Bump version to 0.0.200

.github/workflows/ci.yaml

@@ -121,31 +121,35 @@ jobs:
       - run: cargo test --all
       - run: cargo test --package ruff --test black_compatibility_test -- --ignored
 
-  wasm-pack-test:
-    name: "wasm-pack test"
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v3
-      - uses: actions-rs/toolchain@v1
-        with:
-          profile: minimal
-          toolchain: nightly-2022-11-01
-          override: true
-      - uses: actions/cache@v3
-        env:
-          cache-name: cache-cargo
-        with:
-          path: |
-            ~/.cargo/registry
-            ~/.cargo/git
-          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
-          restore-keys: |
-            ${{ runner.os }}-build-${{ env.cache-name }}-
-            ${{ runner.os }}-build-
-            ${{ runner.os }}-
-      - uses: jetli/wasm-pack-action@v0.4.0
-      - uses: jetli/wasm-bindgen-action@v0.2.0
-      - run: wasm-pack test --node
+# TODO(charlie): Re-enable the `wasm-pack` tests.
+# See: https://github.com/charliermarsh/ruff/issues/1425
+#  wasm-pack-test:
+#    name: "wasm-pack test"
+#    runs-on: ubuntu-latest
+#    env:
+#      WASM_BINDGEN_TEST_TIMEOUT: 60
+#    steps:
+#      - uses: actions/checkout@v3
+#      - uses: actions-rs/toolchain@v1
+#        with:
+#          profile: minimal
+#          toolchain: nightly-2022-11-01
+#          override: true
+#      - uses: actions/cache@v3
+#        env:
+#          cache-name: cache-cargo
+#        with:
+#          path: |
+#            ~/.cargo/registry
+#            ~/.cargo/git
+#          key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ hashFiles('**/Cargo.lock') }}
+#          restore-keys: |
+#            ${{ runner.os }}-build-${{ env.cache-name }}-
+#            ${{ runner.os }}-build-
+#            ${{ runner.os }}-
+#      - uses: jetli/wasm-pack-action@v0.4.0
+#      - uses: jetli/wasm-bindgen-action@v0.2.0
+#      - run: wasm-pack test --node
 
   maturin-build:
     name: "maturin build"

.pre-commit-config.yaml

@@ -1,6 +1,6 @@
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.196
+    rev: v0.0.200
     hooks:
       - id: ruff
 

Cargo.lock

@@ -750,7 +750,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8-to-ruff"
-version = "0.0.196-dev.0"
+version = "0.0.200-dev.0"
 dependencies = [
  "anyhow",
  "clap 4.0.32",
@@ -1878,7 +1878,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.196"
+version = "0.0.200"
 dependencies = [
  "annotate-snippets 0.9.1",
  "anyhow",
@@ -1930,6 +1930,7 @@ dependencies = [
  "serde-wasm-bindgen",
  "serde_json",
  "shellexpand",
+ "similar",
  "strum",
  "strum_macros",
  "test-case",
@@ -1945,7 +1946,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_dev"
-version = "0.0.196"
+version = "0.0.200"
 dependencies = [
  "anyhow",
  "clap 4.0.32",
@@ -1966,7 +1967,7 @@ dependencies = [
 
 [[package]]
 name = "ruff_macros"
-version = "0.0.196"
+version = "0.0.200"
 dependencies = [
  "proc-macro2",
  "quote",

Cargo.toml

@@ -6,9 +6,15 @@ members = [
 
 [package]
 name = "ruff"
-version = "0.0.196"
+version = "0.0.200"
+authors = ["Charlie Marsh <charlie.r.marsh@gmail.com>"]
 edition = "2021"
 rust-version = "1.65.0"
+documentation = "https://github.com/charliermarsh/ruff"
+homepage = "https://github.com/charliermarsh/ruff"
+repository = "https://github.com/charliermarsh/ruff"
+readme = "README.md"
+license = "MIT"
 
 [lib]
 name = "ruff"
@@ -45,7 +51,7 @@ path-absolutize = { version = "3.0.14", features = ["once_cell_cache", "use_unix
 quick-junit = { version = "0.3.2" }
 regex = { version = "1.6.0" }
 ropey = { version = "1.5.0", features = ["cr_lines", "simd"], default-features = false }
-ruff_macros = { version = "0.0.196", path = "ruff_macros" }
+ruff_macros = { version = "0.0.200", path = "ruff_macros" }
 rustc-hash = { version = "1.1.0" }
 rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "68d26955b3e24198a150315e7959719b03709dee" }
 rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "68d26955b3e24198a150315e7959719b03709dee" }
@@ -55,6 +61,7 @@ semver = { version = "1.0.16" }
 serde = { version = "1.0.147", features = ["derive"] }
 serde_json = { version = "1.0.87" }
 shellexpand = { version = "3.0.0" }
+similar = { version = "2.2.1" }
 strum = { version = "0.24.1", features = ["strum_macros"] }
 strum_macros = { version = "0.24.3" }
 textwrap = { version = "0.16.0" }

README.md

@@ -167,7 +167,7 @@ Ruff also works with [pre-commit](https://pre-commit.com):
 ```yaml
 - repo: https://github.com/charliermarsh/ruff-pre-commit
   # Ruff version.
-  rev: 'v0.0.196'
+  rev: 'v0.0.200'
   hooks:
     - id: ruff
       # Respect `exclude` and `extend-exclude` settings.
@@ -225,8 +225,8 @@ max-complexity = 10
 ```
 
 As an example, the following would configure Ruff to: (1) avoid checking for line-length
-violations (`E501`); (2), always autofix, but never remove unused imports (`F401`); and (3) ignore
-import-at-top-of-file errors (`E402`) in `__init__.py` files:
+violations (`E501`); (2) never remove unused imports (`F401`); and (3) ignore import-at-top-of-file
+errors (`E402`) in `__init__.py` files:
 
 ```toml
 [tool.ruff]
@@ -236,8 +236,7 @@ select = ["E", "F"]
 # Never enforce `E501` (line length violations).
 ignore = ["E501"]
 
-# Always autofix, but never try to fix `F401` (unused imports).
-fix = true
+# Never try to fix `F401` (unused imports).
 unfixable = ["F401"]
 
 # Ignore `E402` (import violations) in all `__init__.py` files, and in `path/to/file.py`.
@@ -257,6 +256,17 @@ select = ["E", "F", "Q"]
 docstring-quotes = "double"
 ```
 
+Ruff mirrors Flake8's error code system, in which each error code consists of a one-to-three letter
+prefix, followed by three digits (e.g., `F401`). The prefix indicates that "source" of the error
+code (e.g., `F` for Pyflakes, `E` for `pycodestyle`, `ANN` for `flake8-annotations`). The set of
+enabled errors is determined by the `select` and `ignore` options, which support both the full
+error code (e.g., `F401`) and the prefix (e.g., `F`).
+
+As a special-case, Ruff also supports the `ALL` error code, which enables all error codes. Note that
+some of the `pydocstyle` error codes are conflicting (e.g., `D203` and `D211`) as they represent
+alternative docstring formats. Enabling `ALL` without further configuration may result in suboptimal
+behavior, especially for the `pydocstyle` plugin.
+
 As an alternative to `pyproject.toml`, Ruff will also respect a `ruff.toml` file, which implements
 an equivalent schema (though the `[tool.ruff]` hierarchy can be omitted). For example, the above
 `pyproject.toml` described above would be represented via the following `ruff.toml`:
@@ -313,6 +323,8 @@ Options:
           Attempt to automatically fix lint errors
       --fix-only
           Fix any fixable lint errors, but don't report on leftover violations. Implies `--fix`
+      --diff
+          Avoid writing any fixed files back; instead, output a diff for each changed file to stdout
   -n, --no-cache
           Disable cache reads
       --select <SELECT>
@@ -334,13 +346,15 @@ 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 [possible values: text, json, junit, grouped, github]
+          Output serialization format for error messages [possible values: text, json, junit, grouped, github, gitlab]
       --show-source
           Show violations with source code
       --respect-gitignore
           Respect file exclusions via `.gitignore` and other standard ignore files
       --force-exclude
           Enforce exclusions, even for paths passed to Ruff directly on the command-line
+      --update-check
+          Enable or disable automatic update checks
       --show-files
           See the files Ruff will be run against with the current settings
       --show-settings
@@ -661,6 +675,8 @@ For more, see [pyupgrade](https://pypi.org/project/pyupgrade/3.2.0/) on PyPI.
 | UP019 | TypingTextStrAlias | `typing.Text` is deprecated, use `str` | 🛠 |
 | UP020 | OpenAlias | Use builtin `open` | 🛠 |
 | UP021 | ReplaceUniversalNewlines | `universal_newlines` is deprecated, use `text` | 🛠 |
+| UP022 | ReplaceStdoutStderr | Sending stdout and stderr to pipe is deprecated, use `capture_output` | 🛠 |
+| UP023 | RewriteCElementTree | `cElementTree` is deprecated, use `ElementTree` | 🛠 |
 
 ### pep8-naming (N)
 
@@ -957,6 +973,7 @@ For more, see [pygrep-hooks](https://github.com/pre-commit/pygrep-hooks) on GitH
 | PGH001 | NoEval | No builtin `eval()` allowed |  |
 | PGH002 | DeprecatedLogWarn | `warn` is deprecated in favor of `warning` |  |
 | PGH003 | BlanketTypeIgnore | Use specific error codes when ignoring type issues |  |
+| PGH004 | BlanketNOQA | Use specific error codes when using `noqa` |  |
 
 ### Pylint (PLC, PLE, PLR, PLW)
 
@@ -984,6 +1001,7 @@ For more, see [Pylint](https://pypi.org/project/pylint/2.15.7/) on PyPI.
 | RUF001 | AmbiguousUnicodeCharacterString | String contains ambiguous unicode character '𝐁' (did you mean 'B'?) | 🛠 |
 | RUF002 | AmbiguousUnicodeCharacterDocstring | Docstring contains ambiguous unicode character '𝐁' (did you mean 'B'?) | 🛠 |
 | RUF003 | AmbiguousUnicodeCharacterComment | Comment contains ambiguous unicode character '𝐁' (did you mean 'B'?) |  |
+| RUF004 | KeywordArgumentBeforeStarArgument | Keyword argument `...` must come after starred arguments |  |
 | RUF100 | UnusedNOQA | Unused blanket `noqa` directive | 🛠 |
 
