccc
+else:
+    b = ddddddddddddddddddddddddddddddddddddd
+
+
+# OK (too long)
+if True:
+    if a:
+        b = cccccccccccccccccccccccccccccccccccc
+    else:
+        b = ddddddddddddddddddddddddddddddddddddd

resources/test/fixtures/flake8_simplify/SIM110.py

@@ -1,5 +1,6 @@
 def f():
-    for x in iterable:  # SIM110
+    # SIM110
+    for x in iterable:
         if check(x):
             return True
     return False
@@ -20,14 +21,16 @@ def f():
 
 
 def f():
-    for x in iterable:  # SIM111
+    # SIM111
+    for x in iterable:
         if check(x):
             return False
     return True
 
 
 def f():
-    for x in iterable:  # SIM111
+    # SIM111
+    for x in iterable:
         if not x.is_empty():
             return False
     return True
@@ -45,3 +48,70 @@ def f():
         if check(x):
             return "foo"
     return "bar"
+
+
+def f():
+    # SIM110
+    for x in iterable:
+        if check(x):
+            return True
+    else:
+        return False
+
+
+def f():
+    # SIM111
+    for x in iterable:
+        if check(x):
+            return False
+    else:
+        return True
+
+
+def f():
+    # SIM110
+    for x in iterable:
+        if check(x):
+            return True
+    else:
+        return False
+    return True
+
+
+def f():
+    # SIM111
+    for x in iterable:
+        if check(x):
+            return False
+    else:
+        return True
+    return False
+
+
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+        elif x.is_empty():
+            return True
+    return False
+
+
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+        else:
+            return True
+    return False
+
+
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+        elif x.is_empty():
+            return True
+    else:
+        return True
+    return False

resources/test/fixtures/flake8_simplify/SIM111.py

@@ -1,10 +1,18 @@
 def f():
-    for x in iterable:  # SIM110
+    # SIM110
+    for x in iterable:
         if check(x):
             return True
     return False
 
 
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+    return True
+
+
 def f():
     for el in [1, 2, 3]:
         if is_true(el):
@@ -13,21 +21,97 @@ def f():
 
 
 def f():
-    for x in iterable:  # SIM111
+    # SIM111
+    for x in iterable:
         if check(x):
             return False
     return True
 
 
 def f():
-    for x in iterable:  # SIM 111
+    # SIM111
+    for x in iterable:
         if not x.is_empty():
             return False
     return True
 
 
+def f():
+    for x in iterable:
+        if check(x):
+            return False
+    return False
+
+
 def f():
     for x in iterable:
         if check(x):
             return "foo"
     return "bar"
+
+
+def f():
+    # SIM110
+    for x in iterable:
+        if check(x):
+            return True
+    else:
+        return False
+
+
+def f():
+    # SIM111
+    for x in iterable:
+        if check(x):
+            return False
+    else:
+        return True
+
+
+def f():
+    # SIM110
+    for x in iterable:
+        if check(x):
+            return True
+    else:
+        return False
+    return True
+
+
+def f():
+    # SIM111
+    for x in iterable:
+        if check(x):
+            return False
+    else:
+        return True
+    return False
+
+
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+        elif x.is_empty():
+            return True
+    return False
+
+
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+        else:
+            return True
+    return False
+
+
+def f():
+    for x in iterable:
+        if check(x):
+            return True
+        elif x.is_empty():
+            return True
+    else:
+        return True
+    return False

resources/test/fixtures/flake8_simplify/SIM112.py

@@ -0,0 +1,19 @@
+import os
+
+# Bad
+os.environ['foo']
+
+os.environ.get('foo')
+
+os.environ.get('foo', 'bar')
+
+os.getenv('foo')
+
+# Good
+os.environ['FOO']
+
+os.environ.get('FOO')
+
+os.environ.get('FOO', 'bar')
+
+os.getenv('FOO')

resources/test/fixtures/flake8_simplify/SIM115.py

@@ -0,0 +1,6 @@
+f = open('foo.txt')  # SIM115
+data = f.read()
+f.close()
+
+with open('foo.txt') as f:  # OK
+    data = f.read()

resources/test/fixtures/flake8_simplify/SIM401.py

@@ -0,0 +1,87 @@
+###
+# Positive cases
+###
+
+# SIM401 (pattern-1)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var = "default1"
+
+# SIM401 (pattern-2)
+if key not in a_dict:
+    var = "default2"
+else:
+    var = a_dict[key]
+
+# SIM401 (default with a complex expression)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var = val1 + val2
+
+# SIM401 (complex expression in key)
+if keys[idx] in a_dict:
+    var = a_dict[keys[idx]]
+else:
+    var = "default"
+
+# SIM401 (complex expression in dict)
+if key in dicts[idx]:
+    var = dicts[idx][key]
+else:
+    var = "default"
+
+# SIM401 (complex expression in var)
+if key in a_dict:
+    vars[idx] = a_dict[key]
+else:
+    vars[idx] = "default"
+
+###
+# Negative cases
+###
+
+# OK (false negative)
+if not key in a_dict:
+    var = "default"
+else:
+    var = a_dict[key]
+
+# OK (different dict)
+if key in a_dict:
+    var = other_dict[key]
+else:
+    var = "default"
+
+# OK (different key)
+if key in a_dict:
+    var = a_dict[other_key]
+else:
+    var = "default"
+
+# OK (different var)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    other_var = "default"
+
+# OK (extra vars in body)
+if key in a_dict:
+    var = a_dict[key]
+    var2 = value2
+else:
+    var = "default"
+
+# OK (extra vars in orelse)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var2 = value2
+    var = "default"
+
+# OK (complex default value)
+if key in a_dict:
+    var = a_dict[key]
+else:
+    var = foo()

resources/test/fixtures/flake8_unused_arguments/ARG.py

@@ -181,3 +181,17 @@ def f(a: int, b: int) -> str:
 
 def f(a, b):
     return f"{a}{b}"
+
+
+###
+# Unused arguments on magic methods.
+###
+class C:
+    def __init__(self, x) -> None:
+        print("Hello, world!")
+
+    def __str__(self) -> str:
+        return "Hello, world!"
+
+    def __exit__(self, exc_type, exc_value, traceback) -> None:
+        print("Hello, world!")

resources/test/fixtures/isort/order_by_type_with_custom_classes.py

@@ -0,0 +1,4 @@
+from sklearn.svm import func, SVC, CONST, Klass
+from subprocess import N_CLASS, PIPE, Popen, STDOUT
+from module import CLASS, Class, CONSTANT, function, BASIC, Apple
+from torch.nn import SELU, AClass, A_CONSTANT

resources/test/fixtures/isort/relative_imports_order.py

@@ -0,0 +1,3 @@
+from ... import a
+from .. import b
+from . import c

resources/test/fixtures/isort/required_imports/comment.py

@@ -0,0 +1,3 @@
+#!/usr/bin/env python3
+
+x = 1

resources/test/fixtures/isort/required_imports/docstring.py

@@ -0,0 +1,3 @@
+"""Hello, world!"""
+
+x = 1

resources/test/fixtures/isort/required_imports/docstring_only.py

@@ -0,0 +1 @@
+"""Hello, world!"""

resources/test/fixtures/isort/required_imports/docstring_with_continuation.py

@@ -0,0 +1,2 @@
+"""Hello, world!"""; x = \
+    1; y = 2

resources/test/fixtures/isort/required_imports/docstring_with_semicolon.py

@@ -0,0 +1 @@
+"""Hello, world!"""; x = 1

resources/test/fixtures/isort/required_imports/existing_import.py

@@ -0,0 +1,2 @@
+from __future__ import generator_stop
+import os

resources/test/fixtures/pycodestyle/W505.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python3
+"""Here's a top-level docstring that's over the limit."""
+
+
+def f():
+    """Here's a docstring that's also over the limit."""
+
+    x = 1  # Here's a comment that's over the limit, but it's not standalone.
+
+    # Here's a standalone comment that's over the limit.
+
+    print("Here's a string that's over the limit, but it's not a docstring.")
+
+
+"This is also considered a docstring, and is over the limit."

resources/test/fixtures/pyflakes/F401_6.py

@@ -9,7 +9,6 @@ from .background import BackgroundTasks
 # F401 `datastructures.UploadFile` imported but unused
 from .datastructures import UploadFile as FileUpload
 
-
 # OK
 import applications as applications
 

resources/test/fixtures/pygrep-hooks/PGH002_0.py

@@ -5,4 +5,3 @@ from warnings import warn
 warnings.warn("this is ok")
 warn("by itself is also ok")
 logging.warning("this is fine")
-log.warning("this is ok")

resources/test/fixtures/pygrep-hooks/PGH002_1.py

@@ -2,14 +2,4 @@ import logging
 from logging import warn
 
 logging.warn("this is not ok")
-log.warn("this is also not ok")
 warn("not ok")
-
-
-def foo():
-    from logging import warn
-
-    def warn():
-        pass
-
-    warn("has been redefined, but we will still report it")

resources/test/fixtures/pylint/constant_comparison.py

@@ -0,0 +1,59 @@
+"""Check that magic values are not used in comparisons"""
+
+if 100 == 100: # [comparison-of-constants]
+    pass
+
+if 1 == 3: # [comparison-of-constants]
+    pass
+
+if 1 != 3: # [comparison-of-constants]
+    pass
+
+x = 0
+if 4 == 3 == x: # [comparison-of-constants]
+    pass
+
+if x == 0: # correct
+    pass
+
+y = 1
+if x == y: # correct
+    pass
+
+if 1 > 0: # [comparison-of-constants]
+    pass
+
+if x > 0: # correct
+    pass
+
+if 1 >= 0: # [comparison-of-constants]
+    pass
+
+if x >= 0: # correct
+    pass
+
+if 1 < 0: # [comparison-of-constants]
+    pass
+
+if x < 0: # correct
+    pass
+
+if 1 <= 0: # [comparison-of-constants]
+    pass
+
+if x <= 0: # correct
+    pass
+
+word = "hello"
+if word == "": # correct
+    pass
+
+if "hello" == "": # [comparison-of-constants]
+    pass
+
+truthy = True
+if truthy == True: # correct
+    pass
+
+if True == False: # [comparison-of-constants]
+    pass

resources/test/fixtures/pylint/magic_value_comparison.py

@@ -0,0 +1,71 @@
+"""Check that magic values are not used in comparisons"""
+import cmath
+
+user_input = 10
+
+if 10 > user_input: # [magic-value-comparison]
+    pass
+
+if 10 == 100: # [comparison-of-constants] R0133
+    pass
+
+if 1 == 3: # [comparison-of-constants] R0133
+    pass
+
+x = 0
+if 4 == 3 == x: # [comparison-of-constants] R0133
+    pass
+
+time_delta = 7224
+ONE_HOUR = 3600
+
+if time_delta > ONE_HOUR: # correct
+    pass
+
+argc = 1
+
+if argc != -1: # correct
+    pass
+
+if argc != 0: # correct
+    pass
+
+if argc != 1: # correct
+    pass
+
+if argc != 2: # [magic-value-comparison]
+    pass
+
+if __name__ == "__main__": # correct
+    pass
+
+ADMIN_PASSWORD = "SUPERSECRET"
+input_password = "password"
+
+if input_password == "": # correct
+    pass
+
+if input_password == ADMIN_PASSWORD: # correct
+    pass
+
+if input_password == "Hunter2": # [magic-value-comparison]
+    pass
+
+PI = 3.141592653589793238
+pi_estimation = 3.14
+
+if pi_estimation == 3.141592653589793238: # [magic-value-comparison]
+    pass
+
+if pi_estimation == PI: # correct
+    pass
+
+HELLO_WORLD = b"Hello, World!"
+user_input = b"Hello, There!"
+
+if user_input == b"something": # [magic-value-comparison]
+    pass
+
+if user_input == HELLO_WORLD: # correct
+    pass
+

resources/test/fixtures/pyupgrade/UP024_3.py

@@ -0,0 +1,8 @@
+class SocketError(Exception):
+    pass
+
+
+try:
+    raise SocketError()
+except SocketError:
+    pass

resources/test/fixtures/pyupgrade/UP030_0.py

@@ -0,0 +1,36 @@
+# Invalid calls; errors expected.
+
+"{0}" "{1}" "{2}".format(1, 2, 3)
+
+"a {3} complicated {1} string with {0} {2}".format(
+    "first", "second", "third", "fourth"
+)
+
+'{0}'.format(1)
+
+'{0:x}'.format(30)
+
+x = '{0}'.format(1)
+
+'''{0}\n{1}\n'''.format(1, 2)
+
+x = "foo {0}" \
+    "bar {1}".format(1, 2)
+
+("{0}").format(1)
+
+"\N{snowman} {0}".format(1)
+
+'{' '0}'.format(1)
+
+# These will not change because we are waiting for libcst to fix this issue:
+# https://github.com/Instagram/LibCST/issues/846
+print(
+    'foo{0}'
+    'bar{1}'.format(1, 2)
+)
+
+print(
+    'foo{0}'  # ohai\n"
+    'bar{1}'.format(1, 2)
+)

resources/test/fixtures/pyupgrade/UP030_1.py

@@ -0,0 +1,23 @@
+# Valid calls; no errors expected.
+
+'{}'.format(1)
+
+
+x = ('{0} {1}',)
+
+'{0} {0}'.format(1)
+
+'{0:<{1}}'.format(1, 4)
+
+f"{0}".format(a)
+
+f"{0}".format(1)
+
+print(f"{0}".format(1))
+
+# I did not include the following tests because ruff does not seem to work with
+# invalid python syntax (which is a good thing)
+
+# "{0}"format(1)
+# '{'.format(1)", "'}'.format(1)
+# ("{0}" # {1}\n"{2}").format(1, 2, 3)

resources/test/project/README.md

@@ -17,7 +17,7 @@ resources/test/project/examples/docs/docs/file.py:8:5: F841 Local variable `x` i
 resources/test/project/project/file.py:1:8: F401 `os` imported but unused
 resources/test/project/project/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
 Found 7 error(s).
-6 potentially fixable with the --fix option.
+7 potentially fixable with the --fix option.
 ```
 
 Running from the project directory itself should exhibit the same behavior:
@@ -32,7 +32,7 @@ examples/docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never
 project/file.py:1:8: F401 `os` imported but unused
 project/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
 Found 7 error(s).
-6 potentially fixable with the --fix option.
+7 potentially fixable with the --fix option.
 ```
 
 Running from the sub-package directory should exhibit the same behavior, but omit the top-level
@@ -43,7 +43,7 @@ files:
 docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
 docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
 Found 2 error(s).
-1 potentially fixable with the --fix option.
+2 potentially fixable with the --fix option.
 ```
 
 `--config` should force Ruff to use the specified `pyproject.toml` for all files, and resolve
@@ -74,7 +74,7 @@ docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
 docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
 excluded/script.py:5:5: F841 Local variable `x` is assigned to but never used
 Found 4 error(s).
-1 potentially fixable with the --fix option.
+4 potentially fixable with the --fix option.
 ```
 
