Bump version to 0.0.181

.github/workflows/ci.yaml

@@ -20,6 +20,9 @@ jobs:
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
+          toolchain: nightly-2022-11-01
+          override: true
+          components: rustfmt
       - uses: actions/cache@v3
         env:
           cache-name: cache-cargo
@@ -33,6 +36,12 @@ jobs:
             ${{ runner.os }}-build-
             ${{ runner.os }}-
       - run: cargo build --all --release
+      - run: ./target/release/ruff_dev generate-rules-table
+      - run: ./target/release/ruff_dev generate-options
+      - run: git diff --quiet README.md || echo "::error file=README.md::This file is outdated. You may have to rerun 'cargo dev generate-options' and/or 'cargo dev generate-rules-table'."
+      - run: ./target/release/ruff_dev generate-check-code-prefix && cargo fmt -- src/checks_gen.rs
+      - run: git diff --quiet src/checks_gen.rs || echo "::error file=src/checks_gen.rs::This file is outdated. You may have to rerun 'cargo dev generate-check-code-prefix'."
+      - run: git diff --exit-code -- README.md src/checks_gen.rs
 
   cargo_fmt:
     name: "cargo fmt"

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.172
+    rev: v0.0.181
     hooks:
       - id: ruff
 

BREAKING_CHANGES.md

@@ -0,0 +1,23 @@
+# Breaking Changes
+
+## 0.0.181
+
+### Files excluded by `.gitignore` are now ignored ([#1234](https://github.com/charliermarsh/ruff/pull/1234))
+
+Ruff will now avoid checking files that are excluded by `.ignore`, `.gitignore`,
+`.git/info/exclude`, and global `gitignore` files. This behavior is powered by the [`ignore`](https://docs.rs/ignore/latest/ignore/struct.WalkBuilder.html#ignore-rules)
+crate, and is applied in addition to Ruff's built-in `exclude` system.
+
+To disable this behavior, set `respect-gitignore = false` in your `pyproject.toml` file.
+
+Note that hidden files (i.e., files and directories prefixed with a `.`) are _not_ ignored by
+default.
+
+## 0.0.178
+
+### Configuration files are now resolved hierarchically ([#1190](https://github.com/charliermarsh/ruff/pull/1190))
+
+`pyproject.toml` files are now resolved hierarchically, such that for each Python file, we find
+the first `pyproject.toml` file in its path, and use that to determine its lint settings.
+
+See the [README](https://github.com/charliermarsh/ruff#pyprojecttoml-discovery) for more.

Cargo.lock

@@ -724,7 +724,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8-to-ruff"
-version = "0.0.172-dev.0"
+version = "0.0.181-dev.0"
 dependencies = [
  "anyhow",
  "clap 4.0.29",
@@ -796,6 +796,12 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "glob"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9b919933a397b79c37e33b77bb2aa3dc8eb6e165ad809e58ff75bc7db2e34574"
+
 [[package]]
 name = "globset"
 version = "0.4.9"
@@ -888,6 +894,24 @@ dependencies = [
  "unicode-normalization",
 ]
 
+[[package]]
+name = "ignore"
+version = "0.4.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "713f1b139373f96a2e0ce3ac931cd01ee973c3c5dd7c40c0c2efe96ad2b6751d"
+dependencies = [
+ "crossbeam-utils",
+ "globset",
+ "lazy_static",
+ "log",
+ "memchr",
+ "regex",
+ "same-file",
+ "thread_local",
+ "walkdir",
+ "winapi-util",
+]
+
 [[package]]
 name = "indexmap"
 version = "1.9.2"
@@ -1821,7 +1845,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.172"
+version = "0.0.181"
 dependencies = [
  "annotate-snippets 0.9.1",
  "anyhow",
@@ -1841,7 +1865,9 @@ dependencies = [
  "fern",
  "filetime",
  "getrandom 0.2.8",
+ "glob",
  "globset",
+ "ignore",
  "insta",
  "itertools",
  "libcst",
@@ -1874,7 +1900,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_dev"
-version = "0.0.172"
+version = "0.0.181"
 dependencies = [
  "anyhow",
  "clap 4.0.29",
@@ -1892,7 +1918,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_macros"
-version = "0.0.172"
+version = "0.0.181"
 dependencies = [
  "proc-macro2",
  "quote",
@@ -1935,7 +1961,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "num-bigint",
  "rustpython-common",
@@ -1945,7 +1971,7 @@ dependencies = [
 [[package]]
 name = "rustpython-common"
 version = "0.0.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ascii",
  "cfg-if 1.0.0",
@@ -1968,7 +1994,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "bincode",
  "bitflags",
@@ -1985,7 +2011,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ahash",
  "anyhow",
@@ -2297,6 +2323,15 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "thread_local"
+version = "1.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5516c27b78311c50bf42c071425c560ac799b11c30b31f87e3081965fe5e0180"
+dependencies = [
+ "once_cell",
+]
+
 [[package]]
 name = "time"
 version = "0.1.45"

Cargo.toml

@@ -6,7 +6,7 @@ members = [
 
 [package]
 name = "ruff"
-version = "0.0.172"
+version = "0.0.181"
 edition = "2021"
 rust-version = "1.65.0"
 
@@ -28,7 +28,9 @@ common-path = { version = "1.0.0" }
 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" }
 itertools = { version = "0.10.5" }
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a8725d161fe8b3ed73a6758b21e177" }
 log = { version = "0.4.17" }
@@ -41,11 +43,11 @@ quick-junit = { version = "0.3.2" }
 rayon = { version = "1.5.3" }
 regex = { version = "1.6.0" }
 ropey = { version = "1.5.0", features = ["cr_lines", "simd"], default-features = false }
-ruff_macros = { version = "0.0.172", path = "ruff_macros" }
+ruff_macros = { version = "0.0.181", path = "ruff_macros" }
 rustc-hash = { version = "1.1.0" }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "28f9f65ccc625f00835d84bbb5fba274dce5aa89" }
-rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "28f9f65ccc625f00835d84bbb5fba274dce5aa89" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "28f9f65ccc625f00835d84bbb5fba274dce5aa89" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
 serde = { version = "1.0.147", features = ["derive"] }
 serde_json = { version = "1.0.87" }
 strum = { version = "0.24.1", features = ["strum_macros"] }

LICENSE

@@ -438,6 +438,31 @@ are:
     SOFTWARE.
   """
 
+- flake8-simplify, licensed as follows:
+  """
+    MIT License
+
+    Copyright (c) 2020 Martin Thoma
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+  """
+
 - isort, licensed as follows:
   """
     The MIT License (MIT)

README.md

@@ -41,6 +41,7 @@ Ruff is extremely actively developed and used in major open-source projects like
 - [Pydantic](https://github.com/pydantic/pydantic)
 - [Saleor](https://github.com/saleor/saleor)
 - [Hatch](https://github.com/pypa/hatch)
+- [Jupyter Server](https://github.com/jupyter-server/jupyter_server)
 
 Read the [launch blog post](https://notes.crmarsh.com/python-tooling-could-be-much-much-faster).
 
@@ -89,6 +90,7 @@ of [Conda](https://docs.conda.io/en/latest/):
    1. [flake8-print (T20)](#flake8-print-t20)
    1. [flake8-quotes (Q)](#flake8-quotes-q)
    1. [flake8-return (RET)](#flake8-return-ret)
+   1. [flake8-simplify (SIM)](#flake8-simplify-sim)
    1. [flake8-tidy-imports (TID)](#flake8-tidy-imports-tid)
    1. [flake8-unused-arguments (ARG)](#flake8-unused-arguments-arg)
    1. [eradicate (ERA)](#eradicate-era)
@@ -120,12 +122,18 @@ For **macOS Homebrew** and **Linuxbrew** users, Ruff is also available as [`ruff
 brew install ruff
 ```
 
-For Conda users, Ruff is also available as [`ruff`](https://anaconda.org/conda-forge/ruff) on `conda-forge`:
+For **Conda** users, Ruff is also available as [`ruff`](https://anaconda.org/conda-forge/ruff) on `conda-forge`:
 