 <!-- End auto-generated sections. -->
@@ -1368,6 +1386,22 @@ src = ["src", "tests"]
 known-first-party = ["my_module1", "my_module2"]
 ```
 
+### Does Ruff support Jupyter Notebooks?
+
+Ruff is integrated into [nbQA](https://github.com/nbQA-dev/nbQA), a tool for running linters and
+code formatters over Jupyter Notebooks.
+
+After installing `ruff` and `nbqa`, you can run Ruff over a notebook like so:
+
+```shell
+> nbqa ruff Untitled.ipynb
+Untitled.ipynb:cell_1:2:5: F841 Local variable `x` is assigned to but never used
+Untitled.ipynb:cell_2:1:1: E402 Module level import not at top of file
+Untitled.ipynb:cell_2:1:8: F401 `os` imported but unused
+Found 3 error(s).
+1 potentially fixable with the --fix option.
+```
+
 ### Does Ruff support NumPy- or Google-style docstrings?
 
 Yes! To enable a specific docstring convention, start by enabling all `pydocstyle` error codes, and
@@ -1902,8 +1936,9 @@ force-exclude = true
 
 The style in which violation messages should be formatted: `"text"`
 (default), `"grouped"` (group messages by file), `"json"`
-(machine-readable), `"junit"` (machine-readable XML), or `"github"`
-(GitHub Actions annotations).
+(machine-readable), `"junit"` (machine-readable XML), `"github"`
+(GitHub Actions annotations) or `"gitlab"`
+(GitLab CI code quality report).
 
 **Default value**: `"text"`
 
@@ -2165,6 +2200,24 @@ unfixable = ["F401"]
 
 ---
 
+#### [`update-check`](#update-check)
+
+Enable or disable automatic update checks (overridden by the
+`--update-check` and `--no-update-check` command-line flags).
+
+**Default value**: `true`
+
+**Type**: `bool`
+
+**Example usage**:
+
+```toml
+[tool.ruff]
+update-check = false
+```
+
+---
+
 ### `flake8-annotations`
 
 #### [`allow-star-arg-any`](#allow-star-arg-any)
@@ -2408,7 +2461,7 @@ multiline-quotes = "single"
 #### [`ban-relative-imports`](#ban-relative-imports)
 
 Whether to ban all relative imports (`"all"`), or only those imports
-that extend into the parent module and beyond (`"parents"`).
+that extend into the parent module or beyond (`"parents"`).
 
 **Default value**: `"parents"`
 
@@ -2693,7 +2746,7 @@ Whether to use Google-style or Numpy-style conventions when detecting
 docstring sections. By default, conventions will be inferred from
 the available sections.
 
-**Default value**: `"convention"`
+**Default value**: `None`
 
 **Type**: `Convention`
 

flake8_to_ruff/Cargo.lock

@@ -771,7 +771,7 @@ checksum = "0ce7134b9999ecaf8bcd65542e436736ef32ddca1b3e06094cb6ec5755203b80"
 
 [[package]]
 name = "flake8_to_ruff"
-version = "0.0.196"
+version = "0.0.200"
 dependencies = [
  "anyhow",
  "clap",
@@ -1975,7 +1975,7 @@ dependencies = [
 
 [[package]]
 name = "ruff"
-version = "0.0.196"
+version = "0.0.200"
 dependencies = [
  "anyhow",
  "bincode",

flake8_to_ruff/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "flake8-to-ruff"
-version = "0.0.196-dev.0"
+version = "0.0.200-dev.0"
 edition = "2021"
 
 [lib]

flake8_to_ruff/src/converter.rs

@@ -4,11 +4,12 @@ use anyhow::Result;
 use ruff::checks_gen::CheckCodePrefix;
 use ruff::flake8_quotes::settings::Quote;
 use ruff::flake8_tidy_imports::settings::Strictness;
+use ruff::pydocstyle::settings::Convention;
 use ruff::settings::options::Options;
 use ruff::settings::pyproject::Pyproject;
 use ruff::{
     flake8_annotations, flake8_bugbear, flake8_errmsg, flake8_quotes, flake8_tidy_imports, mccabe,
-    pep8_naming,
+    pep8_naming, pydocstyle,
 };
 
 use crate::black::Black;
@@ -91,6 +92,7 @@ pub fn convert(
     let mut flake8_tidy_imports = flake8_tidy_imports::settings::Options::default();
     let mut mccabe = mccabe::settings::Options::default();
     let mut pep8_naming = pep8_naming::settings::Options::default();
+    let mut pydocstyle = pydocstyle::settings::Options::default();
     for (key, value) in flake8 {
         if let Some(value) = value {
             match key.as_str() {
@@ -200,9 +202,12 @@ pub fn convert(
                     _ => eprintln!("Unexpected '{key}' value: {value}"),
                 },
                 // flake8-docstrings
-                "docstring-convention" => {
-                    // No-op (handled above).
-                }
+                "docstring-convention" => match value.trim() {
+                    "google" => pydocstyle.convention = Some(Convention::Google),
+                    "numpy" => pydocstyle.convention = Some(Convention::Numpy),
+                    "pep257" | "all" => pydocstyle.convention = None,
+                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                },
                 // mccabe
                 "max-complexity" | "max_complexity" => match value.clone().parse::<usize>() {
                     Ok(max_complexity) => mccabe.max_complexity = Some(max_complexity),
@@ -247,6 +252,9 @@ pub fn convert(
     if pep8_naming != pep8_naming::settings::Options::default() {
         options.pep8_naming = Some(pep8_naming);
     }
+    if pydocstyle != pydocstyle::settings::Options::default() {
+        options.pydocstyle = Some(pydocstyle);
+    }
 
     // Extract any settings from the existing `pyproject.toml`.
     if let Some(black) = black {
@@ -271,9 +279,10 @@ mod tests {
 
     use anyhow::Result;
     use ruff::checks_gen::CheckCodePrefix;
-    use ruff::flake8_quotes;
+    use ruff::pydocstyle::settings::Convention;
     use ruff::settings::options::Options;
     use ruff::settings::pyproject::Pyproject;
+    use ruff::{flake8_quotes, pydocstyle};
 
     use crate::converter::convert;
     use crate::plugin::Plugin;
@@ -287,6 +296,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -314,7 +324,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,
@@ -345,6 +355,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -372,7 +383,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,
@@ -403,6 +414,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -430,7 +442,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,
@@ -461,6 +473,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -488,7 +501,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,
@@ -519,6 +532,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -546,7 +560,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,
@@ -585,6 +599,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -648,7 +663,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,
@@ -659,7 +674,9 @@ mod tests {
             isort: None,
             mccabe: None,
             pep8_naming: None,
-            pydocstyle: None,
+            pydocstyle: Some(pydocstyle::settings::Options {
+                convention: Some(Convention::Numpy),
+            }),
             pyupgrade: None,
         });
         assert_eq!(actual, expected);
@@ -679,6 +696,7 @@ mod tests {
         )?;
         let expected = Pyproject::new(Options {
             allowed_confusables: None,
+            cache_dir: None,
             dummy_variable_rgx: None,
             exclude: None,
             extend: None,
@@ -707,7 +725,7 @@ mod tests {
             src: None,
             target_version: None,
             unfixable: None,
-            cache_dir: None,
+            update_check: None,
             flake8_annotations: None,
             flake8_bugbear: None,
             flake8_errmsg: None,

playground/README.md

@@ -8,3 +8,7 @@ In-browser playground for Ruff. Available [https://ruff.pages.dev/](https://ruff
   root directory.
 - Install TypeScript dependencies with: `npm install`.
 - Start the development server with: `npm run dev`.
+
+## Implementation
+
+Design based on [Tailwind Play](https://play.tailwindcss.com/). Themed with [`ayu`](https://github.com/dempfi/ayu).

playground/index.html

@@ -13,17 +13,10 @@
       rel="icon"
       href="data:image/svg+xml,<svg xmlns=%22http://www.w3.org/2000/svg%22 viewBox=%220 0 100 100%22><text y=%22.9em%22 font-size=%2290%22>🛠️</text></svg>"
     />
+    <link rel="stylesheet" href="https://rsms.me/inter/inter.css" />
   </head>
   <body>
     <div id="root"></div>
-    <div style="display: flex; position: fixed; right: 16px; top: 16px">
-      <a href="https://GitHub.com/charliermarsh/ruff"
-        ><img
-          src="https://img.shields.io/github/stars/charliermarsh/ruff.svg?style=social&label=GitHub&maxAge=2592000&?logoWidth=100"
-          alt="GitHub stars"
-          style="width: 120px"
-      /></a>
-    </div>
     <script type="module" src="/src/main.tsx"></script>
   </body>
 </html>

playground/package.json

@@ -14,6 +14,7 @@
   },
   "dependencies": {
     "@monaco-editor/react": "^4.4.6",
+    "classnames": "^2.3.2",
     "lz-string": "^1.4.4",
     "monaco-editor": "^0.34.1",
     "react": "^18.2.0",
@@ -25,13 +26,16 @@
     "@typescript-eslint/eslint-plugin": "^5.47.1",
     "@typescript-eslint/parser": "^5.47.1",
     "@vitejs/plugin-react-swc": "^3.0.0",
+    "autoprefixer": "^10.4.13",
     "eslint": "^8.30.0",
     "eslint-config-prettier": "^8.5.0",
     "eslint-plugin-import": "^2.26.0",
     "eslint-plugin-prettier": "^4.2.1",
     "eslint-plugin-react": "^7.31.11",
     "eslint-plugin-react-hooks": "^4.6.0",
+    "postcss": "^8.4.20",
     "prettier": "^2.8.1",
+    "tailwindcss": "^3.2.4",
     "typescript": "^4.9.3",
     "vite": "^4.0.0"
   }

playground/postcss.config.cjs

@@ -0,0 +1,6 @@
+module.exports = {
+  plugins: {
+    tailwindcss: {},
+    autoprefixer: {},
+  },
+};

playground/src/App.tsx

@@ -1,200 +0,0 @@
-import lzstring from "lz-string";
-import Editor, { useMonaco } from "@monaco-editor/react";
-import { MarkerSeverity } from "monaco-editor/esm/vs/editor/editor.api";
-import { useEffect, useState, useCallback } from "react";
-
-import init, { Check, check } from "./pkg/ruff.js";
-import { AVAILABLE_OPTIONS } from "./ruff_options";
-import { Config, getDefaultConfig, toRuffConfig } from "./config";
-import { Options } from "./Options";
-
-const DEFAULT_SOURCE =
-  "# Define a function that takes an integer n and returns the nth number in the Fibonacci\n" +
-  "# sequence.\n" +
-  "def fibonacci(n):\n" +
-  "  if n == 0:\n" +
-  "    return 0\n" +
-  "  elif n == 1:\n" +
-  "    return 1\n" +
-  "  else:\n" +
-  "    return fibonacci(n-1) + fibonacci(n-2)\n" +
-  "\n" +
-  "# Use a for loop to generate and print the first 10 numbers in the Fibonacci sequence.\n" +
-  "for i in range(10):\n" +
-  "  print(fibonacci(i))\n" +
-  "\n" +
-  "# Output:\n" +
-  "# 0\n" +
-  "# 1\n" +
-  "# 1\n" +
-  "# 2\n" +
-  "# 3\n" +
-  "# 5\n" +
-  "# 8\n" +
-  "# 13\n" +
-  "# 21\n" +
-  "# 34\n";
-
-function restoreConfigAndSource(): [Config, string] {
-  const value = lzstring.decompressFromEncodedURIComponent(
-    window.location.hash.slice(1)
-  );
-  let config = {};
-  let source = DEFAULT_SOURCE;
-
-  if (value) {
-    const parts = value.split("$$$");
-    config = JSON.parse(parts[0]);
-    source = parts[1];
-  }
-
-  return [config, source];
-}
-
-function persistConfigAndSource(config: Config, source: string) {
-  window.location.hash = lzstring.compressToEncodedURIComponent(
-    JSON.stringify(config) + "$$$" + source
-  );
-}
-
-const defaultConfig = getDefaultConfig(AVAILABLE_OPTIONS);
-
-export default function App() {
-  const monaco = useMonaco();
-  const [initialized, setInitialized] = useState<boolean>(false);
-  const [config, setConfig] = useState<Config | null>(null);
-  const [source, setSource] = useState<string | null>(null);
-  const [error, setError] = useState<string | null>(null);
-
-  useEffect(() => {
-    init().then(() => setInitialized(true));
-  }, []);
-
-  useEffect(() => {
-    if (source == null && config == null && monaco) {
-      const [config, source] = restoreConfigAndSource();
-      setConfig(config);
-      setSource(source);
-    }
-  }, [monaco, source, config]);
-
-  useEffect(() => {
-    if (config != null && source != null) {
-      persistConfigAndSource(config, source);
-    }
-  }, [config, source]);
-
-  useEffect(() => {
-    const editor = monaco?.editor;
-    const model = editor?.getModels()[0];
-    if (!editor || !model || !initialized || source == null || config == null) {
-      return;
-    }
-
-    let checks: Check[];
-    try {
-      checks = check(source, toRuffConfig(config));
-      setError(null);
-    } catch (e) {
-      setError(String(e));
-      return;
-    }
-
-    editor.setModelMarkers(
-      model,
-      "owner",
-      checks.map((check) => ({
-        startLineNumber: check.location.row,
-        startColumn: check.location.column + 1,
-        endLineNumber: check.end_location.row,
-        endColumn: check.end_location.column + 1,
-        message: `${check.code}: ${check.message}`,
-        severity: MarkerSeverity.Error,
-      }))
-    );
-
-    const codeActionProvider = monaco?.languages.registerCodeActionProvider(
-      "python",
-      {
-        // @ts-expect-error: The type definition is wrong.
-        provideCodeActions: function (model, position) {
-          const actions = checks
-            .filter((check) => position.startLineNumber === check.location.row)
-            .filter((check) => check.fix)
-            .map((check) => ({
-              title: `Fix ${check.code}`,
-              id: `fix-${check.code}`,
-              kind: "quickfix",
-              edit: check.fix
-                ? {
-                    edits: [
-                      {
-                        resource: model.uri,
-                        versionId: model.getVersionId(),
-                        edit: {
-                          range: {
-                            startLineNumber: check.fix.location.row,
-                            startColumn: check.fix.location.column + 1,
-                            endLineNumber: check.fix.end_location.row,
-                            endColumn: check.fix.end_location.column + 1,
-                          },
-                          text: check.fix.content,
-                        },
-                      },
-                    ],
-                  }
-                : undefined,
-            }));
-          return { actions, dispose: () => {} };
-        },
-      }
-    );
-
-    return () => {
-      codeActionProvider?.dispose();
-    };
-  }, [config, source, monaco, initialized]);
-
-  const handleEditorChange = useCallback(
-    (value: string | undefined) => {
-      setSource(value || "");
-    },
-    [setSource]
-  );
-
-  const handleOptionChange = useCallback(
-    (groupName: string, fieldName: string, value: string) => {
-      const group = Object.assign({}, (config || {})[groupName]);
-      if (value === defaultConfig[groupName][fieldName] || value === "") {
-        delete group[fieldName];
-      } else {
-        group[fieldName] = value;
-      }
-
-      setConfig({
-        ...config,
-        [groupName]: group,
-      });
-    },
-    [config]
-  );
-
-  return (
-    <div id="app">
-      <Options
-        config={config}
-        defaultConfig={defaultConfig}
-        onChange={handleOptionChange}
-      />
-      <Editor
-        options={{ readOnly: false, minimap: { enabled: false } }}
-        wrapperProps={{ className: "editor" }}
-        defaultLanguage="python"
-        value={source || ""}
-        theme={"light"}
-        onChange={handleEditorChange}
-      />
-      {error && <div id="error">{error}</div>}
-    </div>
-  );
-}

playground/src/Editor/Editor.tsx

@@ -0,0 +1,137 @@
+import { useCallback, useEffect, useState } from "react";
+import { persist, restore } from "./config";
+import { DEFAULT_CONFIG_SOURCE, DEFAULT_PYTHON_SOURCE } from "../constants";
+import { ErrorMessage } from "./ErrorMessage";
+import Header from "./Header";
+import init, { check, current_version, Check } from "../pkg";
+import SettingsEditor from "./SettingsEditor";
+import SourceEditor from "./SourceEditor";
+import Themes from "./Themes";
+
+type Tab = "Source" | "Settings";
+
+export default function Editor() {
+  const [initialized, setInitialized] = useState<boolean>(false);
+  const [version, setVersion] = useState<string | null>(null);
+  const [tab, setTab] = useState<Tab>("Source");
+  const [edit, setEdit] = useState<number>(0);
+  const [configSource, setConfigSource] = useState<string | null>(null);
+  const [pythonSource, setPythonSource] = useState<string | null>(null);
+  const [checks, setChecks] = useState<Check[]>([]);
+  const [error, setError] = useState<string | null>(null);
+
+  useEffect(() => {
+    init().then(() => setInitialized(true));
+  }, []);
+
+  useEffect(() => {
+    if (!initialized || configSource == null || pythonSource == null) {
+      return;
+    }
+
+    let config: any;
+    let checks: Check[];
+
+    try {
+      config = JSON.parse(configSource);
+    } catch (e) {
+      setChecks([]);
+      setError((e as Error).message);
+      return;
+    }
+
+    try {
+      checks = check(pythonSource, config);
+    } catch (e) {
+      setError(e as string);
+      return;
+    }
+
+    setError(null);
+    setChecks(checks);
+  }, [initialized, configSource, pythonSource]);
+
+  useEffect(() => {
+    if (configSource == null || pythonSource == null) {
+      const payload = restore();
+      if (payload) {
+        const [configSource, pythonSource] = payload;
+        setConfigSource(configSource);
+        setPythonSource(pythonSource);
+      } else {
+        setConfigSource(DEFAULT_CONFIG_SOURCE);
+        setPythonSource(DEFAULT_PYTHON_SOURCE);
+      }
+    }
+  }, [configSource, pythonSource]);
+
+  useEffect(() => {
+    if (!initialized) {
+      return;
+    }
+
+    setVersion(current_version());
+  }, [initialized]);
+
+  const handleShare = useCallback(() => {
+    if (!initialized || configSource == null || pythonSource == null) {
+      return;
+    }
+
+    persist(configSource, pythonSource);
+  }, [initialized, configSource, pythonSource]);
+
+  const handlePythonSourceChange = useCallback((pythonSource: string) => {
+    setEdit((edit) => edit + 1);
+    setPythonSource(pythonSource);
+  }, []);
+
+  const handleConfigSourceChange = useCallback((configSource: string) => {
+    setEdit((edit) => edit + 1);
+    setConfigSource(configSource);
+  }, []);
+
+  return (
+    <main className={"h-full w-full flex flex-auto"}>
+      <Header
+        edit={edit}
+        version={version}
+        tab={tab}
+        onChange={setTab}
+        onShare={initialized ? handleShare : undefined}
+      />
+
+      <Themes />
+
+      <div className={"mt-12 relative flex-auto"}>
+        {initialized && configSource != null && pythonSource != null ? (
+          <>
+            <SourceEditor
+              visible={tab === "Source"}
+              source={pythonSource}
+              checks={checks}
+              onChange={handlePythonSourceChange}
+            />
+            <SettingsEditor
+              visible={tab === "Settings"}
+              source={configSource}
+              onChange={handleConfigSourceChange}
+            />
+          </>
+        ) : null}
+      </div>
+      {error && tab === "Source" ? (
+        <div
+          style={{
+            position: "fixed",
+            left: "10%",
+            right: "10%",
+            bottom: "10%",
+          }}
+        >
+          <ErrorMessage>{error}</ErrorMessage>
+        </div>
+      ) : null}
+    </main>
+  );
+}

playground/src/Editor/ErrorMessage.tsx

@@ -0,0 +1,26 @@
+function truncate(str: string, length: number) {
+  if (str.length > length) {
+    return str.slice(0, length) + "...";
+  } else {
+    return str;
+  }
+}
+
+export function ErrorMessage({ children }: { children: string }) {
+  return (
+    <div
+      className="bg-orange-100 border-l-4 border-orange-500 text-orange-700 p-4"
+      role="alert"
+    >
+      <p className="font-bold">Error</p>
+      <p className="block sm:inline">
+        {truncate(
+          children.startsWith("Error: ")
+            ? children.slice("Error: ".length)
+            : children,
+          120
+        )}
+      </p>
+    </div>
+  );
+}

playground/src/Editor/Header.tsx

@@ -0,0 +1,73 @@
+import classNames from "classnames";
+import ShareButton from "./ShareButton";
+import VersionTag from "./VersionTag";
+
+export type Tab = "Source" | "Settings";
+
+export default function Header({
+  edit,
+  version,
+  tab,
+  onChange,
+  onShare,
+}: {
+  edit: number;
+  version: string | null;
+  tab: Tab;
+  onChange: (tab: Tab) => void;
+  onShare?: () => void;
+}) {
+  return (
+    <div
+      className="w-full flex items-center justify-between flex-none pl-5 sm:pl-6 pr-4 lg:pr-6 absolute z-10 top-0 left-0 -mb-px antialiased border-b border-gray-200 dark:border-gray-800"
+      style={{ background: "#f8f9fa" }}
+    >
+      <div className="flex space-x-5">
+        <button
+          type="button"
+          className={classNames(
+            "relative flex py-3 text-sm leading-6 font-semibold focus:outline-none",
+            tab === "Source"
+              ? "text-ayu"
+              : "text-gray-700 hover:text-gray-900 focus:text-gray-900 dark:text-gray-300 dark:hover:text-white"
+          )}
+          onClick={() => onChange("Source")}
+        >
+          <span
+            className={classNames(
+              "absolute bottom-0 inset-x-0 bg-ayu h-0.5 rounded-full transition-opacity duration-150",
+              tab === "Source" ? "opacity-100" : "opacity-0"
+            )}
+          />
+          Source
+        </button>
+        <button
+          type="button"
+          className={classNames(
+            "relative flex py-3 text-sm leading-6 font-semibold focus:outline-none",
+            tab === "Settings"
+              ? "text-ayu"
+              : "text-gray-700 hover:text-gray-900 focus:text-gray-900 dark:text-gray-300 dark:hover:text-white"
+          )}
+          onClick={() => onChange("Settings")}
+        >
+          <span
+            className={classNames(
+              "absolute bottom-0 inset-x-0 bg-ayu h-0.5 rounded-full transition-opacity duration-150",
+              tab === "Settings" ? "opacity-100" : "opacity-0"
+            )}
+          />
+          Settings
+        </button>
+        {version ? (
+          <div className={"flex items-center"}>
+            <VersionTag>v{version}</VersionTag>
+          </div>
+        ) : null}
+      </div>
+      <div className={"hidden sm:flex items-center min-w-0"}>
+        <ShareButton key={edit} onShare={onShare} />
+      </div>
+    </div>
+  );
+}

playground/src/Editor/SettingsEditor.tsx

@@ -0,0 +1,54 @@
+/**
+ * Editor for the settings JSON.
+ */
+
+import Editor, { useMonaco } from "@monaco-editor/react";
+import { useCallback, useEffect } from "react";
+import schema from "../../../ruff.schema.json";
+
+export default function SettingsEditor({
+  visible,
+  source,
+  onChange,
+}: {
+  visible: boolean;
+  source: string;
+  onChange: (source: string) => void;
+}) {
+  const monaco = useMonaco();
+
+  useEffect(() => {
+    monaco?.languages.json.jsonDefaults.setDiagnosticsOptions({
+      schemas: [
+        {
+          uri: "https://raw.githubusercontent.com/charliermarsh/ruff/main/ruff.schema.json",
+          fileMatch: ["*"],
+          schema,
+        },
+      ],
+    });
+  }, [monaco]);
+
+  const handleChange = useCallback(
+    (value: string | undefined) => {
+      onChange(value ?? "");
+    },
+    [onChange]
+  );
+  return (
+    <Editor
+      options={{
+        readOnly: false,
+        minimap: { enabled: false },
+        fontSize: 14,
+        roundedSelection: false,
+        scrollBeyondLastLine: false,
+      }}
+      wrapperProps={visible ? {} : { style: { display: "none" } }}
+      language={"json"}
+      value={source}
+      theme={"Ayu-Light"}
+      onChange={handleChange}
+    />
+  );
+}

playground/src/Editor/ShareButton.tsx

@@ -0,0 +1,53 @@
+import { useEffect, useState } from "react";
+
+export default function ShareButton({ onShare }: { onShare?: () => void }) {
+  const [copied, setCopied] = useState(false);
+
+  useEffect(() => {
+    if (copied) {
+      const timeout = setTimeout(() => setCopied(false), 2000);
+      return () => clearTimeout(timeout);
+    }
+  }, [copied]);
+
+  return copied ? (
+    <button
+      type="button"
+      className="relative flex-none rounded-md text-sm font-semibold leading-6 py-1.5 px-3 cursor-auto text-ayu shadow-copied dark:bg-ayu/10"
+    >
+      <span
+        className="absolute inset-0 flex items-center justify-center invisible"
+        aria-hidden="true"
+      >
+        Share
+      </span>
+      <span className="" aria-hidden="false">
+        Copied!
+      </span>
+    </button>
+  ) : (
+    <button
+      type="button"
+      className="relative flex-none rounded-md text-sm font-semibold leading-6 py-1.5 px-3 enabled:hover:bg-ayu/80 bg-ayu text-white shadow-sm dark:shadow-highlight/20 disabled:opacity-50"
+      disabled={!onShare || copied}
+      onClick={
+        onShare
+          ? () => {
+              setCopied(true);
+              onShare();
+            }
+          : undefined
+      }
+    >
+      <span
+        className="absolute inset-0 flex items-center justify-center"
+        aria-hidden="false"
+      >
+        Share
+      </span>
+      <span className="invisible" aria-hidden="true">
+        Copied!
+      </span>
+    </button>
+  );
+}

playground/src/Editor/SourceEditor.tsx

@@ -0,0 +1,114 @@
+/**
+ * Editor for the Python source code.
+ */
+
+import Editor, { useMonaco } from "@monaco-editor/react";
+import { MarkerSeverity, MarkerTag } from "monaco-editor";
+import { useCallback, useEffect } from "react";
+import { Check } from "../pkg";
+
+export type Mode = "JSON" | "Python";
+
+export default function SourceEditor({
+  visible,
+  source,
+  checks,
+  onChange,
+}: {
+  visible: boolean;
+  source: string;
+  checks: Check[];
+  onChange: (pythonSource: string) => void;
+}) {
+  const monaco = useMonaco();
+
+  useEffect(() => {
+    const editor = monaco?.editor;
+    const model = editor?.getModels()[0];
+    if (!editor || !model) {
+      return;
+    }
+
+    editor.setModelMarkers(
+      model,
+      "owner",
+      checks.map((check) => ({
+        startLineNumber: check.location.row,
+        startColumn: check.location.column + 1,
+        endLineNumber: check.end_location.row,
+        endColumn: check.end_location.column + 1,
+        message: `${check.code}: ${check.message}`,
+        severity: MarkerSeverity.Error,
+        tags:
+          check.code === "F401" || check.code === "F841"
+            ? [MarkerTag.Unnecessary]
+            : [],
+      }))
+    );
+
+    const codeActionProvider = monaco?.languages.registerCodeActionProvider(
+      "python",
+      {
+        // @ts-expect-error: The type definition is wrong.
+        provideCodeActions: function (model, position) {
+          const actions = checks
+            .filter((check) => position.startLineNumber === check.location.row)
+            .filter((check) => check.fix)
+            .map((check) => ({
+              title: `Fix ${check.code}`,
+              id: `fix-${check.code}`,
+              kind: "quickfix",
+              edit: check.fix
+                ? {
+                    edits: [
+                      {
+                        resource: model.uri,
+                        versionId: model.getVersionId(),
+                        edit: {
+                          range: {
+                            startLineNumber: check.fix.location.row,
+                            startColumn: check.fix.location.column + 1,
+                            endLineNumber: check.fix.end_location.row,
+                            endColumn: check.fix.end_location.column + 1,
+                          },
+                          text: check.fix.content,
+                        },
+                      },
+                    ],
+                  }
+                : undefined,
+            }));
+          return { actions, dispose: () => {} };
+        },
+      }
+    );
+
+    return () => {
+      codeActionProvider?.dispose();
+    };
+  }, [checks, monaco]);
+
+  const handleChange = useCallback(
+    (value: string | undefined) => {
+      onChange(value ?? "");
+    },
+    [onChange]
+  );
+
+  return (
+    <Editor
+      options={{
+        readOnly: false,
+        minimap: { enabled: false },
+        fontSize: 14,
+        roundedSelection: false,
+        scrollBeyondLastLine: false,
+      }}
+      wrapperProps={visible ? {} : { style: { display: "none" } }}
+      theme={"Ayu-Light"}
+      language={"python"}
+      value={source}
+      onChange={handleChange}
+    />
+  );
+}

playground/src/Editor/Themes.tsx

@@ -0,0 +1,645 @@
+import { useMonaco } from "@monaco-editor/react";
+import { useEffect } from "react";
+
+export default function Themes() {
+  const monaco = useMonaco();
+
+  useEffect(() => {
+    // Generated via `monaco-vscode-textmate-theme-converter`.
+    // See: https://github.com/ayu-theme/vscode-ayu/blob/91839e8a9dfa78d61e58dbcf9b52272a01fee66a/ayu-light.json.
+    monaco?.editor.defineTheme("Ayu-Light", {
+      inherit: false,
+      base: "vs-dark",
+      colors: {
+        focusBorder: "#ffaa33b3",
+        foreground: "#8a9199",
+        "widget.shadow": "#00000026",
+        "selection.background": "#035bd626",
+        "icon.foreground": "#8a9199",
+        errorForeground: "#e65050",
+        descriptionForeground: "#8a9199",
+        "textBlockQuote.background": "#f3f4f5",
+        "textLink.foreground": "#ffaa33",
+        "textLink.activeForeground": "#ffaa33",
+        "textPreformat.foreground": "#5c6166",
+        "button.background": "#ffaa33",
+        "button.foreground": "#f8f9fa",
+        "button.hoverBackground": "#f9a52e",
+        "button.secondaryBackground": "#8a919933",
+        "button.secondaryForeground": "#5c6166",
+        "button.secondaryHoverBackground": "#8a919980",
+        "dropdown.background": "#fcfcfc",
+        "dropdown.foreground": "#8a9199",
+        "dropdown.border": "#8a919945",
+        "input.background": "#fcfcfc",
+        "input.border": "#8a919945",
+        "input.foreground": "#5c6166",
+        "input.placeholderForeground": "#8a919980",
+        "inputOption.activeBorder": "#f4a0284d",
+        "inputOption.activeBackground": "#ffaa3333",