 Passing an excluded directory directly should report errors in the contained files:

ruff.schema.json

@@ -40,7 +40,7 @@
       ]
     },
     "exclude": {
-      "description": "A list of file patterns to exclude from linting.\n\nExclusions are based on globs, and can be either:\n\n- Single-path patterns, like `.mypy_cache` (to exclude any directory named `.mypy_cache` in the tree), `foo.py` (to exclude any file named `foo.py`), or `foo_*.py` (to exclude any file matching `foo_*.py` ). - Relative patterns, like `directory/foo.py` (to exclude that specific file) or `directory/*.py` (to exclude any Python files in `directory`). Note that these paths are relative to the project root (e.g., the directory containing your `pyproject.toml`).\n\nNote that you'll typically want to use [`extend-exclude`](#extend-exclude) to modify the excluded paths.",
+      "description": "A list of file patterns to exclude from linting.\n\nExclusions are based on globs, and can be either:\n\n- Single-path patterns, like `.mypy_cache` (to exclude any directory named `.mypy_cache` in the tree), `foo.py` (to exclude any file named `foo.py`), or `foo_*.py` (to exclude any file matching `foo_*.py` ). - Relative patterns, like `directory/foo.py` (to exclude that specific file) or `directory/*.py` (to exclude any Python files in `directory`). Note that these paths are relative to the project root (e.g., the directory containing your `pyproject.toml`).\n\nFor more information on the glob syntax, refer to the [`globset` documentation](https://docs.rs/globset/latest/globset/#syntax).\n\nNote that you'll typically want to use [`extend-exclude`](#extend-exclude) to modify the excluded paths.",
       "type": [
         "array",
         "null"
@@ -57,7 +57,7 @@
       ]
     },
     "extend-exclude": {
-      "description": "A list of file patterns to omit from linting, in addition to those specified by `exclude`.",
+      "description": "A list of file patterns to omit from linting, in addition to those specified by `exclude`.\n\nExclusions are based on globs, and can be either:\n\n- Single-path patterns, like `.mypy_cache` (to exclude any directory named `.mypy_cache` in the tree), `foo.py` (to exclude any file named `foo.py`), or `foo_*.py` (to exclude any file matching `foo_*.py` ). - Relative patterns, like `directory/foo.py` (to exclude that specific file) or `directory/*.py` (to exclude any Python files in `directory`). Note that these paths are relative to the project root (e.g., the directory containing your `pyproject.toml`).\n\nFor more information on the glob syntax, refer to the [`globset` documentation](https://docs.rs/globset/latest/globset/#syntax).",
       "type": [
         "array",
         "null"
@@ -67,7 +67,7 @@
       }
     },
     "extend-ignore": {
-      "description": "A list of rule codes or prefixes to ignore, in addition to those specified by `ignore`.",
+      "description": "A list of rule codes or prefixes to ignore, in addition to those specified by `ignore`.\n\nNote that `extend-ignore` is applied after resolving rules from `ignore`/`select` and a less specific rule in `extend-ignore` would overwrite a more specific rule in `select`. It is recommended to only use `extend-ignore` when extending a `pyproject.toml` file via `extend`.",
       "type": [
         "array",
         "null"
@@ -77,7 +77,7 @@
       }
     },
     "extend-select": {
-      "description": "A list of rule codes or prefixes to enable, in addition to those specified by `select`.",
+      "description": "A list of rule codes or prefixes to enable, in addition to those specified by `select`.\n\nNote that `extend-select` is applied after resolving rules from `ignore`/`select` and a less specific rule in `extend-select` would overwrite a more specific rule in `ignore`. It is recommended to only use `extend-select` when extending a `pyproject.toml` file via `extend`.",
       "type": [
         "array",
         "null"
@@ -755,6 +755,16 @@
     "IsortOptions": {
       "type": "object",
       "properties": {
+        "classes": {
+          "description": "An override list of tokens to always recognize as a Class for `order-by-type` regardless of casing.",
+          "type": [
+            "array",
+            "null"
+          ],
+          "items": {
+            "type": "string"
+          }
+        },
         "combine-as-imports": {
           "description": "Combines as imports on the same line. See isort's [`combine-as-imports`](https://pycqa.github.io/isort/docs/configuration/options.html#combine-as-imports) option.",
           "type": [
@@ -820,6 +830,27 @@
             "null"
           ]
         },
+        "relative-imports-order": {
+          "description": "Whether to place \"closer\" imports (fewer `.` characters, most local) before \"further\" imports (more `.` characters, least local), or vice versa.\n\nThe default (\"furthest-to-closest\") is equivalent to isort's `reverse-relative` default (`reverse-relative = false`); setting this to \"closest-to-furthest\" is equivalent to isort's `reverse-relative = true`.",
+          "anyOf": [
+            {
+              "$ref": "#/definitions/RelatveImportsOrder"
+            },
+            {
+              "type": "null"
+            }
+          ]
+        },
+        "required-imports": {
+          "description": "Add the specified import line to all files.",
+          "type": [
+            "array",
+            "null"
+          ],
+          "items": {
+            "type": "string"
+          }
+        },
         "single-line-exclusions": {
           "description": "One or more modules to exclude from the single line rule.",
           "type": [
@@ -935,6 +966,15 @@
             "boolean",
             "null"
           ]
+        },
+        "max-doc-length": {
+          "description": "The maximum line length to allow for line-length violations within documentation (`W505`), including standalone comments.",
+          "type": [
+            "integer",
+            "null"
+          ],
+          "format": "uint",
+          "minimum": 0.0
         }
       },
       "additionalProperties": false
@@ -988,6 +1028,24 @@
         }
       ]
     },
+    "RelatveImportsOrder": {
+      "oneOf": [
+        {
+          "description": "Place \"closer\" imports (fewer `.` characters, most local) before \"further\" imports (more `.` characters, least local).",
+          "type": "string",
+          "enum": [
+            "closest-to-furthest"
+          ]
+        },
+        {
+          "description": "Place \"further\" imports (more `.` characters, least local) imports before \"closer\" imports (fewer `.` characters, most local).",
+          "type": "string",
+          "enum": [
+            "furthest-to-closest"
+          ]
+        }
+      ]
+    },
     "RuleCodePrefix": {
       "type": "string",
       "enum": [
@@ -1268,6 +1326,7 @@
         "I0",
         "I00",
         "I001",
+        "I002",
         "I2",
         "I25",
         "I252",
@@ -1384,6 +1443,9 @@
         "PLE1142",
         "PLR",
         "PLR0",
+        "PLR01",
+        "PLR013",
+        "PLR0133",
         "PLR02",
         "PLR020",
         "PLR0206",
@@ -1396,6 +1458,10 @@
         "PLR1701",
         "PLR172",
         "PLR1722",
+        "PLR2",
+        "PLR20",
+        "PLR200",
+        "PLR2004",
         "PLW",
         "PLW0",
         "PLW01",
@@ -1493,6 +1559,11 @@
         "S50",
         "S501",
         "S506",
+        "S508",
+        "S509",
+        "S7",
+        "S70",
+        "S701",
         "SIM",
         "SIM1",
         "SIM10",
@@ -1506,6 +1577,8 @@
         "SIM11",
         "SIM110",
         "SIM111",
+        "SIM112",
+        "SIM115",
         "SIM117",
         "SIM118",
         "SIM2",
@@ -1525,6 +1598,9 @@
         "SIM3",
         "SIM30",
         "SIM300",
+        "SIM4",
+        "SIM40",
+        "SIM401",
         "T",
         "T1",
         "T10",
@@ -1592,10 +1668,15 @@
         "UP027",
         "UP028",
         "UP029",
+        "UP03",
+        "UP030",
         "W",
         "W2",
         "W29",
         "W292",
+        "W5",
+        "W50",
+        "W505",
         "W6",
         "W60",
         "W605",

ruff_cli/Cargo.toml

@@ -0,0 +1,62 @@
+[package]
+name = "ruff_cli"
+version = "0.0.221"
+authors = ["Charlie Marsh <charlie.r.marsh@gmail.com>"]
+edition = "2021"
+rust-version = "1.65.0"
+documentation = "https://github.com/charliermarsh/ruff"
+homepage = "https://github.com/charliermarsh/ruff"
+repository = "https://github.com/charliermarsh/ruff"
+readme = "../README.md"
+license = "MIT"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[[bin]]
+name = "ruff"
+path = "src/main.rs"
+doctest = false
+
+[dependencies]
+ruff = { path = ".." }
+
+annotate-snippets = { version = "0.9.1", features = ["color"] }
+anyhow = { version = "1.0.66" }
+atty = { version = "0.2.14" }
+bincode = { version = "1.3.3" }
+cachedir = { version = "0.3.0" }
+chrono = { version = "0.4.21", default-features = false, features = ["clock"] }
+clap = { version = "4.0.1", features = ["derive", "env"] }
+clap_complete_command = { version = "0.4.0" }
+clearscreen = { version = "2.0.0" }
+colored = { version = "2.0.0" }
+filetime = { version = "0.2.17" }
+glob = { version = "0.3.0" }
+ignore = { version = "0.4.18" }
+itertools = { version = "0.10.5" }
+log = { version = "0.4.17" }
+notify = { version = "5.0.0" }
+path-absolutize = { version = "3.0.14", features = ["once_cell_cache"] }
+quick-junit = { version = "0.3.2" }
+rayon = { version = "1.5.3" }
+regex = { version = "1.6.0" }
+rustc-hash = { version = "1.1.0" }
+serde = { version = "1.0.147", features = ["derive"] }
+serde_json = { version = "1.0.87" }
+similar = { version = "2.2.1" }
+textwrap = { version = "0.16.0" }
+update-informer = { version = "0.6.0", default-features = false, features = ["pypi"], optional = true }
+walkdir = { version = "2.3.2" }
+
+[dev-dependencies]
+assert_cmd = { version = "2.0.4" }
+strum = { version = "0.24.1" }
+ureq = { version = "2.5.0", features = [] }
+
+[features]
+default = ["update-informer"]
+update-informer = ["dep:update-informer"]
+
+[package.metadata.maturin]
+name = "ruff"
+# Setting the name here is necessary for maturin to include the package in its builds.

ruff_cli/src/cache.rs

@@ -0,0 +1,124 @@
+use std::collections::hash_map::DefaultHasher;
+use std::fs;
+use std::hash::{Hash, Hasher};
+use std::io::Write;
+use std::path::Path;
+
+use anyhow::Result;
+use filetime::FileTime;
+use log::error;
+use path_absolutize::Absolutize;
+use ruff::message::Message;
+use ruff::settings::{flags, Settings};
+use serde::{Deserialize, Serialize};
+
+const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
+
+#[derive(Serialize, Deserialize)]
+struct CacheMetadata {
+    mtime: i64,
+}
+
+#[derive(Serialize)]
+struct CheckResultRef<'a> {
+    metadata: &'a CacheMetadata,
+    messages: &'a [Message],
+}
+
+#[derive(Deserialize)]
+struct CheckResult {
+    metadata: CacheMetadata,
+    messages: Vec<Message>,
+}
+
+fn content_dir() -> &'static Path {
+    Path::new("content")
+}
+
+fn cache_key<P: AsRef<Path>>(path: P, settings: &Settings, autofix: flags::Autofix) -> u64 {
+    let mut hasher = DefaultHasher::new();
+    CARGO_PKG_VERSION.hash(&mut hasher);
+    path.as_ref().absolutize().unwrap().hash(&mut hasher);
+    settings.hash(&mut hasher);
+    autofix.hash(&mut hasher);
+    hasher.finish()
+}
+
+#[allow(dead_code)]
+/// Initialize the cache at the specified `Path`.
+pub fn init(path: &Path) -> Result<()> {
+    // Create the cache directories.
+    fs::create_dir_all(path.join(content_dir()))?;
+
+    // Add the CACHEDIR.TAG.
+    if !cachedir::is_tagged(path)? {
+        cachedir::add_tag(path)?;
+    }
+
+    // Add the .gitignore.
+    let gitignore_path = path.join(".gitignore");
+    if !gitignore_path.exists() {
+        let mut file = fs::File::create(gitignore_path)?;
+        file.write_all(b"*")?;
+    }
+
+    Ok(())
+}
+
+fn write_sync(cache_dir: &Path, key: u64, value: &[u8]) -> Result<(), std::io::Error> {
+    fs::write(
+        cache_dir.join(content_dir()).join(format!("{key:x}")),
+        value,
+    )
+}
+
+fn read_sync(cache_dir: &Path, key: u64) -> Result<Vec<u8>, std::io::Error> {
+    fs::read(cache_dir.join(content_dir()).join(format!("{key:x}")))
+}
+
+/// Get a value from the cache.
+pub fn get<P: AsRef<Path>>(
+    path: P,
+    metadata: &fs::Metadata,
+    settings: &Settings,
+    autofix: flags::Autofix,
+) -> Option<Vec<Message>> {
+    let encoded = read_sync(&settings.cache_dir, cache_key(path, settings, autofix)).ok()?;
+    let (mtime, messages) = match bincode::deserialize::<CheckResult>(&encoded[..]) {
+        Ok(CheckResult {
+            metadata: CacheMetadata { mtime },
+            messages,
+        }) => (mtime, messages),
+        Err(e) => {
+            error!("Failed to deserialize encoded cache entry: {e:?}");
+            return None;
+        }
+    };
+    if FileTime::from_last_modification_time(metadata).unix_seconds() != mtime {
+        return None;
+    }
+    Some(messages)
+}
+
+/// Set a value in the cache.
+pub fn set<P: AsRef<Path>>(
+    path: P,
+    metadata: &fs::Metadata,
+    settings: &Settings,
+    autofix: flags::Autofix,
+    messages: &[Message],
+) {
+    let check_result = CheckResultRef {
+        metadata: &CacheMetadata {
+            mtime: FileTime::from_last_modification_time(metadata).unix_seconds(),
+        },
+        messages,
+    };
+    if let Err(e) = write_sync(
+        &settings.cache_dir,
+        cache_key(path, settings, autofix),
+        &bincode::serialize(&check_result).unwrap(),
+    ) {
+        error!("Failed to write to cache: {e:?}");
+    }
+}

ruff_cli/src/cli.rs

@@ -2,17 +2,21 @@ use std::path::{Path, PathBuf};
 
 use clap::{command, Parser};
 use regex::Regex;
-use rustc_hash::FxHashMap;
-
-use crate::fs;
-use crate::logging::LogLevel;
-use crate::registry::{RuleCode, RuleCodePrefix};
-use crate::settings::types::{
+use ruff::logging::LogLevel;
+use ruff::registry::{RuleCode, RuleCodePrefix};
+use ruff::resolver::ConfigProcessor;
+use ruff::settings::types::{
     FilePattern, PatternPrefixPair, PerFileIgnore, PythonVersion, SerializationFormat,
 };
+use ruff::{fs, mccabe};
+use rustc_hash::FxHashMap;
 
 #[derive(Debug, Parser)]
-#[command(author, about = "Ruff: An extremely fast Python linter.")]
+#[command(
+    author,
+    name = "ruff",
+    about = "Ruff: An extremely fast Python linter."
+)]
 #[command(version)]
 #[allow(clippy::struct_excessive_bools)]
 pub struct Cli {
@@ -61,33 +65,33 @@ pub struct Cli {
     pub isolated: bool,
     /// Comma-separated list of rule codes to enable (or ALL, to enable all
     /// rules).
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "RULE_CODE")]
     pub select: Option<Vec<RuleCodePrefix>>,
     /// Like --select, but adds additional rule codes on top of the selected
     /// ones.
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "RULE_CODE")]
     pub extend_select: Option<Vec<RuleCodePrefix>>,
     /// Comma-separated list of rule codes to disable.
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "RULE_CODE")]
     pub ignore: Option<Vec<RuleCodePrefix>>,
     /// Like --ignore, but adds additional rule codes on top of the ignored
     /// ones.
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "RULE_CODE")]
     pub extend_ignore: Option<Vec<RuleCodePrefix>>,
     /// List of paths, used to omit files and/or directories from analysis.
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "FILE_PATTERN")]
     pub exclude: Option<Vec<FilePattern>>,
     /// Like --exclude, but adds additional files and directories on top of
     /// those already excluded.
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "FILE_PATTERN")]
     pub extend_exclude: Option<Vec<FilePattern>>,
     /// List of rule codes to treat as eligible for autofix. Only applicable
     /// when autofix itself is enabled (e.g., via `--fix`).
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "RULE_CODE")]
     pub fixable: Option<Vec<RuleCodePrefix>>,
     /// List of rule codes to treat as ineligible for autofix. Only applicable
     /// when autofix itself is enabled (e.g., via `--fix`).
-    #[arg(long, value_delimiter = ',')]
+    #[arg(long, value_delimiter = ',', value_name = "RULE_CODE")]
     pub unfixable: Option<Vec<RuleCodePrefix>>,
     /// List of mappings from file pattern to code to exclude
     #[arg(long, value_delimiter = ',')]
@@ -344,6 +348,87 @@ pub struct Overrides {
     pub update_check: Option<bool>,
 }
 
+impl ConfigProcessor for &Overrides {
+    fn process_config(&self, config: &mut ruff::settings::configuration::Configuration) {
+        if let Some(cache_dir) = &self.cache_dir {
+            config.cache_dir = Some(cache_dir.clone());
+        }
+        if let Some(dummy_variable_rgx) = &self.dummy_variable_rgx {
+            config.dummy_variable_rgx = Some(dummy_variable_rgx.clone());
+        }
+        if let Some(exclude) = &self.exclude {
+            config.exclude = Some(exclude.clone());
+        }
+        if let Some(extend_exclude) = &self.extend_exclude {
+            config.extend_exclude.extend(extend_exclude.clone());
+        }
+        if let Some(fix) = &self.fix {
+            config.fix = Some(*fix);
+        }
+        if let Some(fix_only) = &self.fix_only {
+            config.fix_only = Some(*fix_only);
+        }
+        if let Some(fixable) = &self.fixable {
+            config.fixable = Some(fixable.clone());
+        }
+        if let Some(format) = &self.format {
+            config.format = Some(*format);
+        }
+        if let Some(force_exclude) = &self.force_exclude {
+            config.force_exclude = Some(*force_exclude);
+        }
+        if let Some(ignore) = &self.ignore {
+            config.ignore = Some(ignore.clone());
+        }
+        if let Some(line_length) = &self.line_length {
+            config.line_length = Some(*line_length);
+        }
+        if let Some(max_complexity) = &self.max_complexity {
+            config.mccabe = Some(mccabe::settings::Options {
+                max_complexity: Some(*max_complexity),
+            });
+        }
+        if let Some(per_file_ignores) = &self.per_file_ignores {
+            config.per_file_ignores = Some(collect_per_file_ignores(per_file_ignores.clone()));
+        }
+        if let Some(respect_gitignore) = &self.respect_gitignore {
+            config.respect_gitignore = Some(*respect_gitignore);
+        }
+        if let Some(select) = &self.select {
+            config.select = Some(select.clone());
+        }
+        if let Some(show_source) = &self.show_source {
+            config.show_source = Some(*show_source);
+        }
+        if let Some(target_version) = &self.target_version {
+            config.target_version = Some(*target_version);
+        }
+        if let Some(unfixable) = &self.unfixable {
+            config.unfixable = Some(unfixable.clone());
+        }
+        if let Some(update_check) = &self.update_check {
+            config.update_check = Some(*update_check);
+        }
+        // Special-case: `extend_ignore` and `extend_select` are parallel arrays, so
+        // push an empty array if only one of the two is provided.
+        match (&self.extend_ignore, &self.extend_select) {
+            (Some(extend_ignore), Some(extend_select)) => {
+                config.extend_ignore.push(extend_ignore.clone());
+                config.extend_select.push(extend_select.clone());
+            }
+            (Some(extend_ignore), None) => {
+                config.extend_ignore.push(extend_ignore.clone());
+                config.extend_select.push(Vec::new());
+            }
+            (None, Some(extend_select)) => {
+                config.extend_ignore.push(Vec::new());
+                config.extend_select.push(extend_select.clone());
+            }
+            (None, None) => {}
+        }
+    }
+}
+
 /// Map the CLI settings to a `LogLevel`.
 pub fn extract_log_level(cli: &Arguments) -> LogLevel {
     if cli.silent {

ruff_cli/src/commands.rs

@@ -11,22 +11,22 @@ use log::{debug, error};
 use path_absolutize::path_dedot;
 #[cfg(not(target_family = "wasm"))]
 use rayon::prelude::*;
-use rustpython_ast::Location;
+use ruff::cache::CACHE_DIR_NAME;
+use ruff::linter::add_noqa_to_path;
+use ruff::logging::LogLevel;
+use ruff::message::{Location, Message};
+use ruff::registry::RuleCode;
+use ruff::resolver::{FileDiscovery, PyprojectDiscovery};
+use ruff::settings::flags;
+use ruff::settings::types::SerializationFormat;
+use ruff::{fix, fs, packaging, resolver, violations, warn_user_once};
 use serde::Serialize;
 use walkdir::WalkDir;
 