 ```shell
 conda install -c conda-forge ruff
 ```
 
+For **Arch Linux** users, Ruff is also available as [`ruff`](https://archlinux.org/packages/community/x86_64/ruff/) on the official repositories:
+
+```shell
+pacman -S ruff
+```
+
 ### Usage
 
 To run Ruff, try any of the following:
@@ -147,7 +155,7 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.172
+    rev: v0.0.181
     hooks:
       - id: ruff
 ```
@@ -296,13 +304,15 @@ Options:
       --per-file-ignores <PER_FILE_IGNORES>
           List of mappings from file pattern to code to exclude
       --format <FORMAT>
-          Output serialization format for error messages [default: text] [possible values: text, json, junit, grouped]
+          Output serialization format for error messages [possible values: text, json, junit, grouped, github]
       --show-source
           Show violations with source code
+      --respect-gitignore
+          Respect file exclusions via `.gitignore` and other standard ignore files
       --show-files
           See the files Ruff will be run against with the current settings
       --show-settings
-          See Ruff's settings
+          See the settings Ruff will use to check a given Python file
       --add-noqa
           Enable automatic additions of noqa directives to failing lines
       --dummy-variable-rgx <DUMMY_VARIABLE_RGX>
@@ -323,6 +333,52 @@ Options:
           Print version information
 ```
 
+### `pyproject.toml` discovery
+
+Similar to [ESLint](https://eslint.org/docs/latest/user-guide/configuring/configuration-files#cascading-and-hierarchy),
+Ruff supports hierarchical configuration, such that the "closest" `pyproject.toml` file in the
+directory hierarchy is used for every individual file, with all paths in the `pyproject.toml` file
+(e.g., `exclude` globs, `src` paths) being resolved relative to the directory containing the
+`pyproject.toml` file.
+
+There are a few exceptions to these rules:
+
+1. If a configuration file is passed directly via `--config`, those settings are used for across
+   files. Any relative paths in that configuration file (like `exclude` globs or `src` paths) are
+   resolved relative to the _current working directory_.
+2. If no `pyproject.toml` file is found in the filesystem hierarchy, Ruff will fall back to using
+   a default configuration. If a user-specific configuration file exists at `${config_dir}/ruff/pyproject.toml`,
+   that file will be used instead of the default configuration, with `${config_dir}` being determined
+   via the [`dirs](https://docs.rs/dirs/4.0.0/dirs/fn.config_dir.html) crate, and all relative paths
+   being again resolved relative to the _current working directory_.
+3. Any `pyproject.toml`-supported settings that are provided on the command-line (e.g., via
+   `--select`) will override the settings in _every_ resolved configuration file.
+
+Unlike [ESLint](https://eslint.org/docs/latest/user-guide/configuring/configuration-files#cascading-and-hierarchy),
+Ruff does not merge settings across configuration files; instead, the "closest" configuration file
+is used, and any parent configuration files are ignored. In lieu of this implicit cascade, Ruff
+supports an [`extend`](#extend) field, which allows you to inherit the settings from another
+`pyproject.toml` file, like so:
+
+```toml
+# Extend the `pyproject.toml` file in the parent directory.
+extend = "../pyproject.toml"
+# But use a different line length.
+line-length = 100
+```
+
+### Python file discovery
+
+When passed a path on the command-line, Ruff will automatically discover all Python files in that
+path, taking into account the [`exclude`](#exclude) and [`extend-exclude`](#extend-exclude) settings
+in each directory's `pyproject.toml` file.
+
+By default, Ruff will also skip any files that are omitted via `.ignore`, `.gitignore`,
+`.git/info/exclude`, and global `gitignore` files (see: [`respect-gitignore`](#respect-gitignore)).
+
+Files that are passed to `ruff` directly are always checked, regardless of the above criteria.
+For example, `ruff /path/to/excluded/file.py` will always check `file.py`.
+
 ### Ignoring errors
 
 To omit a lint check entirely, add it to the "ignore" list via [`ignore`](#ignore) or
@@ -362,7 +418,7 @@ For targeted exclusions across entire files (e.g., "Ignore all F841 violations i
 ### "Action Comments"
 
 Ruff respects `isort`'s ["Action Comments"](https://pycqa.github.io/isort/docs/configuration/action_comments.html)
-(`# isort: skip_file`, `# isort: on`, `# isort: off`, `# isort: skip`, and `isort: split`), which
+(`# isort: skip_file`, `# isort: on`, `# isort: off`, `# isort: skip`, and `# isort: split`), which
 enable selectively enabling and disabling import sorting for blocks of code and other inline
 configuration.
 
@@ -412,14 +468,14 @@ For more, see [Pyflakes](https://pypi.org/project/pyflakes/2.5.0/) on PyPI.
 | F501 | PercentFormatInvalidFormat | '...' % ... has invalid format string: ... |  |
 | F502 | PercentFormatExpectedMapping | '...' % ... expected mapping but got sequence |  |
 | F503 | PercentFormatExpectedSequence | '...' % ... expected sequence but got mapping |  |
-| F504 | PercentFormatExtraNamedArguments | '...' % ... has unused named argument(s): ... |  |
+| F504 | PercentFormatExtraNamedArguments | '...' % ... has unused named argument(s): ... | 🛠 |
 | F505 | PercentFormatMissingArgument | '...' % ... is missing argument(s) for placeholder(s): ... |  |
 | F506 | PercentFormatMixedPositionalAndNamed | '...' % ... has mixed positional and named placeholders |  |
 | F507 | PercentFormatPositionalCountMismatch | '...' % ... has 4 placeholder(s) but 2 substitution(s) |  |
 | F508 | PercentFormatStarRequiresSequence | '...' % ... `*` specifier requires sequence |  |
 | F509 | PercentFormatUnsupportedFormatCharacter | '...' % ... has unsupported format character 'c' |  |
 | F521 | StringDotFormatInvalidFormat | '...'.format(...) has invalid format string: ... |  |
-| F522 | StringDotFormatExtraNamedArguments | '...'.format(...) has unused named argument(s): ... |  |
+| F522 | StringDotFormatExtraNamedArguments | '...'.format(...) has unused named argument(s): ... | 🛠 |
 | F523 | StringDotFormatExtraPositionalArguments | '...'.format(...) has unused arguments at position(s): ... |  |
 | F524 | StringDotFormatMissingArguments | '...'.format(...) is missing argument(s) for placeholder(s): ... |  |
 | F525 | StringDotFormatMixingAutomatic | '...'.format(...) mixes automatic and manual numbering |  |
@@ -709,7 +765,7 @@ For more, see [flake8-comprehensions](https://pypi.org/project/flake8-comprehens
 | C409 | UnnecessaryLiteralWithinTupleCall | Unnecessary `(list\|tuple)` literal passed to `tuple()` (remove the outer call to `tuple()`) | 🛠 |
 | C410 | UnnecessaryLiteralWithinListCall | Unnecessary `(list\|tuple)` literal passed to `list()` (rewrite as a `list` literal) | 🛠 |
 | C411 | UnnecessaryListCall | Unnecessary `list` call (remove the outer call to `list()`) | 🛠 |
-| C413 | UnnecessaryCallAroundSorted | Unnecessary `(list\|reversed)` call around `sorted()` |  |
+| C413 | UnnecessaryCallAroundSorted | Unnecessary `(list\|reversed)` call around `sorted()` | 🛠 |
 | C414 | UnnecessaryDoubleCastOrProcess | Unnecessary `(list\|reversed\|set\|sorted\|tuple)` call within `(list\|set\|sorted\|tuple)()` |  |
 | C415 | UnnecessarySubscriptReversal | Unnecessary subscript reversal of iterable within `(reversed\|set\|sorted)()` |  |
 | C416 | UnnecessaryComprehension | Unnecessary `(list\|set)` comprehension (rewrite using `(list\|set)()`) | 🛠 |
@@ -764,6 +820,14 @@ For more, see [flake8-return](https://pypi.org/project/flake8-return/1.2.0/) on
 | RET507 | SuperfluousElseContinue | Unnecessary `else` after `continue` statement |  |
 | RET508 | SuperfluousElseBreak | Unnecessary `else` after `break` statement |  |
 
+### flake8-simplify (SIM)
+
+For more, see [flake8-simplify](https://pypi.org/project/flake8-simplify/0.19.3/) on PyPI.
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| SIM118 | KeyInDict | Use `key in dict` instead of `key in dict.keys()` | 🛠 |
+
 ### flake8-tidy-imports (TID)
 
 For more, see [flake8-tidy-imports](https://pypi.org/project/flake8-tidy-imports/4.8.0/) on PyPI.
@@ -809,12 +873,15 @@ For more, see [Pylint](https://pypi.org/project/pylint/2.15.7/) on PyPI.
 | PLC0414 | UselessImportAlias | Import alias does not rename original package | 🛠 |
 | PLC2201 | MisplacedComparisonConstant | Comparison should be ... | 🛠 |
 | PLC3002 | UnnecessaryDirectLambdaCall | Lambda expression called directly. Execute the expression inline instead. |  |
+| PLE0117 | NonlocalWithoutBinding | Nonlocal name `...` found without binding |  |
+| PLE0118 | UsedPriorGlobalDeclaration | Name `...` is used prior to global declaration on line 1 |  |
 | 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 |  |
 | PLR1701 | ConsiderMergingIsinstance | Merge these isinstance calls: `isinstance(..., (...))` |  |
 | PLR1722 | UseSysExit | Use `sys.exit()` instead of `exit` | 🛠 |
 | 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 |  |
 
 ### Ruff-specific rules (RUF)
 
@@ -833,6 +900,37 @@ For more, see [Pylint](https://pypi.org/project/pylint/2.15.7/) on PyPI.
 
 Download the [Ruff VS Code extension](https://marketplace.visualstudio.com/items?itemName=charliermarsh.ruff).
 
+### Language Server Protocol
+
+Ruff is available as a [Language Server Protocol (LSP)](https://microsoft.github.io/language-server-protocol/)
+server, distributed as the [`python-lsp-ruff`](https://github.com/python-lsp/python-lsp-ruff) plugin
+for [`python-lsp-server`](https://github.com/python-lsp/python-lsp-server), both of which are
+installable via [PyPI](https://pypi.org/project/python-lsp-ruff/):
+
+```shell
+pip install python-lsp-server python-lsp-ruff
+```
+
+The LSP server can be used with any editor that supports the Language Server Protocol. For example,
+to use it with Neovim, you would add something like the following to your `init.lua`:
+
+```lua
+require'lspconfig'.pylsp.setup {
+  settings = {
+    pylsp = {
+      plugins = {
+        ruff = {
+          enabled = true
+        }
+      }
+    }
+  },
+}
+```
+
+[`ruffd`](https://github.com/Seamooo/ruffd) is another implementation of the Language Server
+Protocol (LSP) for Ruff, written in Rust.
+
 ### PyCharm
 
 Ruff can be installed as an [External Tool](https://www.jetbrains.com/help/pycharm/configuring-third-party-tools.html)
@@ -845,10 +943,13 @@ Ruff should then appear as a runnable action:
 
 ![Ruff as a runnable action](https://user-images.githubusercontent.com/1309177/193156026-732b0aaf-3dd9-4549-9b4d-2de6d2168a33.png)
 
-### Vim & Neovim (Unofficial)
+### Vim & Neovim
 
-Ruff is available as part of the [coc-pyright](https://github.com/fannheyward/coc-pyright) extension
-for coc.nvim.
+Ruff can be integrated into any editor that supports the Language Server Protocol (LSP) (see:
+[Language Server Protocol](#language-server-protocol)).
+
+Ruff is also available as part of the [coc-pyright](https://github.com/fannheyward/coc-pyright)
+extension for `coc.nvim`.
 
 <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>
@@ -904,11 +1005,6 @@ null_ls.setup({
 
 </details>
 
-### Language Server Protocol (Unofficial)
-
-[`ruffd`](https://github.com/Seamooo/ruffd) is a Rust-based language server for Ruff that implements
-the Language Server Protocol (LSP).
-
 ### GitHub Actions
 
 GitHub Actions has everything you need to run Ruff out-of-the-box:
@@ -956,9 +1052,8 @@ Under those conditions, Ruff implements every rule in Flake8.
 Ruff also re-implements some of the most popular Flake8 plugins and related code quality tools
 natively, including:
 
-- [`isort`](https://pypi.org/project/isort/)
-- [`pydocstyle`](https://pypi.org/project/pydocstyle/)
-- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
+- [`autoflake`](https://pypi.org/project/autoflake/) (1/7)
+- [`eradicate`](https://pypi.org/project/eradicate/)
 - [`flake8-2020`](https://pypi.org/project/flake8-2020/)
 - [`flake8-annotations`](https://pypi.org/project/flake8-annotations/)
 - [`flake8-bandit`](https://pypi.org/project/flake8-bandit/) (6/40)
@@ -976,12 +1071,13 @@ natively, including:
 - [`flake8-return`](https://pypi.org/project/flake8-return/)
 - [`flake8-super`](https://pypi.org/project/flake8-super/)
 - [`flake8-tidy-imports`](https://pypi.org/project/flake8-tidy-imports/) (1/3)
+- [`isort`](https://pypi.org/project/isort/)
 - [`mccabe`](https://pypi.org/project/mccabe/)
-- [`yesqa`](https://github.com/asottile/yesqa)
-- [`eradicate`](https://pypi.org/project/eradicate/)
-- [`pyupgrade`](https://pypi.org/project/pyupgrade/) (16/33)
+- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
+- [`pydocstyle`](https://pypi.org/project/pydocstyle/)
 - [`pygrep-hooks`](https://github.com/pre-commit/pygrep-hooks) (1/10)
-- [`autoflake`](https://pypi.org/project/autoflake/) (1/7)
+- [`pyupgrade`](https://pypi.org/project/pyupgrade/) (16/33)
+- [`yesqa`](https://github.com/asottile/yesqa)
 
 Note that, in some cases, Ruff uses different error code prefixes than would be found in the
 originating Flake8 plugins. For example, Ruff uses `TID252` to represent the `I252` rule from
@@ -991,8 +1087,7 @@ conflicts with the `isort` rules, like `I001`).
 
 Beyond the rule set, Ruff suffers from the following limitations vis-à-vis Flake8:
 
-1. Ruff does not yet support a few Python 3.9 and 3.10 language features, including structural
-   pattern matching and parenthesized context managers.
+1. Ruff does not yet support structural pattern matching.
 2. Flake8 has a plugin architecture and supports writing custom lint rules. (Instead, popular Flake8
    plugins are re-implemented in Rust as part of Ruff itself.)
 
@@ -1012,8 +1107,6 @@ Pylint parity is being tracked in [#689](https://github.com/charliermarsh/ruff/i
 
 Today, Ruff can be used to replace Flake8 when used with any of the following plugins:
 
-- [`pydocstyle`](https://pypi.org/project/pydocstyle/)
-- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
 - [`flake8-2020`](https://pypi.org/project/flake8-2020/)
 - [`flake8-annotations`](https://pypi.org/project/flake8-annotations/)
 - [`flake8-bandit`](https://pypi.org/project/flake8-bandit/) (6/40)
@@ -1032,6 +1125,8 @@ Today, Ruff can be used to replace Flake8 when used with any of the following pl
 - [`flake8-super`](https://pypi.org/project/flake8-super/)
 - [`flake8-tidy-imports`](https://pypi.org/project/flake8-tidy-imports/) (1/3)
 - [`mccabe`](https://pypi.org/project/mccabe/)
+- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
+- [`pydocstyle`](https://pypi.org/project/pydocstyle/)
 
 Ruff can also replace [`isort`](https://pypi.org/project/isort/),
 [`yesqa`](https://github.com/asottile/yesqa), [`eradicate`](https://pypi.org/project/eradicate/),
@@ -1374,7 +1469,7 @@ Exclusions are based on globs, and can be either:
   (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`).
 
-Note that you'll typically want to use [`extend_exclude`](#extend_exclude) to modify
+Note that you'll typically want to use [`extend-exclude`](#extend-exclude) to modify
 the excluded paths.
 
 **Default value**: `[".bzr", ".direnv", ".eggs", ".git", ".hg", ".mypy_cache", ".nox", ".pants.d", ".ruff_cache", ".svn", ".tox", ".venv", "__pypackages__", "_build", "buck-out", "build", "dist", "node_modules", "venv"]`
@@ -1390,6 +1485,30 @@ exclude = [".venv"]
 
 ---
 
+#### [`extend`](#extend)
+
+A path to a local `pyproject.toml` file to merge into this configuration.
+
+To resolve the current `pyproject.toml` file, Ruff will first resolve this base
+configuration file, then merge in any properties defined in the current configuration
+file.
+
+**Default value**: `None`
+
+**Type**: `Path`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+# Extend the `pyproject.toml` file in the parent directory.
+extend = "../pyproject.toml"
+# But use a different line length.
+line-length = 100
+```
+
+---
+
 #### [`extend-exclude`](#extend-exclude)
 
 A list of file patterns to omit from linting, in addition to those specified by `exclude`.
@@ -1602,6 +1721,24 @@ any matching files.
 
 ---
 
+#### [`respect-gitignore`](#respect-gitignore)
+
+Whether to automatically exclude files that are ignored by `.ignore`, `.gitignore`,
+`.git/info/exclude`, and global `gitignore` files. Enabled by default.
+
+**Default value**: `true`
+
+**Type**: `bool`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+respect_gitignore = false
+```
+
+---
+
 #### [`select`](#select)
 
 A list of check code prefixes to enable. Prefixes can specify exact checks (like
@@ -1647,6 +1784,25 @@ show-source = true
 
 The source code paths to consider, e.g., when resolving first- vs. third-party imports.
 
+As an example: given a Python package structure like:
+
+```text
+my_package/
+  pyproject.toml
+  src/
+    my_package/
+      __init__.py
+      foo.py
+      bar.py
+```
+
+The `src` directory should be included in `source` (e.g., `source = ["src"]`), such that
+when resolving imports, `my_package.foo` is considered a first-party import.
+
+This field supports globs. For example, if you have a series of Python packages in
+a `python_modules` directory, `src = ["python_modules/*"]` would expand to incorporate
+all of the packages in that directory.
+
 **Default value**: `["."]`
 
 **Type**: `Vec<PathBuf>`

flake8_to_ruff/Cargo.lock

@@ -771,7 +771,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8_to_ruff"
-version = "0.0.172"
+version = "0.0.181"
 dependencies = [
  "anyhow",
  "clap",
@@ -1975,7 +1975,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.172"
+version = "0.0.181"
 dependencies = [
  "anyhow",
  "bincode",
@@ -2028,7 +2028,7 @@ dependencies = [
 [[package]]
 name = "rustpython-ast"
 version = "0.1.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "num-bigint",
  "rustpython-common",
@@ -2038,7 +2038,7 @@ dependencies = [
 [[package]]
 name = "rustpython-common"
 version = "0.0.0"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ascii",
  "cfg-if 1.0.0",
@@ -2061,7 +2061,7 @@ dependencies = [
 [[package]]
 name = "rustpython-compiler-core"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "bincode",
  "bitflags",
@@ -2078,7 +2078,7 @@ dependencies = [
 [[package]]
 name = "rustpython-parser"
 version = "0.1.2"
-source = "git+https://github.com/RustPython/RustPython.git?rev=28f9f65ccc625f00835d84bbb5fba274dce5aa89#28f9f65ccc625f00835d84bbb5fba274dce5aa89"
+source = "git+https://github.com/RustPython/RustPython.git?rev=8d879a53197f9c73062f6160410bdba796a71cbf#8d879a53197f9c73062f6160410bdba796a71cbf"
 dependencies = [
  "ahash",
  "anyhow",

flake8_to_ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "flake8-to-ruff"
-version = "0.0.172-dev.0"
+version = "0.0.181-dev.0"
 edition = "2021"
 
 [lib]

flake8_to_ruff/src/converter.rs

@@ -246,6 +246,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -257,6 +258,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -291,6 +293,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -302,6 +305,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: Some(100),
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -336,6 +340,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -347,6 +352,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: Some(100),
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -381,6 +387,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -392,6 +399,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -426,6 +434,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -437,6 +446,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,
@@ -479,6 +489,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -490,6 +501,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::D100,
                 CheckCodePrefix::D101,
@@ -560,6 +572,7 @@ mod tests {
             allowed_confusables: None,
             dummy_variable_rgx: None,
             exclude: None,
+            extend: None,
             extend_exclude: None,
             extend_ignore: None,
             extend_select: None,
@@ -571,6 +584,7 @@ mod tests {
             ignore_init_module_imports: None,
             line_length: None,
             per_file_ignores: None,
+            respect_gitignore: None,
             select: Some(vec![
                 CheckCodePrefix::E,
                 CheckCodePrefix::F,

flake8_to_ruff/src/plugin.rs

@@ -18,6 +18,7 @@ pub enum Plugin {
     Flake8Print,
     Flake8Quotes,
     Flake8Return,
+    Flake8Simplify,
     Flake8TidyImports,
     McCabe,
     PEP8Naming,
@@ -41,6 +42,7 @@ impl FromStr for Plugin {
             "flake8-print" => Ok(Plugin::Flake8Print),
             "flake8-quotes" => Ok(Plugin::Flake8Quotes),
             "flake8-return" => Ok(Plugin::Flake8Return),
+            "flake8-simplify" => Ok(Plugin::Flake8Simplify),