+        "inputOption.activeForeground": "#f4a028",
+        "inputValidation.errorBackground": "#fcfcfc",
+        "inputValidation.errorBorder": "#e65050",
+        "inputValidation.infoBackground": "#f8f9fa",
+        "inputValidation.infoBorder": "#55b4d4",
+        "inputValidation.warningBackground": "#f8f9fa",
+        "inputValidation.warningBorder": "#f2ae49",
+        "scrollbar.shadow": "#6b7d8f00",
+        "scrollbarSlider.background": "#8a919966",
+        "scrollbarSlider.hoverBackground": "#8a919999",
+        "scrollbarSlider.activeBackground": "#8a9199b3",
+        "badge.background": "#ffaa3333",
+        "badge.foreground": "#f4a028",
+        "progressBar.background": "#ffaa33",
+        "list.activeSelectionBackground": "#56728f1f",
+        "list.activeSelectionForeground": "#5c6166",
+        "list.focusBackground": "#56728f1f",
+        "list.focusForeground": "#5c6166",
+        "list.focusOutline": "#56728f1f",
+        "list.highlightForeground": "#ffaa33",
+        "list.deemphasizedForeground": "#e65050",
+        "list.hoverBackground": "#56728f1f",
+        "list.inactiveSelectionBackground": "#6b7d8f1f",
+        "list.inactiveSelectionForeground": "#8a9199",
+        "list.invalidItemForeground": "#8a91994d",
+        "list.errorForeground": "#e65050",
+        "tree.indentGuidesStroke": "#8a919959",
+        "listFilterWidget.background": "#f3f4f5",
+        "listFilterWidget.outline": "#ffaa33",
+        "listFilterWidget.noMatchesOutline": "#e65050",
+        "list.filterMatchBackground": "#8f30efcc",
+        "list.filterMatchBorder": "#9f40ffcc",
+        "activityBar.background": "#f8f9fa",
+        "activityBar.foreground": "#8a9199cc",
+        "activityBar.inactiveForeground": "#8a919999",
+        "activityBar.border": "#f8f9fa",
+        "activityBar.activeBorder": "#ffaa33b3",
+        "activityBarBadge.background": "#ffaa33",
+        "activityBarBadge.foreground": "#f8f9fa",
+        "sideBar.background": "#f8f9fa",
+        "sideBar.border": "#f8f9fa",
+        "sideBarTitle.foreground": "#8a9199",
+        "sideBarSectionHeader.background": "#f8f9fa",
+        "sideBarSectionHeader.foreground": "#8a9199",
+        "sideBarSectionHeader.border": "#f8f9fa",
+        "minimap.background": "#f8f9fa",
+        "minimap.selectionHighlight": "#035bd626",
+        "minimap.errorHighlight": "#e65050",
+        "minimap.findMatchHighlight": "#9f40ff2b",
+        "minimapGutter.addedBackground": "#6cbf43",
+        "minimapGutter.modifiedBackground": "#478acc",
+        "minimapGutter.deletedBackground": "#ff7383",
+        "editorGroup.border": "#6b7d8f1f",
+        "editorGroup.background": "#f3f4f5",
+        "editorGroupHeader.noTabsBackground": "#f8f9fa",
+        "editorGroupHeader.tabsBackground": "#f8f9fa",
+        "editorGroupHeader.tabsBorder": "#f8f9fa",
+        "tab.activeBackground": "#f8f9fa",
+        "tab.activeForeground": "#5c6166",
+        "tab.border": "#f8f9fa",
+        "tab.activeBorder": "#ffaa33",
+        "tab.unfocusedActiveBorder": "#8a9199",
+        "tab.inactiveBackground": "#f8f9fa",
+        "tab.inactiveForeground": "#8a9199",
+        "tab.unfocusedActiveForeground": "#8a9199",
+        "tab.unfocusedInactiveForeground": "#8a9199",
+        "editor.background": "#f8f9fa",
+        "editor.foreground": "#5c6166",
+        "editorLineNumber.foreground": "#8a919966",
+        "editorLineNumber.activeForeground": "#8a9199cc",
+        "editorCursor.foreground": "#ffaa33",
+        "editor.inactiveSelectionBackground": "#035bd612",
+        "editor.selectionBackground": "#035bd626",
+        "editor.selectionHighlightBackground": "#6cbf4326",
+        "editor.selectionHighlightBorder": "#6cbf4300",
+        "editor.wordHighlightBackground": "#478acc14",
+        "editor.wordHighlightStrongBackground": "#6cbf4314",
+        "editor.wordHighlightBorder": "#478acc80",
+        "editor.wordHighlightStrongBorder": "#6cbf4380",
+        "editor.findMatchBackground": "#9f40ff2b",
+        "editor.findMatchBorder": "#9f40ff2b",
+        "editor.findMatchHighlightBackground": "#9f40ffcc",
+        "editor.findMatchHighlightBorder": "#8f30efcc",
+        "editor.findRangeHighlightBackground": "#9f40ff40",
+        "editor.rangeHighlightBackground": "#9f40ff33",
+        "editor.lineHighlightBackground": "#8a91991a",
+        "editorLink.activeForeground": "#ffaa33",
+        "editorWhitespace.foreground": "#8a919966",
+        "editorIndentGuide.background": "#8a91992e",
+        "editorIndentGuide.activeBackground": "#8a919959",
+        "editorRuler.foreground": "#8a91992e",
+        "editorCodeLens.foreground": "#787b8099",
+        "editorBracketMatch.background": "#8a91994d",
+        "editorBracketMatch.border": "#8a91994d",
+        "editor.snippetTabstopHighlightBackground": "#6cbf4333",
+        "editorOverviewRuler.border": "#6b7d8f1f",
+        "editorOverviewRuler.modifiedForeground": "#478acc",
+        "editorOverviewRuler.addedForeground": "#6cbf43",
+        "editorOverviewRuler.deletedForeground": "#ff7383",
+        "editorOverviewRuler.errorForeground": "#e65050",
+        "editorOverviewRuler.warningForeground": "#ffaa33",
+        "editorOverviewRuler.bracketMatchForeground": "#8a9199b3",
+        "editorOverviewRuler.wordHighlightForeground": "#478acc66",
+        "editorOverviewRuler.wordHighlightStrongForeground": "#6cbf4366",
+        "editorOverviewRuler.findMatchForeground": "#9f40ff2b",
+        "editorError.foreground": "#e65050",
+        "editorWarning.foreground": "#ffaa33",
+        "editorGutter.modifiedBackground": "#478acccc",
+        "editorGutter.addedBackground": "#6cbf43cc",
+        "editorGutter.deletedBackground": "#ff7383cc",
+        "diffEditor.insertedTextBackground": "#6cbf431f",
+        "diffEditor.removedTextBackground": "#ff73831f",
+        "diffEditor.diagonalFill": "#6b7d8f1f",
+        "editorWidget.background": "#f3f4f5",
+        "editorWidget.border": "#6b7d8f1f",
+        "editorHoverWidget.background": "#f3f4f5",
+        "editorHoverWidget.border": "#6b7d8f1f",
+        "editorSuggestWidget.background": "#f3f4f5",
+        "editorSuggestWidget.border": "#6b7d8f1f",
+        "editorSuggestWidget.highlightForeground": "#ffaa33",
+        "editorSuggestWidget.selectedBackground": "#56728f1f",
+        "debugExceptionWidget.border": "#6b7d8f1f",
+        "debugExceptionWidget.background": "#f3f4f5",
+        "editorMarkerNavigation.background": "#f3f4f5",
+        "peekView.border": "#56728f1f",
+        "peekViewTitle.background": "#56728f1f",
+        "peekViewTitleDescription.foreground": "#8a9199",
+        "peekViewTitleLabel.foreground": "#5c6166",
+        "peekViewEditor.background": "#f3f4f5",
+        "peekViewEditor.matchHighlightBackground": "#9f40ffcc",
+        "peekViewEditor.matchHighlightBorder": "#8f30efcc",
+        "peekViewResult.background": "#f3f4f5",
+        "peekViewResult.fileForeground": "#5c6166",
+        "peekViewResult.lineForeground": "#8a9199",
+        "peekViewResult.matchHighlightBackground": "#9f40ffcc",
+        "peekViewResult.selectionBackground": "#56728f1f",
+        "panel.background": "#f8f9fa",
+        "panel.border": "#6b7d8f1f",
+        "panelTitle.activeBorder": "#ffaa33",
+        "panelTitle.activeForeground": "#5c6166",
+        "panelTitle.inactiveForeground": "#8a9199",
+        "statusBar.background": "#f8f9fa",
+        "statusBar.foreground": "#8a9199",
+        "statusBar.border": "#f8f9fa",
+        "statusBar.debuggingBackground": "#ed9366",
+        "statusBar.debuggingForeground": "#fcfcfc",
+        "statusBar.noFolderBackground": "#f3f4f5",
+        "statusBarItem.activeBackground": "#8a919933",
+        "statusBarItem.hoverBackground": "#8a919933",
+        "statusBarItem.prominentBackground": "#6b7d8f1f",
+        "statusBarItem.prominentHoverBackground": "#00000030",
+        "statusBarItem.remoteBackground": "#ffaa33",
+        "statusBarItem.remoteForeground": "#fcfcfc",
+        "titleBar.activeBackground": "#f8f9fa",
+        "titleBar.activeForeground": "#5c6166",
+        "titleBar.inactiveBackground": "#f8f9fa",
+        "titleBar.inactiveForeground": "#8a9199",
+        "titleBar.border": "#f8f9fa",
+        "extensionButton.prominentForeground": "#fcfcfc",
+        "extensionButton.prominentBackground": "#ffaa33",
+        "extensionButton.prominentHoverBackground": "#f9a52e",
+        "pickerGroup.border": "#6b7d8f1f",
+        "pickerGroup.foreground": "#8a919980",
+        "debugToolBar.background": "#f3f4f5",
+        "debugIcon.breakpointForeground": "#ed9366",
+        "debugIcon.breakpointDisabledForeground": "#ed936680",
+        "debugConsoleInputIcon.foreground": "#ffaa33",
+        "welcomePage.tileBackground": "#f8f9fa",
+        "welcomePage.tileShadow": "#00000026",
+        "welcomePage.progress.background": "#8a91991a",
+        "welcomePage.buttonBackground": "#ffaa3366",
+        "walkThrough.embeddedEditorBackground": "#f3f4f5",
+        "gitDecoration.modifiedResourceForeground": "#478accb3",
+        "gitDecoration.deletedResourceForeground": "#ff7383b3",
+        "gitDecoration.untrackedResourceForeground": "#6cbf43b3",
+        "gitDecoration.ignoredResourceForeground": "#8a919980",
+        "gitDecoration.conflictingResourceForeground": "",
+        "gitDecoration.submoduleResourceForeground": "#a37accb3",
+        "settings.headerForeground": "#5c6166",
+        "settings.modifiedItemIndicator": "#478acc",
+        "keybindingLabel.background": "#8a91991a",
+        "keybindingLabel.foreground": "#5c6166",
+        "keybindingLabel.border": "#5c61661a",
+        "keybindingLabel.bottomBorder": "#5c61661a",
+        "terminal.background": "#f8f9fa",
+        "terminal.foreground": "#5c6166",
+        "terminal.ansiBlack": "#000000",
+        "terminal.ansiRed": "#ea6c6d",
+        "terminal.ansiGreen": "#6cbf43",
+        "terminal.ansiYellow": "#eca944",
+        "terminal.ansiBlue": "#3199e1",
+        "terminal.ansiMagenta": "#9e75c7",
+        "terminal.ansiCyan": "#46ba94",
+        "terminal.ansiWhite": "#c7c7c7",
+        "terminal.ansiBrightBlack": "#686868",
+        "terminal.ansiBrightRed": "#f07171",
+        "terminal.ansiBrightGreen": "#86b300",
+        "terminal.ansiBrightYellow": "#f2ae49",
+        "terminal.ansiBrightBlue": "#399ee6",
+        "terminal.ansiBrightMagenta": "#a37acc",
+        "terminal.ansiBrightCyan": "#4cbf99",
+        "terminal.ansiBrightWhite": "#d1d1d1",
+      },
+      rules: [
+        {
+          fontStyle: "italic",
+          foreground: "#787b8099",
+          token: "comment",
+        },
+        {
+          foreground: "#86b300",
+          token: "string",
+        },
+        {
+          foreground: "#86b300",
+          token: "constant.other.symbol",
+        },
+        {
+          foreground: "#4cbf99",
+          token: "string.regexp",
+        },
+        {
+          foreground: "#4cbf99",
+          token: "constant.character",
+        },
+        {
+          foreground: "#4cbf99",
+          token: "constant.other",
+        },
+        {
+          foreground: "#a37acc",
+          token: "constant.numeric",
+        },
+        {
+          foreground: "#a37acc",
+          token: "constant.language",
+        },
+        {
+          foreground: "#5c6166",
+          token: "variable",
+        },
+        {
+          foreground: "#5c6166",
+          token: "variable.parameter.function-call",
+        },
+        {
+          foreground: "#f07171",
+          token: "variable.member",
+        },
+        {
+          fontStyle: "italic",
+          foreground: "#55b4d4",
+          token: "variable.language",
+        },
+        {
+          foreground: "#fa8d3e",
+          token: "storage",
+        },
+        {
+          foreground: "#fa8d3e",
+          token: "keyword",
+        },
+        {
+          foreground: "#ed9366",
+          token: "keyword.operator",
+        },
+        {
+          foreground: "#5c6166b3",
+          token: "punctuation.separator",
+        },
+        {
+          foreground: "#5c6166b3",
+          token: "punctuation.terminator",
+        },
+        {
+          foreground: "#5c6166",
+          token: "punctuation.section",
+        },
+        {
+          foreground: "#ed9366",
+          token: "punctuation.accessor",
+        },
+        {
+          foreground: "#fa8d3e",
+          token: "punctuation.definition.template-expression",
+        },
+        {
+          foreground: "#fa8d3e",
+          token: "punctuation.section.embedded",
+        },
+        {
+          foreground: "#5c6166",
+          token: "meta.embedded",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.java storage.type",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.haskell storage.type",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.c storage.type",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "entity.other.inherited-class",
+        },
+        {
+          foreground: "#fa8d3e",
+          token: "storage.type.function",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "source.java storage.type.primitive",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "entity.name.function",
+        },
+        {
+          foreground: "#a37acc",
+          token: "variable.parameter",
+        },
+        {
+          foreground: "#a37acc",
+          token: "meta.parameter",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "variable.function",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "variable.annotation",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "meta.function-call.generic",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "support.function.go",
+        },
+        {
+          foreground: "#f07171",
+          token: "support.function",
+        },
+        {
+          foreground: "#f07171",
+          token: "support.macro",
+        },
+        {
+          foreground: "#86b300",
+          token: "entity.name.import",
+        },
+        {
+          foreground: "#86b300",
+          token: "entity.name.package",
+        },
+        {
+          foreground: "#399ee6",
+          token: "entity.name",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "entity.name.tag",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "meta.tag.sgml",
+        },
+        {
+          foreground: "#399ee6",
+          token: "support.class.component",
+        },
+        {
+          foreground: "#55b4d480",
+          token: "punctuation.definition.tag.end",
+        },
+        {
+          foreground: "#55b4d480",
+          token: "punctuation.definition.tag.begin",
+        },
+        {
+          foreground: "#55b4d480",
+          token: "punctuation.definition.tag",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "entity.other.attribute-name",
+        },
+        {
+          fontStyle: "italic",
+          foreground: "#ed9366",
+          token: "support.constant",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "support.type",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "support.class",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "source.go storage.type",
+        },
+        {
+          foreground: "#e6ba7e",
+          token: "meta.decorator variable.other",
+        },
+        {
+          foreground: "#e6ba7e",
+          token: "meta.decorator punctuation.decorator",
+        },
+        {
+          foreground: "#e6ba7e",
+          token: "storage.type.annotation",
+        },
+        {
+          foreground: "#e65050",
+          token: "invalid",
+        },
+        {
+          foreground: "#c594c5",
+          token: "meta.diff",
+        },
+        {
+          foreground: "#c594c5",
+          token: "meta.diff.header",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "source.ruby variable.other.readwrite",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.css entity.name.tag",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.sass entity.name.tag",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.scss entity.name.tag",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.less entity.name.tag",
+        },
+        {
+          foreground: "#399ee6",
+          token: "source.stylus entity.name.tag",
+        },
+        {
+          foreground: "#787b8099",
+          token: "source.css support.type",
+        },
+        {
+          foreground: "#787b8099",
+          token: "source.sass support.type",
+        },
+        {
+          foreground: "#787b8099",
+          token: "source.scss support.type",
+        },
+        {
+          foreground: "#787b8099",
+          token: "source.less support.type",
+        },
+        {
+          foreground: "#787b8099",
+          token: "source.stylus support.type",
+        },
+        {
+          fontStyle: "normal",
+          foreground: "#55b4d4",
+          token: "support.type.property-name",
+        },
+        {
+          foreground: "#787b8099",
+          token: "constant.numeric.line-number.find-in-files - match",
+        },
+        {
+          foreground: "#fa8d3e",
+          token: "constant.numeric.line-number.match",
+        },
+        {
+          foreground: "#86b300",
+          token: "entity.name.filename.find-in-files",
+        },
+        {
+          foreground: "#e65050",
+          token: "message.error",
+        },
+        {
+          fontStyle: "bold",
+          foreground: "#86b300",
+          token: "markup.heading",
+        },
+        {
+          fontStyle: "bold",
+          foreground: "#86b300",
+          token: "markup.heading entity.name",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "markup.underline.link",
+        },
+        {
+          foreground: "#55b4d4",
+          token: "string.other.link",
+        },
+        {
+          fontStyle: "italic",
+          foreground: "#f07171",
+          token: "markup.italic",
+        },
+        {
+          fontStyle: "bold",
+          foreground: "#f07171",
+          token: "markup.bold",
+        },
+        {
+          fontStyle: "bold italic",
+          token: "markup.italic markup.bold",
+        },
+        {
+          fontStyle: "bold italic",
+          token: "markup.bold markup.italic",
+        },
+        {
+          background: "#5c616605",
+          token: "markup.raw",
+        },
+        {
+          background: "#5c61660f",
+          token: "markup.raw.inline",
+        },
+        {
+          fontStyle: "bold",
+          background: "#5c61660f",
+          foreground: "#787b8099",
+          token: "meta.separator",
+        },
+        {
+          foreground: "#4cbf99",
+          fontStyle: "italic",
+          token: "markup.quote",
+        },
+        {
+          foreground: "#f2ae49",
+          token: "markup.list punctuation.definition.list.begin",
+        },
+        {
+          foreground: "#6cbf43",
+          token: "markup.inserted",
+        },
+        {
+          foreground: "#478acc",
+          token: "markup.changed",
+        },
+        {
+          foreground: "#ff7383",
+          token: "markup.deleted",
+        },
+        {
+          foreground: "#e6ba7e",
+          token: "markup.strike",
+        },
+        {
+          background: "#5c61660f",
+          foreground: "#55b4d4",
+          token: "markup.table",
+        },
+        {
+          foreground: "#ed9366",
+          token: "text.html.markdown markup.inline.raw",
+        },
+        {
+          background: "#787b8099",
+          foreground: "#787b8099",
+          token: "text.html.markdown meta.dummy.line-break",
+        },
+        {
+          background: "#5c6166",
+          foreground: "#787b8099",
+          token: "punctuation.definition.markdown",
+        },
+        // Edits.
+        {
+          foreground: "#fa8d3e",
+          token: "number",
+        },
+      ],
+      encodedTokensColors: [],
+    });
+  }, [monaco]);
+
+  return null;
+}

playground/src/Editor/VersionTag.tsx

@@ -0,0 +1,26 @@
+import classNames from "classnames";
+import { ReactNode } from "react";
+
+export default function VersionTag({ children }: { children: ReactNode }) {
+  return (
+    <div
+      className={classNames(
+        "text-gray-500",
+        "text-xs",
+        "leading-5",
+        "font-semibold",
+        "bg-gray-400/10",
+        "rounded-full",
+        "py-1",
+        "px-3",
+        "flex",
+        "items-center",
+        "dark:bg-gray-800",
+        "dark:text-gray-400",
+        "dark:shadow-highlight/4"
+      )}
+    >
+      {children}
+    </div>
+  );
+}

playground/src/Editor/config.ts

@@ -0,0 +1,63 @@
+import lzstring from "lz-string";
+import { OptionGroup } from "../ruff_options";
+
+export type Config = { [K: string]: any };
+
+/**
+ * Parse an encoded value from the options export.
+ *
+ * TODO(charlie): Use JSON for the default values.
+ */
+function parse(value: any): any {
+  if (value == "None") {
+    return null;
+  }
+  return JSON.parse(value);
+}
+
+/**
+ * The default configuration for the playground.
+ */
+export function defaultConfig(availableOptions: OptionGroup[]): Config {
+  const config: Config = {};
+  for (const group of availableOptions) {
+    if (group.name == "globals") {
+      for (const field of group.fields) {
+        config[field.name] = parse(field.default);
+      }
+    } else {
+      config[group.name] = {};
+      for (const field of group.fields) {
+        config[group.name][field.name] = parse(field.default);
+      }
+    }
+  }
+  return config;
+}
+
+/**
+ * Persist the configuration to a URL.
+ */
+export function persist(configSource: string, pythonSource: string) {
+  window.location.hash = lzstring.compressToEncodedURIComponent(
+    configSource + "$$$" + pythonSource
+  );
+}
+
+/**
+ * Restore the configuration from a URL.
+ */
+export function restore(): [string, string] | null {
+  const value = lzstring.decompressFromEncodedURIComponent(
+    window.location.hash.slice(1)
+  );
+
+  if (value) {
+    const parts = value.split("$$$");
+    const configSource = parts[0];
+    const pythonSource = parts[1];
+    return [configSource, pythonSource];
+  } else {
+    return null;
+  }
+}

playground/src/Editor/index.tsx

@@ -0,0 +1,3 @@
+import Editor from "./Editor";
+
+export default Editor;

playground/src/Options.tsx

@@ -1,72 +0,0 @@
-import { Config } from "./config";
-import { AVAILABLE_OPTIONS } from "./ruff_options";
-
-function OptionEntry({
-  config,
-  defaultConfig,
-  groupName,
-  fieldName,
-  onChange,
-}: {
-  config: Config | null;
-  defaultConfig: Config;
-  groupName: string;
-  fieldName: string;
-  onChange: (groupName: string, fieldName: string, value: string) => void;
-}) {
-  const value =
-    config && config[groupName] && config[groupName][fieldName]
-      ? config[groupName][fieldName]
-      : "";
-
-  return (
-    <span>
-      <label>
-        {fieldName}
-        <input
-          value={value}
-          placeholder={defaultConfig[groupName][fieldName]}
-          type="text"
-          onChange={(event) => {
-            onChange(groupName, fieldName, event.target.value);
-          }}
-        />
-      </label>
-    </span>
-  );
-}
-
-export function Options({
-  config,
-  defaultConfig,
-  onChange,
-}: {
-  config: Config | null;
-  defaultConfig: Config;
-  onChange: (groupName: string, fieldName: string, value: string) => void;
-}) {
-  return (
-    <div className="options">
-      {AVAILABLE_OPTIONS.map((group) => (
-        <details key={group.name}>
-          <summary>{group.name}</summary>
-          <div>
-            <ul>
-              {group.fields.map((field) => (
-                <li key={field.name}>
-                  <OptionEntry
-                    config={config}
-                    defaultConfig={defaultConfig}
-                    groupName={group.name}
-                    fieldName={field.name}
-                    onChange={onChange}
-                  />
-                </li>
-              ))}
-            </ul>
-          </div>
-        </details>
-      ))}
-    </div>
-  );
-}

playground/src/config.ts

@@ -1,52 +0,0 @@
-import { OptionGroup } from "./ruff_options";
-
-export type Config = { [key: string]: { [key: string]: string } };
-
-export function getDefaultConfig(availableOptions: OptionGroup[]): Config {
-  const config: Config = {};
-  availableOptions.forEach((group) => {
-    config[group.name] = {};
-    group.fields.forEach((f) => {
-      config[group.name][f.name] = f.default;
-    });
-  });
-  return config;
-}
-
-/**
- * Convert the config in the application to something Ruff accepts.
- *
- * Application config is always nested one level. Ruff allows for some
- * top-level options.
- *
- * Any option value is parsed as JSON to convert it to a native JS object.
- * If that fails, e.g. while a user is typing, we let the application handle that
- * and show an error.
- */
-export function toRuffConfig(config: Config): any {
-  const convertValue = (value: string): any => {
-    return value === "None" ? null : JSON.parse(value);
-  };
-
-  const result: any = {};
-  Object.keys(config).forEach((group_name) => {
-    const fields = config[group_name];
-    if (!fields || Object.keys(fields).length === 0) {
-      return;
-    }
-
-    if (group_name === "globals") {
-      Object.keys(fields).forEach((field_name) => {
-        result[field_name] = convertValue(fields[field_name]);
-      });
-    } else {
-      result[group_name] = {};
-
-      Object.keys(fields).forEach((field_name) => {
-        result[group_name][field_name] = convertValue(fields[field_name]);
-      });
-    }
-  });
-
-  return result;
-}

playground/src/constants.ts

@@ -0,0 +1,40 @@
+import { defaultConfig } from "./Editor/config";
+import { AVAILABLE_OPTIONS } from "./ruff_options";
+
+export const DEFAULT_PYTHON_SOURCE =
+  "import os\n" +
+  "\n" +
+  "# Define a function that takes an integer n and returns the nth number in the Fibonacci\n" +
+  "# sequence.\n" +
+  "def fibonacci(n):\n" +
+  '    """Compute the nth number in the Fibonacci sequence."""\n' +
+  "    x = 1\n" +
+  "    if n == 0:\n" +
+  "        return 0\n" +
+  "    elif n == 1:\n" +
+  "        return 1\n" +
+  "    else:\n" +
+  "        return fibonacci(n - 1) + fibonacci(n - 2)\n" +
+  "\n" +
+  "\n" +
+  "# Use a for loop to generate and print the first 10 numbers in the Fibonacci sequence.\n" +
+  "for i in range(10):\n" +
+  "    print(fibonacci(i))\n" +
+  "\n" +
+  "# Output:\n" +
+  "# 0\n" +
+  "# 1\n" +
+  "# 1\n" +
+  "# 2\n" +
+  "# 3\n" +
+  "# 5\n" +
+  "# 8\n" +
+  "# 13\n" +
+  "# 21\n" +
+  "# 34\n";
+
+export const DEFAULT_CONFIG_SOURCE = JSON.stringify(
+  defaultConfig(AVAILABLE_OPTIONS),
+  null,
+  2
+);

playground/src/index.css

@@ -0,0 +1,24 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+* {
+  box-sizing: border-box;
+}
+
+body,
+html,
+#root {
+  margin: 0;
+  height: 100%;
+  width: 100%;
+}
+
+.shadow-copied {
+  --tw-shadow: 0 0 0 1px #f07171, inset 0 0 0 1px #f07171;
+  --tw-shadow-colored: 0 0 0 1px var(--tw-shadow-color),
+    inset 0 0 0 1px var(--tw-shadow-color);
+
+  box-shadow: var(--tw-ring-offset-shadow, 0 0 #0000),
+    var(--tw-ring-shadow, 0 0 #0000), var(--tw-shadow);
+}

playground/src/main.tsx

@@ -1,10 +1,10 @@
 import React from "react";
 import ReactDOM from "react-dom/client";
-import App from "./App";
-import "./style.css";
+import Editor from "./Editor";
+import "./index.css";
 
 ReactDOM.createRoot(document.getElementById("root") as HTMLElement).render(
   <React.StrictMode>
-    <App />
+    <Editor />
   </React.StrictMode>
 );

playground/src/ruff_options.ts

@@ -71,6 +71,11 @@ export const AVAILABLE_OPTIONS: OptionGroup[] = [
             "default": '[]',
             "type": 'Vec<CheckCodePrefix>',
         },
+        {
+            "name": "update-check",
+            "default": 'true',
+            "type": 'bool',
+        },
     ]},
     {"name": "flake8-annotations", "fields": [
         {
@@ -225,7 +230,7 @@ export const AVAILABLE_OPTIONS: OptionGroup[] = [
     {"name": "pydocstyle", "fields": [
         {
             "name": "convention",
-            "default": '"convention"',
+            "default": 'None',
             "type": 'Convention',
         },
     ]},

playground/src/style.css

@@ -1,60 +0,0 @@
-* {
-  box-sizing: border-box;
-}
-
-body,
-html,
-#root,
-#app {
-  margin: 0;
-  height: 100%;
-  width: 100%;
-}
-
-#app {
-  display: flex;
-}
-
-.options {
-  height: 100vh;
-  overflow-y: scroll;
-  padding: 1em;
-  min-width: 300px;
-  border-right: 1px solid lightgray;
-}
-
-.options ul {
-  padding-left: 1em;
-  list-style-type: none;
-}
-
-.options li {
-  margin-bottom: 0.3em;
-}
-
-.options details {
-  margin-bottom: 1em;
-}
-
-.options summary {
-  font-size: 1.3rem;
-}
-
-.options input {
-  display: block;
-  width: 100%;
-}
-
-.editor {
-  padding: 1em;
-}
-
-#error {
-  position: fixed;
-  bottom: 0;
-  width: 100%;
-  min-height: 1em;
-  padding: 1em;
-  background: darkred;
-  color: white;
-}

playground/tailwind.config.cjs

@@ -0,0 +1,17 @@
+/** @type {import('tailwindcss').Config} */
+const defaultTheme = require("tailwindcss/defaultTheme");
+
+module.exports = {
+  content: ["./index.html", "./src/**/*.{js,ts,jsx,tsx}"],
+  theme: {
+    extend: {
+      colors: {
+        ayu: "#f07171",
+      },
+      fontFamily: {
+        sans: ["Inter var", ...defaultTheme.fontFamily.sans],
+      },
+    },
+  },
+  plugins: [],
+};

pyproject.toml

@@ -34,6 +34,7 @@ bindings = "bin"
 strip = true
 
 [tool.ruff]
+update-check = true
 
 [tool.ruff.isort]
 force-wrap-aliases = true

resources/test/fixtures/pygrep-hooks/PGH004_0.py

@@ -0,0 +1,11 @@
+x = 1  # noqa
+x = 1  # NOQA:F401,W203
+# noqa
+# NOQA
+# noqa:F401
+# noqa:F401,W203
+
+x = 1
+x = 1  # noqa: F401, W203
+# noqa: F401
+# noqa: F401, W203

resources/test/fixtures/pyupgrade/UP022.py

@@ -0,0 +1,42 @@
+from subprocess import run
+import subprocess
+
+output = run(["foo"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+output = subprocess.run(["foo"], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+