-use crate::autofix::fixer;
-use crate::cache::CACHE_DIR_NAME;
+use crate::cache;
 use crate::cli::Overrides;
+use crate::diagnostics::{lint_path, lint_stdin, Diagnostics};
 use crate::iterators::par_iter;
-use crate::linter::{add_noqa_to_path, lint_path, lint_stdin, Diagnostics};
-use crate::logging::LogLevel;
-use crate::message::Message;
-use crate::registry::RuleCode;
-use crate::resolver::{FileDiscovery, PyprojectDiscovery};
-use crate::settings::flags;
-use crate::settings::types::SerializationFormat;
-use crate::{cache, fs, packages, resolver, violations, warn_user_once};
 
 /// Run the linter over a collection of files.
 pub fn run(
@@ -35,7 +35,7 @@ pub fn run(
     file_strategy: &FileDiscovery,
     overrides: &Overrides,
     cache: flags::Cache,
-    autofix: fixer::Mode,
+    autofix: fix::FixMode,
 ) -> Result<Diagnostics> {
     // Collect all the Python files to check.
     let start = Instant::now();
@@ -77,7 +77,7 @@ pub fn run(
     };
 
     // Discover the package root for each Python file.
-    let package_roots = packages::detect_package_roots(
+    let package_roots = packaging::detect_package_roots(
         &paths
             .iter()
             .flatten()
@@ -156,7 +156,7 @@ pub fn run_stdin(
     pyproject_strategy: &PyprojectDiscovery,
     file_strategy: &FileDiscovery,
     overrides: &Overrides,
-    autofix: fixer::Mode,
+    autofix: fix::FixMode,
 ) -> Result<Diagnostics> {
     if let Some(filename) = filename {
         if !resolver::python_file_at_path(filename, pyproject_strategy, file_strategy, overrides)? {
@@ -169,7 +169,7 @@ pub fn run_stdin(
     };
     let package_root = filename
         .and_then(Path::parent)
-        .and_then(packages::detect_package_root);
+        .and_then(packaging::detect_package_root);
     let stdin = read_from_stdin()?;
     let mut diagnostics = lint_stdin(filename, package_root, &stdin, settings, autofix)?;
     diagnostics.messages.sort_unstable();
@@ -288,7 +288,7 @@ struct Explanation<'a> {
 }
 
 /// Explain a `RuleCode` to the user.
-pub fn explain(code: &RuleCode, format: &SerializationFormat) -> Result<()> {
+pub fn explain(code: &RuleCode, format: SerializationFormat) -> Result<()> {
     match format {
         SerializationFormat::Text | SerializationFormat::Grouped => {
             println!(

ruff_cli/src/diagnostics.rs

@@ -0,0 +1,155 @@
+#![cfg_attr(target_family = "wasm", allow(dead_code))]
+use std::fs::write;
+use std::io;
+use std::io::Write;
+use std::ops::AddAssign;
+use std::path::Path;
+
+use anyhow::Result;
+use log::debug;
+use ruff::linter::{lint_fix, lint_only};
+use ruff::message::Message;
+use ruff::settings::{flags, Settings};
+use ruff::{fix, fs};
+use similar::TextDiff;
+
+use crate::cache;
+
+#[derive(Debug, Default)]
+pub struct Diagnostics {
+    pub messages: Vec<Message>,
+    pub fixed: usize,
+}
+
+impl Diagnostics {
+    pub fn new(messages: Vec<Message>) -> Self {
+        Self { messages, fixed: 0 }
+    }
+}
+
+impl AddAssign for Diagnostics {
+    fn add_assign(&mut self, other: Self) {
+        self.messages.extend(other.messages);
+        self.fixed += other.fixed;
+    }
+}
+
+/// Lint the source code at the given `Path`.
+pub fn lint_path(
+    path: &Path,
+    package: Option<&Path>,
+    settings: &Settings,
+    cache: flags::Cache,
+    autofix: fix::FixMode,
+) -> Result<Diagnostics> {
+    // Validate the `Settings` and return any errors.
+    settings.validate()?;
+
+    // Check the cache.
+    // TODO(charlie): `fixer::Mode::Apply` and `fixer::Mode::Diff` both have
+    // side-effects that aren't captured in the cache. (In practice, it's fine
+    // to cache `fixer::Mode::Apply`, since a file either has no fixes, or we'll
+    // write the fixes to disk, thus invalidating the cache. But it's a bit hard
+    // to reason about. We need to come up with a better solution here.)
+    let metadata = if matches!(cache, flags::Cache::Enabled)
+        && matches!(autofix, fix::FixMode::None | fix::FixMode::Generate)
+    {
+        let metadata = path.metadata()?;
+        if let Some(messages) = cache::get(path, &metadata, settings, autofix.into()) {
+            debug!("Cache hit for: {}", path.to_string_lossy());
+            return Ok(Diagnostics::new(messages));
+        }
+        Some(metadata)
+    } else {
+        None
+    };
+
+    // Read the file from disk.
+    let contents = fs::read_file(path)?;
+
+    // Lint the file.
+    let (messages, fixed) = if matches!(autofix, fix::FixMode::Apply | fix::FixMode::Diff) {
+        let (transformed, fixed, messages) = lint_fix(&contents, path, package, settings)?;
+        if fixed > 0 {
+            if matches!(autofix, fix::FixMode::Apply) {
+                write(path, transformed)?;
+            } else if matches!(autofix, fix::FixMode::Diff) {
+                let mut stdout = io::stdout().lock();
+                TextDiff::from_lines(&contents, &transformed)
+                    .unified_diff()
+                    .header(&fs::relativize_path(path), &fs::relativize_path(path))
+                    .to_writer(&mut stdout)?;
+                stdout.write_all(b"\n")?;
+                stdout.flush()?;
+            }
+        }
+        (messages, fixed)
+    } else {
+        let messages = lint_only(&contents, path, package, settings, autofix.into())?;
+        let fixed = 0;
+        (messages, fixed)
+    };
+
+    // Re-populate the cache.
+    if let Some(metadata) = metadata {
+        cache::set(path, &metadata, settings, autofix.into(), &messages);
+    }
+
+    Ok(Diagnostics { messages, fixed })
+}
+
+/// Generate `Diagnostic`s from source code content derived from
+/// stdin.
+pub fn lint_stdin(
+    path: Option<&Path>,
+    package: Option<&Path>,
+    contents: &str,
+    settings: &Settings,
+    autofix: fix::FixMode,
+) -> Result<Diagnostics> {
+    // Validate the `Settings` and return any errors.
+    settings.validate()?;
+
+    // Lint the inputs.
+    let (messages, fixed) = if matches!(autofix, fix::FixMode::Apply | fix::FixMode::Diff) {
+        let (transformed, fixed, messages) = lint_fix(
+            contents,
+            path.unwrap_or_else(|| Path::new("-")),
+            package,
+            settings,
+        )?;
+
+        if matches!(autofix, fix::FixMode::Apply) {
+            // Write the contents to stdout, regardless of whether any errors were fixed.
+            io::stdout().write_all(transformed.as_bytes())?;
+        } else if matches!(autofix, fix::FixMode::Diff) {
+            // But only write a diff if it's non-empty.
+            if fixed > 0 {
+                let text_diff = TextDiff::from_lines(contents, &transformed);
+                let mut unified_diff = text_diff.unified_diff();
+                if let Some(path) = path {
+                    unified_diff.header(&fs::relativize_path(path), &fs::relativize_path(path));
+                }
+
+                let mut stdout = io::stdout().lock();
+                unified_diff.to_writer(&mut stdout)?;
+                stdout.write_all(b"\n")?;
+                stdout.flush()?;
+            }
+        }
+
+        (messages, fixed)
+    } else {
+        let messages = lint_only(
+            contents,
+            path.unwrap_or_else(|| Path::new("-")),
+            package,
+            settings,
+            autofix.into(),
+        )?;
+        let fixed = 0;
+        (messages, fixed)
+    };
+
+    Ok(Diagnostics { messages, fixed })
+}

ruff_cli/src/lib.rs

@@ -0,0 +1,6 @@
+#![allow(clippy::must_use_candidate, dead_code)]
+
+mod cli;
+
+// used by ruff_dev::generate_cli_help
+pub use cli::Cli;

ruff_cli/src/main.rs

@@ -1,24 +1,40 @@
+#![allow(
+    clippy::match_same_arms,
+    clippy::missing_errors_doc,
+    clippy::module_name_repetitions,
+    clippy::too_many_lines
+)]
+#![forbid(unsafe_code)]
+
 use std::io::{self};
 use std::path::{Path, PathBuf};
 use std::process::ExitCode;
 use std::sync::mpsc::channel;
 
-use ::ruff::autofix::fixer;
-use ::ruff::cli::{extract_log_level, Cli, Overrides};
 use ::ruff::logging::{set_up_logging, LogLevel};
-use ::ruff::printer::{Printer, Violations};
-use ::ruff::resolver::{resolve_settings, FileDiscovery, PyprojectDiscovery, Relativity};
+use ::ruff::resolver::{
+    resolve_settings_with_processor, ConfigProcessor, FileDiscovery, PyprojectDiscovery, Relativity,
+};
 use ::ruff::settings::configuration::Configuration;
 use ::ruff::settings::types::SerializationFormat;
 use ::ruff::settings::{pyproject, Settings};
-#[cfg(feature = "update-informer")]
-use ::ruff::updates;
-use ::ruff::{commands, warn_user_once};
+use ::ruff::{fix, fs, warn_user_once};
 use anyhow::Result;
 use clap::{CommandFactory, Parser};
+use cli::{extract_log_level, Cli, Overrides};
 use colored::Colorize;
 use notify::{recommended_watcher, RecursiveMode, Watcher};
 use path_absolutize::path_dedot;
+use printer::{Printer, Violations};
+
+mod cache;
+mod cli;
+mod commands;
+mod diagnostics;
+mod iterators;
+mod printer;
+#[cfg(all(feature = "update-informer"))]
+pub mod updates;
 
 /// Resolve the relevant settings strategy and defaults for the current
 /// invocation.
@@ -31,14 +47,14 @@ fn resolve(
     if isolated {
         // First priority: if we're running in isolated mode, use the default settings.
         let mut config = Configuration::default();
-        config.apply(overrides.clone());
+        overrides.process_config(&mut config);
         let settings = Settings::from_configuration(config, &path_dedot::CWD)?;
         Ok(PyprojectDiscovery::Fixed(settings))
     } else if let Some(pyproject) = config {
         // Second priority: the user specified a `pyproject.toml` file. Use that
         // `pyproject.toml` for _all_ configuration, and resolve paths relative to the
         // current working directory. (This matches ESLint's behavior.)
-        let settings = resolve_settings(pyproject, &Relativity::Cwd, Some(overrides))?;
+        let settings = resolve_settings_with_processor(pyproject, &Relativity::Cwd, overrides)?;
         Ok(PyprojectDiscovery::Fixed(settings))
     } else if let Some(pyproject) = pyproject::find_settings_toml(
         stdin_filename
@@ -50,14 +66,14 @@ fn resolve(
         // that directory. (With `Strategy::Hierarchical`, we'll end up finding
         // the "closest" `pyproject.toml` file for every Python file later on,
         // so these act as the "default" settings.)
-        let settings = resolve_settings(&pyproject, &Relativity::Parent, Some(overrides))?;
+        let settings = resolve_settings_with_processor(&pyproject, &Relativity::Parent, overrides)?;
         Ok(PyprojectDiscovery::Hierarchical(settings))
     } else if let Some(pyproject) = pyproject::find_user_settings_toml() {
         // Fourth priority: find a user-specific `pyproject.toml`, but resolve all paths
         // relative the current working directory. (With `Strategy::Hierarchical`, we'll
         // end up the "closest" `pyproject.toml` file for every Python file later on, so
         // these act as the "default" settings.)
-        let settings = resolve_settings(&pyproject, &Relativity::Cwd, Some(overrides))?;
+        let settings = resolve_settings_with_processor(&pyproject, &Relativity::Cwd, overrides)?;
         Ok(PyprojectDiscovery::Hierarchical(settings))
     } else {
         // Fallback: load Ruff's default settings, and resolve all paths relative to the
@@ -65,13 +81,13 @@ fn resolve(
         // "closest" `pyproject.toml` file for every Python file later on, so these act
         // as the "default" settings.)
         let mut config = Configuration::default();
-        config.apply(overrides.clone());
+        overrides.process_config(&mut config);
         let settings = Settings::from_configuration(config, &path_dedot::CWD)?;
         Ok(PyprojectDiscovery::Hierarchical(settings))
     }
 }
 
-pub(crate) fn inner_main() -> Result<ExitCode> {
+pub fn main() -> Result<ExitCode> {
     // Extract command-line arguments.
     let (cli, overrides) = Cli::parse().partition();
     let log_level = extract_log_level(&cli);
@@ -129,7 +145,7 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
     };
 
     if let Some(code) = cli.explain {
-        commands::explain(&code, &format)?;
+        commands::explain(&code, format)?;
         return Ok(ExitCode::SUCCESS);
     }
     if cli.show_settings {
@@ -152,13 +168,13 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
     // but not apply fixes. That would allow us to avoid special-casing JSON
     // here.
     let autofix = if cli.diff {
-        fixer::Mode::Diff
+        fix::FixMode::Diff
     } else if fix || fix_only {
-        fixer::Mode::Apply
+        fix::FixMode::Apply
     } else if matches!(format, SerializationFormat::Json) {
-        fixer::Mode::Generate
+        fix::FixMode::Generate
     } else {
-        fixer::Mode::None
+        fix::FixMode::None
     };
     let violations = if cli.diff || fix_only {
         Violations::Hide
@@ -176,7 +192,7 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
 
     let printer = Printer::new(&format, &log_level, &autofix, &violations);
     if cli.watch {
-        if !matches!(autofix, fixer::Mode::None) {
+        if !matches!(autofix, fix::FixMode::None) {
             warn_user_once!("--fix is not enabled in watch mode.");
         }
         if format != SerializationFormat::Text {
@@ -193,9 +209,9 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
             &file_strategy,
             &overrides,
             cache.into(),
-            fixer::Mode::None,
+            fix::FixMode::None,
         )?;
-        printer.write_continuously(&messages)?;
+        printer.write_continuously(&messages);
 
         // Configure the file watcher.
         let (tx, rx) = channel();
@@ -223,9 +239,9 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
                             &file_strategy,
                             &overrides,
                             cache.into(),
-                            fixer::Mode::None,
+                            fix::FixMode::None,
                         )?;
-                        printer.write_continuously(&messages)?;
+                        printer.write_continuously(&messages);
                     }
                 }
                 Err(err) => return Err(err.into()),
@@ -243,7 +259,7 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
         // Generate lint violations.
         let diagnostics = if is_stdin {
             commands::run_stdin(
-                cli.stdin_filename.as_deref(),
+                cli.stdin_filename.map(fs::normalize_path).as_deref(),
                 &pyproject_strategy,
                 &file_strategy,
                 &overrides,
@@ -263,7 +279,7 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
         // Always try to print violations (the printer itself may suppress output),
         // unless we're writing fixes via stdin (in which case, the transformed
         // source code goes to stdout).
-        if !(is_stdin && matches!(autofix, fixer::Mode::Apply | fixer::Mode::Diff)) {
+        if !(is_stdin && matches!(autofix, fix::FixMode::Apply | fix::FixMode::Diff)) {
             printer.write_once(&diagnostics)?;
         }
 

ruff_cli/src/printer.rs

@@ -6,18 +6,16 @@ use annotate_snippets::snippet::{Annotation, AnnotationType, Slice, Snippet, Sou
 use anyhow::Result;
 use colored::Colorize;
 use itertools::iterate;
-use rustpython_parser::ast::Location;
+use ruff::fs::relativize_path;
+use ruff::logging::LogLevel;
+use ruff::message::{Location, Message};
+use ruff::registry::RuleCode;
+use ruff::settings::types::SerializationFormat;
+use ruff::{fix, notify_user};
 use serde::Serialize;
 use serde_json::json;
 
-use crate::autofix::fixer;
-use crate::fs::relativize_path;
-use crate::linter::Diagnostics;
-use crate::logging::LogLevel;
-use crate::message::Message;
-use crate::notify_user;
-use crate::registry::RuleCode;
-use crate::settings::types::SerializationFormat;
+use crate::diagnostics::Diagnostics;
 
 /// Enum to control whether lint violations are shown to the user.
 pub enum Violations {
@@ -46,7 +44,7 @@ struct ExpandedMessage<'a> {
 pub struct Printer<'a> {
     format: &'a SerializationFormat,
     log_level: &'a LogLevel,
-    autofix: &'a fixer::Mode,
+    autofix: &'a fix::FixMode,
     violations: &'a Violations,
 }
 