             "flake8-tidy-imports" => Ok(Plugin::Flake8TidyImports),
             "mccabe" => Ok(Plugin::McCabe),
             "pep8-naming" => Ok(Plugin::PEP8Naming),
@@ -65,6 +67,7 @@ impl Plugin {
             Plugin::Flake8Print => CheckCodePrefix::T2,
             Plugin::Flake8Quotes => CheckCodePrefix::Q,
             Plugin::Flake8Return => CheckCodePrefix::RET,
+            Plugin::Flake8Simplify => CheckCodePrefix::SIM,
             Plugin::Flake8TidyImports => CheckCodePrefix::I25,
             Plugin::McCabe => CheckCodePrefix::C9,
             Plugin::PEP8Naming => CheckCodePrefix::N,
@@ -101,6 +104,7 @@ impl Plugin {
             Plugin::Flake8Print => vec![CheckCodePrefix::T2],
             Plugin::Flake8Quotes => vec![CheckCodePrefix::Q],
             Plugin::Flake8Return => vec![CheckCodePrefix::RET],
+            Plugin::Flake8Simplify => vec![CheckCodePrefix::SIM],
             Plugin::Flake8TidyImports => vec![CheckCodePrefix::I25],
             Plugin::McCabe => vec![CheckCodePrefix::C9],
             Plugin::PEP8Naming => vec![CheckCodePrefix::N],
@@ -397,6 +401,7 @@ pub fn infer_plugins_from_codes(codes: &BTreeSet<CheckCodePrefix>) -> Vec<Plugin
         Plugin::Flake8Print,
         Plugin::Flake8Quotes,
         Plugin::Flake8Return,
+        Plugin::Flake8Simplify,
         Plugin::Flake8TidyImports,
         Plugin::PEP8Naming,
         Plugin::Pyupgrade,

resources/test/fixtures/README.md

@@ -0,0 +1,3 @@
+# fixtures
+
+Fixture files used for snapshot testing.

resources/test/fixtures/flake8_bugbear/B009_B010.py

@@ -20,6 +20,8 @@ getattr(foo, "_123abc")
 getattr(foo, "abc123")
 getattr(foo, r"abc123")
 _ = lambda x: getattr(x, "bar")
+if getattr(x, "bar"):
+    pass
 
 # Valid setattr usage
 setattr(foo, bar, None)
@@ -28,6 +30,8 @@ setattr(foo, "123abc", None)
 setattr(foo, r"123\abc", None)
 setattr(foo, "except", None)
 _ = lambda x: setattr(x, "bar", 1)
+if setattr(x, "bar", 1):
+    pass
 
 # Invalid usage
 setattr(foo, "bar", None)

resources/test/fixtures/flake8_simplify/SIM118.py

@@ -0,0 +1,12 @@
+key in dict.keys() # SIM118
+
+foo["bar"] in dict.keys() # SIM118
+
+foo() in dict.keys() # SIM118
+
+for key in dict.keys(): # SIM118
+    pass
+
+for key in list(dict.keys()):
+    if some_property(key):
+        del dict[key]

resources/test/fixtures/isort/insert_empty_lines.py

@@ -39,3 +39,27 @@ if True:
     import collections
     import typing
     def f(): pass
+
+
+import os
+
+# Comment goes here.
+
+def f():
+    pass
+
+
+import os
+
+# Comment goes here.
+def f():
+    pass
+
+
+import os
+
+# Comment goes here.
+
+# And another.
+def f():
+    pass

resources/test/fixtures/isort/insert_empty_lines.pyi

@@ -39,3 +39,27 @@ if True:
     import collections
     import typing
     def f(): pass
+
+
+import os
+
+# Comment goes here.
+
+def f():
+    pass
+
+
+import os
+
+# Comment goes here.
+def f():
+    pass
+
+
+import os
+
+# Comment goes here.
+
+# And another.
+def f():
+    pass

resources/test/fixtures/pyflakes/F504.py

@@ -4,3 +4,6 @@ a = "wrong"
 
 hidden = {"a": "!"}
 "%(a)s %(c)s" % {"x": 1, **hidden}  # Ok (cannot see through splat)
+
+"%(a)s" % {"a": 1, r"b": "!"}  # F504 ("b" not used)
+"%(a)s" % {'a': 1, u"b": "!"}  # F504 ("b" not used)

resources/test/fixtures/pyflakes/F541.py

@@ -9,3 +9,4 @@ e = (
 )
 
 g = f"ghi{123:{45}}"
+h = "x" "y" f"z"

resources/test/fixtures/pyflakes/F821_6.py

@@ -0,0 +1,17 @@
+"""Test: annotated global."""
+
+
+n: int
+
+
+def f():
+    print(n)
+
+
+def g():
+    global n
+    n = 1
+
+
+g()
+f()

resources/test/fixtures/pyflakes/F841_0.py

@@ -10,13 +10,13 @@ except ValueError as e:
     print(e)
 
 
-def f1():
+def f():
     x = 1
     y = 2
     z = x + y
 
 
-def f2():
+def f():
     foo = (1, 2)
     (a, b) = (1, 2)
 
@@ -26,12 +26,12 @@ def f2():
     (x, y) = baz = bar
 
 
-def f3():
+def f():
     locals()
     x = 1
 
 
-def f4():
+def f():
     _ = 1
     __ = 1
     _discarded = 1
@@ -40,26 +40,26 @@ def f4():
 a = 1
 
 
-def f5():
+def f():
     global a
 
-    # Used in `f7` via `nonlocal`.
+    # Used in `c` via `nonlocal`.
     b = 1
 
-    def f6():
+    def c():
         # F841
         b = 1
 
-    def f7():
+    def d():
         nonlocal b
 
 
-def f6():
+def f():
     annotations = []
     assert len([annotations for annotations in annotations])
 
 
-def f7():
+def f():
     def connect():
         return None, None
 
@@ -67,6 +67,22 @@ def f7():
         cursor.execute("SELECT * FROM users")
 
 
-def f8():
-    with open("file") as f, open("") as ((a, b)):
+def f():
+    def connect():
+        return None, None
+
+    with (connect() as (connection, cursor)):
+        cursor.execute("SELECT * FROM users")
+
+
+def f():
+    with open("file") as my_file, open("") as ((this, that)):
+        print("hello")
+
+
+def f():
+    with (
+        open("file") as my_file,
+        open("") as ((this, that)),
+    ):
         print("hello")

resources/test/fixtures/pylint/global_variable_not_assigned.py

@@ -0,0 +1,32 @@
+###
+# Errors.
+###
+def f():
+    global x
+
+
+def f():
+    global x
+
+    print(x)
+
+
+###
+# Non-errors.
+###
+def f():
+    global x
+
+    x = 1
+
+
+def f():
+    global x
+
+    (x, y) = (1, 2)
+
+
+def f():
+    global x
+
+    del x

resources/test/fixtures/pylint/nonlocal_without_binding.py

@@ -0,0 +1,19 @@
+nonlocal x
+
+
+def f():
+    nonlocal x
+
+
+def f():
+    nonlocal y
+
+
+def f():
+    x = 1
+
+    def f():
+        nonlocal x
+
+    def f():
+        nonlocal y

resources/test/fixtures/pylint/used_prior_global_declaration.py

@@ -0,0 +1,148 @@
+###
+# Errors.
+###
+def f():
+    print(x)
+
+    global x
+
+    print(x)
+
+
+def f():
+    global x
+
+    print(x)
+
+    global x
+
+    print(x)
+
+
+def f():
+    print(x)
+
+    global x, y
+
+    print(x)
+
+
+def f():
+    global x, y
+
+    print(x)
+
+    global x, y
+
+    print(x)
+
+
+def f():
+    x = 1
+
+    global x
+
+    x = 1
+
+
+def f():
+    global x
+
+    x = 1
+
+    global x
+
+    x = 1
+
+
+def f():
+    del x
+
+    global x, y
+
+    del x
+
+
+def f():
+    global x, y
+
+    del x
+
+    global x, y
+
+    del x
+
+
+def f():
+    del x
+
+    global x
+
+    del x
+
+
+def f():
+    global x
+
+    del x
+
+    global x
+
+    del x
+
+
+def f():
+    del x
+
+    global x, y
+
+    del x
+
+
+def f():
+    global x, y
+
+    del x
+
+    global x, y
+
+    del x
+
+
+###
+# Non-errors.
+###
+def f():
+    global x
+
+    print(x)
+
+
+def f():
+    global x, y
+
+    print(x)
+
+
+def f():
+    global x
+
+    x = 1
+
+
+def f():
+    global x, y
+
+    x = 1
+
+
+def f():
+    global x
+
+    del x
+
+
+def f():
+    global x, y
+
+    del x

resources/test/project/.gitignore

@@ -0,0 +1 @@
+examples/generated

resources/test/project/README.md

@@ -0,0 +1,90 @@
+# project
+
+An example multi-package Python project used to test setting resolution and other complex
+behaviors.
+
+## Expected behavior
+
+Running from the repo root should pick up and enforce the appropriate settings for each package:
+
+```
+∴ cargo run resources/test/project/
+Found 7 error(s).
+resources/test/project/examples/.dotfiles/script.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/.dotfiles/script.py:5:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/examples/docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+resources/test/project/examples/docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/src/file.py:1:8: F401 `os` imported but unused
+resources/test/project/src/file.py:5:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/src/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
+4 potentially fixable with the --fix option.
+```
+
+Running from the project directory itself should exhibit the same behavior:
+
+```
+∴ (cd resources/test/project/ && cargo run .)
+Found 7 error(s).
+examples/.dotfiles/script.py:1:8: F401 `os` imported but unused
+examples/.dotfiles/script.py:5:5: F841 Local variable `x` is assigned to but never used
+examples/docs/docs/file.py:1:1: I001 Import block is un-sorted or un-formatted
+examples/docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+src/file.py:1:8: F401 `os` imported but unused
+src/file.py:5:5: F841 Local variable `x` is assigned to but never used
+src/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
+4 potentially fixable with the --fix option.
+```
+
+Running from the sub-package directory should exhibit the same behavior, but omit the top-level
+files:
+
+```
+∴ (cd resources/test/project/examples/docs && cargo run .)
+Found 2 error(s).
+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
+1 potentially fixable with the --fix option.
+```
+
+`--config` should force Ruff to use the specified `pyproject.toml` for all files, and resolve
+file paths from the current working directory:
+
+```
+∴ (cargo run -- --config=resources/test/project/pyproject.toml resources/test/project/)
+Found 11 error(s).
+resources/test/project/examples/.dotfiles/script.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/.dotfiles/script.py:5:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/examples/docs/docs/concepts/file.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/docs/docs/concepts/file.py:5:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/examples/docs/docs/file.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/docs/docs/file.py:3:8: F401 `numpy` imported but unused
+resources/test/project/examples/docs/docs/file.py:4:27: F401 `docs.concepts.file` imported but unused
+resources/test/project/examples/docs/docs/file.py:8:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/src/file.py:1:8: F401 `os` imported but unused
+resources/test/project/src/file.py:5:5: F841 Local variable `x` is assigned to but never used
+resources/test/project/src/import_file.py:1:1: I001 Import block is un-sorted or un-formatted
+7 potentially fixable with the --fix option.
+```
+
+Running from a parent directory should this "ignore" the `exclude` (hence, `concepts/file.py` gets
+included in the output):
+
+```
+∴ (cd resources/test/project/examples && cargo run -- --config=docs/pyproject.toml .)
+Found 4 error(s).
+.dotfiles/script.py:5:5: F841 Local variable `x` is assigned to but never used
+docs/docs/concepts/file.py:5:5: F841 Local variable `x` is assigned to but never used
+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
+1 potentially fixable with the --fix option.
+```
+
+Passing an excluded directory directly should report errors in the contained files:
+
+```
+∴ cargo run resources/test/project/examples/excluded/
+Found 2 error(s).
+resources/test/project/examples/excluded/script.py:1:8: F401 `os` imported but unused
+resources/test/project/examples/excluded/script.py:5:5: F841 Local variable `x` is assigned to but never used
+1 potentially fixable with the --fix option.
+```

resources/test/project/examples/.dotfiles/script.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/examples/docs/docs/concepts/file.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/examples/docs/docs/file.py

@@ -0,0 +1,8 @@
+import os
+
+import numpy as np
+from docs.concepts import file
+
+
+def f():
+    x = 1

resources/test/project/examples/docs/pyproject.toml

@@ -0,0 +1,6 @@
+[tool.ruff]
+extend = "../../pyproject.toml"
+src = ["."]
+extend-select = ["I001"]
+extend-ignore = ["F401"]
+extend-exclude = ["./docs/concepts/file.py"]

resources/test/project/examples/excluded/script.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/pyproject.toml

@@ -0,0 +1,4 @@
+[tool.ruff]
+src = [".", "python_modules/*"]
+exclude = ["examples/excluded"]
+extend-select = ["I001"]

resources/test/project/src/file.py

@@ -0,0 +1,5 @@
+import os
+
+
+def f():
+    x = 1

resources/test/project/src/import_file.py

@@ -0,0 +1,7 @@
+import numpy as np
+from app import app_file
+from core import core_file
+
+np.array([1, 2, 3])
+app_file()
+core_file()

ruff_dev/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_dev"
-version = "0.0.172"
+version = "0.0.181"
 edition = "2021"
 
 [dependencies]
@@ -11,8 +11,8 @@ itertools = { version = "0.10.5" }
 libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "f2f0b7a487a8725d161fe8b3ed73a6758b21e177" }
 once_cell = { version = "1.16.0" }
 ruff = { path = ".." }
-rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "28f9f65ccc625f00835d84bbb5fba274dce5aa89" }
-rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "28f9f65ccc625f00835d84bbb5fba274dce5aa89" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "28f9f65ccc625f00835d84bbb5fba274dce5aa89" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "8d879a53197f9c73062f6160410bdba796a71cbf" }
 strum = { version = "0.24.1", features = ["strum_macros"] }
 strum_macros = { version = "0.24.3" }

ruff_macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_macros"
-version = "0.0.172"
+version = "0.0.181"
 edition = "2021"
 
 [lib]

src/ast/operations.rs

@@ -1,9 +1,12 @@
+use rustc_hash::FxHashMap;
 use rustpython_ast::{Cmpop, Located};
 use rustpython_parser::ast::{Constant, Expr, ExprKind, Stmt, StmtKind};
 use rustpython_parser::lexer;
 use rustpython_parser::lexer::Tok;
 
 use crate::ast::types::{Binding, BindingKind, Scope};
+use crate::ast::visitor;
+use crate::ast::visitor::Visitor;
 
 /// Extract the names bound to a given __all__ assignment.
 pub fn extract_all_names(stmt: &Stmt, scope: &Scope, bindings: &[Binding]) -> Vec<String> {
@@ -69,6 +72,38 @@ pub fn extract_all_names(stmt: &Stmt, scope: &Scope, bindings: &[Binding]) -> Ve
     names
 }
 
+#[derive(Default)]
+struct GlobalVisitor<'a> {
+    globals: FxHashMap<&'a str, &'a Stmt>,
+}
+
+impl<'a> Visitor<'a> for GlobalVisitor<'a> {
+    fn visit_stmt(&mut self, stmt: &'a Stmt) {
+        match &stmt.node {
+            StmtKind::Global { names } => {
+                for name in names {
+                    self.globals.insert(name, stmt);
+                }
+            }
+            StmtKind::FunctionDef { .. }
+            | StmtKind::AsyncFunctionDef { .. }
+            | StmtKind::ClassDef { .. } => {
+                // Don't recurse.
+            }
+            _ => visitor::walk_stmt(self, stmt),
+        }
+    }
+}
+
+/// Extract a map from global name to its last-defining `Stmt`.
+pub fn extract_globals(body: &[Stmt]) -> FxHashMap<&str, &Stmt> {
+    let mut visitor = GlobalVisitor::default();
+    for stmt in body {
+        visitor.visit_stmt(stmt);
+    }
+    visitor.globals
+}
+
 /// Check if a node is parent of a conditional branch.
 pub fn on_conditional_branch<'a>(parents: &mut impl Iterator<Item = &'a Stmt>) -> bool {
     parents.any(|parent| {

src/ast/types.rs

@@ -32,23 +32,29 @@ impl Range {
 
 #[derive(Debug)]
 pub struct FunctionDef<'a> {
+    // Properties derived from StmtKind::FunctionDef.
     pub name: &'a str,
     pub args: &'a Arguments,
     pub body: &'a [Stmt],
     pub decorator_list: &'a [Expr],
     // pub returns: Option<&'a Expr>,
     // pub type_comment: Option<&'a str>,
+    // Scope-specific properties.
     // TODO(charlie): Create AsyncFunctionDef to mirror the AST.
     pub async_: bool,
+    pub globals: FxHashMap<&'a str, &'a Stmt>,
 }
 
 #[derive(Debug)]
 pub struct ClassDef<'a> {
+    // Properties derived from StmtKind::ClassDef.
     pub name: &'a str,
     pub bases: &'a [Expr],
     pub keywords: &'a [Keyword],
     // pub body: &'a [Stmt],
     pub decorator_list: &'a [Expr],
+    // Scope-specific properties.
+    pub globals: FxHashMap<&'a str, &'a Stmt>,
 }
 
 #[derive(Debug)]
@@ -73,7 +79,11 @@ pub struct Scope<'a> {
     pub kind: ScopeKind<'a>,
     pub import_starred: bool,
     pub uses_locals: bool,
+    /// A map from bound name to binding index.
     pub values: FxHashMap<&'a str, usize>,
+    /// A list of (name, index) pairs for bindings that were overridden in the
+    /// scope.
+    pub overridden: Vec<(&'a str, usize)>,
 }
 
 impl<'a> Scope<'a> {
@@ -84,6 +94,7 @@ impl<'a> Scope<'a> {
             import_starred: false,
             uses_locals: false,
             values: FxHashMap::default(),
+            overridden: Vec::new(),
         }
     }
 }
@@ -117,8 +128,6 @@ pub struct Binding<'a> {
     /// Tuple of (scope index, range) indicating the scope and range at which
     /// the binding was last used.
     pub used: Option<(usize, Range)>,
-    /// A list of pointers to `Binding` instances that redefined this binding.
-    pub redefined: Vec<usize>,
 }
 
 // Pyflakes defines the following binding hierarchy (via inheritance):

src/ast/whitespace.rs

@@ -1,3 +1,4 @@
+use std::borrow::Cow;
 use std::str::Lines;
 
 use rustpython_ast::{Located, Location};
@@ -5,31 +6,26 @@ use rustpython_ast::{Located, Location};
 use crate::ast::types::Range;
 use crate::check_ast::Checker;
 
+/// Extract the leading indentation from a line.
+pub fn indentation<'a, T>(checker: &'a Checker, located: &'a Located<T>) -> Cow<'a, str> {
+    let range = Range::from_located(located);
+    checker.locator.slice_source_code_range(&Range {
+        location: Location::new(range.location.row(), 0),
+        end_location: Location::new(range.location.row(), range.location.column()),
+    })
+}
+
 /// Extract the leading words from a line of text.
-pub fn leading_words(line: &str) -> String {
-    line.trim()
-        .chars()
-        .take_while(|char| char.is_alphanumeric() || char.is_whitespace())
-        .collect()
+pub fn leading_words(line: &str) -> &str {
+    let line = line.trim();
+    line.find(|char: char| !char.is_alphanumeric() && !char.is_whitespace())
+        .map_or(line, |index| &line[..index])
 }
 
 /// Extract the leading whitespace from a line of text.
-pub fn leading_space(line: &str) -> String {
-    line.chars()
-        .take_while(|char| char.is_whitespace())
-        .collect()
-}
-
-/// Extract the leading indentation from a line.
-pub fn indentation<T>(checker: &Checker, located: &Located<T>) -> String {
-    let range = Range::from_located(located);
-    checker
-        .locator
-        .slice_source_code_range(&Range {
-            location: Location::new(range.location.row(), 0),
-            end_location: Location::new(range.location.row(), range.location.column()),
-        })
-        .to_string()
+pub fn leading_space(line: &str) -> &str {
+    line.find(|char: char| !char.is_whitespace())
+        .map_or(line, |index| &line[..index])
 }
 
 /// Replace any non-whitespace characters from an indentation string.

src/autofix/fixer.rs

@@ -10,7 +10,7 @@ use crate::autofix::Fix;
 use crate::checks::Check;
 use crate::source_code_locator::SourceCodeLocator;
 
-#[derive(Hash)]
+#[derive(Debug, Hash)]
 pub enum Mode {
     Generate,
     Apply,

src/autofix/mod.rs

@@ -35,12 +35,4 @@ impl Fix {
             end_location: at,
         }
     }
-
-    pub fn dummy(location: Location) -> Self {
-        Self {
-            content: String::new(),
-            location,
-            end_location: location,
-        }
-    }
 }

src/check_imports.rs

@@ -37,7 +37,7 @@ pub fn check_imports(
     autofix: bool,
     path: &Path,
 ) -> Vec<Check> {
-    let mut tracker = ImportTracker::new(directives, path);
+    let mut tracker = ImportTracker::new(locator, directives, path);
     for stmt in python_ast {
         tracker.visit_stmt(stmt);
     }

src/checks.rs

@@ -99,12 +99,15 @@ pub enum CheckCode {
     PLC0414,
     PLC2201,
     PLC3002,
+    PLE0117,
+    PLE0118,
     PLE1142,
     PLR0206,
     PLR0402,
     PLR1701,
     PLR1722,
     PLW0120,
+    PLW0602,
     // flake8-builtins
     A001,
     A002,
@@ -203,6 +206,8 @@ pub enum CheckCode {
     YTT301,
     YTT302,
     YTT303,
+    // flake8-simplify
+    SIM118,
     // pyupgrade
     UP001,
     UP003,
@@ -334,6 +339,7 @@ pub enum CheckCategory {
     Flake8Print,
     Flake8Quotes,
     Flake8Return,
+    Flake8Simplify,
     Flake8TidyImports,
     Flake8UnusedArguments,
     Eradicate,
@@ -374,6 +380,7 @@ impl CheckCategory {
             CheckCategory::Flake8Quotes => "flake8-quotes",
             CheckCategory::Flake8Return => "flake8-return",
             CheckCategory::Flake8TidyImports => "flake8-tidy-imports",
+            CheckCategory::Flake8Simplify => "flake8-simplify",
             CheckCategory::Flake8UnusedArguments => "flake8-unused-arguments",
             CheckCategory::Isort => "isort",
             CheckCategory::McCabe => "mccabe",
@@ -403,6 +410,7 @@ impl CheckCategory {
             CheckCategory::Flake8Print => vec![CheckCodePrefix::T20],
             CheckCategory::Flake8Quotes => vec![CheckCodePrefix::Q],
             CheckCategory::Flake8Return => vec![CheckCodePrefix::RET],
+            CheckCategory::Flake8Simplify => vec![CheckCodePrefix::SIM],
             CheckCategory::Flake8TidyImports => vec![CheckCodePrefix::TID],
             CheckCategory::Flake8UnusedArguments => vec![CheckCodePrefix::ARG],