+output = subprocess.run(stdout=subprocess.PIPE, args=["foo"],  stderr=subprocess.PIPE)
+
+output = subprocess.run(
+    ["foo"], stdout=subprocess.PIPE, check=True, stderr=subprocess.PIPE
+)
+
+output = subprocess.run(
+    ["foo"], stderr=subprocess.PIPE, check=True, stdout=subprocess.PIPE
+)
+
+output = subprocess.run(
+    ["foo"],
+    stdout=subprocess.PIPE,
+    check=True,
+    stderr=subprocess.PIPE,
+    text=True,
+    encoding="utf-8",
+    close_fds=True,
+)
+
+if output:
+    output = subprocess.run(
+        ["foo"],
+        stdout=subprocess.PIPE,
+        check=True,
+        stderr=subprocess.PIPE,
+        text=True,
+        encoding="utf-8",
+    )
+
+
+# Examples that should NOT trigger the rule
+from foo import PIPE
+subprocess.run(["foo"], stdout=PIPE, stderr=PIPE)
+run(["foo"], stdout=None, stderr=PIPE)

resources/test/fixtures/pyupgrade/UP023.py

@@ -0,0 +1,31 @@
+# These two imports have something after cElementTree, so they should be fixed.
+from xml.etree.cElementTree import XML, Element, SubElement
+import xml.etree.cElementTree as ET
+
+# Weird spacing should not cause issues.
+from   xml.etree.cElementTree    import  XML
+import    xml.etree.cElementTree       as      ET
+
+# Multi line imports should also work fine.
+from xml.etree.cElementTree import (
+    XML,
+    Element,
+    SubElement,
+)
+if True:
+    import xml.etree.cElementTree as ET
+    from xml.etree import cElementTree as CET
+
+from xml.etree import cElementTree as ET
+
+import contextlib, xml.etree.cElementTree as ET
+
+# This should fix the second, but not the first invocation.
+import xml.etree.cElementTree, xml.etree.cElementTree as ET
+
+# The below items should NOT be changed.
+import xml.etree.cElementTree
+
+from .xml.etree.cElementTree import XML
+
+from xml.etree import cElementTree

resources/test/fixtures/ruff/RUF004.py

@@ -0,0 +1,15 @@
+def f(*args, **kwargs):
+    pass
+
+
+a = (1, 2)
+b = (3, 4)
+c = (5, 6)
+d = (7, 8)
+
+f(a, b)
+f(a, kw=b)
+f(*a, kw=b)
+f(kw=a, *b)
+f(kw=a, *b, *c)
+f(*a, kw=b, *c, kw1=d)

ruff.schema.json

@@ -111,7 +111,7 @@
       }
     },
     "flake8-annotations": {
-      "description": "Plugins Options for the `flake8-annotations` plugin.",
+      "description": "Options for the `flake8-annotations` plugin.",
       "anyOf": [
         {
           "$ref": "#/definitions/Flake8AnnotationsOptions"
@@ -195,7 +195,7 @@
       ]
     },
     "format": {
-      "description": "The style in which violation messages should be formatted: `\"text\"` (default), `\"grouped\"` (group messages by file), `\"json\"` (machine-readable), `\"junit\"` (machine-readable XML), or `\"github\"` (GitHub Actions annotations).",
+      "description": "The style in which violation messages should be formatted: `\"text\"` (default), `\"grouped\"` (group messages by file), `\"json\"` (machine-readable), `\"junit\"` (machine-readable XML), `\"github\"` (GitHub Actions annotations) or `\"gitlab\"` (GitLab CI code quality report).",
       "anyOf": [
         {
           "$ref": "#/definitions/SerializationFormat"
@@ -364,6 +364,13 @@
       "items": {
         "$ref": "#/definitions/CheckCodePrefix"
       }
+    },
+    "update-check": {
+      "description": "Enable or disable automatic update checks (overridden by the `--update-check` and `--no-update-check` command-line flags).",
+      "type": [
+        "boolean",
+        "null"
+      ]
     }
   },
   "additionalProperties": false,
@@ -377,6 +384,7 @@
         "A001",
         "A002",
         "A003",
+        "ALL",
         "ANN",
         "ANN0",
         "ANN00",
@@ -725,6 +733,7 @@
         "PGH001",
         "PGH002",
         "PGH003",
+        "PGH004",
         "PLC",
         "PLC0",
         "PLC04",
@@ -805,6 +814,7 @@
         "RUF001",
         "RUF002",
         "RUF003",
+        "RUF004",
         "RUF1",
         "RUF10",
         "RUF100",
@@ -879,6 +889,8 @@
         "UP02",
         "UP020",
         "UP021",
+        "UP022",
+        "UP023",
         "W",
         "W2",
         "W29",
@@ -906,10 +918,21 @@
       ]
     },
     "Convention": {
-      "type": "string",
-      "enum": [
-        "google",
-        "numpy"
+      "oneOf": [
+        {
+          "description": "Use Google-style docstrings.",
+          "type": "string",
+          "enum": [
+            "google"
+          ]
+        },
+        {
+          "description": "Use NumPy-style docstrings.",
+          "type": "string",
+          "enum": [
+            "numpy"
+          ]
+        }
       ]
     },
     "Flake8AnnotationsOptions": {
@@ -1053,7 +1076,7 @@
       "type": "object",
       "properties": {
         "ban-relative-imports": {
-          "description": "Whether to ban all relative imports (`\"all\"`), or only those imports that extend into the parent module and beyond (`\"parents\"`).",
+          "description": "Whether to ban all relative imports (`\"all\"`), or only those imports that extend into the parent module or beyond (`\"parents\"`).",
           "anyOf": [
             {
               "$ref": "#/definitions/Strictness"
@@ -1249,10 +1272,21 @@
       ]
     },
     "Quote": {
-      "type": "string",
-      "enum": [
-        "single",
-        "double"
+      "oneOf": [
+        {
+          "description": "Use single quotes (`'`).",
+          "type": "string",
+          "enum": [
+            "single"
+          ]
+        },
+        {
+          "description": "Use double quotes (`\"`).",
+          "type": "string",
+          "enum": [
+            "double"
+          ]
+        }
       ]
     },
     "SerializationFormat": {
@@ -1262,14 +1296,26 @@
         "json",
         "junit",
         "grouped",
-        "github"
+        "github",
+        "gitlab"
       ]
     },
     "Strictness": {
-      "type": "string",
-      "enum": [
-        "parents",
-        "all"
+      "oneOf": [
+        {
+          "description": "Ban imports that extend into the parent module or beyond.",
+          "type": "string",
+          "enum": [
+            "parents"
+          ]
+        },
+        {
+          "description": "Ban all relative imports.",
+          "type": "string",
+          "enum": [
+            "all"
+          ]
+        }
       ]
     },
     "Version": {

ruff_dev/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_dev"
-version = "0.0.196"
+version = "0.0.200"
 edition = "2021"
 
 [dependencies]

ruff_dev/src/generate_check_code_prefix.rs

@@ -13,6 +13,8 @@ use itertools::Itertools;
 use ruff::checks::{CheckCode, PREFIX_REDIRECTS};
 use strum::IntoEnumIterator;
 
+const ALL: &str = "ALL";
+
 #[derive(Parser)]
 #[command(author, version, about, long_about = None)]
 pub struct Cli {
@@ -34,9 +36,15 @@ pub fn main(cli: &Cli) -> Result<()> {
         let code_suffix_len = code_str.len() - code_prefix_len;
         for i in 0..=code_suffix_len {
             let prefix = code_str[..code_prefix_len + i].to_string();
-            let entry = prefix_to_codes.entry(prefix).or_default();
-            entry.insert(check_code.clone());
+            prefix_to_codes
+                .entry(prefix)
+                .or_default()
+                .insert(check_code.clone());
         }
+        prefix_to_codes
+            .entry(ALL.to_string())
+            .or_default()
+            .insert(check_code.clone());
     }
 
     // Add any prefix aliases (e.g., "U" to "UP").
@@ -79,6 +87,7 @@ pub fn main(cli: &Cli) -> Result<()> {
         .derive("Eq")
         .derive("PartialOrd")
         .derive("Ord")
+        .push_variant(Variant::new("None"))
         .push_variant(Variant::new("Zero"))
         .push_variant(Variant::new("One"))
         .push_variant(Variant::new("Two"))
@@ -129,14 +138,18 @@ pub fn main(cli: &Cli) -> Result<()> {
         .line("#[allow(clippy::match_same_arms)]")
         .line("match self {");
     for prefix in prefix_to_codes.keys() {
-        let num_numeric = prefix.chars().filter(|char| char.is_numeric()).count();
-        let specificity = match num_numeric {
-            0 => "Zero",
-            1 => "One",
-            2 => "Two",
-            3 => "Three",
-            4 => "Four",
-            _ => panic!("Invalid prefix: {prefix}"),
+        let specificity = if prefix == "ALL" {
+            "None"
+        } else {
+            let num_numeric = prefix.chars().filter(|char| char.is_numeric()).count();
+            match num_numeric {
+                0 => "Zero",
+                1 => "One",
+                2 => "Two",
+                3 => "Three",
+                4 => "Four",
+                _ => panic!("Invalid prefix: {prefix}"),
+            }
         };
         gen = gen.line(format!(
             "CheckCodePrefix::{prefix} => SuffixLength::{specificity},"

ruff_dev/src/round_trip.rs

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

ruff_macros/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "ruff_macros"
-version = "0.0.196"
+version = "0.0.200"
 edition = "2021"
 
 [lib]

src/autofix/fixer.rs

@@ -14,6 +14,7 @@ use crate::source_code_locator::SourceCodeLocator;
 pub enum Mode {
     Generate,
     Apply,
+    Diff,
     None,
 }
 

src/cache.rs

@@ -12,7 +12,6 @@ use once_cell::sync::Lazy;
 use path_absolutize::Absolutize;
 use serde::{Deserialize, Serialize};
 
-use crate::autofix::fixer;
 use crate::message::Message;
 use crate::settings::{flags, Settings};
 
@@ -48,7 +47,7 @@ fn content_dir() -> &'static Path {
     Path::new("content")
 }
 
-fn cache_key<P: AsRef<Path>>(path: P, settings: &Settings, autofix: fixer::Mode) -> u64 {
+fn cache_key<P: AsRef<Path>>(path: P, settings: &Settings, autofix: flags::Autofix) -> u64 {
     let mut hasher = DefaultHasher::new();
     CARGO_PKG_VERSION.hash(&mut hasher);
     path.as_ref().absolutize().unwrap().hash(&mut hasher);
@@ -93,13 +92,8 @@ pub fn get<P: AsRef<Path>>(
     path: P,
     metadata: &Metadata,
     settings: &Settings,
-    autofix: fixer::Mode,
-    cache: flags::Cache,
+    autofix: flags::Autofix,
 ) -> Option<Vec<Message>> {
-    if matches!(cache, flags::Cache::Disabled) {
-        return None;
-    };
-
     let encoded = read_sync(&settings.cache_dir, cache_key(path, settings, autofix)).ok()?;
     let (mtime, messages) = match bincode::deserialize::<CheckResult>(&encoded[..]) {
         Ok(CheckResult {
@@ -122,14 +116,9 @@ pub fn set<P: AsRef<Path>>(
     path: P,
     metadata: &Metadata,
     settings: &Settings,
-    autofix: fixer::Mode,
+    autofix: flags::Autofix,
     messages: &[Message],
-    cache: flags::Cache,
 ) {
-    if matches!(cache, flags::Cache::Disabled) {
-        return;
-    };
-
     let check_result = CheckResultRef {
         metadata: &CacheMetadata {
             mtime: FileTime::from_last_modification_time(metadata).unix_seconds(),

src/checkers/ast.rs

@@ -33,14 +33,16 @@ use crate::python::typing::SubscriptKind;
 use crate::settings::types::PythonVersion;
 use crate::settings::{flags, Settings};
 use crate::source_code_locator::SourceCodeLocator;
-use crate::vendored::cformat::{CFormatError, CFormatErrorType};
+use crate::source_code_style::SourceCodeStyleDetector;
+use crate::vendor::cformat::{CFormatError, CFormatErrorType};
 use crate::visibility::{module_visibility, transition_scope, Modifier, Visibility, VisibleScope};
 use crate::{
     docstrings, flake8_2020, flake8_annotations, flake8_bandit, flake8_blind_except,
     flake8_boolean_trap, flake8_bugbear, flake8_builtins, flake8_comprehensions, flake8_datetimez,
     flake8_debugger, flake8_errmsg, flake8_import_conventions, flake8_print, flake8_return,
     flake8_simplify, flake8_tidy_imports, flake8_unused_arguments, mccabe, noqa, pandas_vet,
-    pep8_naming, pycodestyle, pydocstyle, pyflakes, pygrep_hooks, pylint, pyupgrade, visibility,
+    pep8_naming, pycodestyle, pydocstyle, pyflakes, pygrep_hooks, pylint, pyupgrade, ruff,
+    visibility,
 };
 
 const GLOBAL_SCOPE_INDEX: usize = 0;
@@ -56,6 +58,7 @@ pub struct Checker<'a> {
     pub(crate) settings: &'a Settings,
     pub(crate) noqa_line_for: &'a IntMap<usize, usize>,
     pub(crate) locator: &'a SourceCodeLocator<'a>,
+    pub(crate) style: &'a SourceCodeStyleDetector<'a>,
     // Computed checks.
     checks: Vec<Check>,
     // Function and class definition tracking (e.g., for docstring enforcement).
@@ -107,6 +110,7 @@ impl<'a> Checker<'a> {
         noqa: flags::Noqa,
         path: &'a Path,
         locator: &'a SourceCodeLocator,
+        style: &'a SourceCodeStyleDetector,
     ) -> Checker<'a> {
         Checker {
             settings,
@@ -115,6 +119,7 @@ impl<'a> Checker<'a> {
             noqa,
             path,
             locator,
+            style,
             checks: vec![],
             definitions: vec![],
             deletions: FxHashSet::default(),
@@ -645,6 +650,9 @@ where
                         ));
                     }
                 }
+                if self.settings.enabled.contains(&CheckCode::UP023) {
+                    pyupgrade::plugins::replace_c_element_tree(self, stmt);
+                }
 
                 for alias in names {
                     if alias.node.name.contains('.') && alias.node.asname.is_none() {
@@ -814,6 +822,9 @@ where
             } => {
                 // Track `import from` statements, to ensure that we can correctly attribute
                 // references like `from typing import Union`.
+                if self.settings.enabled.contains(&CheckCode::UP023) {
+                    pyupgrade::plugins::replace_c_element_tree(self, stmt);
+                }
                 if level.map(|level| level == 0).unwrap_or(true) {
                     if let Some(module) = module {
                         self.from_imports
@@ -1547,9 +1558,6 @@ where
                     pyupgrade::plugins::use_pep585_annotation(self, expr, attr);
                 }
 
-                if self.settings.enabled.contains(&CheckCode::UP019) {
-                    pyupgrade::plugins::typing_text_str_alias(self, expr);
-                }
                 if self.settings.enabled.contains(&CheckCode::UP016) {
                     pyupgrade::plugins::remove_six_compat(self, expr);
                 }
@@ -1559,7 +1567,9 @@ where
                 {
                     pyupgrade::plugins::datetime_utc_alias(self, expr);
                 }
-
+                if self.settings.enabled.contains(&CheckCode::UP019) {
+                    pyupgrade::plugins::typing_text_str_alias(self, expr);
+                }
                 if self.settings.enabled.contains(&CheckCode::YTT202) {
                     flake8_2020::plugins::name_or_attribute(self, expr);
                 }
@@ -1642,25 +1652,35 @@ where
                 }
 
                 // pyupgrade
+                if self.settings.enabled.contains(&CheckCode::UP003) {
+                    pyupgrade::plugins::type_of_primitive(self, expr, func, args);
+                }
                 if self.settings.enabled.contains(&CheckCode::UP005) {
                     pyupgrade::plugins::deprecated_unittest_alias(self, func);
                 }
+                if self.settings.enabled.contains(&CheckCode::UP008) {
+                    pyupgrade::plugins::super_call_with_parameters(self, expr, func, args);
+                }
                 if self.settings.enabled.contains(&CheckCode::UP012) {
                     pyupgrade::plugins::unnecessary_encode_utf8(self, expr, func, args, keywords);
                 }
+                if self.settings.enabled.contains(&CheckCode::UP015) {
+                    pyupgrade::plugins::redundant_open_modes(self, expr);
+                }
                 if self.settings.enabled.contains(&CheckCode::UP016) {
                     pyupgrade::plugins::remove_six_compat(self, expr);
                 }
                 if self.settings.enabled.contains(&CheckCode::UP018) {
                     pyupgrade::plugins::native_literals(self, expr, func, args, keywords);
                 }
+                if self.settings.enabled.contains(&CheckCode::UP020) {
+                    pyupgrade::plugins::open_alias(self, expr, func);
+                }
                 if self.settings.enabled.contains(&CheckCode::UP021) {
                     pyupgrade::plugins::replace_universal_newlines(self, expr, keywords);
                 }
-
-                // flake8-super
-                if self.settings.enabled.contains(&CheckCode::UP008) {
-                    pyupgrade::plugins::super_call_with_parameters(self, expr, func, args);
+                if self.settings.enabled.contains(&CheckCode::UP022) {
+                    pyupgrade::plugins::replace_stdout_stderr(self, expr, keywords);
                 }
 
                 // flake8-print
@@ -1725,7 +1745,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C401) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_generator_set(
                         expr,
@@ -1739,7 +1758,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C402) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_generator_dict(
                         expr,
@@ -1753,7 +1771,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C403) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_list_comprehension_set(
@@ -1769,7 +1786,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C404) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_list_comprehension_dict(
@@ -1785,7 +1801,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C405) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_literal_set(
                         expr,
@@ -1799,7 +1814,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C406) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_literal_dict(
                         expr,
@@ -1813,7 +1827,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C408) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_collection_call(
                         expr,
@@ -1827,7 +1840,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C409) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_literal_within_tuple_call(
@@ -1842,7 +1854,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C410) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_literal_within_list_call(
@@ -1857,7 +1868,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C411) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_list_call(
                         expr,
@@ -1870,7 +1880,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C413) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_call_around_sorted(
@@ -1885,7 +1894,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C414) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_double_cast_or_process(
@@ -1897,7 +1905,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C415) {
                     if let Some(check) =
                         flake8_comprehensions::checks::unnecessary_subscript_reversal(
@@ -1909,7 +1916,6 @@ where
                         self.add_check(check);
                     };
                 }
-
                 if self.settings.enabled.contains(&CheckCode::C417) {
                     if let Some(check) = flake8_comprehensions::checks::unnecessary_map(
                         func,
@@ -1920,19 +1926,6 @@ where
                     };
                 }
 
-                // pyupgrade
-                if self.settings.enabled.contains(&CheckCode::UP003) {
-                    pyupgrade::plugins::type_of_primitive(self, expr, func, args);
-                }
-
-                if self.settings.enabled.contains(&CheckCode::UP015) {
-                    pyupgrade::plugins::redundant_open_modes(self, expr);
-                }
-
-                if self.settings.enabled.contains(&CheckCode::UP020) {
-                    pyupgrade::plugins::open_alias(self, expr, func);
-                }
-
                 // flake8-boolean-trap
                 if self.settings.enabled.contains(&CheckCode::FBT003) {
                     flake8_boolean_trap::plugins::check_boolean_positional_value_in_function_call(
@@ -1963,7 +1956,6 @@ where
                 if self.settings.enabled.contains(&CheckCode::PD002) {
                     self.add_checks(pandas_vet::checks::inplace_argument(keywords).into_iter());
                 }
-
                 for (code, name) in vec![
                     (CheckCode::PD003, "isnull"),
                     (CheckCode::PD004, "notnull"),
@@ -1980,7 +1972,6 @@ where
                         }
                     }
                 }
-
                 if self.settings.enabled.contains(&CheckCode::PD015) {
                     if let Some(check) = pandas_vet::checks::use_of_pd_merge(func) {
                         self.add_check(check);
@@ -2074,6 +2065,14 @@ where
                 if self.settings.enabled.contains(&CheckCode::PLR1722) {
                     pylint::plugins::use_sys_exit(self, func);
                 }
+
+                // ruff
+                if self.settings.enabled.contains(&CheckCode::RUF004) {
+                    self.add_checks(
+                        ruff::checks::keyword_argument_before_star_argument(args, keywords)
+                            .into_iter(),
+                    );
+                }
             }
             ExprKind::Dict { keys, .. } => {
                 let check_repeated_literals = self.settings.enabled.contains(&CheckCode::F601);
@@ -3926,16 +3925,26 @@ impl<'a> Checker<'a> {
     }
 }
 
+#[allow(clippy::too_many_arguments)]
 pub fn check_ast(
     python_ast: &Suite,
     locator: &SourceCodeLocator,
+    stylist: &SourceCodeStyleDetector,
     noqa_line_for: &IntMap<usize, usize>,
     settings: &Settings,
     autofix: flags::Autofix,
     noqa: flags::Noqa,
     path: &Path,
 ) -> Vec<Check> {
-    let mut checker = Checker::new(settings, noqa_line_for, autofix, noqa, path, locator);
+    let mut checker = Checker::new(
+        settings,
+        noqa_line_for,
+        autofix,
+        noqa,
+        path,
+        locator,
+        stylist,
+    );
     checker.push_scope(Scope::new(ScopeKind::Module));
     checker.bind_builtins();
 

src/checkers/lines.rs

@@ -2,7 +2,7 @@
 
 use crate::checks::{Check, CheckCode};
 use crate::pycodestyle::checks::{line_too_long, no_newline_at_end_of_file};
-use crate::pygrep_hooks::plugins::blanket_type_ignore;
+use crate::pygrep_hooks::plugins::{blanket_noqa, blanket_type_ignore};
 use crate::pyupgrade::checks::unnecessary_coding_comment;
 use crate::settings::{flags, Settings};
 
@@ -18,6 +18,7 @@ pub fn check_lines(
     let enforce_line_too_long = settings.enabled.contains(&CheckCode::E501);
     let enforce_no_newline_at_end_of_file = settings.enabled.contains(&CheckCode::W292);
     let enforce_blanket_type_ignore = settings.enabled.contains(&CheckCode::PGH003);
+    let enforce_blanket_noqa = settings.enabled.contains(&CheckCode::PGH004);
 
     let mut commented_lines_iter = commented_lines.iter().peekable();
     for (index, line) in contents.lines().enumerate() {
@@ -45,6 +46,14 @@ pub fn check_lines(
                     }
                 }
             }
+
+            if enforce_blanket_noqa {
+                if commented_lines.contains(&(index + 1)) {
+                    if let Some(check) = blanket_noqa(index, line) {
+                        checks.push(check);
+                    }
+                }
+            }
         }
 
         if enforce_line_too_long {

src/checkers/noqa.rs

@@ -49,6 +49,9 @@ pub fn check_noqa(
         while let Some((index, check)) =
             checks_iter.next_if(|(_index, check)| check.location.row() <= *lineno)
         {
+            if check.kind == CheckKind::BlanketNOQA {
+                continue;
+            }
             // Grab the noqa (logical) line number for the current (physical) line.
             // If there are newlines at the end of the file, they won't be represented in
             // `noqa_line_for`, so fallback to the current line.

src/checks.rs

@@ -229,6 +229,8 @@ pub enum CheckCode {
     UP019,
     UP020,
     UP021,
+    UP022,
+    UP023,
     // pydocstyle
     D100,
     D101,
@@ -328,11 +330,13 @@ pub enum CheckCode {
     RUF001,
     RUF002,
     RUF003,
+    RUF004,
     RUF100,
     // pygrep-hooks
     PGH001,
     PGH002,
     PGH003,
+    PGH004,
     // pandas-vet
     PD002,
     PD003,
@@ -843,6 +847,8 @@ pub enum CheckKind {
     NativeLiterals,
     OpenAlias,
     ReplaceUniversalNewlines,
+    ReplaceStdoutStderr,
+    RewriteCElementTree,
     // pydocstyle
     BlankLineAfterLastSection(String),
     BlankLineAfterSection(String),
@@ -926,6 +932,7 @@ pub enum CheckKind {
     NoEval,
     DeprecatedLogWarn,
     BlanketTypeIgnore,
+    BlanketNOQA,
     // flake8-unused-arguments
     UnusedFunctionArgument(String),
     UnusedMethodArgument(String),
@@ -955,6 +962,7 @@ pub enum CheckKind {
     AmbiguousUnicodeCharacterString(char, char),
     AmbiguousUnicodeCharacterDocstring(char, char),
     AmbiguousUnicodeCharacterComment(char, char),
+    KeywordArgumentBeforeStarArgument(String),
     UnusedNOQA(Option<UnusedCodes>),
     // flake8-datetimez
     CallDatetimeWithoutTzinfo,
@@ -974,9 +982,11 @@ impl CheckCode {
     pub fn lint_source(&self) -> &'static LintSource {
         match self {
             CheckCode::RUF100 => &LintSource::NoQA,
-            CheckCode::E501 | CheckCode::W292 | CheckCode::UP009 | CheckCode::PGH003 => {
-                &LintSource::Lines
-            }
+            CheckCode::E501
+            | CheckCode::W292
+            | CheckCode::UP009
+            | CheckCode::PGH003
+            | CheckCode::PGH004 => &LintSource::Lines,
             CheckCode::ERA001
             | CheckCode::Q000
             | CheckCode::Q001
@@ -1221,6 +1231,8 @@ impl CheckCode {
             CheckCode::UP019 => CheckKind::TypingTextStrAlias,
             CheckCode::UP020 => CheckKind::OpenAlias,
             CheckCode::UP021 => CheckKind::ReplaceUniversalNewlines,
+            CheckCode::UP022 => CheckKind::ReplaceStdoutStderr,
+            CheckCode::UP023 => CheckKind::RewriteCElementTree,
             // pydocstyle
             CheckCode::D100 => CheckKind::PublicModule,
             CheckCode::D101 => CheckKind::PublicClass,
@@ -1319,6 +1331,7 @@ impl CheckCode {
             CheckCode::PGH001 => CheckKind::NoEval,
             CheckCode::PGH002 => CheckKind::DeprecatedLogWarn,
             CheckCode::PGH003 => CheckKind::BlanketTypeIgnore,
+            CheckCode::PGH004 => CheckKind::BlanketNOQA,
             // flake8-unused-arguments
             CheckCode::ARG001 => CheckKind::UnusedFunctionArgument("...".to_string()),
             CheckCode::ARG002 => CheckKind::UnusedMethodArgument("...".to_string()),
@@ -1360,6 +1373,7 @@ impl CheckCode {
             CheckCode::RUF001 => CheckKind::AmbiguousUnicodeCharacterString('𝐁', 'B'),
             CheckCode::RUF002 => CheckKind::AmbiguousUnicodeCharacterDocstring('𝐁', 'B'),
             CheckCode::RUF003 => CheckKind::AmbiguousUnicodeCharacterComment('𝐁', 'B'),
+            CheckCode::RUF004 => CheckKind::KeywordArgumentBeforeStarArgument("...".to_string()),
             CheckCode::RUF100 => CheckKind::UnusedNOQA(None),
         }
     }
@@ -1585,6 +1599,7 @@ impl CheckCode {
             CheckCode::PGH001 => CheckCategory::PygrepHooks,
             CheckCode::PGH002 => CheckCategory::PygrepHooks,
             CheckCode::PGH003 => CheckCategory::PygrepHooks,
+            CheckCode::PGH004 => CheckCategory::PygrepHooks,
             CheckCode::PLC0414 => CheckCategory::Pylint,
             CheckCode::PLC2201 => CheckCategory::Pylint,
             CheckCode::PLC3002 => CheckCategory::Pylint,
@@ -1612,6 +1627,7 @@ impl CheckCode {
             CheckCode::RUF001 => CheckCategory::Ruff,
             CheckCode::RUF002 => CheckCategory::Ruff,
             CheckCode::RUF003 => CheckCategory::Ruff,
+            CheckCode::RUF004 => CheckCategory::Ruff,
             CheckCode::RUF100 => CheckCategory::Ruff,
             CheckCode::S101 => CheckCategory::Flake8Bandit,
             CheckCode::S102 => CheckCategory::Flake8Bandit,
@@ -1643,6 +1659,8 @@ impl CheckCode {
             CheckCode::UP019 => CheckCategory::Pyupgrade,
             CheckCode::UP020 => CheckCategory::Pyupgrade,
             CheckCode::UP021 => CheckCategory::Pyupgrade,
+            CheckCode::UP022 => CheckCategory::Pyupgrade,
+            CheckCode::UP023 => CheckCategory::Pyupgrade,
             CheckCode::W292 => CheckCategory::Pycodestyle,
             CheckCode::W605 => CheckCategory::Pycodestyle,
             CheckCode::YTT101 => CheckCategory::Flake82020,
@@ -1858,6 +1876,8 @@ impl CheckKind {
             CheckKind::TypingTextStrAlias => &CheckCode::UP019,
             CheckKind::OpenAlias => &CheckCode::UP020,
             CheckKind::ReplaceUniversalNewlines => &CheckCode::UP021,
+            CheckKind::ReplaceStdoutStderr => &CheckCode::UP022,
+            CheckKind::RewriteCElementTree => &CheckCode::UP023,
             // pydocstyle
             CheckKind::BlankLineAfterLastSection(..) => &CheckCode::D413,
             CheckKind::BlankLineAfterSection(..) => &CheckCode::D410,
@@ -1941,6 +1961,7 @@ impl CheckKind {
             CheckKind::NoEval => &CheckCode::PGH001,
             CheckKind::DeprecatedLogWarn => &CheckCode::PGH002,
             CheckKind::BlanketTypeIgnore => &CheckCode::PGH003,
+            CheckKind::BlanketNOQA => &CheckCode::PGH004,
             // flake8-unused-arguments
             CheckKind::UnusedFunctionArgument(..) => &CheckCode::ARG001,
             CheckKind::UnusedMethodArgument(..) => &CheckCode::ARG002,
@@ -1980,6 +2001,7 @@ impl CheckKind {
             CheckKind::AmbiguousUnicodeCharacterString(..) => &CheckCode::RUF001,
             CheckKind::AmbiguousUnicodeCharacterDocstring(..) => &CheckCode::RUF002,
             CheckKind::AmbiguousUnicodeCharacterComment(..) => &CheckCode::RUF003,
+            CheckKind::KeywordArgumentBeforeStarArgument(..) => &CheckCode::RUF004,
             CheckKind::UnusedNOQA(..) => &CheckCode::RUF100,
         }
     }
@@ -2590,6 +2612,12 @@ impl CheckKind {
             CheckKind::ReplaceUniversalNewlines => {
                 "`universal_newlines` is deprecated, use `text`".to_string()
             }