@@ -54,7 +52,7 @@ impl<'a> Printer<'a> {
     pub fn new(
         format: &'a SerializationFormat,
         log_level: &'a LogLevel,
-        autofix: &'a fixer::Mode,
+        autofix: &'a fix::FixMode,
         violations: &'a Violations,
     ) -> Self {
         Self {
@@ -84,7 +82,7 @@ impl<'a> Printer<'a> {
                         println!("Found {remaining} error(s).");
                     }
 
-                    if !matches!(self.autofix, fixer::Mode::Apply) {
+                    if !matches!(self.autofix, fix::FixMode::Apply) {
                         let num_fixable = diagnostics
                             .messages
                             .iter()
@@ -98,9 +96,9 @@ impl<'a> Printer<'a> {
                 Violations::Hide => {
                     let fixed = diagnostics.fixed;
                     if fixed > 0 {
-                        if matches!(self.autofix, fixer::Mode::Apply) {
+                        if matches!(self.autofix, fix::FixMode::Apply) {
                             println!("Fixed {fixed} error(s).");
-                        } else if matches!(self.autofix, fixer::Mode::Diff) {
+                        } else if matches!(self.autofix, fix::FixMode::Diff) {
                             println!("Would fix {fixed} error(s).");
                         }
                     }
@@ -241,7 +239,7 @@ impl<'a> Printer<'a> {
                         "::error title=Ruff \
                          ({}),file={},line={},col={},endLine={},endColumn={}::{}",
                         message.kind.code(),
-                        relativize_path(Path::new(&message.filename)),
+                        message.filename,
                         message.location.row(),
                         message.location.column(),
                         message.end_location.row(),
@@ -265,7 +263,7 @@ impl<'a> Printer<'a> {
                                     "severity": "major",
                                     "fingerprint": message.kind.code(),
                                     "location": {
-                                        "path": relativize_path(Path::new(&message.filename)),
+                                        "path": message.filename,
                                         "lines": {
                                             "begin": message.location.row(),
                                             "end": message.end_location.row()
@@ -283,9 +281,9 @@ impl<'a> Printer<'a> {
         Ok(())
     }
 
-    pub fn write_continuously(&self, diagnostics: &Diagnostics) -> Result<()> {
+    pub fn write_continuously(&self, diagnostics: &Diagnostics) {
         if matches!(self.log_level, LogLevel::Silent) {
-            return Ok(());
+            return;
         }
 
         if self.log_level >= &LogLevel::Default {
@@ -303,10 +301,9 @@ impl<'a> Printer<'a> {
                 print_message(message);
             }
         }
-
-        Ok(())
     }
 
+    #[allow(clippy::unused_self)]
     pub fn clear_screen(&self) -> Result<()> {
         #[cfg(not(target_family = "wasm"))]
         clearscreen::clear()?;

ruff_cli/tests/black_compatibility_test.rs

@@ -9,7 +9,7 @@ use std::time::Duration;
 use std::{fs, process, str};
 
 use anyhow::{anyhow, Context, Result};
-use assert_cmd::{crate_name, Command};
+use assert_cmd::Command;
 use itertools::Itertools;
 use log::info;
 use ruff::logging::{set_up_logging, LogLevel};
@@ -24,6 +24,8 @@ struct Blackd {
     client: ureq::Agent,
 }
 
+const BIN_NAME: &str = "ruff";
+
 impl Blackd {
     pub fn new() -> Result<Self> {
         // Get free TCP port to run on
@@ -104,7 +106,7 @@ fn run_test(path: &Path, blackd: &Blackd, ruff_args: &[&str]) -> Result<()> {
     let input = fs::read(path)?;
 
     // Step 1: Run `ruff` on the input.
-    let step_1 = &Command::cargo_bin(crate_name!())?
+    let step_1 = &Command::cargo_bin(BIN_NAME)?
         .args(ruff_args)
         .write_stdin(input)
         .assert()
@@ -121,7 +123,7 @@ fn run_test(path: &Path, blackd: &Blackd, ruff_args: &[&str]) -> Result<()> {
     let step_2_output = blackd.check(&step_1_output)?;
 
     // Step 3: Re-run `ruff` on the input.
-    let step_3 = &Command::cargo_bin(crate_name!())?
+    let step_3 = &Command::cargo_bin(BIN_NAME)?
         .args(ruff_args)
         .write_stdin(step_2_output.clone())
         .assert();

ruff_cli/tests/integration_test.rs

@@ -3,11 +3,14 @@
 use std::str;
 
 use anyhow::Result;
-use assert_cmd::{crate_name, Command};
+use assert_cmd::Command;
+use path_absolutize::path_dedot;
+
+const BIN_NAME: &str = "ruff";
 
 #[test]
 fn test_stdin_success() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     cmd.args(["-", "--format", "text"])
         .write_stdin("")
         .assert()
@@ -17,7 +20,7 @@ fn test_stdin_success() -> Result<()> {
 
 #[test]
 fn test_stdin_error() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "text"])
         .write_stdin("import os\n")
@@ -33,7 +36,7 @@ fn test_stdin_error() -> Result<()> {
 
 #[test]
 fn test_stdin_filename() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "text", "--stdin-filename", "F401.py"])
         .write_stdin("import os\n")
@@ -49,7 +52,7 @@ fn test_stdin_filename() -> Result<()> {
 
 #[test]
 fn test_stdin_json() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "json", "--stdin-filename", "F401.py"])
         .write_stdin("import os\n")
@@ -57,41 +60,44 @@ fn test_stdin_json() -> Result<()> {
         .failure();
     assert_eq!(
         str::from_utf8(&output.get_output().stdout)?,
-        r#"[
-  {
+        format!(
+            r#"[
+  {{
     "code": "F401",
     "message": "`os` imported but unused",
-    "fix": {
+    "fix": {{
       "content": "",
       "message": "Remove unused import: `os`",
-      "location": {
+      "location": {{
         "row": 1,
         "column": 0
-      },
-      "end_location": {
+      }},
+      "end_location": {{
         "row": 2,
         "column": 0
-      }
-    },
-    "location": {
+      }}
+    }},
+    "location": {{
       "row": 1,
       "column": 8
-    },
-    "end_location": {
+    }},
+    "end_location": {{
       "row": 1,
       "column": 10
-    },
-    "filename": "F401.py"
-  }
+    }},
+    "filename": "{}/F401.py"
+  }}
 ]
-"#
+"#,
+            path_dedot::CWD.to_str().unwrap()
+        )
     );
     Ok(())
 }
 
 #[test]
 fn test_stdin_autofix() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "text", "--fix"])
         .write_stdin("import os\nimport sys\n\nprint(sys.version)\n")
@@ -106,7 +112,7 @@ fn test_stdin_autofix() -> Result<()> {
 
 #[test]
 fn test_stdin_autofix_when_not_fixable_should_still_print_contents() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "text", "--fix"])
         .write_stdin("import os\nimport sys\n\nif (1, 2):\n     print(sys.version)\n")
@@ -121,7 +127,7 @@ fn test_stdin_autofix_when_not_fixable_should_still_print_contents() -> Result<(
 
 #[test]
 fn test_stdin_autofix_when_no_issues_should_still_print_contents() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "text", "--fix"])
         .write_stdin("import sys\n\nprint(sys.version)\n")
@@ -136,7 +142,7 @@ fn test_stdin_autofix_when_no_issues_should_still_print_contents() -> Result<()>
 
 #[test]
 fn test_show_source() -> Result<()> {
-    let mut cmd = Command::cargo_bin(crate_name!())?;
+    let mut cmd = Command::cargo_bin(BIN_NAME)?;
     let output = cmd
         .args(["-", "--format", "text", "--show-source"])
         .write_stdin("l = 1")

ruff_dev/Cargo.toml

@@ -1,8 +1,12 @@
 [package]
 name = "ruff_dev"
-version = "0.0.217"
+version = "0.0.221"
 edition = "2021"
 
+[lib]
+name = "ruff_dev"
+doctest = false
+
 [dependencies]
 anyhow = { version = "1.0.66" }
 clap = { version = "4.0.1", features = ["derive"] }
@@ -10,6 +14,7 @@ itertools = { version = "0.10.5" }
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a8725d161fe8b3ed73a6758b21e177" }
 once_cell = { version = "1.16.0" }
 ruff = { path = ".." }
+ruff_cli = { path = "../ruff_cli" }
 rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
 rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }
 rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "d532160333ffeb6dbeca2c2728c2391cd1e53b7f" }

ruff_dev/src/generate_cli_help.rs

@@ -2,7 +2,7 @@
 
 use anyhow::Result;
 use clap::{Args, CommandFactory};
-use ruff::cli::Cli as MainCli;
+use ruff_cli::Cli as MainCli;
 
 use crate::utils::replace_readme_section;
 

ruff_dev/src/round_trip.rs

@@ -5,9 +5,7 @@ use std::path::PathBuf;
 
 use anyhow::Result;
 use clap::Args;
-use ruff::source_code_generator::SourceCodeGenerator;
-use ruff::source_code_locator::SourceCodeLocator;
-use ruff::source_code_style::SourceCodeStyleDetector;
+use ruff::source_code::{Generator, Locator, Stylist};
 use rustpython_parser::parser;
 
 #[derive(Args)]
@@ -20,9 +18,9 @@ pub struct Cli {
 pub fn main(cli: &Cli) -> Result<()> {
     let contents = fs::read_to_string(&cli.file)?;
     let python_ast = parser::parse_program(&contents, &cli.file.to_string_lossy())?;
-    let locator = SourceCodeLocator::new(&contents);
-    let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
-    let mut generator: SourceCodeGenerator = (&stylist).into();
+    let locator = Locator::new(&contents);
+    let stylist = Stylist::from_contents(&contents, &locator);
+    let mut generator: Generator = (&stylist).into();
     generator.unparse_suite(&python_ast);
     println!("{}", generator.generate());
     Ok(())

ruff_macros/Cargo.toml

@@ -1,10 +1,11 @@
 [package]
 name = "ruff_macros"
-version = "0.0.217"
+version = "0.0.221"
 edition = "2021"
 
 [lib]
 proc-macro = true
+doctest = false
 
 [dependencies]
 once_cell = { version = "1.17.0" }

ruff_macros/src/lib.rs

@@ -12,9 +12,12 @@
 )]
 #![forbid(unsafe_code)]
 
-use syn::{parse_macro_input, DeriveInput};
+use proc_macro2::Span;
+use quote::quote;
+use syn::{parse_macro_input, DeriveInput, Ident};
 
 mod config;
+mod prefixes;
 mod rule_code_prefix;
 
 #[proc_macro_derive(ConfigurationOptions, attributes(option, doc, option_group))]
@@ -34,3 +37,23 @@ pub fn derive_rule_code_prefix(input: proc_macro::TokenStream) -> proc_macro::To
         .unwrap_or_else(syn::Error::into_compile_error)
         .into()
 }
+
+#[proc_macro]
+pub fn origin_by_code(item: proc_macro::TokenStream) -> proc_macro::TokenStream {
+    let ident = parse_macro_input!(item as Ident).to_string();
+    let mut iter = prefixes::PREFIX_TO_ORIGIN.iter();
+    let origin = loop {
+        let (prefix, origin) = iter
+            .next()
+            .unwrap_or_else(|| panic!("code doesn't start with any recognized prefix: {ident}"));
+        if ident.starts_with(prefix) {
+            break origin;
+        }
+    };
+    let prefix = Ident::new(origin, Span::call_site());
+
+    quote! {
+        RuleOrigin::#prefix
+    }
+    .into()
+}

ruff_macros/src/prefixes.rs

@@ -0,0 +1,53 @@
+// Longer prefixes should come first so that you can find an origin for a code
+// by simply picking the first entry that starts with the given prefix.
+
+pub const PREFIX_TO_ORIGIN: &[(&str, &str)] = &[
+    ("ANN", "Flake8Annotations"),
+    ("ARG", "Flake8UnusedArguments"),
+    ("A", "Flake8Builtins"),
+    ("BLE", "Flake8BlindExcept"),
+    ("B", "Flake8Bugbear"),
+    ("C4", "Flake8Comprehensions"),
+    ("C9", "McCabe"),
+    ("DTZ", "Flake8Datetimez"),
+    ("D", "Pydocstyle"),
+    ("ERA", "Eradicate"),
+    ("EM", "Flake8ErrMsg"),
+    ("E", "Pycodestyle"),
+    ("FBT", "Flake8BooleanTrap"),
+    ("F", "Pyflakes"),
+    ("ICN", "Flake8ImportConventions"),
+    ("ISC", "Flake8ImplicitStrConcat"),
+    ("I", "Isort"),
+    ("N", "PEP8Naming"),
+    ("PD", "PandasVet"),
+    ("PGH", "PygrepHooks"),
+    ("PL", "Pylint"),
+    ("PT", "Flake8PytestStyle"),
+    ("Q", "Flake8Quotes"),
+    ("RET", "Flake8Return"),
+    ("SIM", "Flake8Simplify"),
+    ("S", "Flake8Bandit"),
+    ("T10", "Flake8Debugger"),
+    ("T20", "Flake8Print"),
+    ("TID", "Flake8TidyImports"),
+    ("UP", "Pyupgrade"),
+    ("W", "Pycodestyle"),
+    ("YTT", "Flake82020"),
+    ("PIE", "Flake8Pie"),
+    ("RUF", "Ruff"),
+];
+
+#[cfg(test)]
+mod tests {
+    use super::PREFIX_TO_ORIGIN;
+
+    #[test]
+    fn order() {
+        for (idx, (prefix, _)) in PREFIX_TO_ORIGIN.iter().enumerate() {
+            for (prior_prefix, _) in PREFIX_TO_ORIGIN[..idx].iter() {
+                assert!(!prefix.starts_with(prior_prefix));
+            }
+        }
+    }
+}

scripts/add_plugin.py

@@ -34,7 +34,7 @@ def main(*, plugin: str, url: str) -> None:
     with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/rules.rs"), "w+") as fp:
         fp.write("use crate::checkers::ast::Checker;\n")
     with open(os.path.join(ROOT_DIR, f"src/{dir_name(plugin)}/mod.rs"), "w+") as fp:
-        fp.write("pub mod rules;\n")
+        fp.write("pub(crate) mod rules;\n")
         fp.write("\n")
         fp.write(
             """#[cfg(test)]

scripts/add_rule.py

@@ -116,33 +116,6 @@ impl Violation for %s {
                 fp.write("\n")
                 has_written = True
 
-    # Add the relevant code-to-origin pair to `src/registry.rs`.
-    with open(os.path.join(ROOT_DIR, "src/registry.rs")) as fp:
-        content = fp.read()
-
-    seen_impl = False
-    has_written = False
-    with open(os.path.join(ROOT_DIR, "src/registry.rs"), "w") as fp:
-        for line in content.splitlines():
-            fp.write(line)
-            fp.write("\n")
-
-            if has_written:
-                continue
-
-            if line.startswith("impl RuleCode"):
-                seen_impl = True
-                continue
-
-            if not seen_impl:
-                continue
-
-            if line.strip() == f"// {origin}":
-                indent = line.split("//")[0]
-                fp.write(f"{indent}RuleCode::{code} => RuleOrigin::{pascal_case(origin)},")
-                fp.write("\n")
-                has_written = True
-
 
 if __name__ == "__main__":
     parser = argparse.ArgumentParser(

src/ast/cast.rs

@@ -1,5 +1,12 @@
 use rustpython_ast::{Expr, Stmt, StmtKind};
 
+pub fn name(stmt: &Stmt) -> &str {
+    match &stmt.node {
+        StmtKind::FunctionDef { name, .. } | StmtKind::AsyncFunctionDef { name, .. } => name,
+        _ => panic!("Expected StmtKind::FunctionDef | StmtKind::AsyncFunctionDef"),
+    }
+}
+
 pub fn decorator_list(stmt: &Stmt) -> &Vec<Expr> {
     match &stmt.node {
         StmtKind::FunctionDef { decorator_list, .. }

src/ast/comparable.rs

@@ -388,6 +388,12 @@ impl<'a> From<&'a Box<Expr>> for Box<ComparableExpr<'a>> {
     }
 }
 
+impl<'a> From<&'a Box<Expr>> for ComparableExpr<'a> {
+    fn from(expr: &'a Box<Expr>) -> Self {
+        (&**expr).into()
+    }
+}
+
 impl<'a> From<&'a Expr> for ComparableExpr<'a> {
     fn from(expr: &'a Expr) -> Self {
         match &expr.node {

src/ast/function_type.rs

@@ -1,10 +1,8 @@
-use rustc_hash::{FxHashMap, FxHashSet};
 use rustpython_ast::Expr;
 
-use crate::ast::helpers::{
-    collect_call_paths, dealias_call_path, match_call_path, to_module_and_member,
-};
+use crate::ast::helpers::to_call_path;
 use crate::ast::types::{Scope, ScopeKind};
+use crate::checkers::ast::Checker;
 
 const CLASS_METHODS: [&str; 3] = ["__new__", "__init_subclass__", "__class_getitem__"];
 const METACLASS_BASES: [(&str, &str); 2] = [("", "type"), ("abc", "ABCMeta")];
@@ -18,11 +16,10 @@ pub enum FunctionType {
 