             CheckCategory::Isort => vec![CheckCodePrefix::I],
@@ -478,6 +486,10 @@ impl CheckCategory {
                 "https://pypi.org/project/flake8-return/1.2.0/",
                 &Platform::PyPI,
             )),
+            CheckCategory::Flake8Simplify => Some((
+                "https://pypi.org/project/flake8-simplify/0.19.3/",
+                &Platform::PyPI,
+            )),
             CheckCategory::Flake8TidyImports => Some((
                 "https://pypi.org/project/flake8-tidy-imports/4.8.0/",
                 &Platform::PyPI,
@@ -635,15 +647,18 @@ pub enum CheckKind {
     UnusedVariable(String),
     YieldOutsideFunction(DeferralKeyword),
     // pylint
-    ConsiderMergingIsinstance(String, Vec<String>),
-    UselessImportAlias,
-    MisplacedComparisonConstant(String),
-    UnnecessaryDirectLambdaCall,
-    PropertyWithParameters,
-    ConsiderUsingFromImport(String, String),
     AwaitOutsideAsync,
-    UselessElseOnLoop,
+    ConsiderMergingIsinstance(String, Vec<String>),
+    ConsiderUsingFromImport(String, String),
+    GlobalVariableNotAssigned(String),
+    MisplacedComparisonConstant(String),
+    NonlocalWithoutBinding(String),
+    PropertyWithParameters,
+    UnnecessaryDirectLambdaCall,
     UseSysExit(String),
+    UsedPriorGlobalDeclaration(String, usize),
+    UselessElseOnLoop,
+    UselessImportAlias,
     // flake8-builtins
     BuiltinVariableShadowing(String),
     BuiltinArgumentShadowing(String),
@@ -740,6 +755,8 @@ pub enum CheckKind {
     SysVersion0Referenced,
     SysVersionCmpStr10,
     SysVersionSlice1Referenced,
+    // flake8-simplify
+    KeyInDict(String, String),
     // pyupgrade
     TypeOfPrimitive(Primitive),
     UselessMetaclassType,
@@ -950,6 +967,8 @@ impl CheckCode {
             CheckCode::PLC0414 => CheckKind::UselessImportAlias,
             CheckCode::PLC2201 => CheckKind::MisplacedComparisonConstant("...".to_string()),
             CheckCode::PLC3002 => CheckKind::UnnecessaryDirectLambdaCall,
+            CheckCode::PLE0117 => CheckKind::NonlocalWithoutBinding("...".to_string()),
+            CheckCode::PLE0118 => CheckKind::UsedPriorGlobalDeclaration("...".to_string(), 1),
             CheckCode::PLE1142 => CheckKind::AwaitOutsideAsync,
             CheckCode::PLR0402 => {
                 CheckKind::ConsiderUsingFromImport("...".to_string(), "...".to_string())
@@ -960,6 +979,7 @@ impl CheckCode {
             }
             CheckCode::PLR1722 => CheckKind::UseSysExit("exit".to_string()),
             CheckCode::PLW0120 => CheckKind::UselessElseOnLoop,
+            CheckCode::PLW0602 => CheckKind::GlobalVariableNotAssigned("...".to_string()),
             // flake8-builtins
             CheckCode::A001 => CheckKind::BuiltinVariableShadowing("...".to_string()),
             CheckCode::A002 => CheckKind::BuiltinArgumentShadowing("...".to_string()),
@@ -1073,6 +1093,8 @@ impl CheckCode {
             CheckCode::YTT303 => CheckKind::SysVersionSlice1Referenced,
             // flake8-blind-except
             CheckCode::BLE001 => CheckKind::BlindExcept("Exception".to_string()),
+            // flake8-simplify
+            CheckCode::SIM118 => CheckKind::KeyInDict("key".to_string(), "dict".to_string()),
             // pyupgrade
             CheckCode::UP001 => CheckKind::UselessMetaclassType,
             CheckCode::UP003 => CheckKind::TypeOfPrimitive(Primitive::Str),
@@ -1402,12 +1424,15 @@ impl CheckCode {
             CheckCode::PLC0414 => CheckCategory::Pylint,
             CheckCode::PLC2201 => CheckCategory::Pylint,
             CheckCode::PLC3002 => CheckCategory::Pylint,
+            CheckCode::PLE0117 => CheckCategory::Pylint,
+            CheckCode::PLE0118 => CheckCategory::Pylint,
             CheckCode::PLE1142 => CheckCategory::Pylint,
             CheckCode::PLR0206 => CheckCategory::Pylint,
             CheckCode::PLR0402 => CheckCategory::Pylint,
             CheckCode::PLR1701 => CheckCategory::Pylint,
             CheckCode::PLR1722 => CheckCategory::Pylint,
             CheckCode::PLW0120 => CheckCategory::Pylint,
+            CheckCode::PLW0602 => CheckCategory::Pylint,
             CheckCode::Q000 => CheckCategory::Flake8Quotes,
             CheckCode::Q001 => CheckCategory::Flake8Quotes,
             CheckCode::Q002 => CheckCategory::Flake8Quotes,
@@ -1430,6 +1455,7 @@ impl CheckCode {
             CheckCode::S105 => CheckCategory::Flake8Bandit,
             CheckCode::S106 => CheckCategory::Flake8Bandit,
             CheckCode::S107 => CheckCategory::Flake8Bandit,
+            CheckCode::SIM118 => CheckCategory::Flake8Simplify,
             CheckCode::T100 => CheckCategory::Flake8Debugger,
             CheckCode::T201 => CheckCategory::Flake8Print,
             CheckCode::T203 => CheckCategory::Flake8Print,
@@ -1530,15 +1556,18 @@ impl CheckKind {
             CheckKind::NoNewLineAtEndOfFile => &CheckCode::W292,
             CheckKind::InvalidEscapeSequence(_) => &CheckCode::W605,
             // pylint
-            CheckKind::UselessImportAlias => &CheckCode::PLC0414,
-            CheckKind::MisplacedComparisonConstant(..) => &CheckCode::PLC2201,
-            CheckKind::UnnecessaryDirectLambdaCall => &CheckCode::PLC3002,
             CheckKind::AwaitOutsideAsync => &CheckCode::PLE1142,
             CheckKind::ConsiderMergingIsinstance(..) => &CheckCode::PLR1701,
-            CheckKind::PropertyWithParameters => &CheckCode::PLR0206,
             CheckKind::ConsiderUsingFromImport(..) => &CheckCode::PLR0402,
+            CheckKind::GlobalVariableNotAssigned(..) => &CheckCode::PLW0602,
+            CheckKind::MisplacedComparisonConstant(..) => &CheckCode::PLC2201,
+            CheckKind::PropertyWithParameters => &CheckCode::PLR0206,
+            CheckKind::UnnecessaryDirectLambdaCall => &CheckCode::PLC3002,
             CheckKind::UseSysExit(_) => &CheckCode::PLR1722,
+            CheckKind::NonlocalWithoutBinding(..) => &CheckCode::PLE0117,
+            CheckKind::UsedPriorGlobalDeclaration(..) => &CheckCode::PLE0118,
             CheckKind::UselessElseOnLoop => &CheckCode::PLW0120,
+            CheckKind::UselessImportAlias => &CheckCode::PLC0414,
             // flake8-builtins
             CheckKind::BuiltinVariableShadowing(_) => &CheckCode::A001,
             CheckKind::BuiltinArgumentShadowing(_) => &CheckCode::A002,
@@ -1635,6 +1664,8 @@ impl CheckKind {
             CheckKind::SysVersion0Referenced => &CheckCode::YTT301,
             CheckKind::SysVersionCmpStr10 => &CheckCode::YTT302,
             CheckKind::SysVersionSlice1Referenced => &CheckCode::YTT303,
+            // flake8-simplify
+            CheckKind::KeyInDict(..) => &CheckCode::SIM118,
             // pyupgrade
             CheckKind::TypeOfPrimitive(_) => &CheckCode::UP003,
             CheckKind::UselessMetaclassType => &CheckCode::UP001,
@@ -1947,6 +1978,9 @@ impl CheckKind {
             CheckKind::MisplacedComparisonConstant(comparison) => {
                 format!("Comparison should be {comparison}")
             }
+            CheckKind::NonlocalWithoutBinding(name) => {
+                format!("Nonlocal name `{name}` found without binding")
+            }
             CheckKind::UnnecessaryDirectLambdaCall => "Lambda expression called directly. Execute \
                                                        the expression inline instead."
                 .to_string(),
@@ -1956,6 +1990,12 @@ impl CheckKind {
             CheckKind::ConsiderUsingFromImport(module, name) => {
                 format!("Use `from {module} import {name}` in lieu of alias")
             }
+            CheckKind::UsedPriorGlobalDeclaration(name, line) => {
+                format!("Name `{name}` is used prior to global declaration on line {line}")
+            }
+            CheckKind::GlobalVariableNotAssigned(name) => {
+                format!("Using global for `{name}` but no assignment is done")
+            }
             CheckKind::AwaitOutsideAsync => {
                 "`await` should be used within an async function".to_string()
             }
@@ -2292,6 +2332,10 @@ impl CheckKind {
             CheckKind::SysVersionSlice1Referenced => {
                 "`sys.version[:1]` referenced (python10), use `sys.version_info`".to_string()
             }
+            // flake8-simplify
+            CheckKind::KeyInDict(key, dict) => {
+                format!("Use `{key} in {dict}` instead of `{key} in {dict}.keys()`")
+            }
             // pyupgrade
             CheckKind::TypeOfPrimitive(primitive) => {
                 format!("Use `{}` instead of `type(...)`", primitive.builtin())
@@ -2636,6 +2680,7 @@ impl CheckKind {
                 | CheckKind::ImplicitReturn
                 | CheckKind::ImplicitReturnValue
                 | CheckKind::IsLiteral
+                | CheckKind::KeyInDict(..)
                 | CheckKind::MisplacedComparisonConstant(..)
                 | CheckKind::NewLineAfterLastParagraph
                 | CheckKind::NewLineAfterSectionName(..)
@@ -2651,6 +2696,7 @@ impl CheckKind {
                 | CheckKind::NotIsTest
                 | CheckKind::OneBlankLineAfterClass(..)
                 | CheckKind::OneBlankLineBeforeClass(..)
+                | CheckKind::PercentFormatExtraNamedArguments(..)
                 | CheckKind::PEP3120UnnecessaryCodingComment
                 | CheckKind::PPrintFound
                 | CheckKind::PrintFound
@@ -2663,9 +2709,11 @@ impl CheckKind {
                 | CheckKind::SectionUnderlineMatchesSectionLength(..)
                 | CheckKind::SectionUnderlineNotOverIndented(..)
                 | CheckKind::SetAttrWithConstant
+                | CheckKind::StringDotFormatExtraNamedArguments(..)
                 | CheckKind::SuperCallWithParameters
                 | CheckKind::TrueFalseComparison(..)
                 | CheckKind::TypeOfPrimitive(..)
+                | CheckKind::UnnecessaryCallAroundSorted(..)
                 | CheckKind::UnnecessaryCollectionCall(..)
                 | CheckKind::UnnecessaryComprehension(..)
                 | CheckKind::UnnecessaryEncodeUTF8

src/checks_gen.rs

@@ -315,6 +315,11 @@ pub enum CheckCodePrefix {
     PLC300,
     PLC3002,
     PLE,
+    PLE0,
+    PLE01,
+    PLE011,
+    PLE0117,
+    PLE0118,
     PLE1,
     PLE11,
     PLE114,
@@ -338,6 +343,9 @@ pub enum CheckCodePrefix {
     PLW01,
     PLW012,
     PLW0120,
+    PLW06,
+    PLW060,
+    PLW0602,
     Q,
     Q0,
     Q00,
@@ -374,6 +382,10 @@ pub enum CheckCodePrefix {
     S105,
     S106,
     S107,
+    SIM,
+    SIM1,
+    SIM11,
+    SIM118,
     T,
     T1,
     T10,
@@ -1343,7 +1355,14 @@ impl CheckCodePrefix {
             CheckCodePrefix::PLC30 => vec![CheckCode::PLC3002],
             CheckCodePrefix::PLC300 => vec![CheckCode::PLC3002],
             CheckCodePrefix::PLC3002 => vec![CheckCode::PLC3002],
-            CheckCodePrefix::PLE => vec![CheckCode::PLE1142],
+            CheckCodePrefix::PLE => {
+                vec![CheckCode::PLE0117, CheckCode::PLE0118, CheckCode::PLE1142]
+            }
+            CheckCodePrefix::PLE0 => vec![CheckCode::PLE0117, CheckCode::PLE0118],
+            CheckCodePrefix::PLE01 => vec![CheckCode::PLE0117, CheckCode::PLE0118],
+            CheckCodePrefix::PLE011 => vec![CheckCode::PLE0117, CheckCode::PLE0118],
+            CheckCodePrefix::PLE0117 => vec![CheckCode::PLE0117],
+            CheckCodePrefix::PLE0118 => vec![CheckCode::PLE0118],
             CheckCodePrefix::PLE1 => vec![CheckCode::PLE1142],
             CheckCodePrefix::PLE11 => vec![CheckCode::PLE1142],
             CheckCodePrefix::PLE114 => vec![CheckCode::PLE1142],
@@ -1367,11 +1386,14 @@ impl CheckCodePrefix {
             CheckCodePrefix::PLR1701 => vec![CheckCode::PLR1701],
             CheckCodePrefix::PLR172 => vec![CheckCode::PLR1722],
             CheckCodePrefix::PLR1722 => vec![CheckCode::PLR1722],
-            CheckCodePrefix::PLW => vec![CheckCode::PLW0120],
-            CheckCodePrefix::PLW0 => vec![CheckCode::PLW0120],
+            CheckCodePrefix::PLW => vec![CheckCode::PLW0120, CheckCode::PLW0602],
+            CheckCodePrefix::PLW0 => vec![CheckCode::PLW0120, CheckCode::PLW0602],
             CheckCodePrefix::PLW01 => vec![CheckCode::PLW0120],
             CheckCodePrefix::PLW012 => vec![CheckCode::PLW0120],
             CheckCodePrefix::PLW0120 => vec![CheckCode::PLW0120],
+            CheckCodePrefix::PLW06 => vec![CheckCode::PLW0602],
+            CheckCodePrefix::PLW060 => vec![CheckCode::PLW0602],
+            CheckCodePrefix::PLW0602 => vec![CheckCode::PLW0602],
             CheckCodePrefix::Q => vec![
                 CheckCode::Q000,
                 CheckCode::Q001,
@@ -1476,6 +1498,10 @@ impl CheckCodePrefix {
             CheckCodePrefix::S105 => vec![CheckCode::S105],
             CheckCodePrefix::S106 => vec![CheckCode::S106],
             CheckCodePrefix::S107 => vec![CheckCode::S107],
+            CheckCodePrefix::SIM => vec![CheckCode::SIM118],
+            CheckCodePrefix::SIM1 => vec![CheckCode::SIM118],
+            CheckCodePrefix::SIM11 => vec![CheckCode::SIM118],
+            CheckCodePrefix::SIM118 => vec![CheckCode::SIM118],
             CheckCodePrefix::T => vec![CheckCode::T100, CheckCode::T201, CheckCode::T203],
             CheckCodePrefix::T1 => vec![CheckCode::T100],
             CheckCodePrefix::T10 => vec![CheckCode::T100],
@@ -2118,6 +2144,11 @@ impl CheckCodePrefix {
             CheckCodePrefix::PLC300 => SuffixLength::Three,
             CheckCodePrefix::PLC3002 => SuffixLength::Four,
             CheckCodePrefix::PLE => SuffixLength::Zero,
+            CheckCodePrefix::PLE0 => SuffixLength::One,
+            CheckCodePrefix::PLE01 => SuffixLength::Two,
+            CheckCodePrefix::PLE011 => SuffixLength::Three,
+            CheckCodePrefix::PLE0117 => SuffixLength::Four,
+            CheckCodePrefix::PLE0118 => SuffixLength::Four,
             CheckCodePrefix::PLE1 => SuffixLength::One,
             CheckCodePrefix::PLE11 => SuffixLength::Two,
             CheckCodePrefix::PLE114 => SuffixLength::Three,
@@ -2141,6 +2172,9 @@ impl CheckCodePrefix {
             CheckCodePrefix::PLW01 => SuffixLength::Two,
             CheckCodePrefix::PLW012 => SuffixLength::Three,
             CheckCodePrefix::PLW0120 => SuffixLength::Four,
+            CheckCodePrefix::PLW06 => SuffixLength::Two,
+            CheckCodePrefix::PLW060 => SuffixLength::Three,
+            CheckCodePrefix::PLW0602 => SuffixLength::Four,
             CheckCodePrefix::Q => SuffixLength::Zero,
             CheckCodePrefix::Q0 => SuffixLength::One,
             CheckCodePrefix::Q00 => SuffixLength::Two,
@@ -2177,6 +2211,10 @@ impl CheckCodePrefix {
             CheckCodePrefix::S105 => SuffixLength::Three,
             CheckCodePrefix::S106 => SuffixLength::Three,
             CheckCodePrefix::S107 => SuffixLength::Three,
+            CheckCodePrefix::SIM => SuffixLength::Zero,
+            CheckCodePrefix::SIM1 => SuffixLength::One,
+            CheckCodePrefix::SIM11 => SuffixLength::Two,
+            CheckCodePrefix::SIM118 => SuffixLength::Three,
             CheckCodePrefix::T => SuffixLength::Zero,
             CheckCodePrefix::T1 => SuffixLength::One,
             CheckCodePrefix::T10 => SuffixLength::Two,
@@ -2277,6 +2315,7 @@ pub const CATEGORIES: &[CheckCodePrefix] = &[
     CheckCodePrefix::RET,
     CheckCodePrefix::RUF,
     CheckCodePrefix::S,
+    CheckCodePrefix::SIM,
     CheckCodePrefix::T,
     CheckCodePrefix::TID,
     CheckCodePrefix::UP,

src/cli.rs

@@ -1,4 +1,4 @@
-use std::path::PathBuf;
+use std::path::{Path, PathBuf};
 
 use clap::{command, Parser};
 use regex::Regex;
@@ -6,6 +6,7 @@ use rustc_hash::FxHashMap;
 
 use crate::checks::CheckCode;
 use crate::checks_gen::CheckCodePrefix;
+use crate::fs;
 use crate::logging::LogLevel;
 use crate::settings::types::{
     FilePattern, PatternPrefixPair, PerFileIgnore, PythonVersion, SerializationFormat,
@@ -47,46 +48,54 @@ pub struct Cli {
     pub no_cache: bool,
     /// List of error codes to enable.
     #[arg(long, value_delimiter = ',')]
-    pub select: Vec<CheckCodePrefix>,
+    pub select: Option<Vec<CheckCodePrefix>>,
     /// Like --select, but adds additional error codes on top of the selected
     /// ones.
     #[arg(long, value_delimiter = ',')]
-    pub extend_select: Vec<CheckCodePrefix>,
+    pub extend_select: Option<Vec<CheckCodePrefix>>,
     /// List of error codes to ignore.
     #[arg(long, value_delimiter = ',')]
-    pub ignore: Vec<CheckCodePrefix>,
+    pub ignore: Option<Vec<CheckCodePrefix>>,
     /// Like --ignore, but adds additional error codes on top of the ignored
     /// ones.
     #[arg(long, value_delimiter = ',')]
-    pub extend_ignore: Vec<CheckCodePrefix>,
+    pub extend_ignore: Option<Vec<CheckCodePrefix>>,
     /// List of paths, used to exclude files and/or directories from checks.
     #[arg(long, value_delimiter = ',')]
-    pub exclude: Vec<FilePattern>,
+    pub exclude: Option<Vec<FilePattern>>,
     /// Like --exclude, but adds additional files and directories on top of the
     /// excluded ones.
     #[arg(long, value_delimiter = ',')]
-    pub extend_exclude: Vec<FilePattern>,
+    pub extend_exclude: Option<Vec<FilePattern>>,
     /// List of error codes to treat as eligible for autofix. Only applicable
     /// when autofix itself is enabled (e.g., via `--fix`).
     #[arg(long, value_delimiter = ',')]
-    pub fixable: Vec<CheckCodePrefix>,
+    pub fixable: Option<Vec<CheckCodePrefix>>,
     /// List of error codes to treat as ineligible for autofix. Only applicable
     /// when autofix itself is enabled (e.g., via `--fix`).
     #[arg(long, value_delimiter = ',')]
-    pub unfixable: Vec<CheckCodePrefix>,
+    pub unfixable: Option<Vec<CheckCodePrefix>>,
     /// List of mappings from file pattern to code to exclude
     #[arg(long, value_delimiter = ',')]
-    pub per_file_ignores: Vec<PatternPrefixPair>,
+    pub per_file_ignores: Option<Vec<PatternPrefixPair>>,
     /// Output serialization format for error messages.
     #[arg(long, value_enum)]
     pub format: Option<SerializationFormat>,
     /// Show violations with source code.
-    #[arg(long)]
-    pub show_source: bool,
+    #[arg(long, overrides_with("no_show_source"))]
+    show_source: bool,
+    #[clap(long, overrides_with("show_source"), hide = true)]
+    no_show_source: bool,
+    /// Respect file exclusions via `.gitignore` and other standard ignore
+    /// files.
+    #[arg(long, overrides_with("no_respect_gitignore"))]
+    respect_gitignore: bool,
+    #[clap(long, overrides_with("respect_gitignore"), hide = true)]
+    no_respect_gitignore: bool,
     /// See the files Ruff will be run against with the current settings.
     #[arg(long)]
     pub show_files: bool,
-    /// See Ruff's settings.
+    /// See the settings Ruff will use to check a given Python file.
     #[arg(long)]
     pub show_settings: bool,
     /// Enable automatic additions of noqa directives to failing lines.
@@ -121,9 +130,51 @@ pub struct Cli {
 }
 
 impl Cli {
-    // See: https://github.com/clap-rs/clap/issues/3146
-    pub fn fix(&self) -> Option<bool> {
-        resolve_bool_arg(self.fix, self.no_fix)
+    /// Partition the CLI into command-line arguments and configuration
+    /// overrides.
+    pub fn partition(self) -> (Arguments, Overrides) {
+        (
+            Arguments {
+                add_noqa: self.add_noqa,
+                autoformat: self.autoformat,
+                config: self.config,
+                exit_zero: self.exit_zero,
+                explain: self.explain,
+                files: self.files,
+                generate_shell_completion: self.generate_shell_completion,
+                no_cache: self.no_cache,
+                quiet: self.quiet,
+                show_files: self.show_files,
+                show_settings: self.show_settings,
+                silent: self.silent,
+                stdin_filename: self.stdin_filename,
+                verbose: self.verbose,
+                watch: self.watch,
+            },
+            Overrides {
+                dummy_variable_rgx: self.dummy_variable_rgx,
+                exclude: self.exclude,
+                extend_exclude: self.extend_exclude,
+                extend_ignore: self.extend_ignore,
+                extend_select: self.extend_select,
+                fixable: self.fixable,
+                ignore: self.ignore,
+                line_length: self.line_length,
+                max_complexity: self.max_complexity,
+                per_file_ignores: self.per_file_ignores,
+                respect_gitignore: resolve_bool_arg(
+                    self.respect_gitignore,
+                    self.no_respect_gitignore,
+                ),
+                select: self.select,
+                show_source: resolve_bool_arg(self.show_source, self.no_show_source),