+            CheckKind::ReplaceStdoutStderr => {
+                "Sending stdout and stderr to pipe is deprecated, use `capture_output`".to_string()
+            }
+            CheckKind::RewriteCElementTree => {
+                "`cElementTree` is deprecated, use `ElementTree`".to_string()
+            }
             CheckKind::ConvertNamedTupleFunctionalToClass(name) => {
                 format!("Convert `{name}` from `NamedTuple` functional to class syntax")
             }
@@ -2795,13 +2823,14 @@ impl CheckKind {
                 "Boolean positional value in function call".to_string()
             }
             // pygrep-hooks
-            CheckKind::NoEval => "No builtin `eval()` allowed".to_string(),
-            CheckKind::DeprecatedLogWarn => {
-                "`warn` is deprecated in favor of `warning`".to_string()
-            }
+            CheckKind::BlanketNOQA => "Use specific error codes when using `noqa`".to_string(),
             CheckKind::BlanketTypeIgnore => {
                 "Use specific error codes when ignoring type issues".to_string()
             }
+            CheckKind::DeprecatedLogWarn => {
+                "`warn` is deprecated in favor of `warning`".to_string()
+            }
+            CheckKind::NoEval => "No builtin `eval()` allowed".to_string(),
             // flake8-unused-arguments
             CheckKind::UnusedFunctionArgument(name) => {
                 format!("Unused function argument: `{name}`")
@@ -2882,6 +2911,9 @@ impl CheckKind {
                      '{representant}'?)"
                 )
             }
+            CheckKind::KeywordArgumentBeforeStarArgument(name) => {
+                format!("Keyword argument `{name}` must come after starred arguments")
+            }
             CheckKind::UnusedNOQA(codes) => match codes {
                 None => "Unused blanket `noqa` directive".to_string(),
                 Some(codes) => {
@@ -3032,6 +3064,8 @@ impl CheckKind {
                 | CheckKind::OpenAlias
                 | CheckKind::NewLineAfterLastParagraph
                 | CheckKind::ReplaceUniversalNewlines
+                | CheckKind::ReplaceStdoutStderr
+                | CheckKind::RewriteCElementTree
                 | CheckKind::NewLineAfterSectionName(..)
                 | CheckKind::NoBlankLineAfterFunction(..)
                 | CheckKind::NoBlankLineBeforeClass(..)

src/checks_gen.rs

@@ -28,6 +28,7 @@ pub enum CheckCodePrefix {
     A001,
     A002,
     A003,
+    ALL,
     ANN,
     ANN0,
     ANN00,
@@ -376,6 +377,7 @@ pub enum CheckCodePrefix {
     PGH001,
     PGH002,
     PGH003,
+    PGH004,
     PLC,
     PLC0,
     PLC04,
@@ -456,6 +458,7 @@ pub enum CheckCodePrefix {
     RUF001,
     RUF002,
     RUF003,
+    RUF004,
     RUF1,
     RUF10,
     RUF100,
@@ -530,6 +533,8 @@ pub enum CheckCodePrefix {
     UP02,
     UP020,
     UP021,
+    UP022,
+    UP023,
     W,
     W2,
     W29,
@@ -558,6 +563,7 @@ pub enum CheckCodePrefix {
 
 #[derive(PartialEq, Eq, PartialOrd, Ord)]
 pub enum SuffixLength {
+    None,
     Zero,
     One,
     Two,
@@ -575,6 +581,300 @@ impl CheckCodePrefix {
             CheckCodePrefix::A001 => vec![CheckCode::A001],
             CheckCodePrefix::A002 => vec![CheckCode::A002],
             CheckCodePrefix::A003 => vec![CheckCode::A003],
+            CheckCodePrefix::ALL => vec![
+                CheckCode::E401,
+                CheckCode::E402,
+                CheckCode::E501,
+                CheckCode::E711,
+                CheckCode::E712,
+                CheckCode::E713,
+                CheckCode::E714,
+                CheckCode::E721,
+                CheckCode::E722,
+                CheckCode::E731,
+                CheckCode::E741,
+                CheckCode::E742,
+                CheckCode::E743,
+                CheckCode::E902,
+                CheckCode::E999,
+                CheckCode::W292,
+                CheckCode::W605,
+                CheckCode::F401,
+                CheckCode::F402,
+                CheckCode::F403,
+                CheckCode::F404,
+                CheckCode::F405,
+                CheckCode::F406,
+                CheckCode::F407,
+                CheckCode::F501,
+                CheckCode::F502,
+                CheckCode::F503,
+                CheckCode::F504,
+                CheckCode::F505,
+                CheckCode::F506,
+                CheckCode::F507,
+                CheckCode::F508,
+                CheckCode::F509,
+                CheckCode::F521,
+                CheckCode::F522,
+                CheckCode::F523,
+                CheckCode::F524,
+                CheckCode::F525,
+                CheckCode::F541,
+                CheckCode::F601,
+                CheckCode::F602,
+                CheckCode::F621,
+                CheckCode::F622,
+                CheckCode::F631,
+                CheckCode::F632,
+                CheckCode::F633,
+                CheckCode::F634,
+                CheckCode::F701,
+                CheckCode::F702,
+                CheckCode::F704,
+                CheckCode::F706,
+                CheckCode::F707,
+                CheckCode::F722,
+                CheckCode::F811,
+                CheckCode::F821,
+                CheckCode::F822,
+                CheckCode::F823,
+                CheckCode::F831,
+                CheckCode::F841,
+                CheckCode::F842,
+                CheckCode::F901,
+                CheckCode::PLC0414,
+                CheckCode::PLC2201,
+                CheckCode::PLC3002,
+                CheckCode::PLE0117,
+                CheckCode::PLE0118,
+                CheckCode::PLE1142,
+                CheckCode::PLR0206,
+                CheckCode::PLR0402,
+                CheckCode::PLR1701,
+                CheckCode::PLR1722,
+                CheckCode::PLW0120,
+                CheckCode::PLW0602,
+                CheckCode::A001,
+                CheckCode::A002,
+                CheckCode::A003,
+                CheckCode::B002,
+                CheckCode::B003,
+                CheckCode::B004,
+                CheckCode::B005,
+                CheckCode::B006,
+                CheckCode::B007,
+                CheckCode::B008,
+                CheckCode::B009,
+                CheckCode::B010,
+                CheckCode::B011,
+                CheckCode::B012,
+                CheckCode::B013,
+                CheckCode::B014,
+                CheckCode::B015,
+                CheckCode::B016,
+                CheckCode::B017,
+                CheckCode::B018,
+                CheckCode::B019,
+                CheckCode::B020,
+                CheckCode::B021,
+                CheckCode::B022,
+                CheckCode::B023,
+                CheckCode::B024,
+                CheckCode::B025,
+                CheckCode::B026,
+                CheckCode::B027,
+                CheckCode::B904,
+                CheckCode::B905,
+                CheckCode::BLE001,
+                CheckCode::C400,
+                CheckCode::C401,
+                CheckCode::C402,
+                CheckCode::C403,
+                CheckCode::C404,
+                CheckCode::C405,
+                CheckCode::C406,
+                CheckCode::C408,
+                CheckCode::C409,
+                CheckCode::C410,
+                CheckCode::C411,
+                CheckCode::C413,
+                CheckCode::C414,
+                CheckCode::C415,
+                CheckCode::C416,
+                CheckCode::C417,
+                CheckCode::T100,
+                CheckCode::C901,
+                CheckCode::TID252,
+                CheckCode::RET501,
+                CheckCode::RET502,
+                CheckCode::RET503,
+                CheckCode::RET504,
+                CheckCode::RET505,
+                CheckCode::RET506,
+                CheckCode::RET507,
+                CheckCode::RET508,
+                CheckCode::T201,
+                CheckCode::T203,
+                CheckCode::Q000,
+                CheckCode::Q001,
+                CheckCode::Q002,
+                CheckCode::Q003,
+                CheckCode::ANN001,
+                CheckCode::ANN002,
+                CheckCode::ANN003,
+                CheckCode::ANN101,
+                CheckCode::ANN102,
+                CheckCode::ANN201,
+                CheckCode::ANN202,
+                CheckCode::ANN204,
+                CheckCode::ANN205,
+                CheckCode::ANN206,
+                CheckCode::ANN401,
+                CheckCode::YTT101,
+                CheckCode::YTT102,
+                CheckCode::YTT103,
+                CheckCode::YTT201,
+                CheckCode::YTT202,
+                CheckCode::YTT203,
+                CheckCode::YTT204,
+                CheckCode::YTT301,
+                CheckCode::YTT302,
+                CheckCode::YTT303,
+                CheckCode::SIM118,
+                CheckCode::UP001,
+                CheckCode::UP003,
+                CheckCode::UP004,
+                CheckCode::UP005,
+                CheckCode::UP006,
+                CheckCode::UP007,
+                CheckCode::UP008,
+                CheckCode::UP009,
+                CheckCode::UP010,
+                CheckCode::UP011,
+                CheckCode::UP012,
+                CheckCode::UP013,
+                CheckCode::UP014,
+                CheckCode::UP015,
+                CheckCode::UP016,
+                CheckCode::UP017,
+                CheckCode::UP018,
+                CheckCode::UP019,
+                CheckCode::UP020,
+                CheckCode::UP021,
+                CheckCode::UP022,
+                CheckCode::UP023,
+                CheckCode::D100,
+                CheckCode::D101,
+                CheckCode::D102,
+                CheckCode::D103,
+                CheckCode::D104,
+                CheckCode::D105,
+                CheckCode::D106,
+                CheckCode::D107,
+                CheckCode::D200,
+                CheckCode::D201,
+                CheckCode::D202,
+                CheckCode::D203,
+                CheckCode::D204,
+                CheckCode::D205,
+                CheckCode::D206,
+                CheckCode::D207,
+                CheckCode::D208,
+                CheckCode::D209,
+                CheckCode::D210,
+                CheckCode::D211,
+                CheckCode::D212,
+                CheckCode::D213,
+                CheckCode::D214,
+                CheckCode::D215,
+                CheckCode::D300,
+                CheckCode::D301,
+                CheckCode::D400,
+                CheckCode::D402,
+                CheckCode::D403,
+                CheckCode::D404,
+                CheckCode::D405,
+                CheckCode::D406,
+                CheckCode::D407,
+                CheckCode::D408,
+                CheckCode::D409,
+                CheckCode::D410,
+                CheckCode::D411,
+                CheckCode::D412,
+                CheckCode::D413,
+                CheckCode::D414,
+                CheckCode::D415,
+                CheckCode::D416,
+                CheckCode::D417,
+                CheckCode::D418,
+                CheckCode::D419,
+                CheckCode::N801,
+                CheckCode::N802,
+                CheckCode::N803,
+                CheckCode::N804,
+                CheckCode::N805,
+                CheckCode::N806,
+                CheckCode::N807,
+                CheckCode::N811,
+                CheckCode::N812,
+                CheckCode::N813,
+                CheckCode::N814,
+                CheckCode::N815,
+                CheckCode::N816,
+                CheckCode::N817,
+                CheckCode::N818,
+                CheckCode::I001,
+                CheckCode::ERA001,
+                CheckCode::S101,
+                CheckCode::S102,
+                CheckCode::S104,
+                CheckCode::S105,
+                CheckCode::S106,
+                CheckCode::S107,
+                CheckCode::FBT001,
+                CheckCode::FBT002,
+                CheckCode::FBT003,
+                CheckCode::ARG001,
+                CheckCode::ARG002,
+                CheckCode::ARG003,
+                CheckCode::ARG004,
+                CheckCode::ARG005,
+                CheckCode::ICN001,
+                CheckCode::DTZ001,
+                CheckCode::DTZ002,
+                CheckCode::DTZ003,
+                CheckCode::DTZ004,
+                CheckCode::DTZ005,
+                CheckCode::DTZ006,
+                CheckCode::DTZ007,
+                CheckCode::DTZ011,
+                CheckCode::DTZ012,
+                CheckCode::RUF001,
+                CheckCode::RUF002,
+                CheckCode::RUF003,
+                CheckCode::RUF004,
+                CheckCode::RUF100,
+                CheckCode::PGH001,
+                CheckCode::PGH002,
+                CheckCode::PGH003,
+                CheckCode::PGH004,
+                CheckCode::PD002,
+                CheckCode::PD003,
+                CheckCode::PD004,
+                CheckCode::PD007,
+                CheckCode::PD008,
+                CheckCode::PD009,
+                CheckCode::PD010,
+                CheckCode::PD011,
+                CheckCode::PD012,
+                CheckCode::PD013,
+                CheckCode::PD015,
+                CheckCode::PD901,
+                CheckCode::EM101,
+                CheckCode::EM102,
+                CheckCode::EM103,
+            ],
             CheckCodePrefix::ANN => vec![
                 CheckCode::ANN001,
                 CheckCode::ANN002,
@@ -1775,12 +2075,28 @@ impl CheckCodePrefix {
                 );
                 vec![CheckCode::PD901]
             }
-            CheckCodePrefix::PGH => vec![CheckCode::PGH001, CheckCode::PGH002, CheckCode::PGH003],
-            CheckCodePrefix::PGH0 => vec![CheckCode::PGH001, CheckCode::PGH002, CheckCode::PGH003],
-            CheckCodePrefix::PGH00 => vec![CheckCode::PGH001, CheckCode::PGH002, CheckCode::PGH003],
+            CheckCodePrefix::PGH => vec![
+                CheckCode::PGH001,
+                CheckCode::PGH002,
+                CheckCode::PGH003,
+                CheckCode::PGH004,
+            ],
+            CheckCodePrefix::PGH0 => vec![
+                CheckCode::PGH001,
+                CheckCode::PGH002,
+                CheckCode::PGH003,
+                CheckCode::PGH004,
+            ],
+            CheckCodePrefix::PGH00 => vec![
+                CheckCode::PGH001,
+                CheckCode::PGH002,
+                CheckCode::PGH003,
+                CheckCode::PGH004,
+            ],
             CheckCodePrefix::PGH001 => vec![CheckCode::PGH001],
             CheckCodePrefix::PGH002 => vec![CheckCode::PGH002],
             CheckCodePrefix::PGH003 => vec![CheckCode::PGH003],
+            CheckCodePrefix::PGH004 => vec![CheckCode::PGH004],
             CheckCodePrefix::PLC => {
                 vec![CheckCode::PLC0414, CheckCode::PLC2201, CheckCode::PLC3002]
             }
@@ -2025,13 +2341,25 @@ impl CheckCodePrefix {
                 CheckCode::RUF001,
                 CheckCode::RUF002,
                 CheckCode::RUF003,
+                CheckCode::RUF004,
                 CheckCode::RUF100,
             ],
-            CheckCodePrefix::RUF0 => vec![CheckCode::RUF001, CheckCode::RUF002, CheckCode::RUF003],
-            CheckCodePrefix::RUF00 => vec![CheckCode::RUF001, CheckCode::RUF002, CheckCode::RUF003],
+            CheckCodePrefix::RUF0 => vec![
+                CheckCode::RUF001,
+                CheckCode::RUF002,
+                CheckCode::RUF003,
+                CheckCode::RUF004,
+            ],
+            CheckCodePrefix::RUF00 => vec![
+                CheckCode::RUF001,
+                CheckCode::RUF002,
+                CheckCode::RUF003,
+                CheckCode::RUF004,
+            ],
             CheckCodePrefix::RUF001 => vec![CheckCode::RUF001],
             CheckCodePrefix::RUF002 => vec![CheckCode::RUF002],
             CheckCodePrefix::RUF003 => vec![CheckCode::RUF003],
+            CheckCodePrefix::RUF004 => vec![CheckCode::RUF004],
             CheckCodePrefix::RUF1 => vec![CheckCode::RUF100],
             CheckCodePrefix::RUF10 => vec![CheckCode::RUF100],
             CheckCodePrefix::RUF100 => vec![CheckCode::RUF100],
@@ -2109,6 +2437,8 @@ impl CheckCodePrefix {
                     CheckCode::UP019,
                     CheckCode::UP020,
                     CheckCode::UP021,
+                    CheckCode::UP022,
+                    CheckCode::UP023,
                 ]
             }
             CheckCodePrefix::U0 => {
@@ -2139,6 +2469,8 @@ impl CheckCodePrefix {
                     CheckCode::UP019,
                     CheckCode::UP020,
                     CheckCode::UP021,
+                    CheckCode::UP022,
+                    CheckCode::UP023,
                 ]
             }
             CheckCodePrefix::U00 => {
@@ -2353,6 +2685,8 @@ impl CheckCodePrefix {
                 CheckCode::UP019,
                 CheckCode::UP020,
                 CheckCode::UP021,
+                CheckCode::UP022,
+                CheckCode::UP023,
             ],
             CheckCodePrefix::UP0 => vec![
                 CheckCode::UP001,
@@ -2375,6 +2709,8 @@ impl CheckCodePrefix {
                 CheckCode::UP019,
                 CheckCode::UP020,
                 CheckCode::UP021,
+                CheckCode::UP022,
+                CheckCode::UP023,
             ],
             CheckCodePrefix::UP00 => vec![
                 CheckCode::UP001,
@@ -2416,9 +2752,16 @@ impl CheckCodePrefix {
             CheckCodePrefix::UP017 => vec![CheckCode::UP017],
             CheckCodePrefix::UP018 => vec![CheckCode::UP018],
             CheckCodePrefix::UP019 => vec![CheckCode::UP019],
-            CheckCodePrefix::UP02 => vec![CheckCode::UP020, CheckCode::UP021],
+            CheckCodePrefix::UP02 => vec![
+                CheckCode::UP020,
+                CheckCode::UP021,
+                CheckCode::UP022,
+                CheckCode::UP023,
+            ],
             CheckCodePrefix::UP020 => vec![CheckCode::UP020],
             CheckCodePrefix::UP021 => vec![CheckCode::UP021],
+            CheckCodePrefix::UP022 => vec![CheckCode::UP022],
+            CheckCodePrefix::UP023 => vec![CheckCode::UP023],
             CheckCodePrefix::W => vec![CheckCode::W292, CheckCode::W605],
             CheckCodePrefix::W2 => vec![CheckCode::W292],
             CheckCodePrefix::W29 => vec![CheckCode::W292],
@@ -2478,6 +2821,7 @@ impl CheckCodePrefix {
             CheckCodePrefix::A001 => SuffixLength::Three,
             CheckCodePrefix::A002 => SuffixLength::Three,
             CheckCodePrefix::A003 => SuffixLength::Three,
+            CheckCodePrefix::ALL => SuffixLength::None,
             CheckCodePrefix::ANN => SuffixLength::Zero,
             CheckCodePrefix::ANN0 => SuffixLength::One,
             CheckCodePrefix::ANN00 => SuffixLength::Two,
@@ -2826,6 +3170,7 @@ impl CheckCodePrefix {
             CheckCodePrefix::PGH001 => SuffixLength::Three,
             CheckCodePrefix::PGH002 => SuffixLength::Three,
             CheckCodePrefix::PGH003 => SuffixLength::Three,
+            CheckCodePrefix::PGH004 => SuffixLength::Three,
             CheckCodePrefix::PLC => SuffixLength::Zero,
             CheckCodePrefix::PLC0 => SuffixLength::One,
             CheckCodePrefix::PLC04 => SuffixLength::Two,
@@ -2906,6 +3251,7 @@ impl CheckCodePrefix {
             CheckCodePrefix::RUF001 => SuffixLength::Three,
             CheckCodePrefix::RUF002 => SuffixLength::Three,
             CheckCodePrefix::RUF003 => SuffixLength::Three,
+            CheckCodePrefix::RUF004 => SuffixLength::Three,
             CheckCodePrefix::RUF1 => SuffixLength::One,
             CheckCodePrefix::RUF10 => SuffixLength::Two,
             CheckCodePrefix::RUF100 => SuffixLength::Three,
@@ -2980,6 +3326,8 @@ impl CheckCodePrefix {
             CheckCodePrefix::UP02 => SuffixLength::Two,
             CheckCodePrefix::UP020 => SuffixLength::Three,
             CheckCodePrefix::UP021 => SuffixLength::Three,
+            CheckCodePrefix::UP022 => SuffixLength::Three,
+            CheckCodePrefix::UP023 => SuffixLength::Three,
             CheckCodePrefix::W => SuffixLength::Zero,
             CheckCodePrefix::W2 => SuffixLength::One,
             CheckCodePrefix::W29 => SuffixLength::Two,
@@ -3010,6 +3358,7 @@ impl CheckCodePrefix {
 
 pub const CATEGORIES: &[CheckCodePrefix] = &[
     CheckCodePrefix::A,
+    CheckCodePrefix::ALL,
     CheckCodePrefix::ANN,
     CheckCodePrefix::ARG,
     CheckCodePrefix::B,

src/cli.rs

@@ -50,6 +50,10 @@ pub struct Cli {
     fix_only: bool,
     #[clap(long, overrides_with("fix_only"), hide = true)]
     no_fix_only: bool,
+    /// Avoid writing any fixed files back; instead, output a diff for each
+    /// changed file to stdout.
+    #[arg(long)]
+    pub diff: bool,
     /// Disable cache reads.
     #[arg(short, long)]
     pub no_cache: bool,
@@ -101,10 +105,15 @@ pub struct Cli {
     no_respect_gitignore: bool,
     /// Enforce exclusions, even for paths passed to Ruff directly on the
     /// command-line.
-    #[arg(long, overrides_with("no_show_source"))]
+    #[arg(long, overrides_with("no_force_exclude"))]
     force_exclude: bool,
     #[clap(long, overrides_with("force_exclude"), hide = true)]
     no_force_exclude: bool,
+    /// Enable or disable automatic update checks.
+    #[arg(long, overrides_with("no_update_check"))]
+    update_check: bool,
+    #[clap(long, overrides_with("update_check"), hide = true)]
+    no_update_check: bool,
     /// See the files Ruff will be run against with the current settings.
     #[arg(long)]
     pub show_files: bool,
@@ -154,6 +163,7 @@ impl Cli {
                 add_noqa: self.add_noqa,
                 autoformat: self.autoformat,
                 config: self.config,
+                diff: self.diff,
                 exit_zero: self.exit_zero,
                 explain: self.explain,
                 files: self.files,
@@ -187,11 +197,12 @@ impl Cli {
                 target_version: self.target_version,
                 unfixable: self.unfixable,
                 // TODO(charlie): Included in `pyproject.toml`, but not inherited.
+                cache_dir: self.cache_dir,
                 fix: resolve_bool_arg(self.fix, self.no_fix),
                 fix_only: resolve_bool_arg(self.fix_only, self.no_fix_only),
-                format: self.format,
                 force_exclude: resolve_bool_arg(self.force_exclude, self.no_force_exclude),
-                cache_dir: self.cache_dir,
+                format: self.format,
+                update_check: resolve_bool_arg(self.update_check, self.no_update_check),
             },
         )
     }
@@ -213,6 +224,7 @@ pub struct Arguments {
     pub add_noqa: bool,
     pub autoformat: bool,
     pub config: Option<PathBuf>,
+    pub diff: bool,
     pub exit_zero: bool,
     pub explain: Option<CheckCode>,
     pub files: Vec<PathBuf>,
@@ -247,11 +259,12 @@ pub struct Overrides {
     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 cache_dir: Option<PathBuf>,
     pub fix: Option<bool>,
     pub fix_only: Option<bool>,
-    pub format: Option<SerializationFormat>,
     pub force_exclude: Option<bool>,
-    pub cache_dir: Option<PathBuf>,
+    pub format: Option<SerializationFormat>,
+    pub update_check: Option<bool>,
 }
 
 /// Map the CLI settings to a `LogLevel`.

src/commands.rs

@@ -332,6 +332,9 @@ pub fn explain(code: &CheckCode, format: &SerializationFormat) -> Result<()> {
         SerializationFormat::Github => {
             bail!("`--explain` does not support GitHub format")
         }
+        SerializationFormat::Gitlab => {
+            bail!("`--explain` does not support GitLab format")
+        }
     };
     Ok(())
 }

src/flake8_bugbear/plugins/assert_false.rs

@@ -4,7 +4,7 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
+use crate::source_code_generator::SourceCodeGenerator;
 
 fn assertion_error(msg: Option<&Expr>) -> Stmt {
     Stmt::new(
@@ -47,7 +47,8 @@ pub fn assert_false(checker: &mut Checker, stmt: &Stmt, test: &Expr, msg: Option
 
     let mut check = Check::new(CheckKind::DoNotAssertFalse, Range::from_located(test));
     if checker.patch(check.kind.code()) {
-        let mut generator = SourceGenerator::new();
+        let mut generator =
+            SourceCodeGenerator::new(checker.style.indentation(), checker.style.quote());
         generator.unparse_stmt(&assertion_error(msg));
         if let Ok(content) = generator.generate() {
             check.amend(Fix::replacement(

src/flake8_bugbear/plugins/duplicate_exceptions.rs

@@ -7,7 +7,7 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckCode, CheckKind};
-use crate::code_gen::SourceGenerator;
+use crate::source_code_generator::SourceCodeGenerator;
 
 fn type_pattern(elts: Vec<&Expr>) -> Expr {
     Expr::new(
@@ -54,7 +54,8 @@ fn duplicate_handler_exceptions<'a>(
                 Range::from_located(expr),
             );
             if checker.patch(check.kind.code()) {
-                let mut generator = SourceGenerator::new();
+                let mut generator =
+                    SourceCodeGenerator::new(checker.style.indentation(), checker.style.quote());
                 if unique_elts.len() == 1 {
                     generator.unparse_expr(unique_elts[0], 0);
                 } else {

src/flake8_bugbear/plugins/getattr_with_constant.rs

@@ -4,9 +4,9 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
 use crate::python::identifiers::IDENTIFIER_REGEX;
 use crate::python::keyword::KWLIST;
+use crate::source_code_generator::SourceCodeGenerator;
 
 fn attribute(value: &Expr, attr: &str) -> Expr {
     Expr::new(
@@ -46,7 +46,8 @@ pub fn getattr_with_constant(checker: &mut Checker, expr: &Expr, func: &Expr, ar
 
     let mut check = Check::new(CheckKind::GetAttrWithConstant, Range::from_located(expr));
     if checker.patch(check.kind.code()) {
-        let mut generator = SourceGenerator::new();
+        let mut generator =
+            SourceCodeGenerator::new(checker.style.indentation(), checker.style.quote());
         generator.unparse_expr(&attribute(obj, value), 0);
         if let Ok(content) = generator.generate() {
             check.amend(Fix::replacement(

src/flake8_bugbear/plugins/redundant_tuple_in_exception_handler.rs

@@ -4,7 +4,7 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
+use crate::source_code_generator::SourceCodeGenerator;
 
 /// B013
 pub fn redundant_tuple_in_exception_handler(checker: &mut Checker, handlers: &[Excepthandler]) {
@@ -23,7 +23,8 @@ pub fn redundant_tuple_in_exception_handler(checker: &mut Checker, handlers: &[E
             Range::from_located(type_),
         );
         if checker.patch(check.kind.code()) {
-            let mut generator = SourceGenerator::new();
+            let mut generator =
+                SourceCodeGenerator::new(checker.style.indentation(), checker.style.quote());
             generator.unparse_expr(elt, 0);
             if let Ok(content) = generator.generate() {
                 check.amend(Fix::replacement(

src/flake8_bugbear/plugins/setattr_with_constant.rs

@@ -6,11 +6,17 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
 use crate::python::identifiers::IDENTIFIER_REGEX;
 use crate::python::keyword::KWLIST;
+use crate::source_code_generator::SourceCodeGenerator;
+use crate::source_code_style::SourceCodeStyleDetector;
 
-fn assignment(obj: &Expr, name: &str, value: &Expr) -> Result<String> {
+fn assignment(
+    obj: &Expr,
+    name: &str,
+    value: &Expr,
+    stylist: &SourceCodeStyleDetector,
+) -> Result<String> {
     let stmt = Stmt::new(
         Location::default(),
         Location::default(),
@@ -28,7 +34,7 @@ fn assignment(obj: &Expr, name: &str, value: &Expr) -> Result<String> {
             type_comment: None,
         },
     );
-    let mut generator = SourceGenerator::new();
+    let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
     generator.unparse_stmt(&stmt);
     generator.generate().map_err(std::convert::Into::into)
 }
@@ -63,7 +69,7 @@ pub fn setattr_with_constant(checker: &mut Checker, expr: &Expr, func: &Expr, ar
         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) {
+                match assignment(obj, name, value, checker.style) {
                     Ok(content) => check.amend(Fix::replacement(
                         content,
                         expr.location,

src/flake8_bugbear/snapshots/ruff__flake8_bugbear__tests__B011_B011.py.snap

@@ -25,7 +25,7 @@ expression: checks
     row: 10
     column: 12
   fix:
-    content: "raise AssertionError('message')"
+    content: "raise AssertionError(\"message\")"
     location:
       row: 10
       column: 0

src/flake8_quotes/settings.rs

@@ -7,7 +7,9 @@ use serde::{Deserialize, Serialize};
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, Hash, JsonSchema)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 pub enum Quote {
+    /// Use single quotes (`'`).
     Single,
+    /// Use double quotes (`"`).
     Double,
 }
 

src/flake8_tidy_imports/settings.rs

@@ -7,7 +7,9 @@ use serde::{Deserialize, Serialize};
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, Hash, JsonSchema)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 pub enum Strictness {
+    /// Ban imports that extend into the parent module or beyond.
     Parents,
+    /// Ban all relative imports.
     All,
 }
 
@@ -29,7 +31,7 @@ pub struct Options {
         "#
     )]
     /// Whether to ban all relative imports (`"all"`), or only those imports
-    /// that extend into the parent module and beyond (`"parents"`).
+    /// that extend into the parent module or beyond (`"parents"`).
     pub ban_relative_imports: Option<Strictness>,
 }
 

src/lib.rs

@@ -24,7 +24,6 @@ mod checkers;
 pub mod checks;
 pub mod checks_gen;
 pub mod cli;
-pub mod code_gen;
 mod cst;
 mod directives;
 mod docstrings;
@@ -60,7 +59,7 @@ mod pandas_vet;
 pub mod pep8_naming;
 pub mod printer;
 mod pycodestyle;
-mod pydocstyle;
+pub mod pydocstyle;
 mod pyflakes;
 mod pygrep_hooks;
 mod pylint;
@@ -70,8 +69,10 @@ pub mod resolver;
 mod ruff;