 /// Classify a function based on its scope, name, and decorators.
 pub fn classify(
+    checker: &Checker,
     scope: &Scope,
     name: &str,
     decorator_list: &[Expr],
-    from_imports: &FxHashMap<&str, FxHashSet<&str>>,
-    import_aliases: &FxHashMap<&str, &str>,
     classmethod_decorators: &[String],
     staticmethod_decorators: &[String],
 ) -> FunctionType {
@@ -33,17 +30,18 @@ pub fn classify(
     if CLASS_METHODS.contains(&name)
         || scope.bases.iter().any(|expr| {
             // The class itself extends a known metaclass, so all methods are class methods.
-            let call_path = dealias_call_path(collect_call_paths(expr), import_aliases);
-            METACLASS_BASES
-                .iter()
-                .any(|(module, member)| match_call_path(&call_path, module, member, from_imports))
+            checker.resolve_call_path(expr).map_or(false, |call_path| {
+                METACLASS_BASES
+                    .iter()
+                    .any(|(module, member)| call_path == [*module, *member])
+            })
         })
         || decorator_list.iter().any(|expr| {
             // The method is decorated with a class method decorator (like `@classmethod`).
-            let call_path = dealias_call_path(collect_call_paths(expr), import_aliases);
-            classmethod_decorators.iter().any(|decorator| {
-                let (module, member) = to_module_and_member(decorator);
-                match_call_path(&call_path, module, member, from_imports)
+            checker.resolve_call_path(expr).map_or(false, |call_path| {
+                classmethod_decorators
+                    .iter()
+                    .any(|decorator| call_path == to_call_path(decorator))
             })
         })
     {
@@ -51,10 +49,10 @@ pub fn classify(
     } else if decorator_list.iter().any(|expr| {
         // The method is decorated with a static method decorator (like
         // `@staticmethod`).
-        let call_path = dealias_call_path(collect_call_paths(expr), import_aliases);
-        staticmethod_decorators.iter().any(|decorator| {
-            let (module, member) = to_module_and_member(decorator);
-            match_call_path(&call_path, module, member, from_imports)
+        checker.resolve_call_path(expr).map_or(false, |call_path| {
+            staticmethod_decorators
+                .iter()
+                .any(|decorator| call_path == to_call_path(decorator))
         })
     }) {
         FunctionType::StaticMethod

src/ast/helpers.rs

@@ -12,9 +12,8 @@ use rustpython_parser::lexer::Tok;
 use rustpython_parser::token::StringKind;
 
 use crate::ast::types::{Binding, BindingKind, Range};
-use crate::source_code_generator::SourceCodeGenerator;
-use crate::source_code_style::SourceCodeStyleDetector;
-use crate::SourceCodeLocator;
+use crate::checkers::ast::Checker;
+use crate::source_code::{Generator, Locator, Stylist};
 
 /// Create an `Expr` with default location from an `ExprKind`.
 pub fn create_expr(node: ExprKind) -> Expr {
@@ -27,15 +26,15 @@ pub fn create_stmt(node: StmtKind) -> Stmt {
 }
 
 /// Generate source code from an `Expr`.
-pub fn unparse_expr(expr: &Expr, stylist: &SourceCodeStyleDetector) -> String {
-    let mut generator: SourceCodeGenerator = stylist.into();
+pub fn unparse_expr(expr: &Expr, stylist: &Stylist) -> String {
+    let mut generator: Generator = stylist.into();
     generator.unparse_expr(expr, 0);
     generator.generate()
 }
 
 /// Generate source code from an `Stmt`.
-pub fn unparse_stmt(stmt: &Stmt, stylist: &SourceCodeStyleDetector) -> String {
-    let mut generator: SourceCodeGenerator = stylist.into();
+pub fn unparse_stmt(stmt: &Stmt, stylist: &Stylist) -> String {
+    let mut generator: Generator = stylist.into();
     generator.unparse_stmt(stmt);
     generator.generate()
 }
@@ -56,150 +55,42 @@ fn collect_call_path_inner<'a>(expr: &'a Expr, parts: &mut Vec<&'a str>) {
     }
 }
 
-/// Convert an `Expr` to its call path (like `List`, or `typing.List`).
-pub fn compose_call_path(expr: &Expr) -> Option<String> {
-    let segments = collect_call_paths(expr);
-    if segments.is_empty() {
-        None
-    } else {
-        Some(segments.join("."))
-    }
-}
-
 /// Convert an `Expr` to its call path segments (like ["typing", "List"]).
-pub fn collect_call_paths(expr: &Expr) -> Vec<&str> {
+pub fn collect_call_path(expr: &Expr) -> Vec<&str> {
     let mut segments = vec![];
     collect_call_path_inner(expr, &mut segments);
     segments
 }
 
-/// Rewrite any import aliases on a call path.
-pub fn dealias_call_path<'a>(
-    call_path: Vec<&'a str>,
-    import_aliases: &FxHashMap<&str, &'a str>,
-) -> Vec<&'a str> {
-    if let Some(head) = call_path.first() {
-        if let Some(origin) = import_aliases.get(head) {
-            let tail = &call_path[1..];
-            let mut call_path: Vec<&str> = vec![];
-            call_path.extend(origin.split('.'));
-            call_path.extend(tail);
-            call_path
-        } else {
-            call_path
-        }
+/// Convert an `Expr` to its call path (like `List`, or `typing.List`).
+pub fn compose_call_path(expr: &Expr) -> Option<String> {
+    let call_path = collect_call_path(expr);
+    if call_path.is_empty() {
+        None
     } else {
-        call_path
+        Some(format_call_path(&call_path))
     }
 }
 
-/// Return `true` if the `Expr` is a reference to `${module}.${target}`.
-///
-/// Useful for, e.g., ensuring that a `Union` reference represents
-/// `typing.Union`.
-pub fn match_module_member(
-    expr: &Expr,
-    module: &str,
-    member: &str,
-    from_imports: &FxHashMap<&str, FxHashSet<&str>>,
-    import_aliases: &FxHashMap<&str, &str>,
-) -> bool {
-    match_call_path(
-        &dealias_call_path(collect_call_paths(expr), import_aliases),
-        module,
-        member,
-        from_imports,
-    )
-}
-
-/// Return `true` if the `call_path` is a reference to `${module}.${target}`.
-///
-/// Optimized version of `match_module_member` for pre-computed call paths.
-pub fn match_call_path(
-    call_path: &[&str],
-    module: &str,
-    member: &str,
-    from_imports: &FxHashMap<&str, FxHashSet<&str>>,
-) -> bool {
-    // If we have no segments, we can't ever match.
-    let num_segments = call_path.len();
-    if num_segments == 0 {
-        return false;
-    }
-
-    // If the last segment doesn't match the member, we can't ever match.
-    if call_path[num_segments - 1] != member {
-        return false;
-    }
-
-    // We now only need the module path, so throw out the member name.
-    let call_path = &call_path[..num_segments - 1];
-    let num_segments = call_path.len();
-
-    // Case (1): It's a builtin (like `list`).
-    // Case (2a): We imported from the parent (`from typing.re import Match`,
-    // `Match`).
-    // Case (2b): We imported star from the parent (`from typing.re import *`,
-    // `Match`).
-    if num_segments == 0 {
-        module.is_empty()
-            || from_imports.get(module).map_or(false, |imports| {
-                imports.contains(member) || imports.contains("*")
-            })
+/// Format a call path for display.
+pub fn format_call_path(call_path: &[&str]) -> String {
+    if call_path
+        .first()
+        .expect("Unable to format empty call path")
+        .is_empty()
+    {
+        call_path[1..].join(".")
     } else {
-        let components: Vec<&str> = module.split('.').collect();
-
-        // Case (3a): it's a fully qualified call path (`import typing`,
-        // `typing.re.Match`). Case (3b): it's a fully qualified call path (`import
-        // typing.re`, `typing.re.Match`).
-        if components == call_path {
-            return true;
-        }
-
-        // Case (4): We imported from the grandparent (`from typing import re`,
-        // `re.Match`)
-        let num_matches = (0..components.len())
-            .take(num_segments)
-            .take_while(|i| components[components.len() - 1 - i] == call_path[num_segments - 1 - i])
-            .count();
-        if num_matches > 0 {
-            let cut = components.len() - num_matches;
-            // TODO(charlie): Rewrite to avoid this allocation.
-            let module = components[..cut].join(".");
-            let member = components[cut];
-            if from_imports
-                .get(&module.as_str())
-                .map_or(false, |imports| imports.contains(member))
-            {
-                return true;
-            }
-        }
-
-        false
+        call_path.join(".")
     }
 }
 
 /// Return `true` if the `Expr` contains a reference to `${module}.${target}`.
-pub fn contains_call_path(
-    expr: &Expr,
-    module: &str,
-    member: &str,
-    import_aliases: &FxHashMap<&str, &str>,
-    from_imports: &FxHashMap<&str, FxHashSet<&str>>,
-) -> bool {
+pub fn contains_call_path(checker: &Checker, expr: &Expr, target: &[&str]) -> bool {
     any_over_expr(expr, &|expr| {
-        let call_path = collect_call_paths(expr);
-        if !call_path.is_empty() {
-            if match_call_path(
-                &dealias_call_path(call_path, import_aliases),
-                module,
-                member,
-                from_imports,
-            ) {
-                return true;
-            }
-        }
-        false
+        checker
+            .resolve_call_path(expr)
+            .map_or(false, |call_path| call_path == target)
     })
 }
 
@@ -391,13 +282,13 @@ pub fn extract_handler_names(handlers: &[Excepthandler]) -> Vec<Vec<&str>> {
                 if let Some(type_) = type_ {
                     if let ExprKind::Tuple { elts, .. } = &type_.node {
                         for type_ in elts {
-                            let call_path = collect_call_paths(type_);
+                            let call_path = collect_call_path(type_);
                             if !call_path.is_empty() {
                                 handler_names.push(call_path);
                             }
                         }
                     } else {
-                        let call_path = collect_call_paths(type_);
+                        let call_path = collect_call_path(type_);
                         if !call_path.is_empty() {
                             handler_names.push(call_path);
                         }
@@ -430,6 +321,13 @@ pub fn collect_arg_names<'a>(arguments: &'a Arguments) -> FxHashSet<&'a str> {
     arg_names
 }
 
+/// Returns `true` if a statement or expression includes at least one comment.
+pub fn has_comments<T>(located: &Located<T>, locator: &Locator) -> bool {
+    lexer::make_tokenizer(&locator.slice_source_code_range(&Range::from_located(located)))
+        .flatten()
+        .any(|(_, tok, _)| matches!(tok, Tok::Comment(..)))
+}
+
 /// Returns `true` if a call is an argumented `super` invocation.
 pub fn is_super_call_with_arguments(func: &Expr, args: &[Expr]) -> bool {
     if let ExprKind::Name { id, .. } = &func.node {
@@ -453,12 +351,37 @@ pub fn format_import_from(level: Option<&usize>, module: Option<&str>) -> String
     module_name
 }
 
+/// Format the member reference name for a relative import.
+pub fn format_import_from_member(
+    level: Option<&usize>,
+    module: Option<&str>,
+    member: &str,
+) -> String {
+    let mut full_name = String::with_capacity(
+        level.map_or(0, |level| *level)
+            + module.as_ref().map_or(0, |module| module.len())
+            + 1
+            + member.len(),
+    );
+    if let Some(level) = level {
+        for _ in 0..*level {
+            full_name.push('.');
+        }
+    }
+    if let Some(module) = module {
+        full_name.push_str(module);
+        full_name.push('.');
+    }
+    full_name.push_str(member);
+    full_name
+}
+
 /// Split a target string (like `typing.List`) into (`typing`, `List`).
-pub fn to_module_and_member(target: &str) -> (&str, &str) {
-    if let Some(index) = target.rfind('.') {
-        (&target[..index], &target[index + 1..])
+pub fn to_call_path(target: &str) -> Vec<&str> {
+    if target.contains('.') {
+        target.split('.').collect()
     } else {
-        ("", target)
+        vec!["", target]
     }
 }
 
@@ -476,14 +399,14 @@ pub fn to_absolute(relative: Location, base: Location) -> Location {
 }
 
 /// Return `true` if a `Stmt` has leading content.
-pub fn match_leading_content(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+pub fn match_leading_content(stmt: &Stmt, locator: &Locator) -> bool {
     let range = Range::new(Location::new(stmt.location.row(), 0), stmt.location);
     let prefix = locator.slice_source_code_range(&range);
     prefix.chars().any(|char| !char.is_whitespace())
 }
 
 /// Return `true` if a `Stmt` has trailing content.
-pub fn match_trailing_content(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+pub fn match_trailing_content(stmt: &Stmt, locator: &Locator) -> bool {
     let range = Range::new(
         stmt.end_location.unwrap(),
         Location::new(stmt.end_location.unwrap().row() + 1, 0),
@@ -501,7 +424,7 @@ pub fn match_trailing_content(stmt: &Stmt, locator: &SourceCodeLocator) -> bool
 }
 
 /// Return the number of trailing empty lines following a statement.
-pub fn count_trailing_lines(stmt: &Stmt, locator: &SourceCodeLocator) -> usize {
+pub fn count_trailing_lines(stmt: &Stmt, locator: &Locator) -> usize {
     let suffix =
         locator.slice_source_code_at(&Location::new(stmt.end_location.unwrap().row() + 1, 0));
     suffix
@@ -513,7 +436,7 @@ pub fn count_trailing_lines(stmt: &Stmt, locator: &SourceCodeLocator) -> usize {
 /// Return the appropriate visual `Range` for any message that spans a `Stmt`.
 /// Specifically, this method returns the range of a function or class name,
 /// rather than that of the entire function or class body.
-pub fn identifier_range(stmt: &Stmt, locator: &SourceCodeLocator) -> Range {
+pub fn identifier_range(stmt: &Stmt, locator: &Locator) -> Range {
     if matches!(
         stmt.node,
         StmtKind::ClassDef { .. }
@@ -532,7 +455,7 @@ pub fn identifier_range(stmt: &Stmt, locator: &SourceCodeLocator) -> Range {
 }
 
 /// Like `identifier_range`, but accepts a `Binding`.
-pub fn binding_range(binding: &Binding, locator: &SourceCodeLocator) -> Range {
+pub fn binding_range(binding: &Binding, locator: &Locator) -> Range {
     if matches!(
         binding.kind,
         BindingKind::ClassDefinition | BindingKind::FunctionDefinition
@@ -548,7 +471,7 @@ pub fn binding_range(binding: &Binding, locator: &SourceCodeLocator) -> Range {
 }
 
 // Return the ranges of `Name` tokens within a specified node.
-pub fn find_names<T>(located: &Located<T>, locator: &SourceCodeLocator) -> Vec<Range> {
+pub fn find_names<T>(located: &Located<T>, locator: &Locator) -> Vec<Range> {
     let contents = locator.slice_source_code_range(&Range::from_located(located));
     lexer::make_tokenizer_located(&contents, located.location)
         .flatten()
@@ -561,10 +484,7 @@ pub fn find_names<T>(located: &Located<T>, locator: &SourceCodeLocator) -> Vec<R
 }
 
 /// Return the `Range` of `name` in `Excepthandler`.
-pub fn excepthandler_name_range(
-    handler: &Excepthandler,
-    locator: &SourceCodeLocator,
-) -> Option<Range> {
+pub fn excepthandler_name_range(handler: &Excepthandler, locator: &Locator) -> Option<Range> {
     let ExcepthandlerKind::ExceptHandler {
         name, type_, body, ..
     } = &handler.node;
@@ -587,7 +507,7 @@ pub fn excepthandler_name_range(
 }
 
 /// Return the `Range` of `except` in `Excepthandler`.
-pub fn except_range(handler: &Excepthandler, locator: &SourceCodeLocator) -> Range {
+pub fn except_range(handler: &Excepthandler, locator: &Locator) -> Range {
     let ExcepthandlerKind::ExceptHandler { body, type_, .. } = &handler.node;
     let end = if let Some(type_) = type_ {
         type_.location
@@ -612,7 +532,7 @@ pub fn except_range(handler: &Excepthandler, locator: &SourceCodeLocator) -> Ran
 }
 
 /// Find f-strings that don't contain any formatted values in a `JoinedStr`.
-pub fn find_useless_f_strings(expr: &Expr, locator: &SourceCodeLocator) -> Vec<(Range, Range)> {
+pub fn find_useless_f_strings(expr: &Expr, locator: &Locator) -> Vec<(Range, Range)> {
     let contents = locator.slice_source_code_range(&Range::from_located(expr));
     lexer::make_tokenizer_located(&contents, expr.location)
         .flatten()
@@ -649,7 +569,7 @@ pub fn find_useless_f_strings(expr: &Expr, locator: &SourceCodeLocator) -> Vec<(
 }
 
 /// Return the `Range` of `else` in `For`, `AsyncFor`, and `While` statements.
-pub fn else_range(stmt: &Stmt, locator: &SourceCodeLocator) -> Option<Range> {
+pub fn else_range(stmt: &Stmt, locator: &Locator) -> Option<Range> {
     match &stmt.node {
         StmtKind::For { body, orelse, .. }
         | StmtKind::AsyncFor { body, orelse, .. }
@@ -683,7 +603,7 @@ pub fn else_range(stmt: &Stmt, locator: &SourceCodeLocator) -> Option<Range> {
 
 /// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
 /// other statements preceding it.
-pub fn preceded_by_continuation(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+pub fn preceded_by_continuation(stmt: &Stmt, locator: &Locator) -> bool {
     // Does the previous line end in a continuation? This will have a specific
     // false-positive, which is that if the previous line ends in a comment, it
     // will be treated as a continuation. So we should only use this information to
@@ -704,16 +624,31 @@ pub fn preceded_by_continuation(stmt: &Stmt, locator: &SourceCodeLocator) -> boo
 