+                target_version: self.target_version,
+                unfixable: self.unfixable,
+                // TODO(charlie): Included in `pyproject.toml`, but not inherited.
+                fix: resolve_bool_arg(self.fix, self.no_fix),
+                format: self.format,
+            },
+        )
     }
 }
 
@@ -136,8 +187,53 @@ fn resolve_bool_arg(yes: bool, no: bool) -> Option<bool> {
     }
 }
 
+/// CLI settings that are distinct from configuration (commands, lists of files,
+/// etc.).
+#[allow(clippy::struct_excessive_bools)]
+pub struct Arguments {
+    pub add_noqa: bool,
+    pub autoformat: bool,
+    pub config: Option<PathBuf>,
+    pub exit_zero: bool,
+    pub explain: Option<CheckCode>,
+    pub files: Vec<PathBuf>,
+    pub generate_shell_completion: Option<clap_complete_command::Shell>,
+    pub no_cache: bool,
+    pub quiet: bool,
+    pub show_files: bool,
+    pub show_settings: bool,
+    pub silent: bool,
+    pub stdin_filename: Option<String>,
+    pub verbose: bool,
+    pub watch: bool,
+}
+
+/// CLI settings that function as configuration overrides.
+#[derive(Clone)]
+#[allow(clippy::struct_excessive_bools)]
+pub struct Overrides {
+    pub dummy_variable_rgx: Option<Regex>,
+    pub exclude: Option<Vec<FilePattern>>,
+    pub extend_exclude: Option<Vec<FilePattern>>,
+    pub extend_ignore: Option<Vec<CheckCodePrefix>>,
+    pub extend_select: Option<Vec<CheckCodePrefix>>,
+    pub fixable: Option<Vec<CheckCodePrefix>>,
+    pub ignore: Option<Vec<CheckCodePrefix>>,
+    pub line_length: Option<usize>,
+    pub max_complexity: Option<usize>,
+    pub per_file_ignores: Option<Vec<PatternPrefixPair>>,
+    pub respect_gitignore: Option<bool>,
+    pub select: Option<Vec<CheckCodePrefix>>,
+    pub show_source: Option<bool>,
+    pub target_version: Option<PythonVersion>,
+    pub unfixable: Option<Vec<CheckCodePrefix>>,
+    // TODO(charlie): Captured in pyproject.toml as a default, but not part of `Settings`.
+    pub fix: Option<bool>,
+    pub format: Option<SerializationFormat>,
+}
+
 /// Map the CLI settings to a `LogLevel`.
-pub fn extract_log_level(cli: &Cli) -> LogLevel {
+pub fn extract_log_level(cli: &Arguments) -> LogLevel {
     if cli.silent {
         LogLevel::Silent
     } else if cli.quiet {
@@ -160,6 +256,9 @@ pub fn collect_per_file_ignores(pairs: Vec<PatternPrefixPair>) -> Vec<PerFileIgn
     }
     per_file_ignores
         .into_iter()
-        .map(|(pattern, prefixes)| PerFileIgnore::new(pattern, &prefixes))
+        .map(|(pattern, prefixes)| {
+            let absolute = fs::normalize_path(Path::new(&pattern));
+            PerFileIgnore::new(pattern, absolute, &prefixes)
+        })
         .collect()
 }

src/commands.rs

@@ -1,36 +1,238 @@
-use std::path::PathBuf;
+use std::io::{self, Read};
+use std::path::{Path, PathBuf};
+use std::time::Instant;
 
 use anyhow::{bail, Result};
+use ignore::Error;
+use itertools::Itertools;
+use log::{debug, error};
+#[cfg(not(target_family = "wasm"))]
+use rayon::prelude::*;
+use rustpython_ast::Location;
 use serde::Serialize;
-use walkdir::DirEntry;
 
-use crate::checks::CheckCode;
-use crate::fs::iter_python_files;
+use crate::autofix::fixer;
+use crate::checks::{CheckCode, CheckKind};
+use crate::cli::Overrides;
+use crate::iterators::par_iter;
+use crate::linter::{add_noqa_to_path, autoformat_path, lint_path, lint_stdin, Diagnostics};
+use crate::message::Message;
+use crate::resolver;
+use crate::resolver::{FileDiscovery, PyprojectDiscovery};
 use crate::settings::types::SerializationFormat;
-use crate::{Configuration, Settings};
+
+/// Run the linter over a collection of files.
+pub fn run(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+    cache: bool,
+    autofix: &fixer::Mode,
+) -> Result<Diagnostics> {
+    // Collect all the files to check.
+    let start = Instant::now();
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    let start = Instant::now();
+    let mut diagnostics: Diagnostics = par_iter(&paths)
+        .map(|entry| {
+            match entry {
+                Ok(entry) => {
+                    let path = entry.path();
+                    let settings = resolver.resolve(path, pyproject_strategy);
+                    lint_path(path, settings, &cache.into(), autofix)
+                        .map_err(|e| (Some(path.to_owned()), e.to_string()))
+                }
+                Err(e) => Err((
+                    if let Error::WithPath { path, .. } = e {
+                        Some(path.clone())
+                    } else {
+                        None
+                    },
+                    e.io_error()
+                        .map_or_else(|| e.to_string(), io::Error::to_string),
+                )),
+            }
+            .unwrap_or_else(|(path, message)| {
+                if let Some(path) = &path {
+                    let settings = resolver.resolve(path, pyproject_strategy);
+                    if settings.enabled.contains(&CheckCode::E902) {
+                        Diagnostics::new(vec![Message {
+                            kind: CheckKind::IOError(message),
+                            location: Location::default(),
+                            end_location: Location::default(),
+                            fix: None,
+                            filename: path.to_string_lossy().to_string(),
+                            source: None,
+                        }])
+                    } else {
+                        error!("Failed to check {}: {message}", path.to_string_lossy());
+                        Diagnostics::default()
+                    }
+                } else {
+                    error!("{message}");
+                    Diagnostics::default()
+                }
+            })
+        })
+        .reduce(Diagnostics::default, |mut acc, item| {
+            acc += item;
+            acc
+        });
+
+    diagnostics.messages.sort_unstable();
+    let duration = start.elapsed();
+    debug!("Checked files in: {:?}", duration);
+
+    Ok(diagnostics)
+}
+
+/// Read a `String` from `stdin`.
+fn read_from_stdin() -> Result<String> {
+    let mut buffer = String::new();
+    io::stdin().lock().read_to_string(&mut buffer)?;
+    Ok(buffer)
+}
+
+/// Run the linter over a single file, read from `stdin`.
+pub fn run_stdin(
+    strategy: &PyprojectDiscovery,
+    filename: &Path,
+    autofix: &fixer::Mode,
+) -> Result<Diagnostics> {
+    let stdin = read_from_stdin()?;
+    let settings = match strategy {
+        PyprojectDiscovery::Fixed(settings) => settings,
+        PyprojectDiscovery::Hierarchical(settings) => settings,
+    };
+    let mut diagnostics = lint_stdin(filename, &stdin, settings, autofix)?;
+    diagnostics.messages.sort_unstable();
+    Ok(diagnostics)
+}
+
+/// Add `noqa` directives to a collection of files.
+pub fn add_noqa(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<usize> {
+    // Collect all the files to check.
+    let start = Instant::now();
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    let start = Instant::now();
+    let modifications: usize = par_iter(&paths)
+        .flatten()
+        .filter_map(|entry| {
+            let path = entry.path();
+            let settings = resolver.resolve(path, pyproject_strategy);
+            match add_noqa_to_path(path, settings) {
+                Ok(count) => Some(count),
+                Err(e) => {
+                    error!("Failed to add noqa to {}: {e}", path.to_string_lossy());
+                    None
+                }
+            }
+        })
+        .sum();
+
+    let duration = start.elapsed();
+    debug!("Added noqa to files in: {:?}", duration);
+
+    Ok(modifications)
+}
+
+/// Automatically format a collection of files.
+pub fn autoformat(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<usize> {
+    // Collect all the files to format.
+    let start = Instant::now();
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+    let duration = start.elapsed();
+    debug!("Identified files to lint in: {:?}", duration);
+
+    let start = Instant::now();
+    let modifications = par_iter(&paths)
+        .flatten()
+        .filter_map(|entry| {
+            let path = entry.path();
+            let settings = resolver.resolve(path, pyproject_strategy);
+            match autoformat_path(path, settings) {
+                Ok(()) => Some(()),
+                Err(e) => {
+                    error!("Failed to autoformat {}: {e}", path.to_string_lossy());
+                    None
+                }
+            }
+        })
+        .count();
+
+    let duration = start.elapsed();
+    debug!("Auto-formatted files in: {:?}", duration);
+
+    Ok(modifications)
+}
 
 /// Print the user-facing configuration settings.
 pub fn show_settings(
-    configuration: &Configuration,
-    project_root: Option<&PathBuf>,
-    pyproject: Option<&PathBuf>,
-) {
-    println!("Resolved configuration: {configuration:#?}");
-    println!("Found project root at: {project_root:?}");
-    println!("Found pyproject.toml at: {pyproject:?}");
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<()> {
+    // Collect all files in the hierarchy.
+    let (paths, resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+
+    // Print the list of files.
+    let Some(entry) = paths
+        .iter()
+        .flatten()
+        .sorted_by(|a, b| a.path().cmp(b.path())).next() else {
+        bail!("No files found under the given path");
+    };
+    let path = entry.path();
+    let settings = resolver.resolve(path, pyproject_strategy);
+    println!("Resolved settings for: {path:?}");
+    println!("{settings:#?}");
+
+    Ok(())
 }
 
 /// Show the list of files to be checked based on current settings.
-pub fn show_files(files: &[PathBuf], settings: &Settings) {
-    let mut entries: Vec<DirEntry> = files
+pub fn show_files(
+    files: &[PathBuf],
+    pyproject_strategy: &PyprojectDiscovery,
+    file_strategy: &FileDiscovery,
+    overrides: &Overrides,
+) -> Result<()> {
+    // Collect all files in the hierarchy.
+    let (paths, _resolver) =
+        resolver::python_files_in_path(files, pyproject_strategy, file_strategy, overrides)?;
+
+    // Print the list of files.
+    for entry in paths
         .iter()
-        .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
         .flatten()
-        .collect();
-    entries.sort_by(|a, b| a.path().cmp(b.path()));
-    for entry in entries {
+        .sorted_by(|a, b| a.path().cmp(b.path()))
+    {
         println!("{}", entry.path().to_string_lossy());
     }
+
+    Ok(())
 }
 
 #[derive(Serialize)]
@@ -41,7 +243,7 @@ struct Explanation<'a> {
 }
 
 /// Explain a `CheckCode` to the user.
-pub fn explain(code: &CheckCode, format: SerializationFormat) -> Result<()> {
+pub fn explain(code: &CheckCode, format: &SerializationFormat) -> Result<()> {
     match format {
         SerializationFormat::Text | SerializationFormat::Grouped => {
             println!(

src/docstrings/definition.rs

@@ -1,6 +1,8 @@
+use std::borrow::Cow;
+
 use rustpython_ast::{Expr, Stmt};
 
-#[derive(Debug)]
+#[derive(Debug, Clone)]
 pub enum DefinitionKind<'a> {
     Module,
     Package,
@@ -17,6 +19,15 @@ pub struct Definition<'a> {
     pub docstring: Option<&'a Expr>,
 }
 
+#[derive(Debug)]
+pub struct Docstring<'a> {
+    pub kind: DefinitionKind<'a>,
+    pub expr: &'a Expr,
+    pub contents: &'a Cow<'a, str>,
+    pub body: &'a str,
+    pub indentation: &'a Cow<'a, str>,
+}
+
 pub enum Documentable {
     Class,
     Function,

src/docstrings/sections.rs

@@ -3,7 +3,7 @@ use crate::docstrings::styles::SectionStyle;
 
 #[derive(Debug)]
 pub(crate) struct SectionContext<'a> {
-    pub(crate) section_name: String,
+    pub(crate) section_name: &'a str,
     pub(crate) previous_line: &'a str,
     pub(crate) line: &'a str,
     pub(crate) following_lines: &'a [&'a str],
@@ -22,7 +22,7 @@ fn is_docstring_section(context: &SectionContext) -> bool {
     let section_name_suffix = context
         .line
         .trim()
-        .strip_prefix(&context.section_name)
+        .strip_prefix(context.section_name)
         .unwrap()
         .trim();
     let this_looks_like_a_section_name =

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__allow_overload.snap

@@ -8,7 +8,7 @@ expression: checks
     row: 29
     column: 4
   end_location:
-    row: 35
-    column: 0
+    row: 30
+    column: 16
   fix: ~
 

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__defaults.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 4
     column: 0
   end_location:
-    row: 9
-    column: 0
+    row: 5
+    column: 8
   fix: ~
 - kind:
     MissingTypeFunctionArgument: a
@@ -35,8 +35,8 @@ expression: checks
     row: 9
     column: 0
   end_location:
-    row: 14
-    column: 0
+    row: 10
+    column: 8
   fix: ~
 - kind:
     MissingTypeFunctionArgument: b
@@ -62,8 +62,8 @@ expression: checks
     row: 19
     column: 0
   end_location:
-    row: 24
-    column: 0
+    row: 20
+    column: 8
   fix: ~
 - kind:
     MissingReturnTypePublicFunction: foo
@@ -71,8 +71,8 @@ expression: checks
     row: 24
     column: 0
   end_location:
-    row: 29
-    column: 0
+    row: 25
+    column: 8
   fix: ~
 - kind:
     DynamicallyTypedExpression: a

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__mypy_init_return.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 5
     column: 4
   end_location:
-    row: 10
-    column: 0
+    row: 6
+    column: 11
   fix: ~
 - kind:
     MissingReturnTypeMagicMethod: __init__
@@ -17,8 +17,8 @@ expression: checks
     row: 11
     column: 4
   end_location:
-    row: 16
-    column: 0
+    row: 12
+    column: 11
   fix: ~
 - kind:
     MissingReturnTypePrivateFunction: __init__
@@ -26,7 +26,7 @@ expression: checks
     row: 40
     column: 0
   end_location:
-    row: 42
-    column: 0
+    row: 41
+    column: 7
   fix: ~
 

src/flake8_annotations/snapshots/ruff__flake8_annotations__tests__suppress_none_returning.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 45
     column: 0
   end_location:
-    row: 50
-    column: 0
+    row: 46
+    column: 15
   fix: ~
 - kind:
     MissingReturnTypePublicFunction: foo
@@ -17,7 +17,7 @@ expression: checks
     row: 50
     column: 0
   end_location:
-    row: 56
-    column: 0
+    row: 55
+    column: 14
   fix: ~
 

src/flake8_bugbear/plugins/setattr_with_constant.rs

@@ -56,16 +56,23 @@ pub fn setattr_with_constant(checker: &mut Checker, expr: &Expr, func: &Expr, ar
     if KWLIST.contains(&name.as_str()) {
         return;
     }
-    let mut check = Check::new(CheckKind::SetAttrWithConstant, Range::from_located(expr));
-    if checker.patch(check.kind.code()) {
-        match assignment(obj, name, value) {
-            Ok(content) => check.amend(Fix::replacement(
-                content,
-                expr.location,
-                expr.end_location.unwrap(),
-            )),
-            Err(e) => error!("Failed to fix invalid comparison: {e}"),
-        };
+    // We can only replace a `setattr` call (which is an `Expr`) with an assignment
+    // (which is a `Stmt`) if the `Expr` is already being used as a `Stmt`
+    // (i.e., it's directly within an `StmtKind::Expr`).
+    if let StmtKind::Expr { value: child } = &checker.current_parent().0.node {
+        if expr == child.as_ref() {
+            let mut check = Check::new(CheckKind::SetAttrWithConstant, Range::from_located(expr));
+            if checker.patch(check.kind.code()) {
+                match assignment(obj, name, value) {
+                    Ok(content) => check.amend(Fix::replacement(
+                        content,
+                        expr.location,
+                        expr.end_location.unwrap(),
+                    )),
+                    Err(e) => error!("Failed to fix invalid comparison: {e}"),
+                };
+            }
+            checker.add_check(check);
+        }
     }
-    checker.add_check(check);
 }

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B009_B009_B010.py.snap

@@ -77,4 +77,19 @@ expression: checks
     end_location:
       row: 22
       column: 31
+- kind: GetAttrWithConstant
+  location:
+    row: 23
+    column: 3
+  end_location:
+    row: 23
+    column: 20
+  fix:
+    content: x.bar
+    location:
+      row: 23
+      column: 3
+    end_location:
+      row: 23
+      column: 20
 

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B010_B009_B010.py.snap

@@ -4,77 +4,77 @@ expression: checks
 ---
 - kind: SetAttrWithConstant
   location:
-    row: 33
+    row: 37
     column: 0
   end_location:
-    row: 33
+    row: 37
     column: 25
   fix:
     content: foo.bar = None
     location:
-      row: 33
+      row: 37
       column: 0
     end_location:
-      row: 33
+      row: 37
       column: 25
 - kind: SetAttrWithConstant
   location:
-    row: 34
+    row: 38
     column: 0
   end_location:
-    row: 34
+    row: 38
     column: 29
   fix:
     content: foo._123abc = None
     location:
-      row: 34
+      row: 38
       column: 0
     end_location:
-      row: 34
+      row: 38
       column: 29
 - kind: SetAttrWithConstant
   location:
-    row: 35
+    row: 39
     column: 0
   end_location:
-    row: 35
+    row: 39
     column: 28
   fix:
     content: foo.abc123 = None
     location:
-      row: 35
+      row: 39
       column: 0
     end_location:
-      row: 35
+      row: 39
       column: 28
 - kind: SetAttrWithConstant
   location:
-    row: 36
+    row: 40
     column: 0
   end_location:
-    row: 36
+    row: 40
     column: 29
   fix:
     content: foo.abc123 = None
     location:
-      row: 36
+      row: 40
       column: 0
     end_location:
-      row: 36
+      row: 40
       column: 29
 - kind: SetAttrWithConstant
   location:
-    row: 37
+    row: 41
     column: 0
   end_location:
-    row: 37
+    row: 41
     column: 30
   fix:
     content: foo.bar.baz = None
     location:
-      row: 37
+      row: 41
       column: 0
     end_location:
-      row: 37
+      row: 41
       column: 30
 

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B017_B017.py.snap

@@ -7,7 +7,7 @@ expression: checks
     row: 22
     column: 8
   end_location:
-    row: 25
-    column: 4
+    row: 23
+    column: 42
   fix: ~
 

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B024_B024.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 17
     column: 0
   end_location:
-    row: 22
-    column: 0
+    row: 19
+    column: 13
   fix: ~
 - kind:
     AbstractBaseClassWithoutAbstractMethod: MetaBase_1
@@ -17,8 +17,8 @@ expression: checks
     row: 58
     column: 0
   end_location:
-    row: 63
-    column: 0
+    row: 60
+    column: 13
   fix: ~
 - kind:
     AbstractBaseClassWithoutAbstractMethod: abc_Base_1
@@ -26,8 +26,8 @@ expression: checks
     row: 69
     column: 0
   end_location:
-    row: 74
-    column: 0
+    row: 71
+    column: 13
   fix: ~
 - kind:
     AbstractBaseClassWithoutAbstractMethod: abc_Base_2
@@ -35,8 +35,8 @@ expression: checks
     row: 74
     column: 0
   end_location:
-    row: 79
-    column: 0
+    row: 76
+    column: 13
   fix: ~
 - kind:
     AbstractBaseClassWithoutAbstractMethod: notabc_Base_1
@@ -44,8 +44,8 @@ expression: checks
     row: 79
     column: 0
   end_location:
-    row: 84
-    column: 0
+    row: 81
+    column: 13
   fix: ~
 - kind:
     AbstractBaseClassWithoutAbstractMethod: abc_set_class_variable_4
@@ -53,7 +53,7 @@ expression: checks
     row: 128
     column: 0
   end_location:
-    row: 130
-    column: 0
+    row: 129
+    column: 7
   fix: ~
 

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B025_B025.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 15
     column: 0
   end_location:
-    row: 22
-    column: 0
+    row: 20
+    column: 9
   fix: ~
 - kind:
     DuplicateTryBlockException: pickle.PickleError
@@ -17,8 +17,8 @@ expression: checks
     row: 22
     column: 0
   end_location:
-    row: 31
-    column: 0
+    row: 29
+    column: 9
   fix: ~
 - kind:
     DuplicateTryBlockException: TypeError
@@ -26,8 +26,8 @@ expression: checks
     row: 31
     column: 0
   end_location:
-    row: 39
-    column: 0
+    row: 38
+    column: 9
   fix: ~
 - kind:
     DuplicateTryBlockException: ValueError
@@ -35,7 +35,7 @@ expression: checks
     row: 31
     column: 0
   end_location:
-    row: 39
-    column: 0
+    row: 38
+    column: 9
   fix: ~
 

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B027_B027.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 12
     column: 4
   end_location:
-    row: 15
-    column: 4
+    row: 13
+    column: 11
   fix: ~
 - kind:
     EmptyMethodWithoutAbstractDecorator: AbstractClass
@@ -17,8 +17,8 @@ expression: checks
     row: 15
     column: 4
   end_location:
-    row: 18
-    column: 4
+    row: 16