 mod rustpython_helpers;
 pub mod settings;
+pub mod source_code_generator;
 pub mod source_code_locator;
-mod vendored;
+pub mod source_code_style;
+mod vendor;
 pub mod visibility;
 
 cfg_if! {

src/lib_native.rs

@@ -11,6 +11,7 @@ use crate::rustpython_helpers::tokenize;
 use crate::settings::configuration::Configuration;
 use crate::settings::{flags, pyproject, Settings};
 use crate::source_code_locator::SourceCodeLocator;
+use crate::source_code_style::SourceCodeStyleDetector;
 use crate::{directives, packages, resolver};
 
 /// Load the relevant `Settings` for a given `Path`.
@@ -38,9 +39,12 @@ pub fn check(path: &Path, contents: &str, autofix: bool) -> Result<Vec<Check>> {
     // Tokenize once.
     let tokens: Vec<LexResult> = tokenize(contents);
 
-    // Initialize the SourceCodeLocator (which computes offsets lazily).
+    // Map row and column locations to byte slices (lazily).
     let locator = SourceCodeLocator::new(contents);
 
+    // Detect the current code style (lazily).
+    let stylist = SourceCodeStyleDetector::from_contents(contents, &locator);
+
     // Extract the `# noqa` and `# isort: skip` directives from the source.
     let directives = directives::extract_directives(
         &tokens,
@@ -55,6 +59,7 @@ pub fn check(path: &Path, contents: &str, autofix: bool) -> Result<Vec<Check>> {
         contents,
         tokens,
         &locator,
+        &stylist,
         &directives,
         &settings,
         autofix.into(),

src/lib_wasm.rs

@@ -14,6 +14,9 @@ use crate::settings::configuration::Configuration;
 use crate::settings::options::Options;
 use crate::settings::{flags, Settings};
 use crate::source_code_locator::SourceCodeLocator;
+use crate::source_code_style::SourceCodeStyleDetector;
+
+const VERSION: &str = env!("CARGO_PKG_VERSION");
 
 #[wasm_bindgen(typescript_custom_section)]
 const TYPES: &'static str = r#"
@@ -58,6 +61,11 @@ pub fn run() {
     console_log::init_with_level(Level::Debug).expect("Initializing logger went wrong.");
 }
 
+#[wasm_bindgen]
+pub fn current_version() -> JsValue {
+    JsValue::from(VERSION)
+}
+
 #[wasm_bindgen]
 pub fn check(contents: &str, options: JsValue) -> Result<JsValue, JsValue> {
     let options: Options = serde_wasm_bindgen::from_value(options).map_err(|e| e.to_string())?;
@@ -69,9 +77,12 @@ pub fn check(contents: &str, options: JsValue) -> Result<JsValue, JsValue> {
     // Tokenize once.
     let tokens: Vec<LexResult> = tokenize(contents);
 
-    // Initialize the SourceCodeLocator (which computes offsets lazily).
+    // Map row and column locations to byte slices (lazily).
     let locator = SourceCodeLocator::new(contents);
 
+    // Detect the current code style (lazily).
+    let stylist = SourceCodeStyleDetector::from_contents(contents, &locator);
+
     // Extract the `# noqa` and `# isort: skip` directives from the source.
     let directives = directives::extract_directives(&tokens, &locator, directives::Flags::empty());
 
@@ -82,6 +93,7 @@ pub fn check(contents: &str, options: JsValue) -> Result<JsValue, JsValue> {
         contents,
         tokens,
         &locator,
+        &stylist,
         &directives,
         &settings,
         flags::Autofix::Enabled,

src/linter.rs

@@ -5,8 +5,10 @@ use std::ops::AddAssign;
 use std::path::Path;
 
 use anyhow::Result;
+use colored::Colorize;
 use log::debug;
 use rustpython_parser::lexer::LexResult;
+use similar::TextDiff;
 
 use crate::ast::types::Range;
 use crate::autofix::fixer;
@@ -17,14 +19,18 @@ use crate::checkers::lines::check_lines;
 use crate::checkers::noqa::check_noqa;
 use crate::checkers::tokens::check_tokens;
 use crate::checks::{Check, CheckCode, CheckKind, LintSource};
-use crate::code_gen::SourceGenerator;
 use crate::directives::Directives;
 use crate::message::{Message, Source};
 use crate::noqa::add_noqa;
 use crate::settings::{flags, Settings};
+use crate::source_code_generator::SourceCodeGenerator;
 use crate::source_code_locator::SourceCodeLocator;
+use crate::source_code_style::SourceCodeStyleDetector;
 use crate::{cache, directives, fs, rustpython_helpers};
 
+const CARGO_PKG_NAME: &str = env!("CARGO_PKG_NAME");
+const CARGO_PKG_REPOSITORY: &str = env!("CARGO_PKG_REPOSITORY");
+
 #[derive(Debug, Default)]
 pub struct Diagnostics {
     pub messages: Vec<Message>,
@@ -53,6 +59,7 @@ pub(crate) fn check_path(
     contents: &str,
     tokens: Vec<LexResult>,
     locator: &SourceCodeLocator,
+    stylist: &SourceCodeStyleDetector,
     directives: &Directives,
     settings: &Settings,
     autofix: flags::Autofix,
@@ -89,6 +96,7 @@ pub(crate) fn check_path(
                     checks.extend(check_ast(
                         &python_ast,
                         locator,
+                        stylist,
                         &directives.noqa_line_for,
                         settings,
                         autofix,
@@ -180,26 +188,54 @@ pub fn lint_path(
     // Validate the `Settings` and return any errors.
     settings.validate()?;
 
-    let metadata = path.metadata()?;
-
     // Check the cache.
-    if let Some(messages) = cache::get(path, &metadata, settings, autofix, cache) {
-        debug!("Cache hit for: {}", path.to_string_lossy());
-        return Ok(Diagnostics::new(messages));
-    }
+    // TODO(charlie): `fixer::Mode::Apply` and `fixer::Mode::Diff` both have
+    // side-effects that aren't captured in the cache. (In practice, it's fine
+    // to cache `fixer::Mode::Apply`, since a file either has no fixes, or we'll
+    // write the fixes to disk, thus invalidating the cache. But it's a bit hard
+    // to reason about. We need to come up with a better solution here.)
+    let metadata = if matches!(cache, flags::Cache::Enabled)
+        && matches!(autofix, fixer::Mode::None | fixer::Mode::Generate)
+    {
+        let metadata = path.metadata()?;
+        if let Some(messages) = cache::get(path, &metadata, settings, autofix.into()) {
+            debug!("Cache hit for: {}", path.to_string_lossy());
+            return Ok(Diagnostics::new(messages));
+        }
+        Some(metadata)
+    } else {
+        None
+    };
 
     // Read the file from disk.
     let contents = fs::read_file(path)?;
 
     // Lint the file.
-    let (contents, fixed, messages) = lint(contents, path, package, settings, autofix)?;
+    let (messages, fixed) = if matches!(autofix, fixer::Mode::Apply | fixer::Mode::Diff) {
+        let (transformed, fixed, messages) = lint_fix(&contents, path, package, settings)?;
+        if fixed > 0 {
+            if matches!(autofix, fixer::Mode::Apply) {
+                write(path, transformed)?;
+            } else if matches!(autofix, fixer::Mode::Diff) {
+                let mut stdout = io::stdout().lock();
+                TextDiff::from_lines(&contents, &transformed)
+                    .unified_diff()
+                    .header(&fs::relativize_path(path), &fs::relativize_path(path))
+                    .to_writer(&mut stdout)?;
+                stdout.write_all(b"\n")?;
+                stdout.flush()?;
+            }
+        }
+        (messages, fixed)
+    } else {
+        let messages = lint_only(&contents, path, package, settings, autofix.into())?;
+        let fixed = 0;
+        (messages, fixed)
+    };
 
     // Re-populate the cache.
-    cache::set(path, &metadata, settings, autofix, &messages, cache);
-
-    // If we applied any fixes, write the contents back to disk.
-    if fixed > 0 {
-        write(path, contents)?;
+    if let Some(metadata) = metadata {
+        cache::set(path, &metadata, settings, autofix.into(), &messages);
     }
 
     Ok(Diagnostics { messages, fixed })
@@ -216,9 +252,12 @@ pub fn add_noqa_to_path(path: &Path, settings: &Settings) -> Result<usize> {
     // Tokenize once.
     let tokens: Vec<LexResult> = rustpython_helpers::tokenize(&contents);
 
-    // Initialize the SourceCodeLocator (which computes offsets lazily).
+    // Map row and column locations to byte slices (lazily).
     let locator = SourceCodeLocator::new(&contents);
 
+    // Detect the current code style (lazily).
+    let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
+
     // Extract the `# noqa` and `# isort: skip` directives from the source.
     let directives = directives::extract_directives(
         &tokens,
@@ -233,6 +272,7 @@ pub fn add_noqa_to_path(path: &Path, settings: &Settings) -> Result<usize> {
         &contents,
         tokens,
         &locator,
+        &stylist,
         &directives,
         settings,
         flags::Autofix::Disabled,
@@ -259,9 +299,15 @@ pub fn autoformat_path(path: &Path, settings: &Settings) -> Result<()> {
     // Tokenize once.
     let tokens: Vec<LexResult> = rustpython_helpers::tokenize(&contents);
 
+    // Map row and column locations to byte slices (lazily).
+    let locator = SourceCodeLocator::new(&contents);
+
+    // Detect the current code style (lazily).
+    let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
+
     // Generate the AST.
     let python_ast = rustpython_helpers::parse_program_tokens(tokens, "<filename>")?;
-    let mut generator = SourceGenerator::default();
+    let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
     generator.unparse_suite(&python_ast);
     write(path, generator.generate()?)?;
 
@@ -273,40 +319,121 @@ pub fn autoformat_path(path: &Path, settings: &Settings) -> Result<()> {
 pub fn lint_stdin(
     path: Option<&Path>,
     package: Option<&Path>,
-    stdin: &str,
+    contents: &str,
     settings: &Settings,
     autofix: fixer::Mode,
 ) -> Result<Diagnostics> {
     // Validate the `Settings` and return any errors.
     settings.validate()?;
 
-    // Read the file from disk.
-    let contents = stdin.to_string();
+    // Lint the inputs.
+    let (messages, fixed) = if matches!(autofix, fixer::Mode::Apply | fixer::Mode::Diff) {
+        let (transformed, fixed, messages) = lint_fix(
+            contents,
+            path.unwrap_or_else(|| Path::new("-")),
+            package,
+            settings,
+        )?;
 
-    // Lint the file.
-    let (contents, fixed, messages) = lint(
-        contents,
-        path.unwrap_or_else(|| Path::new("-")),
-        package,
-        settings,
-        autofix,
-    )?;
+        if matches!(autofix, fixer::Mode::Apply) {
+            // Write the contents to stdout, regardless of whether any errors were fixed.
+            io::stdout().write_all(transformed.as_bytes())?;
+        } else if matches!(autofix, fixer::Mode::Diff) {
+            // But only write a diff if it's non-empty.
+            if fixed > 0 {
+                let text_diff = TextDiff::from_lines(contents, &transformed);
+                let mut unified_diff = text_diff.unified_diff();
+                if let Some(path) = path {
+                    unified_diff.header(&fs::relativize_path(path), &fs::relativize_path(path));
+                }
 
-    // Write the fixed contents to stdout.
-    if matches!(autofix, fixer::Mode::Apply) {
-        io::stdout().write_all(contents.as_bytes())?;
-    }
+                let mut stdout = io::stdout().lock();
+                unified_diff.to_writer(&mut stdout)?;
+                stdout.write_all(b"\n")?;
+                stdout.flush()?;
+            }
+        }
+
+        (messages, fixed)
+    } else {
+        let messages = lint_only(
+            contents,
+            path.unwrap_or_else(|| Path::new("-")),
+            package,
+            settings,
+            autofix.into(),
+        )?;
+        let fixed = 0;
+        (messages, fixed)
+    };
 
     Ok(Diagnostics { messages, fixed })
 }
 
-fn lint(
-    mut contents: String,
+/// Generate a list of `Check` violations (optionally including any autofix
+/// patches) from source code content.
+fn lint_only(
+    contents: &str,
+    path: &Path,
+    package: Option<&Path>,
+    settings: &Settings,
+    autofix: flags::Autofix,
+) -> Result<Vec<Message>> {
+    // Tokenize once.
+    let tokens: Vec<LexResult> = rustpython_helpers::tokenize(contents);
+
+    // Map row and column locations to byte slices (lazily).
+    let locator = SourceCodeLocator::new(contents);
+
+    // Detect the current code style (lazily).
+    let stylist = SourceCodeStyleDetector::from_contents(contents, &locator);
+
+    // Extract the `# noqa` and `# isort: skip` directives from the source.
+    let directives = directives::extract_directives(
+        &tokens,
+        &locator,
+        directives::Flags::from_settings(settings),
+    );
+
+    // Generate checks.
+    let checks = check_path(
+        path,
+        package,
+        contents,
+        tokens,
+        &locator,
+        &stylist,
+        &directives,
+        settings,
+        autofix,
+        flags::Noqa::Enabled,
+    )?;
+
+    // Convert from checks to messages.
+    let path_lossy = path.to_string_lossy();
+    Ok(checks
+        .into_iter()
+        .map(|check| {
+            let source = if settings.show_source {
+                Some(Source::from_check(&check, &locator))
+            } else {
+                None
+            };
+            Message::from_check(check, path_lossy.to_string(), source)
+        })
+        .collect())
+}
+
+/// Generate a list of `Check` violations from source code content, iteratively
+/// autofixing any violations until stable.
+fn lint_fix(
+    contents: &str,
     path: &Path,
     package: Option<&Path>,
     settings: &Settings,
-    autofix: fixer::Mode,
 ) -> Result<(String, usize, Vec<Message>)> {
+    let mut contents = contents.to_string();
+
     // Track the number of fixed errors across iterations.
     let mut fixed = 0;
 
@@ -314,13 +441,16 @@ fn lint(
     let mut iterations = 0;
 
     // Continuously autofix until the source code stabilizes.
-    let messages = loop {
+    loop {
         // Tokenize once.
         let tokens: Vec<LexResult> = rustpython_helpers::tokenize(&contents);
 
-        // Initialize the SourceCodeLocator (which computes offsets lazily).
+        // Map row and column locations to byte slices (lazily).
         let locator = SourceCodeLocator::new(&contents);
 
+        // Detect the current code style (lazily).
+        let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
+
         // Extract the `# noqa` and `# isort: skip` directives from the source.
         let directives = directives::extract_directives(
             &tokens,
@@ -335,15 +465,16 @@ fn lint(
             &contents,
             tokens,
             &locator,
+            &stylist,
             &directives,
             settings,
-            autofix.into(),
+            flags::Autofix::Enabled,
             flags::Noqa::Enabled,
         )?;
 
         // Apply autofix.
-        if matches!(autofix, fixer::Mode::Apply) && iterations < MAX_ITERATIONS {
-            if let Some((fixed_contents, applied)) = fix_file(&checks, &locator) {
+        if let Some((fixed_contents, applied)) = fix_file(&checks, &locator) {
+            if iterations < MAX_ITERATIONS {
                 // Count the number of fixed errors.
                 fixed += applied;
 
@@ -356,11 +487,29 @@ fn lint(
                 // Re-run the linter pass (by avoiding the break).
                 continue;
             }
+
+            eprintln!(
+                "
+{}: Failed to converge after {} iterations.
+
+This likely indicates a bug in `{}`. If you could open an issue at:
+
+{}/issues
+
+quoting the contents of `{}`, along with the `pyproject.toml` settings and executed command, we'd \
+                 be very appreciative!
+",
+                "warning".yellow().bold(),
+                MAX_ITERATIONS,
+                CARGO_PKG_NAME,
+                CARGO_PKG_REPOSITORY,
+                fs::relativize_path(path),
+            );
         }
 
         // Convert to messages.
-        let filename = path.to_string_lossy().to_string();
-        break checks
+        let path_lossy = path.to_string_lossy();
+        let messages = checks
             .into_iter()
             .map(|check| {
                 let source = if settings.show_source {
@@ -368,12 +517,11 @@ fn lint(
                 } else {
                     None
                 };
-                Message::from_check(check, filename.clone(), source)
+                Message::from_check(check, path_lossy.to_string(), source)
             })
             .collect();
-    };
-
-    Ok((contents, fixed, messages))
+        return Ok((contents, fixed, messages));
+    }
 }
 
 #[cfg(test)]
@@ -381,6 +529,7 @@ pub fn test_path(path: &Path, settings: &Settings) -> Result<Vec<Check>> {
     let contents = fs::read_file(path)?;
     let tokens: Vec<LexResult> = rustpython_helpers::tokenize(&contents);
     let locator = SourceCodeLocator::new(&contents);
+    let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
     let directives = directives::extract_directives(
         &tokens,
         &locator,
@@ -392,6 +541,7 @@ pub fn test_path(path: &Path, settings: &Settings) -> Result<Vec<Check>> {
         &contents,
         tokens,
         &locator,
+        &stylist,
         &directives,
         settings,
         flags::Autofix::Enabled,

src/main_native.rs

@@ -117,25 +117,20 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
             PyprojectDiscovery::Hierarchical(settings) => settings.respect_gitignore,
         },
     };
-    let (fix, fix_only, format) = match &pyproject_strategy {
-        PyprojectDiscovery::Fixed(settings) => (settings.fix, settings.fix_only, settings.format),
-        PyprojectDiscovery::Hierarchical(settings) => {
-            (settings.fix, settings.fix_only, settings.format)
-        }
+    let (fix, fix_only, format, update_check) = match &pyproject_strategy {
+        PyprojectDiscovery::Fixed(settings) => (
+            settings.fix,
+            settings.fix_only,
+            settings.format,
+            settings.update_check,
+        ),
+        PyprojectDiscovery::Hierarchical(settings) => (
+            settings.fix,
+            settings.fix_only,
+            settings.format,
+            settings.update_check,
+        ),
     };
-    let autofix = if fix || fix_only {
-        fixer::Mode::Apply
-    } else if matches!(format, SerializationFormat::Json) {
-        fixer::Mode::Generate
-    } else {
-        fixer::Mode::None
-    };
-    let violations = if fix_only {
-        Violations::Hide
-    } else {
-        Violations::Show
-    };
-    let cache = !cli.no_cache;
 
     if let Some(code) = cli.explain {
         commands::explain(&code, &format)?;
@@ -150,9 +145,35 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
         return Ok(ExitCode::SUCCESS);
     }
 
+    // Autofix rules are as follows:
+    // - If `--fix` or `--fix-only` is set, always apply fixes to the filesystem (or
+    //   print them to stdout, if we're reading from stdin).
+    // - Otherwise, if `--format json` is set, generate the fixes (so we print them
+    //   out as part of the JSON payload), but don't write them to disk.
+    // - If `--diff` or `--fix-only` are set, don't print any violations (only
+    //   fixes).
+    // TODO(charlie): Consider adding ESLint's `--fix-dry-run`, which would generate
+    // but not apply fixes. That would allow us to avoid special-casing JSON
+    // here.
+    let autofix = if cli.diff {
+        fixer::Mode::Diff
+    } else if fix || fix_only {
+        fixer::Mode::Apply
+    } else if matches!(format, SerializationFormat::Json) {
+        fixer::Mode::Generate
+    } else {
+        fixer::Mode::None
+    };
+    let violations = if cli.diff || fix_only {
+        Violations::Hide
+    } else {
+        Violations::Show
+    };
+    let cache = !cli.no_cache;
+
     let printer = Printer::new(&format, &log_level, &autofix, &violations);
     if cli.watch {
-        if matches!(autofix, fixer::Mode::Generate | fixer::Mode::Apply) {
+        if !matches!(autofix, fixer::Mode::None) {
             eprintln!("Warning: --fix is not enabled in watch mode.");
         }
         if cli.add_noqa {
@@ -251,18 +272,28 @@ pub(crate) fn inner_main() -> Result<ExitCode> {
         // Always try to print violations (the printer itself may suppress output),
         // unless we're writing fixes via stdin (in which case, the transformed
         // source code goes to stdout).
-        if !(is_stdin && matches!(autofix, fixer::Mode::Apply)) {
+        if !(is_stdin && matches!(autofix, fixer::Mode::Apply | fixer::Mode::Diff)) {
             printer.write_once(&diagnostics)?;
         }
 
         // Check for updates if we're in a non-silent log level.
         #[cfg(feature = "update-informer")]
-        if !is_stdin && log_level >= LogLevel::Default && atty::is(atty::Stream::Stdout) {
+        if update_check
+            && !is_stdin
+            && log_level >= LogLevel::Default
+            && atty::is(atty::Stream::Stdout)
+        {
             drop(updates::check_for_updates());
         }
 
-        if !diagnostics.messages.is_empty() && !cli.exit_zero && !fix_only {
-            return Ok(ExitCode::FAILURE);
+        if !cli.exit_zero {
+            if cli.diff || fix_only {
+                if diagnostics.fixed > 0 {
+                    return Ok(ExitCode::FAILURE);
+                }
+            } else if !diagnostics.messages.is_empty() {
+                return Ok(ExitCode::FAILURE);
+            }
         }
     }
 

src/noqa.rs

@@ -10,7 +10,7 @@ use rustc_hash::{FxHashMap, FxHashSet};
 
 use crate::checks::{Check, CheckCode, CODE_REDIRECTS};
 
-static NO_QA_LINE_REGEX: Lazy<Regex> = Lazy::new(|| {
+static NOQA_LINE_REGEX: Lazy<Regex> = Lazy::new(|| {
     Regex::new(
         r"(?P<spaces>\s*)(?P<noqa>(?i:# noqa)(?::\s?(?P<codes>([A-Z]+[0-9]+(?:[,\s]+)?)+))?)",
     )
@@ -39,7 +39,7 @@ pub enum Directive<'a> {
 
 /// Extract the noqa `Directive` from a line of Python source code.
 pub fn extract_noqa_directive(line: &str) -> Directive {
-    match NO_QA_LINE_REGEX.captures(line) {
+    match NOQA_LINE_REGEX.captures(line) {
         Some(caps) => match caps.name("spaces") {
             Some(spaces) => match caps.name("noqa") {
                 Some(noqa) => match caps.name("codes") {
@@ -206,20 +206,20 @@ mod tests {
 
     use crate::ast::types::Range;
     use crate::checks::{Check, CheckKind};
-    use crate::noqa::{add_noqa_inner, NO_QA_LINE_REGEX};
+    use crate::noqa::{add_noqa_inner, NOQA_LINE_REGEX};
 
     #[test]
     fn regex() {
-        assert!(NO_QA_LINE_REGEX.is_match("# noqa"));
-        assert!(NO_QA_LINE_REGEX.is_match("# NoQA"));
+        assert!(NOQA_LINE_REGEX.is_match("# noqa"));
+        assert!(NOQA_LINE_REGEX.is_match("# NoQA"));
 
-        assert!(NO_QA_LINE_REGEX.is_match("# noqa: F401"));
-        assert!(NO_QA_LINE_REGEX.is_match("# NoQA: F401"));
-        assert!(NO_QA_LINE_REGEX.is_match("# noqa: F401, E501"));
+        assert!(NOQA_LINE_REGEX.is_match("# noqa: F401"));
+        assert!(NOQA_LINE_REGEX.is_match("# NoQA: F401"));
+        assert!(NOQA_LINE_REGEX.is_match("# noqa: F401, E501"));
 
-        assert!(NO_QA_LINE_REGEX.is_match("# noqa:F401"));
-        assert!(NO_QA_LINE_REGEX.is_match("# NoQA:F401"));
-        assert!(NO_QA_LINE_REGEX.is_match("# noqa:F401, E501"));
+        assert!(NOQA_LINE_REGEX.is_match("# noqa:F401"));
+        assert!(NOQA_LINE_REGEX.is_match("# NoQA:F401"));
+        assert!(NOQA_LINE_REGEX.is_match("# noqa:F401, E501"));
     }
 
     #[test]

src/pandas_vet/mod.rs

@@ -14,6 +14,7 @@ mod tests {
     use crate::linter::check_path;
     use crate::settings::flags;
     use crate::source_code_locator::SourceCodeLocator;
+    use crate::source_code_style::SourceCodeStyleDetector;
     use crate::{directives, rustpython_helpers, settings};
 
     fn check_code(contents: &str, expected: &[CheckCode]) -> Result<()> {
@@ -21,6 +22,7 @@ mod tests {
         let settings = settings::Settings::for_rules(CheckCodePrefix::PD.codes());
         let tokens: Vec<LexResult> = rustpython_helpers::tokenize(&contents);
         let locator = SourceCodeLocator::new(&contents);
+        let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
         let directives = directives::extract_directives(
             &tokens,
             &locator,
@@ -32,6 +34,7 @@ mod tests {
             &contents,
             tokens,
             &locator,
+            &stylist,
             &directives,
             &settings,
             flags::Autofix::Enabled,

src/printer.rs

@@ -8,6 +8,7 @@ use colored::Colorize;
 use itertools::iterate;
 use rustpython_parser::ast::Location;
 use serde::Serialize;
+use serde_json::json;
 
 use crate::autofix::{fixer, Fix};
 use crate::checks::CheckCode;
@@ -89,7 +90,11 @@ impl<'a> Printer<'a> {
                 Violations::Hide => {
                     let fixed = diagnostics.fixed;
                     if fixed > 0 {
-                        println!("Fixed {fixed} error(s).");
+                        if matches!(self.autofix, fixer::Mode::Apply) {
+                            println!("Fixed {fixed} error(s).");
+                        } else if matches!(self.autofix, fixer::Mode::Diff) {
+                            println!("Would fix {fixed} error(s).");
+                        }
                     }
                 }
             }
@@ -134,17 +139,8 @@ impl<'a> Printer<'a> {
             SerializationFormat::Junit => {
                 use quick_junit::{NonSuccessKind, Report, TestCase, TestCaseStatus, TestSuite};
 
-                // Group by filename.
-                let mut grouped_messages = BTreeMap::default();
-                for message in &diagnostics.messages {
-                    grouped_messages
-                        .entry(&message.filename)
-                        .or_insert_with(Vec::new)
-                        .push(message);
-                }
-
                 let mut report = Report::new("ruff");
-                for (filename, messages) in grouped_messages {
+                for (filename, messages) in group_messages_by_filename(&diagnostics.messages) {
                     let mut test_suite = TestSuite::new(filename);
                     test_suite
                         .extra
@@ -183,16 +179,7 @@ impl<'a> Printer<'a> {
                 self.post_text(diagnostics);
             }
             SerializationFormat::Grouped => {
-                // Group by filename.
-                let mut grouped_messages = BTreeMap::default();
-                for message in &diagnostics.messages {
-                    grouped_messages
-                        .entry(&message.filename)
-                        .or_insert_with(Vec::new)
-                        .push(message);
-                }
-
-                for (filename, messages) in grouped_messages {
+                for (filename, messages) in group_messages_by_filename(&diagnostics.messages) {
                     // Compute the maximum number of digits in the row and column, for messages in
                     // this file.
                     let row_length = num_digits(
@@ -239,6 +226,34 @@ impl<'a> Printer<'a> {
                     );
                 });
             }
+            SerializationFormat::Gitlab => {
+                // Generate JSON with errors in GitLab CI format
+                // https://docs.gitlab.com/ee/ci/testing/code_quality.html#implementing-a-custom-tool
+                println!(
+                    "{}",
+                    serde_json::to_string_pretty(
+                        &diagnostics
+                            .messages
+                            .iter()
+                            .map(|message| {
+                                json!({
+                                    "description": format!("({}) {}", message.kind.code(), message.kind.body()),
+                                    "severity": "major",
+                                    "fingerprint": message.kind.code(),
+                                    "location": {
+                                        "path": relativize_path(Path::new(&message.filename)),
+                                        "lines": {
+                                            "begin": message.location.row(),
+                                            "end": message.end_location.row()
+                                        }
+                                    }
+                                })
+                            }
+                        )
+                        .collect::<Vec<_>>()
+                    )?
+                );
+            }
         }
 
         Ok(())
@@ -275,6 +290,17 @@ impl<'a> Printer<'a> {
     }
 }
 
+fn group_messages_by_filename(messages: &Vec<Message>) -> BTreeMap<&String, Vec<&Message>> {
+    let mut grouped_messages = BTreeMap::default();
+    for message in messages {
+        grouped_messages
+            .entry(&message.filename)
+            .or_insert_with(Vec::new)
+            .push(message);
+    }
+    grouped_messages
+}
+
 fn num_digits(n: usize) -> usize {
     iterate(n, |&n| n / 10)
         .take_while(|&n| n > 0)

src/pycodestyle/plugins.rs

@@ -12,9 +12,15 @@ use crate::ast::whitespace::leading_space;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind, RejectedCmpop};
-use crate::code_gen::SourceGenerator;
+use crate::source_code_generator::SourceCodeGenerator;
+use crate::source_code_style::SourceCodeStyleDetector;
 
-fn compare(left: &Expr, ops: &[Cmpop], comparators: &[Expr]) -> Option<String> {
+fn compare(
+    left: &Expr,
+    ops: &[Cmpop],
+    comparators: &[Expr],
+    stylist: &SourceCodeStyleDetector,
+) -> Option<String> {
     let cmp = Expr::new(
         Location::default(),
         Location::default(),
@@ -24,7 +30,7 @@ fn compare(left: &Expr, ops: &[Cmpop], comparators: &[Expr]) -> Option<String> {
             comparators: comparators.to_vec(),
         },
     );
-    let mut generator = SourceGenerator::new();
+    let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
     generator.unparse_expr(&cmp, 0);
     generator.generate().ok()
 }
@@ -194,7 +200,7 @@ pub fn literal_comparisons(
             .map(|(idx, op)| bad_ops.get(&idx).unwrap_or(op))
             .cloned()
             .collect::<Vec<_>>();
-        if let Some(content) = compare(left, &ops, comparators) {