 /// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
 /// other statements preceding it.
-pub fn preceded_by_multi_statement_line(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+pub fn preceded_by_multi_statement_line(stmt: &Stmt, locator: &Locator) -> bool {
     match_leading_content(stmt, locator) || preceded_by_continuation(stmt, locator)
 }
 
 /// Return `true` if a `Stmt` appears to be part of a multi-statement line, with
 /// other statements following it.
-pub fn followed_by_multi_statement_line(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+pub fn followed_by_multi_statement_line(stmt: &Stmt, locator: &Locator) -> bool {
     match_trailing_content(stmt, locator)
 }
 
+/// Return `true` if a `Stmt` is a docstring.
+pub fn is_docstring_stmt(stmt: &Stmt) -> bool {
+    if let StmtKind::Expr { value } = &stmt.node {
+        matches!(
+            value.node,
+            ExprKind::Constant {
+                value: Constant::Str { .. },
+                ..
+            }
+        )
+    } else {
+        false
+    }
+}
+
 #[derive(Default)]
 /// A simple representation of a call's positional and keyword arguments.
 pub struct SimpleCallArgs<'a> {
@@ -759,188 +694,48 @@ impl<'a> SimpleCallArgs<'a> {
         }
         None
     }
+
+    /// Get the number of positional and keyword arguments used.
+    #[allow(clippy::len_without_is_empty)]
+    pub fn len(&self) -> usize {
+        self.args.len() + self.kwargs.len()
+    }
 }
 
 #[cfg(test)]
 mod tests {
     use anyhow::Result;
-    use rustc_hash::{FxHashMap, FxHashSet};
     use rustpython_ast::Location;
     use rustpython_parser::parser;
 
-    use crate::ast::helpers::{
-        else_range, identifier_range, match_module_member, match_trailing_content,
-    };
+    use crate::ast::helpers::{else_range, identifier_range, match_trailing_content};
     use crate::ast::types::Range;
-    use crate::source_code_locator::SourceCodeLocator;
-
-    #[test]
-    fn builtin() -> Result<()> {
-        let expr = parser::parse_expression("list", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "",
-            "list",
-            &FxHashMap::default(),
-            &FxHashMap::default(),
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn fully_qualified() -> Result<()> {
-        let expr = parser::parse_expression("typing.re.Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::default(),
-            &FxHashMap::default(),
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn unimported() -> Result<()> {
-        let expr = parser::parse_expression("Match", "<filename>")?;
-        assert!(!match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::default(),
-            &FxHashMap::default(),
-        ));
-        let expr = parser::parse_expression("re.Match", "<filename>")?;
-        assert!(!match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::default(),
-            &FxHashMap::default(),
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn from_star() -> Result<()> {
-        let expr = parser::parse_expression("Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::from_iter([("typing.re", FxHashSet::from_iter(["*"]))]),
-            &FxHashMap::default()
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn from_parent() -> Result<()> {
-        let expr = parser::parse_expression("Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::from_iter([("typing.re", FxHashSet::from_iter(["Match"]))]),
-            &FxHashMap::default()
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn from_grandparent() -> Result<()> {
-        let expr = parser::parse_expression("re.Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::from_iter([("typing", FxHashSet::from_iter(["re"]))]),
-            &FxHashMap::default()
-        ));
-
-        let expr = parser::parse_expression("match.Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re.match",
-            "Match",
-            &FxHashMap::from_iter([("typing.re", FxHashSet::from_iter(["match"]))]),
-            &FxHashMap::default()
-        ));
-
-        let expr = parser::parse_expression("re.match.Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re.match",
-            "Match",
-            &FxHashMap::from_iter([("typing", FxHashSet::from_iter(["re"]))]),
-            &FxHashMap::default()
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn from_alias() -> Result<()> {
-        let expr = parser::parse_expression("IMatch", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::from_iter([("typing.re", FxHashSet::from_iter(["Match"]))]),
-            &FxHashMap::from_iter([("IMatch", "Match")]),
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn from_aliased_parent() -> Result<()> {
-        let expr = parser::parse_expression("t.Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::default(),
-            &FxHashMap::from_iter([("t", "typing.re")]),
-        ));
-        Ok(())
-    }
-
-    #[test]
-    fn from_aliased_grandparent() -> Result<()> {
-        let expr = parser::parse_expression("t.re.Match", "<filename>")?;
-        assert!(match_module_member(
-            &expr,
-            "typing.re",
-            "Match",
-            &FxHashMap::default(),
-            &FxHashMap::from_iter([("t", "typing")]),
-        ));
-        Ok(())
-    }
+    use crate::source_code::Locator;
 
     #[test]
     fn trailing_content() -> Result<()> {
         let contents = "x = 1";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert!(!match_trailing_content(stmt, &locator));
 
         let contents = "x = 1; y = 2";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert!(match_trailing_content(stmt, &locator));
 
         let contents = "x = 1  ";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert!(!match_trailing_content(stmt, &locator));
 
         let contents = "x = 1  # Comment";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert!(!match_trailing_content(stmt, &locator));
 
         let contents = r#"
@@ -950,7 +745,7 @@ y = 2
         .trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert!(!match_trailing_content(stmt, &locator));
 
         Ok(())
@@ -961,7 +756,7 @@ y = 2
         let contents = "def f(): pass".trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             identifier_range(stmt, &locator),
             Range::new(Location::new(1, 4), Location::new(1, 5),)
@@ -975,7 +770,7 @@ def \
         .trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             identifier_range(stmt, &locator),
             Range::new(Location::new(2, 2), Location::new(2, 3),)
@@ -984,7 +779,7 @@ def \
         let contents = "class Class(): pass".trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             identifier_range(stmt, &locator),
             Range::new(Location::new(1, 6), Location::new(1, 11),)
@@ -993,7 +788,7 @@ def \
         let contents = "class Class: pass".trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             identifier_range(stmt, &locator),
             Range::new(Location::new(1, 6), Location::new(1, 11),)
@@ -1007,7 +802,7 @@ class Class():
         .trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             identifier_range(stmt, &locator),
             Range::new(Location::new(2, 6), Location::new(2, 11),)
@@ -1016,7 +811,7 @@ class Class():
         let contents = r#"x = y + 1"#.trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             identifier_range(stmt, &locator),
             Range::new(Location::new(1, 0), Location::new(1, 9),)
@@ -1036,7 +831,7 @@ else:
         .trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         let range = else_range(stmt, &locator).unwrap();
         assert_eq!(range.location.row(), 3);
         assert_eq!(range.location.column(), 0);

src/ast/types.rs

@@ -74,7 +74,6 @@ pub enum ScopeKind<'a> {
     Function(FunctionDef<'a>),
     Generator,
     Module,
-    Arg,
     Lambda(Lambda<'a>),
 }
 
@@ -105,7 +104,7 @@ impl<'a> Scope<'a> {
 }
 
 #[derive(Clone, Debug)]
-pub enum BindingKind {
+pub enum BindingKind<'a> {
     Annotation,
     Argument,
     Assignment,
@@ -119,14 +118,14 @@ pub enum BindingKind {
     Export(Vec<String>),
     FutureImportation,
     StarImportation(Option<usize>, Option<String>),
-    Importation(String, String),
-    FromImportation(String, String),
-    SubmoduleImportation(String, String),
+    Importation(&'a str, &'a str),
+    FromImportation(&'a str, String),
+    SubmoduleImportation(&'a str, &'a str),
 }
 
 #[derive(Clone, Debug)]
 pub struct Binding<'a> {
-    pub kind: BindingKind,
+    pub kind: BindingKind<'a>,
     pub range: Range,
     /// The statement in which the `Binding` was defined.
     pub source: Option<RefEquality<'a, Stmt>>,
@@ -169,19 +168,26 @@ impl<'a> Binding<'a> {
 
     pub fn redefines(&self, existing: &'a Binding) -> bool {
         match &self.kind {
-            BindingKind::Importation(_, full_name) | BindingKind::FromImportation(_, full_name) => {
-                if let BindingKind::SubmoduleImportation(_, existing_full_name) = &existing.kind {
-                    return full_name == existing_full_name;
+            BindingKind::Importation(.., full_name) => {
+                if let BindingKind::SubmoduleImportation(.., existing) = &existing.kind {
+                    return full_name == existing;
                 }
             }
-            BindingKind::SubmoduleImportation(_, full_name) => {
-                if let BindingKind::Importation(_, existing_full_name)
-                | BindingKind::FromImportation(_, existing_full_name)
-                | BindingKind::SubmoduleImportation(_, existing_full_name) = &existing.kind
-                {
-                    return full_name == existing_full_name;
+            BindingKind::FromImportation(.., full_name) => {
+                if let BindingKind::SubmoduleImportation(.., existing) = &existing.kind {
+                    return full_name == existing;
                 }
             }
+            BindingKind::SubmoduleImportation(.., full_name) => match &existing.kind {
+                BindingKind::Importation(.., existing)
+                | BindingKind::SubmoduleImportation(.., existing) => {
+                    return full_name == existing;
+                }
+                BindingKind::FromImportation(.., existing) => {
+                    return full_name == existing;
+                }
+                _ => {}
+            },
             BindingKind::Annotation => {
                 return false;
             }

src/autofix/fixer.rs

@@ -1,225 +1 @@
-use std::borrow::Cow;
-use std::collections::BTreeSet;
 
-use itertools::Itertools;
-use ropey::RopeBuilder;
-use rustpython_parser::ast::Location;
-
-use crate::ast::types::Range;
-use crate::autofix::Fix;
-use crate::registry::Diagnostic;
-use crate::source_code_locator::SourceCodeLocator;
-
-#[derive(Debug, Copy, Clone, Hash)]
-pub enum Mode {
-    Generate,
-    Apply,
-    Diff,
-    None,
-}
-
-impl From<bool> for Mode {
-    fn from(value: bool) -> Self {
-        if value {
-            Mode::Apply
-        } else {
-            Mode::None
-        }
-    }
-}
-
-/// Auto-fix errors in a file, and write the fixed source code to disk.
-pub fn fix_file<'a>(
-    diagnostics: &'a [Diagnostic],
-    locator: &'a SourceCodeLocator<'a>,
-) -> Option<(Cow<'a, str>, usize)> {
-    if diagnostics.iter().all(|check| check.fix.is_none()) {
-        return None;
-    }
-
-    Some(apply_fixes(
-        diagnostics.iter().filter_map(|check| check.fix.as_ref()),
-        locator,
-    ))
-}
-
-/// Apply a series of fixes.
-fn apply_fixes<'a>(
-    fixes: impl Iterator<Item = &'a Fix>,
-    locator: &'a SourceCodeLocator<'a>,
-) -> (Cow<'a, str>, usize) {
-    let mut output = RopeBuilder::new();
-    let mut last_pos: Location = Location::new(1, 0);
-    let mut applied: BTreeSet<&Fix> = BTreeSet::default();
-    let mut num_fixed: usize = 0;
-
-    for fix in fixes.sorted_by_key(|fix| fix.location) {
-        // If we already applied an identical fix as part of another correction, skip
-        // any re-application.
-        if applied.contains(&fix) {
-            num_fixed += 1;
-            continue;
-        }
-
-        // Best-effort approach: if this fix overlaps with a fix we've already applied,
-        // skip it.
-        if last_pos > fix.location {
-            continue;
-        }
-
-        // Add all contents from `last_pos` to `fix.location`.
-        let slice = locator.slice_source_code_range(&Range::new(last_pos, fix.location));
-        output.append(&slice);
-
-        // Add the patch itself.
-        output.append(&fix.content);
-
-        // Track that the fix was applied.
-        last_pos = fix.end_location;
-        applied.insert(fix);
-        num_fixed += 1;
-    }
-
-    // Add the remaining content.
-    let slice = locator.slice_source_code_at(&last_pos);
-    output.append(&slice);
-
-    (Cow::from(output.finish()), num_fixed)
-}
-
-#[cfg(test)]
-mod tests {
-    use rustpython_parser::ast::Location;
-
-    use crate::autofix::fixer::apply_fixes;
-    use crate::autofix::Fix;
-    use crate::SourceCodeLocator;
-
-    #[test]
-    fn empty_file() {
-        let fixes = vec![];
-        let locator = SourceCodeLocator::new(r#""#);
-        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
-        assert_eq!(contents, "");
-        assert_eq!(fixed, 0);
-    }
-
-    #[test]
-    fn apply_single_replacement() {
-        let fixes = vec![Fix {
-            content: "Bar".to_string(),
-            location: Location::new(1, 8),
-            end_location: Location::new(1, 14),
-        }];
-        let locator = SourceCodeLocator::new(
-            r#"
-class A(object):
-    ...
-"#
-            .trim(),
-        );
-        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
-        assert_eq!(
-            contents,
-            r#"
-class A(Bar):
-    ...
-"#
-            .trim(),
-        );
-        assert_eq!(fixed, 1);
-    }
-
-    #[test]
-    fn apply_single_removal() {
-        let fixes = vec![Fix {
-            content: String::new(),
-            location: Location::new(1, 7),
-            end_location: Location::new(1, 15),
-        }];
-        let locator = SourceCodeLocator::new(
-            r#"
-class A(object):
-    ...
-"#
-            .trim(),
-        );
-        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
-        assert_eq!(
-            contents,
-            r#"
-class A:
-    ...
-"#
-            .trim()
-        );
-        assert_eq!(fixed, 1);
-    }
-
-    #[test]
-    fn apply_double_removal() {
-        let fixes = vec![
-            Fix {
-                content: String::new(),
-                location: Location::new(1, 7),
-                end_location: Location::new(1, 16),
-            },
-            Fix {
-                content: String::new(),
-                location: Location::new(1, 16),
-                end_location: Location::new(1, 23),
-            },
-        ];
-        let locator = SourceCodeLocator::new(
-            r#"
-class A(object, object):
-    ...
-"#
-            .trim(),
-        );
-        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
-
-        assert_eq!(
-            contents,
-            r#"
-class A:
-    ...
-"#
-            .trim()
-        );
-        assert_eq!(fixed, 2);
-    }
-
-    #[test]
-    fn ignore_overlapping_fixes() {
-        let fixes = vec![
-            Fix {
-                content: String::new(),
-                location: Location::new(1, 7),
-                end_location: Location::new(1, 15),
-            },
-            Fix {
-                content: "ignored".to_string(),
-                location: Location::new(1, 9),
-                end_location: Location::new(1, 11),
-            },
-        ];
-        let locator = SourceCodeLocator::new(
-            r#"
-class A(object):
-    ...
-"#
-            .trim(),
-        );
-        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
-        assert_eq!(
-            contents,
-            r#"
-class A:
-    ...
-"#
-            .trim(),
-        );
-        assert_eq!(fixed, 1);
-    }
-}

src/autofix/helpers.rs

@@ -9,10 +9,10 @@ use crate::ast::helpers;
 use crate::ast::helpers::to_absolute;
 use crate::ast::types::Range;
 use crate::ast::whitespace::LinesWithTrailingNewline;
-use crate::autofix::Fix;
 use crate::cst::helpers::compose_module_path;
 use crate::cst::matchers::match_module;
-use crate::source_code_locator::SourceCodeLocator;
+use crate::fix::Fix;
+use crate::source_code::Locator;
 
 /// Determine if a body contains only a single statement, taking into account
 /// deleted.
@@ -78,7 +78,7 @@ fn is_lone_child(child: &Stmt, parent: &Stmt, deleted: &[&Stmt]) -> Result<bool>
 
 /// Return the location of a trailing semicolon following a `Stmt`, if it's part
 /// of a multi-statement line.
-fn trailing_semicolon(stmt: &Stmt, locator: &SourceCodeLocator) -> Option<Location> {
+fn trailing_semicolon(stmt: &Stmt, locator: &Locator) -> Option<Location> {
     let contents = locator.slice_source_code_at(&stmt.end_location.unwrap());
     for (row, line) in LinesWithTrailingNewline::from(&contents).enumerate() {
         let trimmed = line.trim();
@@ -100,7 +100,7 @@ fn trailing_semicolon(stmt: &Stmt, locator: &SourceCodeLocator) -> Option<Locati
 }
 
 /// Find the next valid break for a `Stmt` after a semicolon.
-fn next_stmt_break(semicolon: Location, locator: &SourceCodeLocator) -> Location {
+fn next_stmt_break(semicolon: Location, locator: &Locator) -> Location {
     let start_location = Location::new(semicolon.row(), semicolon.column() + 1);
     let contents = locator.slice_source_code_at(&start_location);
     for (row, line) in LinesWithTrailingNewline::from(&contents).enumerate() {
@@ -133,7 +133,7 @@ fn next_stmt_break(semicolon: Location, locator: &SourceCodeLocator) -> Location
 }
 