+    column: 12
   fix: ~
 - kind:
     EmptyMethodWithoutAbstractDecorator: AbstractClass
@@ -26,8 +26,8 @@ expression: checks
     row: 18
     column: 4
   end_location:
-    row: 22
-    column: 4
+    row: 20
+    column: 11
   fix: ~
 - kind:
     EmptyMethodWithoutAbstractDecorator: AbstractClass
@@ -35,7 +35,7 @@ expression: checks
     row: 22
     column: 4
   end_location:
-    row: 29
-    column: 4
+    row: 27
+    column: 12
   fix: ~
 

src/flake8_builtins/snapshots/ruff__flake8_builtins__tests__A001_A001.py.snap

@@ -89,8 +89,8 @@ expression: checks
     row: 10
     column: 0
   end_location:
-    row: 13
-    column: 0
+    row: 11
+    column: 8
   fix: ~
 - kind:
     BuiltinVariableShadowing: slice
@@ -98,8 +98,8 @@ expression: checks
     row: 13
     column: 0
   end_location:
-    row: 16
-    column: 0
+    row: 14
+    column: 8
   fix: ~
 - kind:
     BuiltinVariableShadowing: ValueError
@@ -107,8 +107,8 @@ expression: checks
     row: 18
     column: 0
   end_location:
-    row: 21
-    column: 0
+    row: 19
+    column: 7
   fix: ~
 - kind:
     BuiltinVariableShadowing: memoryview

src/flake8_builtins/snapshots/ruff__flake8_builtins__tests__A003_A003.py.snap

@@ -17,7 +17,7 @@ expression: checks
     row: 7
     column: 4
   end_location:
-    row: 9
-    column: 0
+    row: 8
+    column: 12
   fix: ~
 

src/flake8_return/snapshots/ruff__flake8_return__tests__RET503_RET503.py.snap

@@ -7,8 +7,8 @@ expression: checks
     row: 7
     column: 4
   end_location:
-    row: 12
-    column: 0
+    row: 8
+    column: 16
   fix: ~
 - kind: ImplicitReturn
   location:
@@ -45,8 +45,8 @@ expression: checks
     row: 29
     column: 8
   end_location:
-    row: 34
-    column: 0
+    row: 30
+    column: 20
   fix: ~
 - kind: ImplicitReturn
   location:

src/flake8_return/snapshots/ruff__flake8_return__tests__RET505_RET505.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 5
     column: 4
   end_location:
-    row: 16
-    column: 0
+    row: 13
+    column: 16
   fix: ~
 - kind:
     SuperfluousElseReturn: Elif
@@ -17,8 +17,8 @@ expression: checks
     row: 17
     column: 4
   end_location:
-    row: 27
-    column: 4
+    row: 26
+    column: 13
   fix: ~
 - kind:
     SuperfluousElseReturn: Elif
@@ -26,8 +26,8 @@ expression: checks
     row: 38
     column: 4
   end_location:
-    row: 49
-    column: 0
+    row: 46
+    column: 16
   fix: ~
 - kind:
     SuperfluousElseReturn: Else
@@ -35,8 +35,8 @@ expression: checks
     row: 50
     column: 4
   end_location:
-    row: 58
-    column: 0
+    row: 55
+    column: 16
   fix: ~
 - kind:
     SuperfluousElseReturn: Else
@@ -44,8 +44,8 @@ expression: checks
     row: 61
     column: 8
   end_location:
-    row: 67
-    column: 4
+    row: 66
+    column: 20
   fix: ~
 - kind:
     SuperfluousElseReturn: Else
@@ -53,8 +53,8 @@ expression: checks
     row: 73
     column: 4
   end_location:
-    row: 81
-    column: 4
+    row: 80
+    column: 13
   fix: ~
 - kind:
     SuperfluousElseReturn: Else
@@ -62,8 +62,8 @@ expression: checks
     row: 86
     column: 8
   end_location:
-    row: 91
-    column: 4
+    row: 90
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseReturn: Else
@@ -71,7 +71,7 @@ expression: checks
     row: 97
     column: 4
   end_location:
-    row: 109
-    column: 0
+    row: 103
+    column: 23
   fix: ~
 

src/flake8_return/snapshots/ruff__flake8_return__tests__RET506_RET506.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 5
     column: 4
   end_location:
-    row: 16
-    column: 0
+    row: 13
+    column: 26
   fix: ~
 - kind:
     SuperfluousElseRaise: Elif
@@ -17,8 +17,8 @@ expression: checks
     row: 17
     column: 4
   end_location:
-    row: 27
-    column: 4
+    row: 26
+    column: 13
   fix: ~
 - kind:
     SuperfluousElseRaise: Else
@@ -26,8 +26,8 @@ expression: checks
     row: 31
     column: 4
   end_location:
-    row: 39
-    column: 0
+    row: 36
+    column: 26
   fix: ~
 - kind:
     SuperfluousElseRaise: Else
@@ -35,8 +35,8 @@ expression: checks
     row: 42
     column: 8
   end_location:
-    row: 48
-    column: 4
+    row: 47
+    column: 30
   fix: ~
 - kind:
     SuperfluousElseRaise: Else
@@ -44,8 +44,8 @@ expression: checks
     row: 54
     column: 4
   end_location:
-    row: 62
-    column: 4
+    row: 61
+    column: 13
   fix: ~
 - kind:
     SuperfluousElseRaise: Else
@@ -53,8 +53,8 @@ expression: checks
     row: 67
     column: 8
   end_location:
-    row: 72
-    column: 4
+    row: 71
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseRaise: Else
@@ -62,7 +62,7 @@ expression: checks
     row: 78
     column: 4
   end_location:
-    row: 90
-    column: 0
+    row: 84
+    column: 33
   fix: ~
 

src/flake8_return/snapshots/ruff__flake8_return__tests__RET507_RET507.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 6
     column: 8
   end_location:
-    row: 14
-    column: 0
+    row: 11
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseContinue: Elif
@@ -17,8 +17,8 @@ expression: checks
     row: 16
     column: 8
   end_location:
-    row: 26
-    column: 8
+    row: 25
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseContinue: Else
@@ -26,8 +26,8 @@ expression: checks
     row: 34
     column: 8
   end_location:
-    row: 40
-    column: 0
+    row: 37
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseContinue: Else
@@ -35,8 +35,8 @@ expression: checks
     row: 44
     column: 12
   end_location:
-    row: 50
-    column: 8
+    row: 49
+    column: 24
   fix: ~
 - kind:
     SuperfluousElseContinue: Else
@@ -44,8 +44,8 @@ expression: checks
     row: 57
     column: 8
   end_location:
-    row: 65
-    column: 8
+    row: 64
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseContinue: Else
@@ -53,8 +53,8 @@ expression: checks
     row: 71
     column: 12
   end_location:
-    row: 76
-    column: 8
+    row: 75
+    column: 21
   fix: ~
 - kind:
     SuperfluousElseContinue: Else
@@ -62,7 +62,7 @@ expression: checks
     row: 83
     column: 8
   end_location:
-    row: 92
-    column: 0
+    row: 89
+    column: 24
   fix: ~
 

src/flake8_return/snapshots/ruff__flake8_return__tests__RET508_RET508.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 6
     column: 8
   end_location:
-    row: 14
-    column: 0
+    row: 11
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseBreak: Elif
@@ -17,8 +17,8 @@ expression: checks
     row: 16
     column: 8
   end_location:
-    row: 26
-    column: 8
+    row: 25
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseBreak: Else
@@ -26,8 +26,8 @@ expression: checks
     row: 31
     column: 8
   end_location:
-    row: 37
-    column: 0
+    row: 34
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseBreak: Else
@@ -35,8 +35,8 @@ expression: checks
     row: 41
     column: 12
   end_location:
-    row: 47
-    column: 8
+    row: 46
+    column: 21
   fix: ~
 - kind:
     SuperfluousElseBreak: Else
@@ -44,8 +44,8 @@ expression: checks
     row: 54
     column: 8
   end_location:
-    row: 62
-    column: 8
+    row: 61
+    column: 17
   fix: ~
 - kind:
     SuperfluousElseBreak: Else
@@ -53,8 +53,8 @@ expression: checks
     row: 68
     column: 12
   end_location:
-    row: 73
-    column: 8
+    row: 72
+    column: 21
   fix: ~
 - kind:
     SuperfluousElseBreak: Else
@@ -62,7 +62,7 @@ expression: checks
     row: 80
     column: 8
   end_location:
-    row: 92
-    column: 0
+    row: 86
+    column: 21
   fix: ~
 

src/flake8_simplify/mod.rs

@@ -0,0 +1,29 @@
+pub mod plugins;
+
+#[cfg(test)]
+mod tests {
+    use std::convert::AsRef;
+    use std::path::Path;
+
+    use anyhow::Result;
+    use test_case::test_case;
+
+    use crate::checks::CheckCode;
+    use crate::linter::test_path;
+    use crate::settings;
+
+    #[test_case(CheckCode::SIM118, Path::new("SIM118.py"); "SIM118")]
+    fn checks(check_code: CheckCode, path: &Path) -> Result<()> {
+        let snapshot = format!("{}_{}", check_code.as_ref(), path.to_string_lossy());
+        let mut checks = test_path(
+            Path::new("./resources/test/fixtures/flake8_simplify")
+                .join(path)
+                .as_path(),
+            &settings::Settings::for_rule(check_code),
+            true,
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(snapshot, checks);
+        Ok(())
+    }
+}

src/flake8_simplify/plugins/key_in_dict.rs

@@ -0,0 +1,74 @@
+use rustpython_ast::{Cmpop, Expr, ExprKind};
+
+use crate::ast::types::Range;
+use crate::autofix::Fix;
+use crate::check_ast::Checker;
+use crate::checks::{Check, CheckCode, CheckKind};
+
+/// SIM118
+fn key_in_dict(checker: &mut Checker, left: &Expr, right: &Expr, range: Range) {
+    let ExprKind::Call {
+        func,
+        args,
+        keywords,
+    } = &right.node else {
+        return;
+    };
+    if !(args.is_empty() && keywords.is_empty()) {
+        return;
+    }
+
+    let ExprKind::Attribute { attr, value, .. } = &func.node else {
+        return;
+    };
+    if attr != "keys" {
+        return;
+    }
+
+    let mut check = Check::new(
+        CheckKind::KeyInDict(left.to_string(), value.to_string()),
+        range,
+    );
+    if checker.patch(&CheckCode::SIM118) {
+        let content = right.to_string().replace(".keys()", "");
+        check.amend(Fix::replacement(
+            content,
+            right.location,
+            right.end_location.unwrap(),
+        ));
+    }
+    checker.add_check(check);
+}
+
+/// SIM118 in a for loop
+pub fn key_in_dict_for(checker: &mut Checker, target: &Expr, iter: &Expr) {
+    key_in_dict(
+        checker,
+        target,
+        iter,
+        Range {
+            location: target.location,
+            end_location: iter.end_location.unwrap(),
+        },
+    );
+}
+
+/// SIM118 in a comparison
+pub fn key_in_dict_compare(
+    checker: &mut Checker,
+    expr: &Expr,
+    left: &Expr,
+    ops: &[Cmpop],
+    comparators: &[Expr],
+) {
+    if !matches!(ops[..], [Cmpop::In]) {
+        return;
+    }
+
+    if comparators.len() != 1 {
+        return;
+    }
+    let right = comparators.first().unwrap();
+
+    key_in_dict(checker, left, right, Range::from_located(expr));
+}

src/flake8_simplify/plugins/mod.rs

@@ -0,0 +1,3 @@
+pub use key_in_dict::{key_in_dict_compare, key_in_dict_for};
+
+mod key_in_dict;

src/flake8_simplify/snapshots/ruff__flake8_simplify__tests__SIM118_SIM118.py.snap

@@ -0,0 +1,77 @@
+---
+source: src/flake8_simplify/mod.rs
+expression: checks
+---
+- kind:
+    KeyInDict:
+      - key
+      - dict
+  location:
+    row: 1
+    column: 0
+  end_location:
+    row: 1
+    column: 18
+  fix:
+    content: dict
+    location:
+      row: 1
+      column: 7
+    end_location:
+      row: 1
+      column: 18
+- kind:
+    KeyInDict:
+      - "foo['bar']"
+      - dict
+  location:
+    row: 3
+    column: 0
+  end_location:
+    row: 3
+    column: 25
+  fix:
+    content: dict
+    location:
+      row: 3
+      column: 14
+    end_location:
+      row: 3
+      column: 25
+- kind:
+    KeyInDict:
+      - foo()
+      - dict
+  location:
+    row: 5
+    column: 0
+  end_location:
+    row: 5
+    column: 20
+  fix:
+    content: dict
+    location:
+      row: 5
+      column: 9
+    end_location:
+      row: 5
+      column: 20
+- kind:
+    KeyInDict:
+      - key
+      - dict
+  location:
+    row: 7
+    column: 4
+  end_location:
+    row: 7
+    column: 22
+  fix:
+    content: dict
+    location:
+      row: 7
+      column: 11
+    end_location:
+      row: 7
+      column: 22
+

src/fs.rs

@@ -5,15 +5,13 @@ use std::path::{Path, PathBuf};
 
 use anyhow::{anyhow, Result};
 use globset::GlobMatcher;
-use log::debug;
 use path_absolutize::{path_dedot, Absolutize};
 use rustc_hash::FxHashSet;
-use walkdir::{DirEntry, WalkDir};
 
 use crate::checks::CheckCode;
 
 /// Extract the absolute path and basename (as strings) from a Path.
-fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
+pub fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
     let file_path = path
         .to_str()
         .ok_or_else(|| anyhow!("Unable to parse filename: {:?}", path))?;
@@ -25,62 +23,7 @@ fn extract_path_names(path: &Path) -> Result<(&str, &str)> {
     Ok((file_path, file_basename))
 }
 
-fn is_excluded(file_path: &str, file_basename: &str, exclude: &globset::GlobSet) -> bool {
-    exclude.is_match(file_path) || exclude.is_match(file_basename)
-}
-
-fn is_included(path: &Path) -> bool {
-    let file_name = path.to_string_lossy();
-    file_name.ends_with(".py") || file_name.ends_with(".pyi")
-}
-
-pub fn iter_python_files<'a>(
-    path: &'a Path,
-    exclude: &'a globset::GlobSet,
-    extend_exclude: &'a globset::GlobSet,
-) -> impl Iterator<Item = Result<DirEntry, walkdir::Error>> + 'a {
-    // Run some checks over the provided patterns, to enable optimizations below.
-    let has_exclude = !exclude.is_empty();
-    let has_extend_exclude = !extend_exclude.is_empty();
-
-    WalkDir::new(normalize_path(path))
-        .into_iter()
-        .filter_entry(move |entry| {
-            if !has_exclude && !has_extend_exclude {
-                return true;
-            }
-
-            let path = entry.path();
-            match extract_path_names(path) {
-                Ok((file_path, file_basename)) => {
-                    if has_exclude && is_excluded(file_path, file_basename, exclude) {
-                        debug!("Ignored path via `exclude`: {:?}", path);
-                        false
-                    } else if has_extend_exclude
-                        && is_excluded(file_path, file_basename, extend_exclude)
-                    {
-                        debug!("Ignored path via `extend-exclude`: {:?}", path);
-                        false
-                    } else {
-                        true
-                    }
-                }
-                Err(e) => {
-                    debug!("Ignored path due to error in parsing: {:?}: {}", path, e);
-                    true
-                }
-            }
-        })
-        .filter(|entry| {
-            entry.as_ref().map_or(true, |entry| {
-                (entry.depth() == 0 || is_included(entry.path()))
-                    && !entry.file_type().is_dir()
-                    && !(entry.file_type().is_symlink() && entry.path().is_dir())
-            })
-        })
-}
-
-/// Create tree set with codes matching the pattern/code pairs.
+/// Create a set with codes matching the pattern/code pairs.
 pub(crate) fn ignores_from_path<'a>(
     path: &Path,
     pattern_code_pairs: &'a [(GlobMatcher, GlobMatcher, FxHashSet<CheckCode>)],
@@ -128,114 +71,3 @@ pub(crate) fn read_file(path: &Path) -> Result<String> {
     buf_reader.read_to_string(&mut contents)?;
     Ok(contents)
 }
-
-#[cfg(test)]
-mod tests {
-    use std::path::{Path, PathBuf};
-
-    use anyhow::Result;
-    use globset::GlobSet;
-    use path_absolutize::Absolutize;
-
-    use crate::fs::{extract_path_names, is_excluded, is_included};
-    use crate::settings::types::FilePattern;
-
-    #[test]
-    fn inclusions() {
-        let path = Path::new("foo/bar/baz.py").absolutize().unwrap();
-        assert!(is_included(&path));
-
-        let path = Path::new("foo/bar/baz.pyi").absolutize().unwrap();
-        assert!(is_included(&path));
-
-        let path = Path::new("foo/bar/baz.js").absolutize().unwrap();
-        assert!(!is_included(&path));
-
-        let path = Path::new("foo/bar/baz").absolutize().unwrap();
-        assert!(!is_included(&path));
-    }
-
-    fn make_exclusion(file_pattern: FilePattern, project_root: Option<&PathBuf>) -> GlobSet {
-        let mut builder = globset::GlobSetBuilder::new();
-        file_pattern.add_to(&mut builder, project_root).unwrap();
-        builder.build().unwrap()
-    }
-
-    #[test]
-    fn exclusions() -> Result<()> {
-        let project_root = Path::new("/tmp/");
-
-        let path = Path::new("foo").absolutize_from(project_root).unwrap();
-        let exclude = FilePattern::User("foo".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
-        let exclude = FilePattern::User("bar".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("baz.py".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        let path = Path::new("foo/bar").absolutize_from(project_root).unwrap();
-        let exclude = FilePattern::User("foo/bar".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("foo/bar/baz.py".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("foo/bar/*.py".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        let path = Path::new("foo/bar/baz.py")
-            .absolutize_from(project_root)
-            .unwrap();
-        let exclude = FilePattern::User("baz".to_string());
-        let (file_path, file_basename) = extract_path_names(&path)?;
-        assert!(!is_excluded(
-            file_path,
-            file_basename,
-            &make_exclusion(exclude, Some(&project_root.to_path_buf()))
-        ));
-
-        Ok(())
-    }
-}

src/isort/helpers.rs

@@ -0,0 +1,55 @@
+use rustpython_ast::Stmt;
+
+use crate::source_code_locator::SourceCodeLocator;
+
+/// Return `true` if a `Stmt` is preceded by a "comment break"
+pub fn has_comment_break(stmt: &Stmt, locator: &SourceCodeLocator) -> bool {
+    // Starting from the `Stmt` (`def f(): pass`), we want to detect patterns like
+    // this:
+    //
+    //   import os
+    //
+    //   # Detached comment.
+    //
+    //   def f(): pass
+
+    // This should also be detected:
+    //
+    //   import os
+    //
+    //   # Detached comment.
+    //
+    //   # Direct comment.
+    //   def f(): pass
+
+    // But this should not:
+    //
+    //   import os
+    //
+    //   # Direct comment.
+    //   def f(): pass
+    let mut seen_blank = false;
+    for line in locator
+        .slice_source_code_until(&stmt.location)
+        .lines()
+        .rev()
+    {
+        let line = line.trim();
+        if seen_blank {
+            if line.starts_with('#') {
+                return true;
+            } else if !line.is_empty() {
+                break;
+            }
+        } else {
+            if line.is_empty() {
+                seen_blank = true;
+            } else if line.starts_with('#') || line.starts_with('@') {
+                continue;
+            } else {
+                break;
+            }
+        }
+    }
+    false
+}

src/isort/mod.rs

@@ -18,6 +18,7 @@ use crate::isort::types::{
 mod categorize;
 mod comments;
 pub mod format;
+mod helpers;
 pub mod plugins;
 pub mod settings;
 mod sorting;

src/isort/plugins.rs

@@ -19,14 +19,12 @@ fn extract_range(body: &[&Stmt]) -> Range {
     }
 }
 
-fn extract_indentation(body: &[&Stmt], locator: &SourceCodeLocator) -> String {
+fn extract_indentation_range(body: &[&Stmt]) -> Range {
     let location = body.first().unwrap().location;
-    let range = Range {
+    Range {
         location: Location::new(location.row(), 0),
         end_location: location,
-    };
-    let existing = locator.slice_source_code_range(&range);
-    leading_space(&existing)
+    }
 }
 
 /// I001
@@ -36,8 +34,10 @@ pub fn check_imports(
     settings: &Settings,
     autofix: bool,
 ) -> Option<Check> {
+    let indentation = locator.slice_source_code_range(&extract_indentation_range(&block.imports));
+    let indentation = leading_space(&indentation);
+
     let range = extract_range(&block.imports);
-    let indentation = extract_indentation(&block.imports, locator);
 
     // Extract comments. Take care to grab any inline comments from the last line.
     let comments = comments::collect_comments(
@@ -77,7 +77,7 @@ pub fn check_imports(
             if has_leading_content {
                 content.push('\n');
             }
-            content.push_str(&indent(&expected, &indentation));
+            content.push_str(&indent(&expected, indentation));
             check.amend(Fix::replacement(
                 content,
                 // Preserve leading prefix (but put the imports on a new line).
@@ -104,7 +104,7 @@ pub fn check_imports(
             let mut check = Check::new(CheckKind::UnsortedImports, range);
             if autofix && settings.fixable.contains(check.kind.code()) {
                 check.amend(Fix::replacement(
-                    indent(&expected, &indentation),
+                    indent(&expected, indentation),
                     range.location,
                     range.end_location,
                 ));

src/isort/snapshots/ruff__isort__tests__insert_empty_lines.py.snap

@@ -49,32 +49,17 @@ expression: checks
       column: 0
 - kind: UnsortedImports
   location:
-    row: 33
+    row: 52
     column: 0
   end_location:
-    row: 35
+    row: 54
     column: 0
   fix:
-    content: "    import collections\n    import typing\n\n"
+    content: "import os\n\n\n"