+        if let Some(content) = compare(left, &ops, comparators, checker.style) {
             for check in &mut checks {
                 check.amend(Fix::replacement(
                     content.to_string(),
@@ -233,7 +239,9 @@ pub fn not_tests(
                             let mut check =
                                 Check::new(CheckKind::NotInTest, Range::from_located(operand));
                             if checker.patch(check.kind.code()) && should_fix {
-                                if let Some(content) = compare(left, &[Cmpop::NotIn], comparators) {
+                                if let Some(content) =
+                                    compare(left, &[Cmpop::NotIn], comparators, checker.style)
+                                {
                                     check.amend(Fix::replacement(
                                         content,
                                         expr.location,
@@ -249,7 +257,9 @@ pub fn not_tests(
                             let mut check =
                                 Check::new(CheckKind::NotIsTest, Range::from_located(operand));
                             if checker.patch(check.kind.code()) && should_fix {
-                                if let Some(content) = compare(left, &[Cmpop::IsNot], comparators) {
+                                if let Some(content) =
+                                    compare(left, &[Cmpop::IsNot], comparators, checker.style)
+                                {
                                     check.amend(Fix::replacement(
                                         content,
                                         expr.location,
@@ -267,7 +277,12 @@ pub fn not_tests(
     }
 }
 
-fn function(name: &str, args: &Arguments, body: &Expr) -> Result<String> {
+fn function(
+    name: &str,
+    args: &Arguments,
+    body: &Expr,
+    stylist: &SourceCodeStyleDetector,
+) -> Result<String> {
     let body = Stmt::new(
         Location::default(),
         Location::default(),
@@ -287,7 +302,7 @@ fn function(name: &str, args: &Arguments, body: &Expr) -> Result<String> {
             type_comment: None,
         },
     );
-    let mut generator = SourceGenerator::new();
+    let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
     generator.unparse_stmt(&func);
     Ok(generator.generate()?)
 }
@@ -301,7 +316,7 @@ pub fn do_not_assign_lambda(checker: &mut Checker, target: &Expr, value: &Expr,
                 if !match_leading_content(stmt, checker.locator)
                     && !match_trailing_content(stmt, checker.locator)
                 {
-                    match function(id, args, body) {
+                    match function(id, args, body, checker.style) {
                         Ok(content) => {
                             let first_line = checker.locator.slice_source_code_range(&Range {
                                 location: Location::new(stmt.location.row(), 0),

src/pydocstyle/settings.rs

@@ -7,7 +7,9 @@ use serde::{Deserialize, Serialize};
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize, Hash, JsonSchema)]
 #[serde(deny_unknown_fields, rename_all = "kebab-case")]
 pub enum Convention {
+    /// Use Google-style docstrings.
     Google,
+    /// Use NumPy-style docstrings.
     Numpy,
 }
 
@@ -17,7 +19,7 @@ pub enum Convention {
 #[serde(deny_unknown_fields, rename_all = "kebab-case", rename = "Pydocstyle")]
 pub struct Options {
     #[option(
-        default = r#""convention""#,
+        default = r#"None"#,
         value_type = "Convention",
         example = r#"
             # Use Google-style docstrings.

src/pyflakes/cformat.rs

@@ -4,7 +4,7 @@ use std::str::FromStr;
 
 use rustc_hash::FxHashSet;
 
-use crate::vendored::cformat::{
+use crate::vendor::cformat::{
     CFormatError, CFormatPart, CFormatQuantity, CFormatSpec, CFormatString,
 };
 

src/pyflakes/format.rs

@@ -4,7 +4,7 @@ use std::fmt;
 
 use rustc_hash::FxHashSet;
 
-use crate::vendored::format::{
+use crate::vendor::format::{
     FieldName, FieldType, FormatParseError, FormatPart, FormatString, FromTemplate,
 };
 
@@ -82,7 +82,7 @@ impl TryFrom<&str> for FormatSummary {
 #[cfg(test)]
 mod tests {
     use super::*;
-    use crate::vendored::format::FromTemplate;
+    use crate::vendor::format::FromTemplate;
 
     #[test]
     fn test_format_summary() {

src/pyflakes/mod.rs

@@ -20,6 +20,7 @@ mod tests {
     use crate::linter::{check_path, test_path};
     use crate::settings::flags;
     use crate::source_code_locator::SourceCodeLocator;
+    use crate::source_code_style::SourceCodeStyleDetector;
     use crate::{directives, rustpython_helpers, settings};
 
     #[test_case(CheckCode::F401, Path::new("F401_0.py"); "F401_0")]
@@ -171,6 +172,7 @@ mod tests {
         let settings = settings::Settings::for_rules(CheckCodePrefix::F.codes());
         let tokens: Vec<LexResult> = rustpython_helpers::tokenize(&contents);
         let locator = SourceCodeLocator::new(&contents);
+        let stylist = SourceCodeStyleDetector::from_contents(&contents, &locator);
         let directives = directives::extract_directives(
             &tokens,
             &locator,
@@ -182,6 +184,7 @@ mod tests {
             &contents,
             tokens,
             &locator,
+            &stylist,
             &directives,
             &settings,
             flags::Autofix::Enabled,

src/pygrep_hooks/mod.rs

@@ -17,6 +17,7 @@ mod tests {
     #[test_case(CheckCode::PGH002, Path::new("PGH002_0.py"); "PGH002_0")]
     #[test_case(CheckCode::PGH002, Path::new("PGH002_1.py"); "PGH002_1")]
     #[test_case(CheckCode::PGH003, Path::new("PGH003_0.py"); "PGH003_0")]
+    #[test_case(CheckCode::PGH004, Path::new("PGH004_0.py"); "PGH004_0")]
     fn checks(check_code: CheckCode, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", check_code.as_ref(), path.to_string_lossy());
         let mut checks = test_path(

src/pygrep_hooks/plugins/blanket_noqa.rs

@@ -0,0 +1,22 @@
+use once_cell::sync::Lazy;
+use regex::Regex;
+use rustpython_ast::Location;
+
+use crate::ast::types::Range;
+use crate::checks::{Check, CheckKind};
+
+static BLANKET_NOQA_REGEX: Lazy<Regex> =
+    Lazy::new(|| Regex::new(r"(?i)# noqa($|\s|:[^ ])").unwrap());
+
+/// PGH004 - use of blanket noqa comments
+pub fn blanket_noqa(lineno: usize, line: &str) -> Option<Check> {
+    BLANKET_NOQA_REGEX.find(line).map(|m| {
+        Check::new(
+            CheckKind::BlanketNOQA,
+            Range {
+                location: Location::new(lineno + 1, m.start()),
+                end_location: Location::new(lineno + 1, m.end()),
+            },
+        )
+    })
+}

src/pygrep_hooks/plugins/mod.rs

@@ -1,7 +1,9 @@
+pub use blanket_noqa::blanket_noqa;
 pub use blanket_type_ignore::blanket_type_ignore;
 pub use deprecated_log_warn::deprecated_log_warn;
 pub use no_eval::no_eval;
 
+mod blanket_noqa;
 mod blanket_type_ignore;
 mod deprecated_log_warn;
 mod no_eval;

src/pygrep_hooks/snapshots/ruff__pygrep_hooks__tests__PGH004_PGH004_0.py.snap

@@ -0,0 +1,53 @@
+---
+source: src/pygrep_hooks/mod.rs
+expression: checks
+---
+- kind: BlanketNOQA
+  location:
+    row: 1
+    column: 7
+  end_location:
+    row: 1
+    column: 13
+  fix: ~
+- kind: BlanketNOQA
+  location:
+    row: 2
+    column: 7
+  end_location:
+    row: 2
+    column: 15
+  fix: ~
+- kind: BlanketNOQA
+  location:
+    row: 3
+    column: 0
+  end_location:
+    row: 3
+    column: 6
+  fix: ~
+- kind: BlanketNOQA
+  location:
+    row: 4
+    column: 0
+  end_location:
+    row: 4
+    column: 6
+  fix: ~
+- kind: BlanketNOQA
+  location:
+    row: 5
+    column: 0
+  end_location:
+    row: 5
+    column: 8
+  fix: ~
+- kind: BlanketNOQA
+  location:
+    row: 6
+    column: 0
+  end_location:
+    row: 6
+    column: 8
+  fix: ~
+

src/pyupgrade/mod.rs

@@ -40,6 +40,8 @@ mod tests {
     #[test_case(CheckCode::UP018, Path::new("UP018.py"); "UP018")]
     #[test_case(CheckCode::UP019, Path::new("UP019.py"); "UP019")]
     #[test_case(CheckCode::UP021, Path::new("UP021.py"); "UP021")]
+    #[test_case(CheckCode::UP022, Path::new("UP022.py"); "UP022")]
+    #[test_case(CheckCode::UP023, Path::new("UP023.py"); "UP023")]
     fn checks(check_code: CheckCode, path: &Path) -> Result<()> {
         let snapshot = format!("{}_{}", check_code.as_ref(), path.to_string_lossy());
         let mut checks = test_path(

src/pyupgrade/plugins/convert_named_tuple_functional_to_class.rs

@@ -7,9 +7,10 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
 use crate::python::identifiers::IDENTIFIER_REGEX;
 use crate::python::keyword::KWLIST;
+use crate::source_code_generator::SourceCodeGenerator;
+use crate::source_code_style::SourceCodeStyleDetector;
 
 /// Return the typename, args, keywords and mother class
 fn match_named_tuple_assign<'a>(
@@ -163,8 +164,9 @@ fn convert_to_class(
     typename: &str,
     body: Vec<Stmt>,
     base_class: &ExprKind,
+    stylist: &SourceCodeStyleDetector,
 ) -> Result<Fix> {
-    let mut generator = SourceGenerator::new();
+    let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
     generator.unparse_stmt(&create_class_def_stmt(typename, body, base_class));
     let content = generator.generate()?;
     Ok(Fix::replacement(
@@ -194,7 +196,7 @@ pub fn convert_named_tuple_functional_to_class(
                     Range::from_located(stmt),
                 );
                 if checker.patch(check.kind.code()) {
-                    match convert_to_class(stmt, typename, properties, base_class) {
+                    match convert_to_class(stmt, typename, properties, base_class, checker.style) {
                         Ok(fix) => check.amend(fix),
                         Err(err) => error!("Failed to convert `NamedTuple`: {err}"),
                     }

src/pyupgrade/plugins/convert_typed_dict_functional_to_class.rs

@@ -9,9 +9,10 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
 use crate::python::identifiers::IDENTIFIER_REGEX;
 use crate::python::keyword::KWLIST;
+use crate::source_code_generator::SourceCodeGenerator;
+use crate::source_code_style::SourceCodeStyleDetector;
 
 /// Return the class name, arguments, keywords and base class for a `TypedDict`
 /// assignment.
@@ -196,8 +197,9 @@ fn convert_to_class(
     body: Vec<Stmt>,
     total_keyword: Option<KeywordData>,
     base_class: &ExprKind,
+    stylist: &SourceCodeStyleDetector,
 ) -> Result<Fix> {
-    let mut generator = SourceGenerator::new();
+    let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
     generator.unparse_stmt(&create_class_def_stmt(
         class_name,
         body,
@@ -236,7 +238,14 @@ pub fn convert_typed_dict_functional_to_class(
         Range::from_located(stmt),
     );
     if checker.patch(check.kind.code()) {
-        match convert_to_class(stmt, class_name, body, total_keyword, base_class) {
+        match convert_to_class(
+            stmt,
+            class_name,
+            body,
+            total_keyword,
+            base_class,
+            checker.style,
+        ) {
             Ok(fix) => check.amend(fix),
             Err(err) => error!("Failed to convert TypedDict: {err}"),
         };

src/pyupgrade/plugins/mod.rs

@@ -6,7 +6,9 @@ pub use native_literals::native_literals;
 pub use open_alias::open_alias;
 pub use redundant_open_modes::redundant_open_modes;
 pub use remove_six_compat::remove_six_compat;
+pub use replace_stdout_stderr::replace_stdout_stderr;
 pub use replace_universal_newlines::replace_universal_newlines;
+pub use rewrite_c_element_tree::replace_c_element_tree;
 pub use super_call_with_parameters::super_call_with_parameters;
 pub use type_of_primitive::type_of_primitive;
 pub use typing_text_str_alias::typing_text_str_alias;
@@ -26,7 +28,9 @@ mod native_literals;
 mod open_alias;
 mod redundant_open_modes;
 mod remove_six_compat;
+mod replace_stdout_stderr;
 mod replace_universal_newlines;
+mod rewrite_c_element_tree;
 mod super_call_with_parameters;
 mod type_of_primitive;
 mod typing_text_str_alias;

src/pyupgrade/plugins/remove_six_compat.rs

@@ -7,7 +7,8 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckCode, CheckKind};
-use crate::code_gen::SourceGenerator;
+use crate::source_code_generator::SourceCodeGenerator;
+use crate::source_code_style::SourceCodeStyleDetector;
 use crate::SourceCodeLocator;
 
 /// Return `true` if the `Expr` is a reference to `${module}.${any}`.
@@ -87,13 +88,14 @@ fn replace_call_on_arg_by_arg_attribute(
     arg: &Expr,
     expr: &Expr,
     patch: bool,
+    stylist: &SourceCodeStyleDetector,
 ) -> Result<Check> {
     let attribute = ExprKind::Attribute {
         value: Box::new(arg.clone()),
         attr: attr.to_string(),
         ctx: ExprContext::Load,
     };
-    replace_by_expr_kind(attribute, expr, patch)
+    replace_by_expr_kind(attribute, expr, patch, stylist)
 }
 
 // `func(arg, **args)` => `arg.method(**args)`
@@ -102,6 +104,7 @@ fn replace_call_on_arg_by_arg_method_call(
     args: &[Expr],
     expr: &Expr,
     patch: bool,
+    stylist: &SourceCodeStyleDetector,
 ) -> Result<Option<Check>> {
     if args.is_empty() {
         bail!("Expected at least one argument");
@@ -119,7 +122,7 @@ fn replace_call_on_arg_by_arg_method_call(
                 .collect(),
             keywords: vec![],
         };
-        let expr = replace_by_expr_kind(call, expr, patch)?;
+        let expr = replace_by_expr_kind(call, expr, patch, stylist)?;
         Ok(Some(expr))
     } else {
         Ok(None)
@@ -127,10 +130,15 @@ fn replace_call_on_arg_by_arg_method_call(
 }
 
 // `expr` => `Expr(expr_kind)`
-fn replace_by_expr_kind(node: ExprKind, expr: &Expr, patch: bool) -> Result<Check> {
+fn replace_by_expr_kind(
+    node: ExprKind,
+    expr: &Expr,
+    patch: bool,
+    stylist: &SourceCodeStyleDetector,
+) -> Result<Check> {
     let mut check = Check::new(CheckKind::RemoveSixCompat, Range::from_located(expr));
     if patch {
-        let mut generator = SourceGenerator::new();
+        let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
         generator.unparse_expr(&create_expr(node), 0);
         let content = generator.generate()?;
         check.amend(Fix::replacement(
@@ -142,10 +150,15 @@ fn replace_by_expr_kind(node: ExprKind, expr: &Expr, patch: bool) -> Result<Chec
     Ok(check)
 }
 
-fn replace_by_stmt_kind(node: StmtKind, expr: &Expr, patch: bool) -> Result<Check> {
+fn replace_by_stmt_kind(
+    node: StmtKind,
+    expr: &Expr,
+    patch: bool,
+    stylist: &SourceCodeStyleDetector,
+) -> Result<Check> {
     let mut check = Check::new(CheckKind::RemoveSixCompat, Range::from_located(expr));
     if patch {
-        let mut generator = SourceGenerator::new();
+        let mut generator = SourceCodeGenerator::new(stylist.indentation(), stylist.quote());
         generator.unparse_stmt(&create_stmt(node));
         let content = generator.generate()?;
         check.amend(Fix::replacement(
@@ -163,12 +176,13 @@ fn replace_by_raise_from(
     cause: Option<ExprKind>,
     expr: &Expr,
     patch: bool,
+    stylist: &SourceCodeStyleDetector,
 ) -> Result<Check> {
     let stmt_kind = StmtKind::Raise {
         exc: exc.map(|exc| Box::new(create_expr(exc))),
         cause: cause.map(|cause| Box::new(create_expr(cause))),
     };
-    replace_by_stmt_kind(stmt_kind, expr, patch)
+    replace_by_stmt_kind(stmt_kind, expr, patch, stylist)
 }
 
 fn replace_by_index_on_arg(
@@ -176,16 +190,22 @@ fn replace_by_index_on_arg(
     index: &ExprKind,
     expr: &Expr,
     patch: bool,
+    stylist: &SourceCodeStyleDetector,
 ) -> Result<Check> {
     let index = ExprKind::Subscript {
         value: Box::new(create_expr(arg.node.clone())),
         slice: Box::new(create_expr(index.clone())),
         ctx: ExprContext::Load,
     };
-    replace_by_expr_kind(index, expr, patch)
+    replace_by_expr_kind(index, expr, patch, stylist)
 }
 
-fn handle_reraise(args: &[Expr], expr: &Expr, patch: bool) -> Result<Option<Check>> {
+fn handle_reraise(
+    args: &[Expr],
+    expr: &Expr,
+    patch: bool,
+    stylist: &SourceCodeStyleDetector,
+) -> Result<Option<Check>> {
     if let [_, exc, tb] = args {
         let check = replace_by_raise_from(
             Some(ExprKind::Call {
@@ -200,6 +220,7 @@ fn handle_reraise(args: &[Expr], expr: &Expr, patch: bool) -> Result<Option<Chec
             None,
             expr,
             patch,
+            stylist,
         )?;
         Ok(Some(check))
     } else if let [arg] = args {
@@ -208,7 +229,7 @@ fn handle_reraise(args: &[Expr], expr: &Expr, patch: bool) -> Result<Option<Chec
                 if let ExprKind::Attribute { value, attr, .. } = &func.node {
                     if let ExprKind::Name { id, .. } = &value.node {
                         if id == "sys" && attr == "exc_info" {
-                            let check = replace_by_raise_from(None, None, expr, patch)?;
+                            let check = replace_by_raise_from(None, None, expr, patch, stylist)?;
                             return Ok(Some(check));
                         };
                     };
@@ -227,6 +248,7 @@ fn handle_func(
     keywords: &[Keyword],
     expr: &Expr,
     patch: bool,
+    stylist: &SourceCodeStyleDetector,
     locator: &SourceCodeLocator,
 ) -> Result<Option<Check>> {
     let func_name = match &func.node {
@@ -241,72 +263,82 @@ fn handle_func(
         ("ensure_str", [arg], []) => replace_by_str_literal(arg, false, expr, patch, locator),
         ("ensure_text", [arg], []) => replace_by_str_literal(arg, false, expr, patch, locator),
         ("iteritems", args, []) => {
-            replace_call_on_arg_by_arg_method_call("items", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("items", args, expr, patch, stylist)?
         }
         ("viewitems", args, []) => {
-            replace_call_on_arg_by_arg_method_call("items", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("items", args, expr, patch, stylist)?
         }
         ("iterkeys", args, []) => {
-            replace_call_on_arg_by_arg_method_call("keys", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("keys", args, expr, patch, stylist)?
         }
         ("viewkeys", args, []) => {
-            replace_call_on_arg_by_arg_method_call("keys", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("keys", args, expr, patch, stylist)?
         }
         ("itervalues", args, []) => {
-            replace_call_on_arg_by_arg_method_call("values", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("values", args, expr, patch, stylist)?
         }
         ("viewvalues", args, []) => {
-            replace_call_on_arg_by_arg_method_call("values", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("values", args, expr, patch, stylist)?
         }
         ("get_method_function", [arg], []) => Some(replace_call_on_arg_by_arg_attribute(
-            "__func__", arg, expr, patch,
+            "__func__", arg, expr, patch, stylist,
         )?),
         ("get_method_self", [arg], []) => Some(replace_call_on_arg_by_arg_attribute(
-            "__self__", arg, expr, patch,
+            "__self__", arg, expr, patch, stylist,
         )?),
         ("get_function_closure", [arg], []) => Some(replace_call_on_arg_by_arg_attribute(
             "__closure__",
             arg,
             expr,
             patch,
+            stylist,
         )?),
         ("get_function_code", [arg], []) => Some(replace_call_on_arg_by_arg_attribute(
-            "__code__", arg, expr, patch,
+            "__code__", arg, expr, patch, stylist,
         )?),
         ("get_function_defaults", [arg], []) => Some(replace_call_on_arg_by_arg_attribute(
             "__defaults__",
             arg,
             expr,
             patch,
+            stylist,
         )?),
         ("get_function_globals", [arg], []) => Some(replace_call_on_arg_by_arg_attribute(
             "__globals__",
             arg,
             expr,
             patch,
+            stylist,
+        )?),
+        ("create_unbound_method", [arg, _], _) => Some(replace_by_expr_kind(
+            arg.node.clone(),
+            expr,
+            patch,
+            stylist,
+        )?),
+        ("get_unbound_function", [arg], []) => Some(replace_by_expr_kind(
+            arg.node.clone(),
+            expr,
+            patch,
+            stylist,
         )?),
-        ("create_unbound_method", [arg, _], _) => {
-            Some(replace_by_expr_kind(arg.node.clone(), expr, patch)?)
-        }
-        ("get_unbound_function", [arg], []) => {
-            Some(replace_by_expr_kind(arg.node.clone(), expr, patch)?)
-        }
         ("assertCountEqual", args, []) => {
-            replace_call_on_arg_by_arg_method_call("assertCountEqual", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("assertCountEqual", args, expr, patch, stylist)?
         }
         ("assertRaisesRegex", args, []) => {
-            replace_call_on_arg_by_arg_method_call("assertRaisesRegex", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("assertRaisesRegex", args, expr, patch, stylist)?
         }
         ("assertRegex", args, []) => {
-            replace_call_on_arg_by_arg_method_call("assertRegex", args, expr, patch)?
+            replace_call_on_arg_by_arg_method_call("assertRegex", args, expr, patch, stylist)?
         }
         ("raise_from", [exc, cause], []) => Some(replace_by_raise_from(
             Some(exc.node.clone()),
             Some(cause.node.clone()),
             expr,
             patch,
+            stylist,
         )?),
-        ("reraise", args, []) => handle_reraise(args, expr, patch)?,
+        ("reraise", args, []) => handle_reraise(args, expr, patch, stylist)?,
         ("byte2int", [arg], []) => Some(replace_by_index_on_arg(
             arg,
             &ExprKind::Constant {
@@ -315,10 +347,15 @@ fn handle_func(
             },
             expr,
             patch,
+            stylist,
+        )?),
+        ("indexbytes", [arg, index], []) => Some(replace_by_index_on_arg(
+            arg,
+            &index.node,
+            expr,
+            patch,
+            stylist,
         )?),
-        ("indexbytes", [arg, index], []) => {
-            Some(replace_by_index_on_arg(arg, &index.node, expr, patch)?)
-        }
         ("int2byte", [arg], []) => Some(replace_by_expr_kind(
             ExprKind::Call {
                 func: Box::new(create_expr(ExprKind::Name {
@@ -333,6 +370,7 @@ fn handle_func(
             },
             expr,
             patch,
+            stylist,
         )?),
         _ => None,
     };
@@ -382,6 +420,7 @@ fn handle_next_on_six_dict(expr: &Expr, patch: bool, checker: &Checker) -> Resul
         },
         arg,
         patch,
+        checker.style,
     ) {
         Ok(check) => Ok(Some(check)),
         Err(err) => Err(err),
@@ -409,7 +448,15 @@ pub fn remove_six_compat(checker: &mut Checker, expr: &Expr) {
                 func,
                 args,
                 keywords,
-            } => match handle_func(func, args, keywords, expr, patch, checker.locator) {
+            } => match handle_func(
+                func,
+                args,
+                keywords,
+                expr,
+                patch,
+                checker.style,
+                checker.locator,
+            ) {
                 Ok(check) => check,
                 Err(err) => {
                     error!("Failed to remove `six` reference: {err}");

src/pyupgrade/plugins/replace_stdout_stderr.rs

@@ -0,0 +1,112 @@
+use rustpython_ast::{Expr, Keyword};
+
+use crate::ast::helpers::{find_keyword, match_module_member};
+use crate::ast::types::Range;
+use crate::ast::whitespace::indentation;
+use crate::autofix::Fix;
+use crate::checkers::ast::Checker;
+use crate::checks::{Check, CheckKind};
+
+#[derive(Debug)]
+struct MiddleContent<'a> {
+    contents: &'a str,
+    multi_line: bool,
+}
+
+/// Return the number of "dirty" characters.
+fn dirty_count(iter: impl Iterator<Item = char>) -> usize {
+    let mut the_count = 0;
+    for current_char in iter {
+        if current_char == ' ' || current_char == ',' || current_char == '\n' {
+            the_count += 1;
+        } else {
+            break;
+        }
+    }
+    the_count
+}
+
+/// Extract the `Middle` content between two arguments.
+fn extract_middle(contents: &str) -> Option<MiddleContent> {
+    let multi_line = contents.contains('\n');
+    let start_gap = dirty_count(contents.chars());
+    if contents.len() == start_gap {
+        return None;
+    }
+    let end_gap = dirty_count(contents.chars().rev());
+    Some(MiddleContent {
+        contents: &contents[start_gap..contents.len() - end_gap],
+        multi_line,
+    })
+}
+
+/// UP022
+pub fn replace_stdout_stderr(checker: &mut Checker, expr: &Expr, kwargs: &[Keyword]) {
+    if match_module_member(
+        expr,
+        "subprocess",
+        "run",
+        &checker.from_imports,
+        &checker.import_aliases,
+    ) {
+        // Find `stdout` and `stderr` kwargs.
+        let Some(stdout) = find_keyword(kwargs, "stdout") else {
+            return;
+        };
+        let Some(stderr) = find_keyword(kwargs, "stderr") else {
+            return;
+        };
+
+        // Verify that they're both set to `subprocess.PIPE`.
+        if !match_module_member(
+            &stdout.node.value,
+            "subprocess",
+            "PIPE",
+            &checker.from_imports,
+            &checker.import_aliases,
+        ) || !match_module_member(
+            &stderr.node.value,
+            "subprocess",
+            "PIPE",
+            &checker.from_imports,
+            &checker.import_aliases,
+        ) {
+            return;
+        }
+
+        let mut check = Check::new(CheckKind::ReplaceStdoutStderr, Range::from_located(expr));
+        if checker.patch(check.kind.code()) {
+            let first = if stdout.location < stderr.location {
+                stdout
+            } else {
+                stderr
+            };
+            let last = if stdout.location > stderr.location {
+                stdout
+            } else {
+                stderr
+            };
+            let mut contents = String::from("capture_output=True");
+            if let Some(middle) = extract_middle(&checker.locator.slice_source_code_range(&Range {
+                location: first.end_location.unwrap(),
+                end_location: last.location,
+            })) {
+                if middle.multi_line {
+                    contents.push(',');
+                    contents.push('\n');
+                    contents.push_str(&indentation(checker, first));
+                } else {
+                    contents.push(',');
+                    contents.push(' ');
+                }
+                contents.push_str(middle.contents);
+            }
+            check.amend(Fix::replacement(
+                contents,
+                first.location,
+                last.end_location.unwrap(),
+            ));
+        }
+        checker.add_check(check);
+    }
+}

src/pyupgrade/plugins/rewrite_c_element_tree.rs

@@ -0,0 +1,57 @@
+use rustpython_ast::{Located, Stmt, StmtKind};
+
+use crate::ast::types::Range;
+use crate::autofix::Fix;
+use crate::checkers::ast::Checker;
+use crate::checks::{Check, CheckKind};
+
+fn add_check_for_node<T>(checker: &mut Checker, node: &Located<T>) {
+    let mut check = Check::new(CheckKind::RewriteCElementTree, Range::from_located(node));
+    if checker.patch(check.kind.code()) {
+        let contents = checker
+            .locator
+            .slice_source_code_range(&Range::from_located(node));
+        check.amend(Fix::replacement(
+            contents.replacen("cElementTree", "ElementTree", 1),
+            node.location,
+            node.end_location.unwrap(),
+        ));
+    }
+    checker.add_check(check);
+}
+
+/// UP023
+pub fn replace_c_element_tree(checker: &mut Checker, stmt: &Stmt) {
+    match &stmt.node {
+        StmtKind::Import { names } => {
+            // Ex) `import xml.etree.cElementTree as ET`
+            for name in names {
+                if name.node.name == "xml.etree.cElementTree" && name.node.asname.is_some() {
+                    add_check_for_node(checker, name);
+                }
+            }
+        }
+        StmtKind::ImportFrom {
+            module,
+            names,
+            level,
+        } => {
+            if level.map_or(false, |level| level > 0) {
+                // Ex) `import .xml.etree.cElementTree as ET`
+            } else if let Some(module) = module {
+                if module == "xml.etree.cElementTree" {
+                    // Ex) `from xml.etree.cElementTree import XML`
+                    add_check_for_node(checker, stmt);
+                } else if module == "xml.etree" {
+                    // Ex) `from xml.etree import cElementTree as ET`
+                    for name in names {
+                        if name.node.name == "cElementTree" && name.node.asname.is_some() {
+                            add_check_for_node(checker, name);
+                        }
+                    }
+                }
+            }
+        }
+        _ => unreachable!("Expected StmtKind::Import | StmtKind::ImportFrom"),
+    }
+}

src/pyupgrade/plugins/use_pep604_annotation.rs

@@ -5,7 +5,7 @@ use crate::ast::types::Range;
 use crate::autofix::Fix;
 use crate::checkers::ast::Checker;
 use crate::checks::{Check, CheckKind};
-use crate::code_gen::SourceGenerator;
+use crate::source_code_generator::SourceCodeGenerator;
 
 fn optional(expr: &Expr) -> Expr {
     Expr::new(
@@ -65,7 +65,8 @@ pub fn use_pep604_annotation(checker: &mut Checker, expr: &Expr, value: &Expr, s
     if checker.match_typing_call_path(&call_path, "Optional") {
         let mut check = Check::new(CheckKind::UsePEP604Annotation, Range::from_located(expr));
         if checker.patch(check.kind.code()) {
-            let mut generator = SourceGenerator::new();
+            let mut generator =
+                SourceCodeGenerator::new(checker.style.indentation(), checker.style.quote());
             generator.unparse_expr(&optional(slice), 0);
             if let Ok(content) = generator.generate() {
                 check.amend(Fix::replacement(