 /// Return `true` if a `Stmt` occurs at the end of a file.
-fn is_end_of_file(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+fn is_end_of_file(stmt: &Stmt, locator: &Locator) -> bool {
     let contents = locator.slice_source_code_at(&stmt.end_location.unwrap());
     contents.is_empty()
 }
@@ -155,7 +155,7 @@ pub fn delete_stmt(
     stmt: &Stmt,
     parent: Option<&Stmt>,
     deleted: &[&Stmt],
-    locator: &SourceCodeLocator,
+    locator: &Locator,
 ) -> Result<Fix> {
     if parent
         .map(|parent| is_lone_child(stmt, parent, deleted))
@@ -197,7 +197,7 @@ pub fn remove_unused_imports<'a>(
     stmt: &Stmt,
     parent: Option<&Stmt>,
     deleted: &[&Stmt],
-    locator: &SourceCodeLocator,
+    locator: &Locator,
 ) -> Result<Fix> {
     let module_text = locator.slice_source_code_range(&Range::from_located(stmt));
     let mut tree = match_module(&module_text)?;
@@ -210,14 +210,17 @@ pub fn remove_unused_imports<'a>(
         Some(SmallStatement::Import(import_body)) => (&mut import_body.names, None),
         Some(SmallStatement::ImportFrom(import_body)) => {
             if let ImportNames::Aliases(names) = &mut import_body.names {
-                (names, import_body.module.as_ref())
+                (
+                    names,
+                    Some((&import_body.relative, import_body.module.as_ref())),
+                )
             } else if let ImportNames::Star(..) = &import_body.names {
                 // Special-case: if the import is a `from ... import *`, then we delete the
                 // entire statement.
                 let mut found_star = false;
                 for unused_import in unused_imports {
                     let full_name = match import_body.module.as_ref() {
-                        Some(module_name) => format!("{}.*", compose_module_path(module_name),),
+                        Some(module_name) => format!("{}.*", compose_module_path(module_name)),
                         None => "*".to_string(),
                     };
                     if unused_import == full_name {
@@ -246,11 +249,25 @@ pub fn remove_unused_imports<'a>(
     for unused_import in unused_imports {
         let alias_index = aliases.iter().position(|alias| {
             let full_name = match import_module {
-                Some(module_name) => format!(
-                    "{}.{}",
-                    compose_module_path(module_name),
-                    compose_module_path(&alias.name)
-                ),
+                Some((relative, module)) => {
+                    let module = module.map(compose_module_path);
+                    let member = compose_module_path(&alias.name);
+                    let mut full_name = String::with_capacity(
+                        relative.len()
+                            + module.as_ref().map_or(0, std::string::String::len)
+                            + member.len()
+                            + 1,
+                    );
+                    for _ in 0..relative.len() {
+                        full_name.push('.');
+                    }
+                    if let Some(module) = module {
+                        full_name.push_str(&module);
+                        full_name.push('.');
+                    }
+                    full_name.push_str(&member);
+                    full_name
+                }
                 None => compose_module_path(&alias.name),
             };
             full_name == unused_import
@@ -299,20 +316,20 @@ mod tests {
     use rustpython_parser::parser;
 
     use crate::autofix::helpers::{next_stmt_break, trailing_semicolon};
-    use crate::source_code_locator::SourceCodeLocator;
+    use crate::source_code::Locator;
 
     #[test]
     fn find_semicolon() -> Result<()> {
         let contents = "x = 1";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(trailing_semicolon(stmt, &locator), None);
 
         let contents = "x = 1; y = 1";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             trailing_semicolon(stmt, &locator),
             Some(Location::new(1, 5))
@@ -321,7 +338,7 @@ mod tests {
         let contents = "x = 1 ; y = 1";
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             trailing_semicolon(stmt, &locator),
             Some(Location::new(1, 6))
@@ -334,7 +351,7 @@ x = 1 \
         .trim();
         let program = parser::parse_program(contents, "<filename>")?;
         let stmt = program.first().unwrap();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             trailing_semicolon(stmt, &locator),
             Some(Location::new(2, 2))
@@ -346,14 +363,14 @@ x = 1 \
     #[test]
     fn find_next_stmt_break() {
         let contents = "x = 1; y = 1";
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             next_stmt_break(Location::new(1, 4), &locator),
             Location::new(1, 5)
         );
 
         let contents = "x = 1 ; y = 1";
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             next_stmt_break(Location::new(1, 5), &locator),
             Location::new(1, 6)
@@ -364,7 +381,7 @@ x = 1 \
   ; y = 1
 "#
         .trim();
-        let locator = SourceCodeLocator::new(contents);
+        let locator = Locator::new(contents);
         assert_eq!(
             next_stmt_break(Location::new(2, 2), &locator),
             Location::new(2, 4)

src/autofix/mod.rs

@@ -1,38 +1,210 @@
+use std::borrow::Cow;
+use std::collections::BTreeSet;
+
+use itertools::Itertools;
+use ropey::RopeBuilder;
 use rustpython_ast::Location;
-use serde::{Deserialize, Serialize};
+
+use crate::ast::types::Range;
+use crate::fix::Fix;
+use crate::registry::Diagnostic;
+use crate::source_code::Locator;
 
 pub mod fixer;
 pub mod helpers;
 
-#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
-pub struct Fix {
-    pub content: String,
-    pub location: Location,
-    pub end_location: Location,
+/// Auto-fix errors in a file, and write the fixed source code to disk.
+pub fn fix_file<'a>(
+    diagnostics: &'a [Diagnostic],
+    locator: &'a Locator<'a>,
+) -> Option<(Cow<'a, str>, usize)> {
+    if diagnostics.iter().all(|check| check.fix.is_none()) {
+        return None;
+    }
+
+    Some(apply_fixes(
+        diagnostics.iter().filter_map(|check| check.fix.as_ref()),
+        locator,
+    ))
 }
 
-impl Fix {
-    pub fn deletion(start: Location, end: Location) -> Self {
-        Self {
+/// Apply a series of fixes.
+fn apply_fixes<'a>(
+    fixes: impl Iterator<Item = &'a Fix>,
+    locator: &'a Locator<'a>,
+) -> (Cow<'a, str>, usize) {
+    let mut output = RopeBuilder::new();
+    let mut last_pos: Location = Location::new(1, 0);
+    let mut applied: BTreeSet<&Fix> = BTreeSet::default();
+    let mut num_fixed: usize = 0;
+
+    for fix in fixes.sorted_by_key(|fix| fix.location) {
+        // If we already applied an identical fix as part of another correction, skip
+        // any re-application.
+        if applied.contains(&fix) {
+            num_fixed += 1;
+            continue;
+        }
+
+        // Best-effort approach: if this fix overlaps with a fix we've already applied,
+        // skip it.
+        if last_pos > fix.location {
+            continue;
+        }
+
+        // Add all contents from `last_pos` to `fix.location`.
+        let slice = locator.slice_source_code_range(&Range::new(last_pos, fix.location));
+        output.append(&slice);
+
+        // Add the patch itself.
+        output.append(&fix.content);
+
+        // Track that the fix was applied.
+        last_pos = fix.end_location;
+        applied.insert(fix);
+        num_fixed += 1;
+    }
+
+    // Add the remaining content.
+    let slice = locator.slice_source_code_at(&last_pos);
+    output.append(&slice);
+
+    (Cow::from(output.finish()), num_fixed)
+}
+
+#[cfg(test)]
+mod tests {
+    use rustpython_parser::ast::Location;
+
+    use crate::autofix::apply_fixes;
+    use crate::fix::Fix;
+    use crate::source_code::Locator;
+
+    #[test]
+    fn empty_file() {
+        let fixes = vec![];
+        let locator = Locator::new(r#""#);
+        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
+        assert_eq!(contents, "");
+        assert_eq!(fixed, 0);
+    }
+
+    #[test]
+    fn apply_single_replacement() {
+        let fixes = vec![Fix {
+            content: "Bar".to_string(),
+            location: Location::new(1, 8),
+            end_location: Location::new(1, 14),
+        }];
+        let locator = Locator::new(
+            r#"
+class A(object):
+    ...
+"#
+            .trim(),
+        );
+        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
+        assert_eq!(
+            contents,
+            r#"
+class A(Bar):
+    ...
+"#
+            .trim(),
+        );
+        assert_eq!(fixed, 1);
+    }
+
+    #[test]
+    fn apply_single_removal() {
+        let fixes = vec![Fix {
             content: String::new(),
-            location: start,
-            end_location: end,
-        }
+            location: Location::new(1, 7),
+            end_location: Location::new(1, 15),
+        }];
+        let locator = Locator::new(
+            r#"
+class A(object):
+    ...
+"#
+            .trim(),
+        );
+        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
+        assert_eq!(
+            contents,
+            r#"
+class A:
+    ...
+"#
+            .trim()
+        );
+        assert_eq!(fixed, 1);
     }
 
-    pub fn replacement(content: String, start: Location, end: Location) -> Self {
-        Self {
-            content,
-            location: start,
-            end_location: end,
-        }
+    #[test]
+    fn apply_double_removal() {
+        let fixes = vec![
+            Fix {
+                content: String::new(),
+                location: Location::new(1, 7),
+                end_location: Location::new(1, 16),
+            },
+            Fix {
+                content: String::new(),
+                location: Location::new(1, 16),
+                end_location: Location::new(1, 23),
+            },
+        ];
+        let locator = Locator::new(
+            r#"
+class A(object, object):
+    ...
+"#
+            .trim(),
+        );
+        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
+
+        assert_eq!(
+            contents,
+            r#"
+class A:
+    ...
+"#
+            .trim()
+        );
+        assert_eq!(fixed, 2);
     }
 
-    pub fn insertion(content: String, at: Location) -> Self {
-        Self {
-            content,
-            location: at,
-            end_location: at,
-        }
+    #[test]
+    fn ignore_overlapping_fixes() {
+        let fixes = vec![
+            Fix {
+                content: String::new(),
+                location: Location::new(1, 7),
+                end_location: Location::new(1, 15),
+            },
+            Fix {
+                content: "ignored".to_string(),
+                location: Location::new(1, 9),
+                end_location: Location::new(1, 11),
+            },
+        ];
+        let locator = Locator::new(
+            r#"
+class A(object):
+    ...
+"#
+            .trim(),
+        );
+        let (contents, fixed) = apply_fixes(fixes.iter(), &locator);
+        assert_eq!(
+            contents,
+            r#"
+class A:
+    ...
+"#
+            .trim(),
+        );
+        assert_eq!(fixed, 1);
     }
 }

src/cache.rs

@@ -1,132 +1,9 @@
-use std::collections::hash_map::DefaultHasher;
-use std::fs;
-use std::hash::{Hash, Hasher};
-use std::io::Write;
 use std::path::{Path, PathBuf};
 
-use anyhow::Result;
-use filetime::FileTime;
-use log::error;
-use path_absolutize::Absolutize;
-use serde::{Deserialize, Serialize};
-
-use crate::message::Message;
-use crate::settings::{flags, Settings};
-
 pub const CACHE_DIR_NAME: &str = ".ruff_cache";
 
-const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
-
-#[derive(Serialize, Deserialize)]
-struct CacheMetadata {
-    mtime: i64,
-}
-
-#[derive(Serialize)]
-struct CheckResultRef<'a> {
-    metadata: &'a CacheMetadata,
-    messages: &'a [Message],
-}
-
-#[derive(Deserialize)]
-struct CheckResult {
-    metadata: CacheMetadata,
-    messages: Vec<Message>,
-}
-
 /// Return the cache directory for a given project root. Defers to the
 /// `RUFF_CACHE_DIR` environment variable, if set.
 pub fn cache_dir(project_root: &Path) -> PathBuf {
     project_root.join(CACHE_DIR_NAME)
 }
-
-fn content_dir() -> &'static Path {
-    Path::new("content")
-}
-
-fn cache_key<P: AsRef<Path>>(path: P, settings: &Settings, autofix: flags::Autofix) -> u64 {
-    let mut hasher = DefaultHasher::new();
-    CARGO_PKG_VERSION.hash(&mut hasher);
-    path.as_ref().absolutize().unwrap().hash(&mut hasher);
-    settings.hash(&mut hasher);
-    autofix.hash(&mut hasher);
-    hasher.finish()
-}
-
-/// Initialize the cache at the specified `Path`.
-pub fn init(path: &Path) -> Result<()> {
-    // Create the cache directories.
-    fs::create_dir_all(path.join(content_dir()))?;
-
-    // Add the CACHEDIR.TAG.
-    if !cachedir::is_tagged(path)? {
-        cachedir::add_tag(path)?;
-    }
-
-    // Add the .gitignore.
-    let gitignore_path = path.join(".gitignore");
-    if !gitignore_path.exists() {
-        let mut file = fs::File::create(gitignore_path)?;
-        file.write_all(b"*")?;
-    }
-
-    Ok(())
-}
-
-fn write_sync(cache_dir: &Path, key: u64, value: &[u8]) -> Result<(), std::io::Error> {
-    fs::write(
-        cache_dir.join(content_dir()).join(format!("{key:x}")),
-        value,
-    )
-}
-
-fn read_sync(cache_dir: &Path, key: u64) -> Result<Vec<u8>, std::io::Error> {
-    fs::read(cache_dir.join(content_dir()).join(format!("{key:x}")))
-}
-
-/// Get a value from the cache.
-pub fn get<P: AsRef<Path>>(
-    path: P,
-    metadata: &fs::Metadata,
-    settings: &Settings,
-    autofix: flags::Autofix,
-) -> Option<Vec<Message>> {
-    let encoded = read_sync(&settings.cache_dir, cache_key(path, settings, autofix)).ok()?;
-    let (mtime, messages) = match bincode::deserialize::<CheckResult>(&encoded[..]) {
-        Ok(CheckResult {
-            metadata: CacheMetadata { mtime },
-            messages,
-        }) => (mtime, messages),
-        Err(e) => {
-            error!("Failed to deserialize encoded cache entry: {e:?}");
-            return None;
-        }
-    };
-    if FileTime::from_last_modification_time(metadata).unix_seconds() != mtime {
-        return None;
-    }
-    Some(messages)
-}
-
-/// Set a value in the cache.
-pub fn set<P: AsRef<Path>>(
-    path: P,
-    metadata: &fs::Metadata,
-    settings: &Settings,
-    autofix: flags::Autofix,
-    messages: &[Message],
-) {
-    let check_result = CheckResultRef {
-        metadata: &CacheMetadata {
-            mtime: FileTime::from_last_modification_time(metadata).unix_seconds(),
-        },
-        messages,
-    };
-    if let Err(e) = write_sync(
-        &settings.cache_dir,
-        cache_key(path, settings, autofix),
-        &bincode::serialize(&check_result).unwrap(),
-    ) {
-        error!("Failed to write to cache: {e:?}");
-    }
-}

src/checkers/imports.rs

@@ -7,47 +7,49 @@ use rustpython_parser::ast::Suite;
 use crate::ast::visitor::Visitor;
 use crate::directives::IsortDirectives;
 use crate::isort;
-use crate::isort::track::ImportTracker;
-use crate::registry::Diagnostic;
+use crate::isort::track::{Block, ImportTracker};
+use crate::registry::{Diagnostic, RuleCode};
 use crate::settings::{flags, Settings};
-use crate::source_code_locator::SourceCodeLocator;
-use crate::source_code_style::SourceCodeStyleDetector;
-
-fn check_import_blocks(
-    tracker: ImportTracker,
-    locator: &SourceCodeLocator,
-    settings: &Settings,
-    stylist: &SourceCodeStyleDetector,
-    autofix: flags::Autofix,
-    package: Option<&Path>,
-) -> Vec<Diagnostic> {
-    let mut diagnostics = vec![];
-    for block in tracker.into_iter() {
-        if !block.imports.is_empty() {
-            if let Some(diagnostic) =
-                isort::rules::check_imports(&block, locator, settings, stylist, autofix, package)
-            {
-                diagnostics.push(diagnostic);
-            }
-        }
-    }
-    diagnostics
-}
+use crate::source_code::{Locator, Stylist};
 
 #[allow(clippy::too_many_arguments)]
 pub fn check_imports(
     python_ast: &Suite,
-    locator: &SourceCodeLocator,
+    locator: &Locator,
     directives: &IsortDirectives,
     settings: &Settings,
-    stylist: &SourceCodeStyleDetector,
+    stylist: &Stylist,
     autofix: flags::Autofix,
     path: &Path,
     package: Option<&Path>,
 ) -> Vec<Diagnostic> {
-    let mut tracker = ImportTracker::new(locator, directives, path);
-    for stmt in python_ast {
-        tracker.visit_stmt(stmt);
+    // Extract all imports from the AST.
+    let tracker = {
+        let mut tracker = ImportTracker::new(locator, directives, path);
+        for stmt in python_ast {
+            tracker.visit_stmt(stmt);
+        }
+        tracker
+    };
+    let blocks: Vec<&Block> = tracker.iter().collect();
+
+    // Enforce import rules.
+    let mut diagnostics = vec![];
+    if settings.enabled.contains(&RuleCode::I001) {
+        for block in &blocks {
+            if !block.imports.is_empty() {
+                if let Some(diagnostic) = isort::rules::organize_imports(
+                    block, locator, settings, stylist, autofix, package,
+                ) {
+                    diagnostics.push(diagnostic);
+                }
+            }
+        }
     }
-    check_import_blocks(tracker, locator, settings, stylist, autofix, package)
+    if settings.enabled.contains(&RuleCode::I002) {
+        diagnostics.extend(isort::rules::add_required_imports(
+            &blocks, python_ast, locator, settings, autofix,
+        ));
+    }
+    diagnostics
 }

src/checkers/lines.rs

@@ -1,6 +1,6 @@
 //! Lint rules based on checking raw physical lines.
 