     location:
-      row: 33
+      row: 52
       column: 0
     end_location:
-      row: 35
-      column: 0
-- kind: UnsortedImports
-  location:
-    row: 39
-    column: 0
-  end_location:
-    row: 41
-    column: 0
-  fix:
-    content: "    import collections\n    import typing\n\n"
-    location:
-      row: 39
-      column: 0
-    end_location:
-      row: 41
+      row: 54
       column: 0
 

src/isort/snapshots/ruff__isort__tests__insert_empty_lines.pyi.snap

@@ -47,19 +47,4 @@ expression: checks
     end_location:
       row: 16
       column: 0
-- kind: UnsortedImports
-  location:
-    row: 33
-    column: 0
-  end_location:
-    row: 35
-    column: 0
-  fix:
-    content: "    import collections\n    import typing\n\n"
-    location:
-      row: 33
-      column: 0
-    end_location:
-      row: 35
-      column: 0
 

src/isort/snapshots/ruff__isort__tests__trailing_suffix.py.snap

@@ -25,7 +25,7 @@ expression: checks
     row: 6
     column: 13
   fix:
-    content: "    import os\n    import sys\n\n"
+    content: "    import os\n    import sys\n"
     location:
       row: 5
       column: 0

src/isort/track.rs

@@ -8,20 +8,24 @@ use rustpython_ast::{
 
 use crate::ast::visitor::Visitor;
 use crate::directives::IsortDirectives;
+use crate::isort::helpers;
+use crate::source_code_locator::SourceCodeLocator;
 
+#[derive(Debug)]
 pub enum Trailer {
     Sibling,
     ClassDef,
     FunctionDef,
 }
 
-#[derive(Default)]
+#[derive(Debug, Default)]
 pub struct Block<'a> {
     pub imports: Vec<&'a Stmt>,
     pub trailer: Option<Trailer>,
 }
 
 pub struct ImportTracker<'a> {
+    locator: &'a SourceCodeLocator<'a>,
     directives: &'a IsortDirectives,
     pyi: bool,
     blocks: Vec<Block<'a>>,
@@ -30,8 +34,13 @@ pub struct ImportTracker<'a> {
 }
 
 impl<'a> ImportTracker<'a> {
-    pub fn new(directives: &'a IsortDirectives, path: &'a Path) -> Self {
+    pub fn new(
+        locator: &'a SourceCodeLocator<'a>,
+        directives: &'a IsortDirectives,
+        path: &'a Path,
+    ) -> Self {
         Self {
+            locator,
             directives,
             pyi: path.extension().map_or(false, |ext| ext == "pyi"),
             blocks: vec![Block::default()],
@@ -46,31 +55,46 @@ impl<'a> ImportTracker<'a> {
     }
 
     fn trailer_for(&self, stmt: &'a Stmt) -> Option<Trailer> {
-        if self.pyi {
-            // Black treats interface files differently, limiting to one newline
-            // (`Trailing::Sibling`), and avoiding inserting any newlines in nested function
-            // blocks.
-            if self.nested
-                && matches!(
-                    stmt.node,
-                    StmtKind::FunctionDef { .. } | StmtKind::AsyncFunctionDef { .. }
-                )
-            {
-                None
-            } else {
-                Some(Trailer::Sibling)
-            }
-        } else if self.nested {
-            Some(Trailer::Sibling)
-        } else {
-            Some(match &stmt.node {
-                StmtKind::FunctionDef { .. } | StmtKind::AsyncFunctionDef { .. } => {
-                    Trailer::FunctionDef
-                }
-                StmtKind::ClassDef { .. } => Trailer::ClassDef,
-                _ => Trailer::Sibling,
-            })
+        // No need to compute trailers if we won't be finalizing anything.
+        let index = self.blocks.len() - 1;
+        if self.blocks[index].imports.is_empty() {
+            return None;
         }
+
+        // Similar to isort, avoid enforcing any newline behaviors in nested blocks.
+        if self.nested {
+            return None;
+        }
+
+        Some(if self.pyi {
+            // Black treats interface files differently, limiting to one newline
+            // (`Trailing::Sibling`).
+            Trailer::Sibling
+        } else {
+            // If the import block is followed by a class or function, we want to enforce
+            // two blank lines. The exception: if, between the import and the class or
+            // function, we have at least one commented line, followed by at
+            // least one blank line. In that case, we treat it as a regular
+            // sibling (i.e., as if the comment is the next statement, as
+            // opposed to the class or function).
+            match &stmt.node {
+                StmtKind::FunctionDef { .. } | StmtKind::AsyncFunctionDef { .. } => {
+                    if helpers::has_comment_break(stmt, self.locator) {
+                        Trailer::Sibling
+                    } else {
+                        Trailer::FunctionDef
+                    }
+                }
+                StmtKind::ClassDef { .. } => {
+                    if helpers::has_comment_break(stmt, self.locator) {
+                        Trailer::Sibling
+                    } else {
+                        Trailer::ClassDef
+                    }
+                }
+                _ => Trailer::Sibling,
+            }
+        })
     }
 
     fn finalize(&mut self, trailer: Option<Trailer>) {

src/iterators.rs

@@ -0,0 +1,16 @@
+#[cfg(not(target_family = "wasm"))]
+use rayon::prelude::*;
+
+/// Shim that calls `par_iter` except for wasm because there's no wasm support
+/// in rayon yet (there is a shim to be used for the web, but it requires js
+/// cooperation) Unfortunately, `ParallelIterator` does not implement `Iterator`
+/// so the signatures diverge
+#[cfg(not(target_family = "wasm"))]
+pub fn par_iter<T: Sync>(iterable: &[T]) -> impl ParallelIterator<Item = &T> {
+    iterable.par_iter()
+}
+
+#[cfg(target_family = "wasm")]
+pub fn par_iter<T: Sync>(iterable: &[T]) -> impl Iterator<Item = &T> {
+    iterable.iter()
+}

src/lib.rs

@@ -14,13 +14,14 @@
 use std::path::Path;
 
 use anyhow::Result;
-use log::debug;
+use path_absolutize::path_dedot;
 use rustpython_helpers::tokenize;
 use rustpython_parser::lexer::LexResult;
 use settings::{pyproject, Settings};
 
 use crate::checks::Check;
 use crate::linter::check_path;
+use crate::resolver::Relativity;
 use crate::settings::configuration::Configuration;
 use crate::source_code_locator::SourceCodeLocator;
 
@@ -53,10 +54,12 @@ mod flake8_import_conventions;
 mod flake8_print;
 pub mod flake8_quotes;
 mod flake8_return;
+mod flake8_simplify;
 pub mod flake8_tidy_imports;
 mod flake8_unused_arguments;
 pub mod fs;
 mod isort;
+pub mod iterators;
 mod lex;
 pub mod linter;
 pub mod logging;
@@ -72,6 +75,7 @@ mod pygrep_hooks;
 mod pylint;
 mod python;
 mod pyupgrade;
+pub mod resolver;
 mod ruff;
 mod rustpython_helpers;
 pub mod settings;
@@ -81,24 +85,24 @@ pub mod updates;
 mod vendored;
 pub mod visibility;
 
+/// Load the relevant `Settings` for a given `Path`.
+fn resolve(path: &Path) -> Result<Settings> {
+    if let Some(pyproject) = pyproject::find_pyproject_toml(path) {
+        // First priority: `pyproject.toml` in the current `Path`.
+        resolver::resolve_settings(&pyproject, &Relativity::Parent, None)
+    } else if let Some(pyproject) = pyproject::find_user_pyproject_toml() {
+        // Second priority: user-specific `pyproject.toml`.
+        resolver::resolve_settings(&pyproject, &Relativity::Cwd, None)
+    } else {
+        // Fallback: default settings.
+        Settings::from_configuration(Configuration::default(), &path_dedot::CWD)
+    }
+}
+
 /// Run Ruff over Python source code directly.
 pub fn check(path: &Path, contents: &str, autofix: bool) -> Result<Vec<Check>> {
-    // Find the project root and pyproject.toml.
-    let project_root = pyproject::find_project_root(&[path.to_path_buf()]);
-    match &project_root {
-        Some(path) => debug!("Found project root at: {:?}", path),
-        None => debug!("Unable to identify project root; assuming current directory..."),
-    };
-    let pyproject = pyproject::find_pyproject_toml(project_root.as_ref());
-    match &pyproject {
-        Some(path) => debug!("Found pyproject.toml at: {:?}", path),
-        None => debug!("Unable to find pyproject.toml; using default settings..."),
-    };
-
-    let settings = Settings::from_configuration(
-        Configuration::from_pyproject(pyproject.as_ref(), project_root.as_ref())?,
-        project_root.as_ref(),
-    )?;
+    // Load the relevant `Settings` for the given `Path`.
+    let settings = resolve(path)?;
 
     // Tokenize once.
     let tokens: Vec<LexResult> = tokenize(contents);

src/linter.rs

@@ -211,7 +211,7 @@ pub fn add_noqa_to_path(path: &Path, settings: &Settings) -> Result<usize> {
 }
 
 /// Apply autoformatting to the source code at the given `Path`.
-pub fn autoformat_path(path: &Path) -> Result<()> {
+pub fn autoformat_path(path: &Path, _settings: &Settings) -> Result<()> {
     // Read the file from disk.
     let contents = fs::read_file(path)?;
 

src/main.rs

@@ -11,301 +11,114 @@
     clippy::too_many_lines
 )]
 
-use std::io::{self, Read};
+use std::io::{self};
 use std::path::{Path, PathBuf};
 use std::process::ExitCode;
 use std::sync::mpsc::channel;
-use std::time::Instant;
 
 use ::ruff::autofix::fixer;
-use ::ruff::checks::{CheckCode, CheckKind};
-use ::ruff::cli::{collect_per_file_ignores, extract_log_level, Cli};
-use ::ruff::fs::iter_python_files;
-use ::ruff::linter::{add_noqa_to_path, autoformat_path, lint_path, lint_stdin, Diagnostics};
+use ::ruff::cli::{extract_log_level, Cli};
 use ::ruff::logging::{set_up_logging, LogLevel};
-use ::ruff::message::Message;
 use ::ruff::printer::Printer;
+use ::ruff::resolver::PyprojectDiscovery;
 use ::ruff::settings::configuration::Configuration;
 use ::ruff::settings::types::SerializationFormat;
 use ::ruff::settings::{pyproject, Settings};
 #[cfg(feature = "update-informer")]
 use ::ruff::updates;
-use ::ruff::{cache, commands, fs};
+use ::ruff::{cache, commands};
 use anyhow::Result;
 use clap::{CommandFactory, Parser};
 use colored::Colorize;
-use log::{debug, error};
 use notify::{recommended_watcher, RecursiveMode, Watcher};
-#[cfg(not(target_family = "wasm"))]
-use rayon::prelude::*;
-use rustpython_ast::Location;
-use walkdir::DirEntry;
+use path_absolutize::path_dedot;
+use ruff::cli::Overrides;
+use ruff::resolver::{resolve_settings, FileDiscovery, Relativity};
 
-/// Shim that calls `par_iter` except for wasm because there's no wasm support
-/// in rayon yet (there is a shim to be used for the web, but it requires js
-/// cooperation) Unfortunately, `ParallelIterator` does not implement `Iterator`
-/// so the signatures diverge
-#[cfg(not(target_family = "wasm"))]
-fn par_iter<T: Sync>(iterable: &Vec<T>) -> impl ParallelIterator<Item = &T> {
-    iterable.par_iter()
-}
-
-#[cfg(target_family = "wasm")]
-fn par_iter<T: Sync>(iterable: &Vec<T>) -> impl Iterator<Item = &T> {
-    iterable.iter()
-}
-
-fn read_from_stdin() -> Result<String> {
-    let mut buffer = String::new();
-    io::stdin().lock().read_to_string(&mut buffer)?;
-    Ok(buffer)
-}
-
-fn run_once_stdin(
-    settings: &Settings,
-    filename: &Path,
-    autofix: &fixer::Mode,
-) -> Result<Diagnostics> {
-    let stdin = read_from_stdin()?;
-    let mut diagnostics = lint_stdin(filename, &stdin, settings, autofix)?;
-    diagnostics.messages.sort_unstable();
-    Ok(diagnostics)
-}
-
-fn run_once(
-    files: &[PathBuf],
-    settings: &Settings,
-    cache: bool,
-    autofix: &fixer::Mode,
-) -> Diagnostics {
-    // Collect all the files to check.
-    let start = Instant::now();
-    let paths: Vec<Result<DirEntry, walkdir::Error>> = files
-        .iter()
-        .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
-        .collect();
-    let duration = start.elapsed();
-    debug!("Identified files to lint in: {:?}", duration);
-
-    let start = Instant::now();
-    let mut diagnostics: Diagnostics = par_iter(&paths)
-        .map(|entry| {
-            match entry {
-                Ok(entry) => {
-                    let path = entry.path();
-                    lint_path(path, settings, &cache.into(), autofix)
-                        .map_err(|e| (Some(path.to_owned()), e.to_string()))
-                }
-                Err(e) => Err((
-                    e.path().map(Path::to_owned),
-                    e.io_error()
-                        .map_or_else(|| e.to_string(), io::Error::to_string),
-                )),
-            }
-            .unwrap_or_else(|(path, message)| {
-                if let Some(path) = path {
-                    if settings.enabled.contains(&CheckCode::E902) {
-                        Diagnostics::new(vec![Message {
-                            kind: CheckKind::IOError(message),
-                            location: Location::default(),
-                            end_location: Location::default(),
-                            fix: None,
-                            filename: path.to_string_lossy().to_string(),
-                            source: None,
-                        }])
-                    } else {
-                        error!("Failed to check {}: {message}", path.to_string_lossy());
-                        Diagnostics::default()
-                    }
-                } else {
-                    error!("{message}");
-                    Diagnostics::default()
-                }
-            })
-        })
-        .reduce(Diagnostics::default, |mut acc, item| {
-            acc += item;
-            acc
-        });
-
-    diagnostics.messages.sort_unstable();
-    let duration = start.elapsed();
-    debug!("Checked files in: {:?}", duration);
-
-    diagnostics
-}
-
-fn add_noqa(files: &[PathBuf], settings: &Settings) -> usize {
-    // Collect all the files to check.
-    let start = Instant::now();
-    let paths: Vec<DirEntry> = files
-        .iter()
-        .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
-        .flatten()
-        .collect();
-    let duration = start.elapsed();
-    debug!("Identified files to lint in: {:?}", duration);
-
-    let start = Instant::now();
-    let modifications: usize = par_iter(&paths)
-        .filter_map(|entry| {
-            let path = entry.path();
-            match add_noqa_to_path(path, settings) {
-                Ok(count) => Some(count),
-                Err(e) => {
-                    error!("Failed to add noqa to {}: {e}", path.to_string_lossy());
-                    None
-                }
-            }
-        })
-        .sum();
-
-    let duration = start.elapsed();
-    debug!("Added noqa to files in: {:?}", duration);
-
-    modifications
-}
-
-fn autoformat(files: &[PathBuf], settings: &Settings) -> usize {
-    // Collect all the files to format.
-    let start = Instant::now();
-    let paths: Vec<DirEntry> = files
-        .iter()
-        .flat_map(|path| iter_python_files(path, &settings.exclude, &settings.extend_exclude))
-        .flatten()
-        .collect();
-    let duration = start.elapsed();
-    debug!("Identified files to lint in: {:?}", duration);
-
-    let start = Instant::now();
-    let modifications = par_iter(&paths)
-        .filter_map(|entry| {
-            let path = entry.path();
-            match autoformat_path(path) {
-                Ok(()) => Some(()),
-                Err(e) => {
-                    error!("Failed to autoformat {}: {e}", path.to_string_lossy());
-                    None
-                }
-            }
-        })
-        .count();
-
-    let duration = start.elapsed();
-    debug!("Auto-formatted files in: {:?}", duration);
-
-    modifications
+/// Resolve the relevant settings strategy and defaults for the current
+/// invocation.
+fn resolve(config: Option<PathBuf>, overrides: &Overrides) -> Result<PyprojectDiscovery> {
+    if let Some(pyproject) = config {
+        // First 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))?;
+        Ok(PyprojectDiscovery::Fixed(settings))
+    } else if let Some(pyproject) = pyproject::find_pyproject_toml(path_dedot::CWD.as_path()) {
+        // Second priority: find a `pyproject.toml` file in the current working path,
+        // and resolve all paths relative to 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))?;
+        Ok(PyprojectDiscovery::Hierarchical(settings))
+    } else if let Some(pyproject) = pyproject::find_user_pyproject_toml() {
+        // Third 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))?;
+        Ok(PyprojectDiscovery::Hierarchical(settings))
+    } else {
+        // Fallback: load Ruff's default settings, and resolve all paths relative to 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 mut config = Configuration::default();
+        // Apply command-line options that override defaults.
+        config.apply(overrides.clone());
+        let settings = Settings::from_configuration(config, &path_dedot::CWD)?;
+        Ok(PyprojectDiscovery::Hierarchical(settings))
+    }
 }
 
 fn inner_main() -> Result<ExitCode> {
     // Extract command-line arguments.
-    let cli = Cli::parse();
-    let fix = cli.fix();
+    let (cli, overrides) = Cli::parse().partition();
     let log_level = extract_log_level(&cli);
     set_up_logging(&log_level)?;
 
-    if let Some(shell) = cli.generate_shell_completion {
-        shell.generate(&mut Cli::command(), &mut std::io::stdout());
-        return Ok(ExitCode::SUCCESS);
-    }
-
-    // Find the project root and pyproject.toml.
-    let config: Option<PathBuf> = cli.config;
-    let project_root = config.as_ref().map_or_else(
-        || pyproject::find_project_root(&cli.files),
-        |config| config.parent().map(fs::normalize_path),
-    );
-    let pyproject = config.or_else(|| pyproject::find_pyproject_toml(project_root.as_ref()));
-
-    // Reconcile configuration from pyproject.toml and command-line arguments.
-    let mut configuration =
-        Configuration::from_pyproject(pyproject.as_ref(), project_root.as_ref())?;
-    if !cli.exclude.is_empty() {
-        configuration.exclude = cli.exclude;
-    }
-    if !cli.extend_exclude.is_empty() {
-        configuration.extend_exclude = cli.extend_exclude;
-    }
-    if !cli.per_file_ignores.is_empty() {
-        configuration.per_file_ignores = collect_per_file_ignores(cli.per_file_ignores);
-    }
-    if !cli.select.is_empty() {
-        configuration.select = cli.select;
-    }
-    if !cli.extend_select.is_empty() {
-        configuration.extend_select = cli.extend_select;
-    }
-    if !cli.ignore.is_empty() {
-        configuration.ignore = cli.ignore;
-    }
-    if !cli.extend_ignore.is_empty() {
-        configuration.extend_ignore = cli.extend_ignore;
-    }
-    if !cli.fixable.is_empty() {
-        configuration.fixable = cli.fixable;
-    }
-    if !cli.unfixable.is_empty() {
-        configuration.unfixable = cli.unfixable;
-    }
-    if let Some(format) = cli.format {
-        configuration.format = format;
-    }
-    if let Some(line_length) = cli.line_length {
-        configuration.line_length = line_length;
-    }
-    if let Some(max_complexity) = cli.max_complexity {
-        configuration.mccabe.max_complexity = max_complexity;
-    }
-    if let Some(target_version) = cli.target_version {
-        configuration.target_version = target_version;
-    }
-    if let Some(dummy_variable_rgx) = cli.dummy_variable_rgx {
-        configuration.dummy_variable_rgx = dummy_variable_rgx;
-    }
-    if let Some(fix) = fix {
-        configuration.fix = fix;
-    }
-    if cli.show_source {
-        configuration.show_source = true;
-    }
-
     if cli.show_settings && cli.show_files {
-        eprintln!("Error: specify --show-settings or show-files (not both).");
-        return Ok(ExitCode::FAILURE);
+        anyhow::bail!("specify --show-settings or show-files (not both)")
     }
-    if cli.show_settings {
-        commands::show_settings(&configuration, project_root.as_ref(), pyproject.as_ref());
+    if let Some(shell) = cli.generate_shell_completion {
+        shell.generate(&mut Cli::command(), &mut io::stdout());
         return Ok(ExitCode::SUCCESS);
     }
 
-    // Extract settings for internal use.
-    let autofix = if configuration.fix {
+    // Construct the "default" settings. These are used when no `pyproject.toml`
+    // files are present, or files are injected from outside of the hierarchy.
+    let pyproject_strategy = resolve(cli.config, &overrides)?;
+
+    // Extract options that are included in `Settings`, but only apply at the top
+    // level.
+    let file_strategy = FileDiscovery {
+        respect_gitignore: match &pyproject_strategy {
+            PyprojectDiscovery::Fixed(settings) => settings.respect_gitignore,
+            PyprojectDiscovery::Hierarchical(settings) => settings.respect_gitignore,
+        },
+    };
+    let (fix, format) = match &pyproject_strategy {
+        PyprojectDiscovery::Fixed(settings) => (settings.fix, settings.format),
+        PyprojectDiscovery::Hierarchical(settings) => (settings.fix, settings.format),
+    };