-use crate::pycodestyle::rules::{line_too_long, no_newline_at_end_of_file};
+use crate::pycodestyle::rules::{doc_line_too_long, line_too_long, no_newline_at_end_of_file};
 use crate::pygrep_hooks::rules::{blanket_noqa, blanket_type_ignore};
 use crate::pyupgrade::rules::unnecessary_coding_comment;
 use crate::registry::{Diagnostic, RuleCode};
@@ -9,18 +9,21 @@ use crate::settings::{flags, Settings};
 pub fn check_lines(
     contents: &str,
     commented_lines: &[usize],
+    doc_lines: &[usize],
     settings: &Settings,
     autofix: flags::Autofix,
 ) -> Vec<Diagnostic> {
     let mut diagnostics: Vec<Diagnostic> = vec![];
 
-    let enforce_unnecessary_coding_comment = settings.enabled.contains(&RuleCode::UP009);
+    let enforce_blanket_noqa = settings.enabled.contains(&RuleCode::PGH004);
+    let enforce_blanket_type_ignore = settings.enabled.contains(&RuleCode::PGH003);
+    let enforce_doc_line_too_long = settings.enabled.contains(&RuleCode::W505);
     let enforce_line_too_long = settings.enabled.contains(&RuleCode::E501);
     let enforce_no_newline_at_end_of_file = settings.enabled.contains(&RuleCode::W292);
-    let enforce_blanket_type_ignore = settings.enabled.contains(&RuleCode::PGH003);
-    let enforce_blanket_noqa = settings.enabled.contains(&RuleCode::PGH004);
+    let enforce_unnecessary_coding_comment = settings.enabled.contains(&RuleCode::UP009);
 
     let mut commented_lines_iter = commented_lines.iter().peekable();
+    let mut doc_lines_iter = doc_lines.iter().peekable();
     for (index, line) in contents.lines().enumerate() {
         while commented_lines_iter
             .next_if(|lineno| &(index + 1) == *lineno)
@@ -40,18 +43,25 @@ pub fn check_lines(
             }
 
             if enforce_blanket_type_ignore {
-                if commented_lines.contains(&(index + 1)) {
-                    if let Some(diagnostic) = blanket_type_ignore(index, line) {
-                        diagnostics.push(diagnostic);
-                    }
+                if let Some(diagnostic) = blanket_type_ignore(index, line) {
+                    diagnostics.push(diagnostic);
                 }
             }
 
             if enforce_blanket_noqa {
-                if commented_lines.contains(&(index + 1)) {
-                    if let Some(diagnostic) = blanket_noqa(index, line) {
-                        diagnostics.push(diagnostic);
-                    }
+                if let Some(diagnostic) = blanket_noqa(index, line) {
+                    diagnostics.push(diagnostic);
+                }
+            }
+        }
+
+        while doc_lines_iter
+            .next_if(|lineno| &(index + 1) == *lineno)
+            .is_some()
+        {
+            if enforce_doc_line_too_long {
+                if let Some(diagnostic) = doc_line_too_long(index, line, settings) {
+                    diagnostics.push(diagnostic);
                 }
             }
         }
@@ -90,6 +100,7 @@ mod tests {
             check_lines(
                 line,
                 &[],
+                &[],
                 &Settings {
                     line_length,
                     ..Settings::for_rule(RuleCode::E501)

src/checkers/noqa.rs

@@ -6,7 +6,7 @@ use nohash_hasher::IntMap;
 use rustpython_parser::ast::Location;
 
 use crate::ast::types::Range;
-use crate::autofix::Fix;
+use crate::fix::Fix;
 use crate::noqa::{is_file_exempt, Directive};
 use crate::registry::{Diagnostic, DiagnosticKind, RuleCode, CODE_REDIRECTS};
 use crate::settings::{flags, Settings};

src/checkers/tokens.rs

@@ -5,12 +5,12 @@ use rustpython_parser::lexer::{LexResult, Tok};
 use crate::lex::docstring_detection::StateMachine;
 use crate::registry::{Diagnostic, RuleCode};
 use crate::ruff::rules::Context;
-use crate::settings::flags;
-use crate::source_code_locator::SourceCodeLocator;
-use crate::{eradicate, flake8_implicit_str_concat, flake8_quotes, pycodestyle, ruff, Settings};
+use crate::settings::{flags, Settings};
+use crate::source_code::Locator;
+use crate::{eradicate, flake8_implicit_str_concat, flake8_quotes, pycodestyle, ruff};
 
 pub fn check_tokens(
-    locator: &SourceCodeLocator,
+    locator: &Locator,
     tokens: &[LexResult],
     settings: &Settings,
     autofix: flags::Autofix,
@@ -67,7 +67,8 @@ pub fn check_tokens(
                     start,
                     end,
                     is_docstring,
-                    &settings.flake8_quotes,
+                    settings,
+                    autofix,
                 ) {
                     if settings.enabled.contains(diagnostic.kind.code()) {
                         diagnostics.push(diagnostic);

src/cst/matchers.rs

@@ -1,5 +1,7 @@
 use anyhow::{bail, Result};
-use libcst_native::{Expr, Import, ImportFrom, Module, SmallStatement, Statement};
+use libcst_native::{
+    Call, Expr, Expression, Import, ImportFrom, Module, SmallStatement, Statement,
+};
 
 pub fn match_module(module_text: &str) -> Result<Module> {
     match libcst_native::parse_module(module_text, None) {
@@ -8,6 +10,13 @@ pub fn match_module(module_text: &str) -> Result<Module> {
     }
 }
 
+pub fn match_expression(expression_text: &str) -> Result<Expression> {
+    match libcst_native::parse_expression(expression_text) {
+        Ok(expression) => Ok(expression),
+        Err(_) => bail!("Failed to extract CST from source"),
+    }
+}
+
 pub fn match_expr<'a, 'b>(module: &'a mut Module<'b>) -> Result<&'a mut Expr<'b>> {
     if let Some(Statement::Simple(expr)) = module.body.first_mut() {
         if let Some(SmallStatement::Expr(expr)) = expr.body.first_mut() {
@@ -43,3 +52,11 @@ pub fn match_import_from<'a, 'b>(module: &'a mut Module<'b>) -> Result<&'a mut I
         bail!("Expected Statement::Simple")
     }
 }
+
+pub fn match_call<'a, 'b>(expression: &'a mut Expression<'b>) -> Result<&'a mut Call<'b>> {
+    if let Expression::Call(call) = expression {
+        Ok(call)
+    } else {
+        bail!("Expected SmallStatement::Expr")
+    }
+}

src/directives.rs

@@ -6,7 +6,7 @@ use rustpython_ast::Location;
 use rustpython_parser::lexer::{LexResult, Tok};
 
 use crate::registry::LintSource;
-use crate::Settings;
+use crate::settings::Settings;
 
 bitflags! {
     pub struct Flags: u32 {
@@ -33,6 +33,7 @@ impl Flags {
 pub struct IsortDirectives {
     pub exclusions: IntSet<usize>,
     pub splits: Vec<usize>,
+    pub skip_file: bool,
 }
 
 pub struct Directives {
@@ -89,17 +90,11 @@ pub fn extract_noqa_line_for(lxr: &[LexResult]) -> IntMap<usize, usize> {
 pub fn extract_isort_directives(lxr: &[LexResult]) -> IsortDirectives {
     let mut exclusions: IntSet<usize> = IntSet::default();
     let mut splits: Vec<usize> = Vec::default();
-    let mut skip_file: bool = false;
     let mut off: Option<Location> = None;
     let mut last: Option<Location> = None;
     for &(start, ref tok, end) in lxr.iter().flatten() {
         last = Some(end);
 
-        // No need to keep processing, but we do need to determine the last token.
-        if skip_file {
-            continue;
-        }
-
         let Tok::Comment(comment_text) = tok else {
             continue;
         };
@@ -111,7 +106,10 @@ pub fn extract_isort_directives(lxr: &[LexResult]) -> IsortDirectives {
         if comment_text == "# isort: split" {
             splits.push(start.row());
         } else if comment_text == "# isort: skip_file" || comment_text == "# isort:skip_file" {
-            skip_file = true;
+            return IsortDirectives {
+                skip_file: true,
+                ..IsortDirectives::default()
+            };
         } else if off.is_some() {
             if comment_text == "# isort: on" {
                 if let Some(start) = off {
@@ -130,14 +128,7 @@ pub fn extract_isort_directives(lxr: &[LexResult]) -> IsortDirectives {
         }
     }
 
-    if skip_file {
-        // Enforce `isort: skip_file`.
-        if let Some(end) = last {
-            for row in 1..=end.row() {
-                exclusions.insert(row);
-            }
-        }
-    } else if let Some(start) = off {
+    if let Some(start) = off {
         // Enforce unterminated `isort: off`.
         if let Some(end) = last {
             for row in start.row() + 1..=end.row() {
@@ -145,7 +136,11 @@ pub fn extract_isort_directives(lxr: &[LexResult]) -> IsortDirectives {
             }
         }
     }
-    IsortDirectives { exclusions, splits }
+    IsortDirectives {
+        exclusions,
+        splits,
+        ..IsortDirectives::default()
+    }
 }
 
 #[cfg(test)]
@@ -283,10 +278,7 @@ x = 1
 y = 2
 z = x + 1";
         let lxr: Vec<LexResult> = lexer::make_tokenizer(contents).collect();
-        assert_eq!(
-            extract_isort_directives(&lxr).exclusions,
-            IntSet::from_iter([1, 2, 3, 4])
-        );
+        assert_eq!(extract_isort_directives(&lxr).exclusions, IntSet::default());
 
         let contents = "# isort: off
 x = 1
@@ -295,10 +287,7 @@ y = 2
 # isort: skip_file
 z = x + 1";
         let lxr: Vec<LexResult> = lexer::make_tokenizer(contents).collect();
-        assert_eq!(
-            extract_isort_directives(&lxr).exclusions,
-            IntSet::from_iter([1, 2, 3, 4, 5, 6])
-        );
+        assert_eq!(extract_isort_directives(&lxr).exclusions, IntSet::default());
     }
 
     #[test]

src/doc_lines.rs

@@ -0,0 +1,58 @@
+//! Doc line extraction. In this context, a doc line is a line consisting of a
+//! standalone comment or a constant string statement.
+
+use rustpython_ast::{Constant, ExprKind, Stmt, StmtKind, Suite};
+use rustpython_parser::lexer::{LexResult, Tok};
+
+use crate::ast::visitor;
+use crate::ast::visitor::Visitor;
+
+/// Extract doc lines (standalone comments) from a token sequence.
+pub fn doc_lines_from_tokens(lxr: &[LexResult]) -> Vec<usize> {
+    let mut doc_lines: Vec<usize> = Vec::default();
+    let mut prev: Option<usize> = None;
+    for (start, tok, end) in lxr.iter().flatten() {
+        if matches!(tok, Tok::Indent | Tok::Dedent | Tok::Newline) {
+            continue;
+        }
+        if matches!(tok, Tok::Comment(..)) {
+            if let Some(prev) = prev {
+                if start.row() > prev {
+                    doc_lines.push(start.row());
+                }
+            } else {
+                doc_lines.push(start.row());
+            }
+        }
+        prev = Some(end.row());
+    }
+    doc_lines
+}
+
+#[derive(Default)]
+struct StringLinesVisitor {
+    string_lines: Vec<usize>,
+}
+
+impl Visitor<'_> for StringLinesVisitor {
+    fn visit_stmt(&mut self, stmt: &Stmt) {
+        if let StmtKind::Expr { value } = &stmt.node {
+            if let ExprKind::Constant {
+                value: Constant::Str(..),
+                ..
+            } = &value.node
+            {
+                self.string_lines
+                    .extend(value.location.row()..=value.end_location.unwrap().row());
+            }
+        }
+        visitor::walk_stmt(self, stmt);
+    }
+}
+
+/// Extract doc lines (standalone strings) from an AST.
+pub fn doc_lines_from_ast(python_ast: &Suite) -> Vec<usize> {
+    let mut visitor = StringLinesVisitor::default();
+    visitor.visit_body(python_ast);
+    visitor.string_lines
+}

src/eradicate/mod.rs

@@ -1,5 +1,5 @@
-pub mod detection;
-pub mod rules;
+pub(crate) mod detection;
+pub(crate) mod rules;
 
 #[cfg(test)]
 mod tests {

src/eradicate/rules.rs

@@ -1,11 +1,12 @@
 use rustpython_ast::Location;
 
 use crate::ast::types::Range;
-use crate::autofix::Fix;
 use crate::eradicate::detection::comment_contains_code;
-use crate::registry::RuleCode;
-use crate::settings::flags;
-use crate::{violations, Diagnostic, Settings, SourceCodeLocator};
+use crate::fix::Fix;
+use crate::registry::{Diagnostic, RuleCode};
+use crate::settings::{flags, Settings};
+use crate::source_code::Locator;
+use crate::violations;
 
 fn is_standalone_comment(line: &str) -> bool {
     for char in line.chars() {
@@ -20,7 +21,7 @@ fn is_standalone_comment(line: &str) -> bool {
 
 /// ERA001
 pub fn commented_out_code(
-    locator: &SourceCodeLocator,
+    locator: &Locator,
     start: Location,
     end: Location,
     settings: &Settings,

src/fix.rs

@@ -0,0 +1,53 @@
+use rustpython_ast::Location;
+use serde::{Deserialize, Serialize};
+
+#[derive(Debug, Copy, Clone, Hash)]
+pub enum FixMode {
+    Generate,
+    Apply,
+    Diff,
+    None,
+}
+
+impl From<bool> for FixMode {
+    fn from(value: bool) -> Self {
+        if value {
+            FixMode::Apply
+        } else {
+            FixMode::None
+        }
+    }
+}
+
+#[derive(Clone, Debug, PartialEq, Eq, PartialOrd, Ord, Serialize, Deserialize)]
+pub struct Fix {
+    pub content: String,
+    pub location: Location,
+    pub end_location: Location,
+}
+
+impl Fix {
+    pub fn deletion(start: Location, end: Location) -> Self {
+        Self {
+            content: String::new(),
+            location: start,
+            end_location: end,
+        }
+    }
+
+    pub fn replacement(content: String, start: Location, end: Location) -> Self {
+        Self {
+            content,
+            location: start,
+            end_location: end,
+        }
+    }
+
+    pub fn insertion(content: String, at: Location) -> Self {
+        Self {
+            content,
+            location: at,
+            end_location: at,
+        }
+    }
+}

src/flake8_2020/mod.rs

@@ -1,4 +1,4 @@
-pub mod rules;
+pub(crate) mod rules;
 
 #[cfg(test)]
 mod tests {

src/flake8_2020/rules.rs

@@ -1,20 +1,15 @@
 use num_bigint::BigInt;
 use rustpython_ast::{Cmpop, Constant, Expr, ExprKind, Located};
 
-use crate::ast::helpers::match_module_member;
 use crate::ast::types::Range;
 use crate::checkers::ast::Checker;
 use crate::registry::{Diagnostic, RuleCode};
 use crate::violations;
 
 fn is_sys(checker: &Checker, expr: &Expr, target: &str) -> bool {
-    match_module_member(
-        expr,
-        "sys",
-        target,
-        &checker.from_imports,
-        &checker.import_aliases,
-    )
+    checker
+        .resolve_call_path(expr)
+        .map_or(false, |path| path == ["sys", target])
 }
 
 /// YTT101, YTT102, YTT301, YTT303
@@ -187,13 +182,10 @@ pub fn compare(checker: &mut Checker, left: &Expr, ops: &[Cmpop], comparators: &
 
 /// YTT202
 pub fn name_or_attribute(checker: &mut Checker, expr: &Expr) {
-    if match_module_member(
-        expr,
-        "six",
-        "PY3",
-        &checker.from_imports,
-        &checker.import_aliases,
-    ) {
+    if checker
+        .resolve_call_path(expr)
+        .map_or(false, |path| path == ["six", "PY3"])
+    {
         checker.diagnostics.push(Diagnostic::new(
             violations::SixPY3Referenced,
             Range::from_located(expr),

src/flake8_annotations/fixes.rs

@@ -4,11 +4,11 @@ use rustpython_parser::lexer;
 use rustpython_parser::lexer::Tok;
 
 use crate::ast::types::Range;
-use crate::autofix::Fix;
-use crate::source_code_locator::SourceCodeLocator;
+use crate::fix::Fix;
+use crate::source_code::Locator;
 
 /// ANN204
-pub fn add_return_none_annotation(locator: &SourceCodeLocator, stmt: &Stmt) -> Result<Fix> {
+pub fn add_return_none_annotation(locator: &Locator, stmt: &Stmt) -> Result<Fix> {
     let range = Range::from_located(stmt);
     let contents = locator.slice_source_code_range(&range);
 

src/flake8_annotations/mod.rs

@@ -1,6 +1,6 @@
 mod fixes;
-pub mod helpers;
-pub mod rules;
+pub(crate) mod helpers;
+pub(crate) mod rules;
 pub mod settings;
 
 #[cfg(test)]
@@ -9,9 +9,10 @@ mod tests {
 
     use anyhow::Result;
 
+    use crate::flake8_annotations;
     use crate::linter::test_path;
     use crate::registry::RuleCode;
-    use crate::{flake8_annotations, Settings};
+    use crate::settings::Settings;
 
     #[test]
     fn defaults() -> Result<()> {
@@ -144,4 +145,22 @@ mod tests {
         insta::assert_yaml_snapshot!(diagnostics);
         Ok(())
     }
+
+    #[test]
+    fn allow_nested_overload() -> Result<()> {
+        let diagnostics = test_path(
+            Path::new("./resources/test/fixtures/flake8_annotations/allow_nested_overload.py"),
+            &Settings {
+                ..Settings::for_rules(vec![
+                    RuleCode::ANN201,
+                    RuleCode::ANN202,
+                    RuleCode::ANN204,
+                    RuleCode::ANN205,
+                    RuleCode::ANN206,
+                ])
+            },
+        )?;
+        insta::assert_yaml_snapshot!(diagnostics);
+        Ok(())
+    }
 }