+    let autofix = if fix {
         fixer::Mode::Apply
-    } else if matches!(configuration.format, SerializationFormat::Json) {
+    } else if matches!(format, SerializationFormat::Json) {
         fixer::Mode::Generate
     } else {
         fixer::Mode::None
     };
-    let settings = Settings::from_configuration(configuration, project_root.as_ref())?;
-
-    // Now that we've inferred the appropriate log level, add some debug
-    // information.
-    match &project_root {
-        Some(path) => debug!("Found project root at: {:?}", path),
-        None => debug!("Unable to identify project root; assuming current directory..."),
-    };
-    match &pyproject {
-        Some(path) => debug!("Found pyproject.toml at: {:?}", path),
-        None => debug!("Unable to find pyproject.toml; using default settings..."),
-    };
 
     if let Some(code) = cli.explain {
-        commands::explain(&code, settings.format)?;
+        commands::explain(&code, &format)?;
+        return Ok(ExitCode::SUCCESS);
+    }
+    if cli.show_settings {
+        commands::show_settings(&cli.files, &pyproject_strategy, &file_strategy, &overrides)?;
         return Ok(ExitCode::SUCCESS);
     }
-
     if cli.show_files {
-        commands::show_files(&cli.files, &settings);
+        commands::show_files(&cli.files, &pyproject_strategy, &file_strategy, &overrides)?;
         return Ok(ExitCode::SUCCESS);
     }
 
@@ -316,7 +129,7 @@ fn inner_main() -> Result<ExitCode> {
         cache_enabled = false;
     }
 
-    let printer = Printer::new(&settings.format, &log_level);
+    let printer = Printer::new(&format, &log_level);
     if cli.watch {
         if matches!(autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
             eprintln!("Warning: --fix is not enabled in watch mode.");
@@ -327,7 +140,7 @@ fn inner_main() -> Result<ExitCode> {
         if cli.autoformat {
             eprintln!("Warning: --autoformat is not enabled in watch mode.");
         }
-        if settings.format != SerializationFormat::Text {
+        if format != SerializationFormat::Text {
             eprintln!("Warning: --format 'text' is used in watch mode.");
         }
 
@@ -335,7 +148,14 @@ fn inner_main() -> Result<ExitCode> {
         printer.clear_screen()?;
         printer.write_to_user("Starting linter in watch mode...\n");
 
-        let messages = run_once(&cli.files, &settings, cache_enabled, &fixer::Mode::None);
+        let messages = commands::run(
+            &cli.files,
+            &pyproject_strategy,
+            &file_strategy,
+            &overrides,
+            cache_enabled,
+            &fixer::Mode::None,
+        )?;
         printer.write_continuously(&messages)?;
 
         // Configure the file watcher.
@@ -347,32 +167,40 @@ fn inner_main() -> Result<ExitCode> {
 
         loop {
             match rx.recv() {
-                Ok(e) => {
-                    let paths = e?.paths;
-                    let py_changed = paths.iter().any(|p| {
-                        p.extension()
-                            .map(|ext| ext.eq_ignore_ascii_case("py"))
+                Ok(event) => {
+                    let paths = event?.paths;
+                    let py_changed = paths.iter().any(|path| {
+                        path.extension()
+                            .map(|ext| ext == "py" || ext == "pyi")
                             .unwrap_or_default()
                     });
                     if py_changed {
                         printer.clear_screen()?;
                         printer.write_to_user("File change detected...\n");
 
-                        let messages =
-                            run_once(&cli.files, &settings, cache_enabled, &fixer::Mode::None);
+                        let messages = commands::run(
+                            &cli.files,
+                            &pyproject_strategy,
+                            &file_strategy,
+                            &overrides,
+                            cache_enabled,
+                            &fixer::Mode::None,
+                        )?;
                         printer.write_continuously(&messages)?;
                     }
                 }
-                Err(e) => return Err(e.into()),
+                Err(err) => return Err(err.into()),
             }
         }
     } else if cli.add_noqa {
-        let modifications = add_noqa(&cli.files, &settings);
+        let modifications =
+            commands::add_noqa(&cli.files, &pyproject_strategy, &file_strategy, &overrides)?;
         if modifications > 0 && log_level >= LogLevel::Default {
             println!("Added {modifications} noqa directives.");
         }
     } else if cli.autoformat {
-        let modifications = autoformat(&cli.files, &settings);
+        let modifications =
+            commands::autoformat(&cli.files, &pyproject_strategy, &file_strategy, &overrides)?;
         if modifications > 0 && log_level >= LogLevel::Default {
             println!("Formatted {modifications} files.");
         }
@@ -383,9 +211,16 @@ fn inner_main() -> Result<ExitCode> {
         let diagnostics = if is_stdin {
             let filename = cli.stdin_filename.unwrap_or_else(|| "-".to_string());
             let path = Path::new(&filename);
-            run_once_stdin(&settings, path, &autofix)?
+            commands::run_stdin(&pyproject_strategy, path, &autofix)?
         } else {
-            run_once(&cli.files, &settings, cache_enabled, &autofix)
+            commands::run(
+                &cli.files,
+                &pyproject_strategy,
+                &file_strategy,
+                &overrides,
+                cache_enabled,
+                &autofix,
+            )?
         };
 
         // Always try to print violations (the printer itself may suppress output),

src/mccabe/snapshots/ruff__mccabe__tests__max_complexity_0.snap

@@ -10,8 +10,8 @@ expression: checks
     row: 2
     column: 0
   end_location:
-    row: 7
-    column: 0
+    row: 3
+    column: 8
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -21,8 +21,8 @@ expression: checks
     row: 7
     column: 0
   end_location:
-    row: 12
-    column: 0
+    row: 8
+    column: 10
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -32,8 +32,8 @@ expression: checks
     row: 12
     column: 0
   end_location:
-    row: 19
-    column: 0
+    row: 15
+    column: 12
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -43,8 +43,8 @@ expression: checks
     row: 19
     column: 0
   end_location:
-    row: 29
-    column: 0
+    row: 25
+    column: 47
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -54,8 +54,8 @@ expression: checks
     row: 29
     column: 0
   end_location:
-    row: 40
-    column: 0
+    row: 36
+    column: 47
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -65,8 +65,8 @@ expression: checks
     row: 40
     column: 0
   end_location:
-    row: 46
-    column: 0
+    row: 42
+    column: 16
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -76,8 +76,8 @@ expression: checks
     row: 46
     column: 0
   end_location:
-    row: 54
-    column: 0
+    row: 50
+    column: 19
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -87,8 +87,8 @@ expression: checks
     row: 54
     column: 0
   end_location:
-    row: 62
-    column: 0
+    row: 58
+    column: 16
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -98,8 +98,8 @@ expression: checks
     row: 62
     column: 0
   end_location:
-    row: 73
-    column: 0
+    row: 69
+    column: 7
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -109,8 +109,8 @@ expression: checks
     row: 63
     column: 4
   end_location:
-    row: 69
-    column: 4
+    row: 67
+    column: 11
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -120,8 +120,8 @@ expression: checks
     row: 64
     column: 8
   end_location:
-    row: 67
-    column: 8
+    row: 65
+    column: 16
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -131,8 +131,8 @@ expression: checks
     row: 73
     column: 0
   end_location:
-    row: 85
-    column: 0
+    row: 81
+    column: 16
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -142,8 +142,8 @@ expression: checks
     row: 85
     column: 0
   end_location:
-    row: 96
-    column: 0
+    row: 92
+    column: 16
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -153,8 +153,8 @@ expression: checks
     row: 96
     column: 0
   end_location:
-    row: 107
-    column: 0
+    row: 103
+    column: 12
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -164,8 +164,8 @@ expression: checks
     row: 107
     column: 0
   end_location:
-    row: 112
-    column: 0
+    row: 108
+    column: 17
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -175,8 +175,8 @@ expression: checks
     row: 113
     column: 4
   end_location:
-    row: 139
-    column: 0
+    row: 138
+    column: 40
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -186,8 +186,8 @@ expression: checks
     row: 118
     column: 12
   end_location:
-    row: 121
-    column: 12
+    row: 119
+    column: 20
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -197,8 +197,8 @@ expression: checks
     row: 121
     column: 12
   end_location:
-    row: 125
-    column: 8
+    row: 123
+    column: 24
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -208,8 +208,8 @@ expression: checks
     row: 126
     column: 12
   end_location:
-    row: 129
-    column: 12
+    row: 127
+    column: 20
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -219,8 +219,8 @@ expression: checks
     row: 129
     column: 12
   end_location:
-    row: 132
-    column: 12
+    row: 130
+    column: 20
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -230,8 +230,8 @@ expression: checks
     row: 132
     column: 12
   end_location:
-    row: 135
-    column: 12
+    row: 133
+    column: 20
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -241,7 +241,7 @@ expression: checks
     row: 135
     column: 12
   end_location:
-    row: 138
-    column: 8
+    row: 136
+    column: 20
   fix: ~
 

src/mccabe/snapshots/ruff__mccabe__tests__max_complexity_3.snap

@@ -10,8 +10,8 @@ expression: checks
     row: 73
     column: 0
   end_location:
-    row: 85
-    column: 0
+    row: 81
+    column: 16
   fix: ~
 - kind:
     FunctionIsTooComplex:
@@ -21,7 +21,7 @@ expression: checks
     row: 113
     column: 4
   end_location:
-    row: 139
-    column: 0
+    row: 138
+    column: 40
   fix: ~
 

src/pep8_naming/snapshots/ruff__pep8_naming__tests__N801_N801.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 1
     column: 0
   end_location:
-    row: 5
-    column: 0
+    row: 2
+    column: 8
   fix: ~
 - kind:
     InvalidClassName: _bad
@@ -17,8 +17,8 @@ expression: checks
     row: 5
     column: 0
   end_location:
-    row: 9
-    column: 0
+    row: 6
+    column: 8
   fix: ~
 - kind:
     InvalidClassName: bad_class
@@ -26,8 +26,8 @@ expression: checks
     row: 9
     column: 0
   end_location:
-    row: 13
-    column: 0
+    row: 10
+    column: 8
   fix: ~
 - kind:
     InvalidClassName: Bad_Class
@@ -35,8 +35,8 @@ expression: checks
     row: 13
     column: 0
   end_location:
-    row: 17
-    column: 0
+    row: 14
+    column: 8
   fix: ~
 - kind:
     InvalidClassName: BAD_CLASS
@@ -44,7 +44,7 @@ expression: checks
     row: 17
     column: 0
   end_location:
-    row: 21
-    column: 0
+    row: 18
+    column: 8
   fix: ~
 

src/pep8_naming/snapshots/ruff__pep8_naming__tests__N802_N802.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 4
     column: 0
   end_location:
-    row: 8
-    column: 0
+    row: 5
+    column: 8
   fix: ~
 - kind:
     InvalidFunctionName: _Bad
@@ -17,8 +17,8 @@ expression: checks
     row: 8
     column: 0
   end_location:
-    row: 12
-    column: 0
+    row: 9
+    column: 8
   fix: ~
 - kind:
     InvalidFunctionName: BAD
@@ -26,8 +26,8 @@ expression: checks
     row: 12
     column: 0
   end_location:
-    row: 16
-    column: 0
+    row: 13
+    column: 8
   fix: ~
 - kind:
     InvalidFunctionName: BAD_FUNC
@@ -35,8 +35,8 @@ expression: checks
     row: 16
     column: 0
   end_location:
-    row: 20
-    column: 0
+    row: 17
+    column: 8
   fix: ~
 - kind:
     InvalidFunctionName: testTest
@@ -44,7 +44,7 @@ expression: checks
     row: 40
     column: 4
   end_location:
-    row: 42
-    column: 0
+    row: 41
+    column: 19
   fix: ~
 

src/pep8_naming/snapshots/ruff__pep8_naming__tests__N807_N807.py.snap

@@ -7,15 +7,15 @@ expression: checks
     row: 1
     column: 0
   end_location:
-    row: 5
-    column: 0
+    row: 2
+    column: 8
   fix: ~
 - kind: DunderFunctionName
   location:
     row: 14
     column: 4
   end_location:
-    row: 17
-    column: 4
+    row: 15
+    column: 12
   fix: ~
 

src/pep8_naming/snapshots/ruff__pep8_naming__tests__N818_N818.py.snap

@@ -8,8 +8,8 @@ expression: checks
     row: 9
     column: 0
   end_location:
-    row: 13
-    column: 0
+    row: 10
+    column: 8
   fix: ~
 - kind:
     ErrorSuffixOnExceptionName: E
@@ -17,7 +17,7 @@ expression: checks
     row: 17
     column: 0
   end_location:
-    row: 19
-    column: 0
+    row: 18
+    column: 8
   fix: ~
 

src/pycodestyle/plugins.rs

@@ -59,24 +59,21 @@ pub fn literal_comparisons(
         )
     {
         if matches!(op, Cmpop::Eq) {
-            let mut check = Check::new(
+            let check = Check::new(
                 CheckKind::NoneComparison(RejectedCmpop::Eq),
                 Range::from_located(comparator),
             );
             if checker.patch(check.kind.code()) {
-                // Dummy replacement
-                check.amend(Fix::dummy(expr.location));
                 bad_ops.insert(0, Cmpop::Is);
             }
             checks.push(check);
         }
         if matches!(op, Cmpop::NotEq) {
-            let mut check = Check::new(
+            let check = Check::new(
                 CheckKind::NoneComparison(RejectedCmpop::NotEq),
                 Range::from_located(comparator),
             );
             if checker.patch(check.kind.code()) {
-                check.amend(Fix::dummy(expr.location));
                 bad_ops.insert(0, Cmpop::IsNot);
             }
             checks.push(check);
@@ -90,23 +87,21 @@ pub fn literal_comparisons(
         } = comparator.node
         {
             if matches!(op, Cmpop::Eq) {
-                let mut check = Check::new(
+                let check = Check::new(
                     CheckKind::TrueFalseComparison(value, RejectedCmpop::Eq),
                     Range::from_located(comparator),
                 );
                 if checker.patch(check.kind.code()) {
-                    check.amend(Fix::dummy(expr.location));
                     bad_ops.insert(0, Cmpop::Is);
                 }
                 checks.push(check);
             }
             if matches!(op, Cmpop::NotEq) {
-                let mut check = Check::new(
+                let check = Check::new(
                     CheckKind::TrueFalseComparison(value, RejectedCmpop::NotEq),
                     Range::from_located(comparator),
                 );
                 if checker.patch(check.kind.code()) {
-                    check.amend(Fix::dummy(expr.location));
                     bad_ops.insert(0, Cmpop::IsNot);
                 }
                 checks.push(check);
@@ -126,23 +121,21 @@ pub fn literal_comparisons(
             )
         {
             if matches!(op, Cmpop::Eq) {
-                let mut check = Check::new(
+                let check = Check::new(
                     CheckKind::NoneComparison(RejectedCmpop::Eq),
                     Range::from_located(comparator),
                 );
                 if checker.patch(check.kind.code()) {
-                    check.amend(Fix::dummy(expr.location));
                     bad_ops.insert(idx, Cmpop::Is);
                 }
                 checks.push(check);
             }
             if matches!(op, Cmpop::NotEq) {
-                let mut check = Check::new(
+                let check = Check::new(
                     CheckKind::NoneComparison(RejectedCmpop::NotEq),
                     Range::from_located(comparator),
                 );
                 if checker.patch(check.kind.code()) {
-                    check.amend(Fix::dummy(expr.location));
                     bad_ops.insert(idx, Cmpop::IsNot);
                 }
                 checks.push(check);
@@ -156,23 +149,21 @@ pub fn literal_comparisons(
             } = comparator.node
             {
                 if matches!(op, Cmpop::Eq) {
-                    let mut check = Check::new(
+                    let check = Check::new(
                         CheckKind::TrueFalseComparison(value, RejectedCmpop::Eq),
                         Range::from_located(comparator),
                     );
                     if checker.patch(check.kind.code()) {
-                        check.amend(Fix::dummy(expr.location));
                         bad_ops.insert(idx, Cmpop::Is);
                     }
                     checks.push(check);
                 }
                 if matches!(op, Cmpop::NotEq) {
-                    let mut check = Check::new(
+                    let check = Check::new(
                         CheckKind::TrueFalseComparison(value, RejectedCmpop::NotEq),
                         Range::from_located(comparator),
                     );
                     if checker.patch(check.kind.code()) {
-                        check.amend(Fix::dummy(expr.location));
                         bad_ops.insert(idx, Cmpop::IsNot);
                     }
                     checks.push(check);
@@ -190,9 +181,9 @@ pub fn literal_comparisons(
             .cloned()
             .collect::<Vec<_>>();
         if let Some(content) = compare(left, &ops, comparators) {
-            if let Some(check) = checks.last_mut() {
-                check.fix = Some(Fix::replacement(
-                    content,
+            for check in &mut checks {
+                check.amend(Fix::replacement(
+                    content.to_string(),
                     expr.location,
                     expr.end_location.unwrap(),
                 ));
@@ -298,11 +289,11 @@ pub fn do_not_assign_lambda(checker: &mut Checker, target: &Expr, value: &Expr,
                 {
                     match function(id, args, body) {
                         Ok(content) => {
-                            let indentation =
-                                &leading_space(&checker.locator.slice_source_code_range(&Range {
-                                    location: Location::new(stmt.location.row(), 0),
-                                    end_location: Location::new(stmt.location.row() + 1, 0),
-                                }));
+                            let first_line = checker.locator.slice_source_code_range(&Range {
+                                location: Location::new(stmt.location.row(), 0),
+                                end_location: Location::new(stmt.location.row() + 1, 0),
+                            });
+                            let indentation = &leading_space(&first_line);
                             let mut indented = String::new();
                             for (idx, line) in content.lines().enumerate() {
                                 if idx == 0 {

src/pycodestyle/snapshots/ruff__pycodestyle__tests__E711_E711.py.snap

@@ -139,13 +139,13 @@ expression: checks
     row: 26
     column: 12
   fix:
-    content: ""
+    content: x is None is not None
     location:
       row: 26
       column: 3
     end_location:
       row: 26
-      column: 3
+      column: 20
 - kind:
     NoneComparison: NotEq
   location:

src/pycodestyle/snapshots/ruff__pycodestyle__tests__E712_E712.py.snap

@@ -175,13 +175,13 @@ expression: checks
     row: 25
     column: 14
   fix:
-    content: ""
+    content: res is True is not False
     location:
       row: 25
       column: 3
     end_location:
       row: 25
-      column: 3
+      column: 23
 - kind:
     TrueFalseComparison:
       - false

src/pycodestyle/snapshots/ruff__pycodestyle__tests__E722_E722.py.snap

@@ -7,23 +7,23 @@ expression: checks
     row: 4
     column: 0
   end_location:
-    row: 7
-    column: 0
+    row: 5
+    column: 8
   fix: ~
 - kind: DoNotUseBareExcept
   location:
     row: 11
     column: 0
   end_location:
-    row: 14
-    column: 0
+    row: 12
+    column: 8
   fix: ~
 - kind: DoNotUseBareExcept
   location:
     row: 16
     column: 0
   end_location:
-    row: 19
-    column: 0
+    row: 17
+    column: 8
   fix: ~
 

src/pycodestyle/snapshots/ruff__pycodestyle__tests__E741_E741.py.snap

@@ -215,8 +215,8 @@ expression: checks
     row: 71
     column: 0
   end_location:
-    row: 74
-    column: 0
+    row: 72
+    column: 8
   fix: ~
 - kind:
     AmbiguousVariableName: l