@@ -84,7 +85,10 @@ pub fn use_pep604_annotation(checker: &mut Checker, expr: &Expr, value: &Expr, s
                     // Invalid type annotation.
                 }
                 ExprKind::Tuple { elts, .. } => {
-                    let mut generator = SourceGenerator::new();
+                    let mut generator = SourceCodeGenerator::new(
+                        checker.style.indentation(),
+                        checker.style.quote(),
+                    );
                     generator.unparse_expr(&union(elts), 0);
                     if let Ok(content) = generator.generate() {
                         check.amend(Fix::replacement(
@@ -96,7 +100,10 @@ pub fn use_pep604_annotation(checker: &mut Checker, expr: &Expr, value: &Expr, s
                 }
                 _ => {
                     // Single argument.
-                    let mut generator = SourceGenerator::new();
+                    let mut generator = SourceCodeGenerator::new(
+                        checker.style.indentation(),
+                        checker.style.quote(),
+                    );
                     generator.unparse_expr(slice, 0);
                     if let Ok(content) = generator.generate() {
                         check.amend(Fix::replacement(

src/pyupgrade/snapshots/ruff__pyupgrade__tests__UP013_UP013.py.snap

@@ -75,7 +75,7 @@ expression: checks
     row: 17
     column: 46
   fix:
-    content: "class MyType5(TypedDict):\n    a: 'hello'"
+    content: "class MyType5(TypedDict):\n    a: \"hello\""
     location:
       row: 17
       column: 0
@@ -91,7 +91,7 @@ expression: checks
     row: 18
     column: 41
   fix:
-    content: "class MyType6(TypedDict):\n    a: 'hello'"
+    content: "class MyType6(TypedDict):\n    a: \"hello\""
     location:
       row: 18
       column: 0
@@ -139,7 +139,7 @@ expression: checks
     row: 30
     column: 59
   fix:
-    content: "class MyType10(TypedDict):\n    key: Literal['value']"
+    content: "class MyType10(TypedDict):\n    key: Literal[\"value\"]"
     location:
       row: 30
       column: 0

src/pyupgrade/snapshots/ruff__pyupgrade__tests__UP014_UP014.py.snap

@@ -27,7 +27,7 @@ expression: checks
     row: 12
     column: 1
   fix:
-    content: "class NT2(NamedTuple):\n    a: int\n    b: str = 'foo'\n    c: list[bool] = [True]"
+    content: "class NT2(NamedTuple):\n    a: int\n    b: str = \"foo\"\n    c: list[bool] = [True]"
     location:
       row: 8
       column: 0

src/pyupgrade/snapshots/ruff__pyupgrade__tests__UP022_UP022.py.snap

@@ -0,0 +1,110 @@
+---
+source: src/pyupgrade/mod.rs
+expression: checks
+---
+- kind: ReplaceStdoutStderr
+  location:
+    row: 4
+    column: 9
+  end_location:
+    row: 4
+    column: 69
+  fix:
+    content: capture_output=True
+    location:
+      row: 4
+      column: 22
+    end_location:
+      row: 4
+      column: 68
+- kind: ReplaceStdoutStderr
+  location:
+    row: 6
+    column: 9
+  end_location:
+    row: 6
+    column: 80
+  fix:
+    content: capture_output=True
+    location:
+      row: 6
+      column: 33
+    end_location:
+      row: 6
+      column: 79
+- kind: ReplaceStdoutStderr
+  location:
+    row: 8
+    column: 9
+  end_location:
+    row: 8
+    column: 86
+  fix:
+    content: "capture_output=True, args=[\"foo\"]"
+    location:
+      row: 8
+      column: 24
+    end_location:
+      row: 8
+      column: 85
+- kind: ReplaceStdoutStderr
+  location:
+    row: 10
+    column: 9
+  end_location:
+    row: 12
+    column: 1
+  fix:
+    content: "capture_output=True, check=True"
+    location:
+      row: 11
+      column: 13
+    end_location:
+      row: 11
+      column: 71
+- kind: ReplaceStdoutStderr
+  location:
+    row: 14
+    column: 9
+  end_location:
+    row: 16
+    column: 1
+  fix:
+    content: "capture_output=True, check=True"
+    location:
+      row: 15
+      column: 13
+    end_location:
+      row: 15
+      column: 71
+- kind: ReplaceStdoutStderr
+  location:
+    row: 18
+    column: 9
+  end_location:
+    row: 26
+    column: 1
+  fix:
+    content: "capture_output=True,\n    check=True"
+    location:
+      row: 20
+      column: 4
+    end_location:
+      row: 22
+      column: 26
+- kind: ReplaceStdoutStderr
+  location:
+    row: 29
+    column: 13
+  end_location:
+    row: 36
+    column: 5
+  fix:
+    content: "capture_output=True,\n        check=True"
+    location:
+      row: 31
+      column: 8
+    end_location:
+      row: 33
+      column: 30
+

src/pyupgrade/snapshots/ruff__pyupgrade__tests__UP023_UP023.py.snap

@@ -0,0 +1,155 @@
+---
+source: src/pyupgrade/mod.rs
+expression: checks
+---
+- kind: RewriteCElementTree
+  location:
+    row: 2
+    column: 0
+  end_location:
+    row: 2
+    column: 59
+  fix:
+    content: "from xml.etree.ElementTree import XML, Element, SubElement"
+    location:
+      row: 2
+      column: 0
+    end_location:
+      row: 2
+      column: 59
+- kind: RewriteCElementTree
+  location:
+    row: 3
+    column: 7
+  end_location:
+    row: 3
+    column: 35
+  fix:
+    content: xml.etree.ElementTree as ET
+    location:
+      row: 3
+      column: 7
+    end_location:
+      row: 3
+      column: 35
+- kind: RewriteCElementTree
+  location:
+    row: 6
+    column: 0
+  end_location:
+    row: 6
+    column: 44
+  fix:
+    content: from   xml.etree.ElementTree    import  XML
+    location:
+      row: 6
+      column: 0
+    end_location:
+      row: 6
+      column: 44
+- kind: RewriteCElementTree
+  location:
+    row: 7
+    column: 10
+  end_location:
+    row: 7
+    column: 49
+  fix:
+    content: xml.etree.ElementTree       as      ET
+    location:
+      row: 7
+      column: 10
+    end_location:
+      row: 7
+      column: 49
+- kind: RewriteCElementTree
+  location:
+    row: 10
+    column: 0
+  end_location:
+    row: 14
+    column: 1
+  fix:
+    content: "from xml.etree.ElementTree import (\n    XML,\n    Element,\n    SubElement,\n)"
+    location:
+      row: 10
+      column: 0
+    end_location:
+      row: 14
+      column: 1
+- kind: RewriteCElementTree
+  location:
+    row: 16
+    column: 11
+  end_location:
+    row: 16
+    column: 39
+  fix:
+    content: xml.etree.ElementTree as ET
+    location:
+      row: 16
+      column: 11
+    end_location:
+      row: 16
+      column: 39
+- kind: RewriteCElementTree
+  location:
+    row: 17
+    column: 26
+  end_location:
+    row: 17
+    column: 45
+  fix:
+    content: ElementTree as CET
+    location:
+      row: 17
+      column: 26
+    end_location:
+      row: 17
+      column: 45
+- kind: RewriteCElementTree
+  location:
+    row: 19
+    column: 22
+  end_location:
+    row: 19
+    column: 40
+  fix:
+    content: ElementTree as ET
+    location:
+      row: 19
+      column: 22
+    end_location:
+      row: 19
+      column: 40
+- kind: RewriteCElementTree
+  location:
+    row: 21
+    column: 19
+  end_location:
+    row: 21
+    column: 47
+  fix:
+    content: xml.etree.ElementTree as ET
+    location:
+      row: 21
+      column: 19
+    end_location:
+      row: 21
+      column: 47
+- kind: RewriteCElementTree
+  location:
+    row: 24
+    column: 31
+  end_location:
+    row: 24
+    column: 59
+  fix:
+    content: xml.etree.ElementTree as ET
+    location:
+      row: 24
+      column: 31
+    end_location:
+      row: 24
+      column: 59
+

src/ruff/checks.rs

@@ -1,6 +1,6 @@
 use once_cell::sync::Lazy;
 use rustc_hash::FxHashMap;
-use rustpython_ast::Location;
+use rustpython_ast::{Expr, ExprKind, Keyword, KeywordData, Location};
 
 use crate::ast::types::Range;
 use crate::autofix::Fix;
@@ -1680,3 +1680,25 @@ pub fn ambiguous_unicode_character(
 
     checks
 }
+
+/// RUF004
+pub fn keyword_argument_before_star_argument(args: &[Expr], keywords: &[Keyword]) -> Vec<Check> {
+    let mut checks = vec![];
+    if let Some(arg) = args
+        .iter()
+        .rfind(|arg| matches!(arg.node, ExprKind::Starred { .. }))
+    {
+        for keyword in keywords {
+            if keyword.location < arg.location {
+                let KeywordData { arg, .. } = &keyword.node;
+                if let Some(arg) = arg {
+                    checks.push(Check::new(
+                        CheckKind::KeywordArgumentBeforeStarArgument(arg.to_string()),
+                        Range::from_located(keyword),
+                    ));
+                }
+            }
+        }
+    }
+    checks
+}

src/ruff/mod.rs

@@ -8,10 +8,24 @@ mod tests {
 
     use anyhow::Result;
     use rustc_hash::FxHashSet;
+    use test_case::test_case;
 
     use crate::checks::CheckCode;
     use crate::linter::test_path;
     use crate::settings;
+    #[test_case(CheckCode::RUF004, Path::new("RUF004.py"); "RUF004")]
+    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/ruff")
+                .join(path)
+                .as_path(),
+            &settings::Settings::for_rule(check_code),
+        )?;
+        checks.sort_by_key(|check| check.location);
+        insta::assert_yaml_snapshot!(snapshot, checks);
+        Ok(())
+    }
 
     #[test]
     fn confusables() -> Result<()> {

src/ruff/snapshots/ruff__ruff__tests__RUF004_RUF004.py.snap

@@ -0,0 +1,32 @@
+---
+source: src/ruff/mod.rs
+expression: checks
+---
+- kind:
+    KeywordArgumentBeforeStarArgument: kw
+  location:
+    row: 13
+    column: 2
+  end_location:
+    row: 13
+    column: 6
+  fix: ~
+- kind:
+    KeywordArgumentBeforeStarArgument: kw
+  location:
+    row: 14
+    column: 2
+  end_location:
+    row: 14
+    column: 6
+  fix: ~
+- kind:
+    KeywordArgumentBeforeStarArgument: kw
+  location:
+    row: 15
+    column: 6
+  end_location:
+    row: 15
+    column: 10
+  fix: ~
+

src/settings/configuration.rs

@@ -28,6 +28,7 @@ use crate::{
 #[derive(Debug, Default)]
 pub struct Configuration {
     pub allowed_confusables: Option<Vec<char>>,
+    pub cache_dir: Option<PathBuf>,
     pub dummy_variable_rgx: Option<Regex>,
     pub exclude: Option<Vec<FilePattern>>,
     pub extend: Option<PathBuf>,
@@ -38,8 +39,8 @@ pub struct Configuration {
     pub fix: Option<bool>,
     pub fix_only: Option<bool>,
     pub fixable: Option<Vec<CheckCodePrefix>>,
-    pub format: Option<SerializationFormat>,
     pub force_exclude: Option<bool>,
+    pub format: Option<SerializationFormat>,
     pub ignore: Option<Vec<CheckCodePrefix>>,
     pub ignore_init_module_imports: Option<bool>,
     pub line_length: Option<usize>,
@@ -51,7 +52,7 @@ pub struct Configuration {
     pub src: Option<Vec<PathBuf>>,
     pub target_version: Option<PythonVersion>,
     pub unfixable: Option<Vec<CheckCodePrefix>>,
-    pub cache_dir: Option<PathBuf>,
+    pub update_check: Option<bool>,
     // Plugins
     pub flake8_annotations: Option<flake8_annotations::settings::Options>,
     pub flake8_bugbear: Option<flake8_bugbear::settings::Options>,
@@ -75,6 +76,14 @@ impl Configuration {
     pub fn from_options(options: Options, project_root: &Path) -> Result<Self> {
         Ok(Configuration {
             allowed_confusables: options.allowed_confusables,
+            cache_dir: options
+                .cache_dir
+                .map(|dir| {
+                    let dir = shellexpand::full(&dir);
+                    dir.map(|dir| PathBuf::from(dir.as_ref()))
+                })
+                .transpose()
+                .map_err(|e| anyhow!("Invalid `cache-dir` value: {e}"))?,
             dummy_variable_rgx: options
                 .dummy_variable_rgx
                 .map(|pattern| Regex::new(&pattern))
@@ -139,14 +148,7 @@ impl Configuration {
                 .transpose()?,
             target_version: options.target_version,
             unfixable: options.unfixable,
-            cache_dir: options
-                .cache_dir
-                .map(|dir| {
-                    let dir = shellexpand::full(&dir);
-                    dir.map(|dir| PathBuf::from(dir.as_ref()))
-                })
-                .transpose()
-                .map_err(|e| anyhow!("Invalid `cache-dir` value: {e}"))?,
+            update_check: options.update_check,
             // Plugins
             flake8_annotations: options.flake8_annotations,
             flake8_bugbear: options.flake8_bugbear,
@@ -167,6 +169,7 @@ impl Configuration {
     pub fn combine(self, config: Configuration) -> Self {
         Self {
             allowed_confusables: self.allowed_confusables.or(config.allowed_confusables),
+            cache_dir: self.cache_dir.or(config.cache_dir),
             dummy_variable_rgx: self.dummy_variable_rgx.or(config.dummy_variable_rgx),
             exclude: self.exclude.or(config.exclude),
             extend: self.extend.or(config.extend),
@@ -204,7 +207,7 @@ impl Configuration {
             src: self.src.or(config.src),
             target_version: self.target_version.or(config.target_version),
             unfixable: self.unfixable.or(config.unfixable),
-            cache_dir: self.cache_dir.or(config.cache_dir),
+            update_check: self.update_check.or(config.update_check),
             // Plugins
             flake8_annotations: self.flake8_annotations.or(config.flake8_annotations),
             flake8_bugbear: self.flake8_bugbear.or(config.flake8_bugbear),
@@ -226,6 +229,9 @@ impl Configuration {
     }
 
     pub fn apply(&mut self, overrides: Overrides) {
+        if let Some(cache_dir) = overrides.cache_dir {
+            self.cache_dir = Some(cache_dir);
+        }
         if let Some(dummy_variable_rgx) = overrides.dummy_variable_rgx {
             self.dummy_variable_rgx = Some(dummy_variable_rgx);
         }
@@ -279,8 +285,8 @@ impl Configuration {
         if let Some(unfixable) = overrides.unfixable {
             self.unfixable = Some(unfixable);
         }
-        if let Some(cache_dir) = overrides.cache_dir {
-            self.cache_dir = Some(cache_dir);
+        if let Some(update_check) = overrides.update_check {
+            self.update_check = Some(update_check);
         }
         // Special-case: `extend_ignore` and `extend_select` are parallel arrays, so
         // push an empty array if only one of the two is provided.

src/settings/flags.rs

@@ -1,7 +1,7 @@
 /// Simple flags used to drive program behavior.
 use crate::autofix::fixer;
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Hash)]
 pub enum Autofix {
     Enabled,
     Disabled,
@@ -20,13 +20,13 @@ impl From<bool> for Autofix {
 impl From<fixer::Mode> for Autofix {
     fn from(value: fixer::Mode) -> Self {
         match value {
-            fixer::Mode::Generate | fixer::Mode::Apply => Autofix::Enabled,
+            fixer::Mode::Generate | fixer::Mode::Diff | fixer::Mode::Apply => Autofix::Enabled,
             fixer::Mode::None => Autofix::Disabled,
         }
     }
 }
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Hash)]
 pub enum Noqa {
     Enabled,
     Disabled,
@@ -42,7 +42,7 @@ impl From<bool> for Noqa {
     }
 }
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Hash)]
 pub enum Cache {
     Enabled,
     Disabled,

src/settings/mod.rs

@@ -39,6 +39,7 @@ const CARGO_PKG_VERSION: &str = env!("CARGO_PKG_VERSION");
 #[allow(clippy::struct_excessive_bools)]
 pub struct Settings {
     pub allowed_confusables: FxHashSet<char>,
+    pub cache_dir: PathBuf,
     pub dummy_variable_rgx: Regex,
     pub enabled: FxHashSet<CheckCode>,
     pub exclude: GlobSet,
@@ -47,8 +48,8 @@ pub struct Settings {
     pub fix: bool,
     pub fix_only: bool,
     pub fixable: FxHashSet<CheckCode>,
-    pub format: SerializationFormat,
     pub force_exclude: bool,
+    pub format: SerializationFormat,
     pub ignore_init_module_imports: bool,
     pub line_length: usize,
     pub per_file_ignores: Vec<(GlobMatcher, GlobMatcher, FxHashSet<CheckCode>)>,
@@ -57,7 +58,7 @@ pub struct Settings {
     pub show_source: bool,
     pub src: Vec<PathBuf>,
     pub target_version: PythonVersion,
-    pub cache_dir: PathBuf,
+    pub update_check: bool,
     // Plugins
     pub flake8_annotations: flake8_annotations::settings::Settings,
     pub flake8_bugbear: flake8_bugbear::settings::Settings,
@@ -107,6 +108,7 @@ impl Settings {
                 .allowed_confusables
                 .map(FxHashSet::from_iter)
                 .unwrap_or_default(),
+            cache_dir: config.cache_dir.unwrap_or_else(|| cache_dir(project_root)),
             dummy_variable_rgx: config
                 .dummy_variable_rgx
                 .unwrap_or_else(|| DEFAULT_DUMMY_VARIABLE_RGX.clone()),
@@ -138,7 +140,7 @@ impl Settings {
                 }]
                 .into_iter(),
             ),
-            format: config.format.unwrap_or(SerializationFormat::Text),
+            format: config.format.unwrap_or_default(),
             force_exclude: config.force_exclude.unwrap_or(false),
             ignore_init_module_imports: config.ignore_init_module_imports.unwrap_or_default(),
             line_length: config.line_length.unwrap_or(88),
@@ -147,12 +149,12 @@ impl Settings {
             )?,
             respect_gitignore: config.respect_gitignore.unwrap_or(true),
             required_version: config.required_version,
+            show_source: config.show_source.unwrap_or_default(),
             src: config
                 .src
                 .unwrap_or_else(|| vec![project_root.to_path_buf()]),
             target_version: config.target_version.unwrap_or(PythonVersion::Py310),
-            show_source: config.show_source.unwrap_or_default(),
-            cache_dir: config.cache_dir.unwrap_or_else(|| cache_dir(project_root)),
+            update_check: config.update_check.unwrap_or(true),
             // Plugins
             flake8_annotations: config
                 .flake8_annotations
@@ -210,6 +212,7 @@ impl Settings {
     pub fn for_rule(check_code: CheckCode) -> Self {
         Self {
             allowed_confusables: FxHashSet::from_iter([]),
+            cache_dir: cache_dir(path_dedot::CWD.as_path()),
             dummy_variable_rgx: Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap(),
             enabled: FxHashSet::from_iter([check_code.clone()]),
             exclude: GlobSet::empty(),
@@ -218,8 +221,8 @@ impl Settings {
             fix: false,
             fix_only: false,
             fixable: FxHashSet::from_iter([check_code]),
-            format: SerializationFormat::Text,
             force_exclude: false,
+            format: SerializationFormat::Text,
             ignore_init_module_imports: false,
             line_length: 88,
             per_file_ignores: vec![],
@@ -228,7 +231,7 @@ impl Settings {
             show_source: false,
             src: vec![path_dedot::CWD.clone()],
             target_version: PythonVersion::Py310,
-            cache_dir: cache_dir(path_dedot::CWD.as_path()),
+            update_check: false,
             flake8_annotations: flake8_annotations::settings::Settings::default(),
             flake8_bugbear: flake8_bugbear::settings::Settings::default(),
             flake8_errmsg: flake8_errmsg::settings::Settings::default(),
@@ -247,6 +250,7 @@ impl Settings {
     pub fn for_rules(check_codes: Vec<CheckCode>) -> Self {
         Self {
             allowed_confusables: FxHashSet::from_iter([]),
+            cache_dir: cache_dir(path_dedot::CWD.as_path()),
             dummy_variable_rgx: Regex::new("^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$").unwrap(),
             enabled: FxHashSet::from_iter(check_codes.clone()),
             exclude: GlobSet::empty(),
@@ -255,8 +259,8 @@ impl Settings {
             fix: false,
             fix_only: false,
             fixable: FxHashSet::from_iter(check_codes),
-            format: SerializationFormat::Text,
             force_exclude: false,
+            format: SerializationFormat::Text,
             ignore_init_module_imports: false,
             line_length: 88,
             per_file_ignores: vec![],
@@ -265,7 +269,7 @@ impl Settings {
             show_source: false,
             src: vec![path_dedot::CWD.clone()],
             target_version: PythonVersion::Py310,
-            cache_dir: cache_dir(path_dedot::CWD.as_path()),
+            update_check: false,
             flake8_annotations: flake8_annotations::settings::Settings::default(),
             flake8_bugbear: flake8_bugbear::settings::Settings::default(),
             flake8_errmsg: flake8_errmsg::settings::Settings::default(),
@@ -379,6 +383,7 @@ fn resolve_codes<'a>(specs: impl Iterator<Item = CheckCodeSpec<'a>>) -> FxHashSe
     let mut codes: FxHashSet<CheckCode> = FxHashSet::default();
     for spec in specs {
         for specificity in [
+            SuffixLength::None,
             SuffixLength::Zero,
             SuffixLength::One,
             SuffixLength::Two,

src/settings/options.rs

@@ -30,6 +30,22 @@ pub struct Options {
     /// A list of allowed "confusable" Unicode characters to ignore when
     /// enforcing `RUF001`, `RUF002`, and `RUF003`.
     pub allowed_confusables: Option<Vec<char>>,
+    #[option(
+        default = ".ruff_cache",
+        value_type = "PathBuf",
+        example = r#"cache-dir = "~/.cache/ruff""#
+    )]
+    /// A path to the cache directory.
+    ///
+    /// By default, Ruff stores cache results in a `.ruff_cache` directory in
+    /// the current project root.
+    ///
+    /// However, Ruff will also respect the `RUFF_CACHE_DIR` environment
+    /// variable, which takes precedence over that default.
+    ///
+    /// This setting will override even the `RUFF_CACHE_DIR` environment
+    /// variable, if set.
+    pub cache_dir: Option<String>,
     #[option(
         default = r#""^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$""#,
         value_type = "Regex",
@@ -156,8 +172,9 @@ pub struct Options {
     )]
     /// The style in which violation messages should be formatted: `"text"`
     /// (default), `"grouped"` (group messages by file), `"json"`
-    /// (machine-readable), `"junit"` (machine-readable XML), or `"github"`
-    /// (GitHub Actions annotations).
+    /// (machine-readable), `"junit"` (machine-readable XML), `"github"`
+    /// (GitHub Actions annotations) or `"gitlab"`
+    /// (GitLab CI code quality report).
     pub format: Option<SerializationFormat>,
     #[option(
         default = r#"false"#,
@@ -323,22 +340,13 @@ pub struct Options {
     /// A list of check code prefixes to consider un-autofix-able.
     pub unfixable: Option<Vec<CheckCodePrefix>>,
     #[option(
-        default = ".ruff_cache",
-        value_type = "PathBuf",
-        example = r#"cache-dir = "~/.cache/ruff""#
+        default = "true",
+        value_type = "bool",
+        example = "update-check = false"
     )]
-    /// A path to the cache directory.
-    ///
-    /// By default, Ruff stores cache results in a `.ruff_cache` directory in
-    /// the current project root.
-    ///
-    /// However, Ruff will also respect the `RUFF_CACHE_DIR` environment
-    /// variable, which takes precedence over that default.
-    ///
-    /// This setting will override even the `RUFF_CACHE_DIR` environment
-    /// variable, if set.
-    pub cache_dir: Option<String>,
-    /// Plugins
+    /// Enable or disable automatic update checks (overridden by the
+    /// `--update-check` and `--no-update-check` command-line flags).
+    pub update_check: Option<bool>,
     #[option_group]
     /// Options for the `flake8-annotations` plugin.
     pub flake8_annotations: Option<flake8_annotations::settings::Options>,

src/settings/pyproject.rs

@@ -164,6 +164,7 @@ mod tests {
             Some(Tools {
                 ruff: Some(Options {
                     allowed_confusables: None,
+                    cache_dir: None,
                     dummy_variable_rgx: None,
                     exclude: None,
                     extend: None,
@@ -174,20 +175,20 @@ mod tests {
                     fix: None,
                     fix_only: None,
                     fixable: None,
-                    format: None,
                     force_exclude: None,
+                    format: None,
                     ignore: None,
                     ignore_init_module_imports: None,
                     line_length: None,
                     per_file_ignores: None,
-                    respect_gitignore: None,
                     required_version: None,
+                    respect_gitignore: None,
                     select: None,
                     show_source: None,
                     src: None,
                     target_version: None,
                     unfixable: None,
-                    cache_dir: None,
+                    update_check: None,
                     flake8_annotations: None,
                     flake8_bugbear: None,
                     flake8_errmsg: None,
@@ -239,6 +240,7 @@ line-length = 79
                     src: None,
                     target_version: None,
                     unfixable: None,
+                    update_check: None,
                     cache_dir: None,
                     flake8_annotations: None,
                     flake8_bugbear: None,
@@ -268,6 +270,7 @@ exclude = ["foo.py"]
             Some(Tools {
                 ruff: Some(Options {
                     allowed_confusables: None,
+                    cache_dir: None,
                     dummy_variable_rgx: None,
                     exclude: Some(vec!["foo.py".to_string()]),
                     extend: None,
@@ -284,14 +287,14 @@ exclude = ["foo.py"]
                     ignore_init_module_imports: None,
                     line_length: None,
                     per_file_ignores: None,
-                    respect_gitignore: None,
                     required_version: None,
+                    respect_gitignore: None,
                     select: None,
                     show_source: None,
                     src: None,
                     target_version: None,
                     unfixable: None,
-                    cache_dir: None,
+                    update_check: None,
                     flake8_annotations: None,
                     flake8_errmsg: None,
                     flake8_bugbear: None,
@@ -320,6 +323,7 @@ select = ["E501"]
             Some(Tools {
                 ruff: Some(Options {
                     allowed_confusables: None,
+                    cache_dir: None,
                     dummy_variable_rgx: None,
                     exclude: None,
                     extend: None,
@@ -336,14 +340,14 @@ select = ["E501"]
                     ignore_init_module_imports: None,
                     line_length: None,
                     per_file_ignores: None,
-                    respect_gitignore: None,
                     required_version: None,
+                    respect_gitignore: None,
                     select: Some(vec![CheckCodePrefix::E501]),
                     show_source: None,
                     src: None,
                     target_version: None,
                     unfixable: None,
-                    cache_dir: None,
+                    update_check: None,
                     flake8_annotations: None,
                     flake8_bugbear: None,
                     flake8_errmsg: None,
@@ -373,6 +377,7 @@ ignore = ["E501"]
             Some(Tools {
                 ruff: Some(Options {
                     allowed_confusables: None,
+                    cache_dir: None,
                     dummy_variable_rgx: None,
                     exclude: None,
                     extend: None,
@@ -389,14 +394,14 @@ ignore = ["E501"]
                     ignore_init_module_imports: None,
                     line_length: None,
                     per_file_ignores: None,
-                    respect_gitignore: None,
                     required_version: None,
+                    respect_gitignore: None,
                     select: None,
                     show_source: None,
                     src: None,
                     target_version: None,
                     unfixable: None,
-                    cache_dir: None,
+                    update_check: None,
                     flake8_annotations: None,
                     flake8_bugbear: None,
                     flake8_errmsg: None,
@@ -480,6 +485,7 @@ other-attribute = 1
                 format: None,
                 force_exclude: None,
                 unfixable: None,
+                update_check: None,
                 cache_dir: None,
                 per_file_ignores: Some(FxHashMap::from_iter([(
                     "__init__.py".to_string(),

src/settings/types.rs

@@ -154,6 +154,7 @@ pub enum SerializationFormat {
     Junit,
     Grouped,
     Github,
+    Gitlab,
 }
 
 impl Default for SerializationFormat {
@@ -163,6 +164,12 @@ impl Default for SerializationFormat {
                 return Self::Github;
             }
         }
+
+        if let Ok(gitlab_ci) = env::var("GITLAB_CI") {
+            if gitlab_ci == "true" {
+                return Self::Gitlab;
+            }
+        }
         Self::Text
     }
 }

src/source_code_generator.rs

@@ -1,14 +1,19 @@
+//! Generate Python source code from an abstract syntax tree (AST).
+
 use std::fmt;
+use std::ops::Deref;
 use std::string::FromUtf8Error;
 
 use anyhow::Result;
 use rustpython_ast::{Excepthandler, ExcepthandlerKind, Suite, Withitem};
-use rustpython_common::str;
 use rustpython_parser::ast::{
     Alias, Arg, Arguments, Boolop, Cmpop, Comprehension, Constant, ConversionFlag, Expr, ExprKind,
     Operator, Stmt, StmtKind,
 };
 
+use crate::source_code_style::{Indentation, Quote};
+use crate::vendor::{bytes, str};
+
 mod precedence {
     macro_rules! precedence {
         ($($op:ident,)*) => {
@@ -27,25 +32,27 @@ mod precedence {
     pub const EXPR: u8 = BOR;
 }
 
-pub struct SourceGenerator {
+pub struct SourceCodeGenerator<'a> {
+    /// The indentation style to use.
+    indent: &'a Indentation,
+    /// The quote style to use for string literals.
+    quote: &'a Quote,
     buffer: Vec<u8>,
-    indentation: usize,
-    new_lines: usize,
+    indent_depth: usize,
+    num_newlines: usize,
     initial: bool,
 }
 
-impl Default for SourceGenerator {
-    fn default() -> Self {
-        Self::new()
-    }
-}
-
-impl SourceGenerator {
-    pub fn new() -> Self {
-        SourceGenerator {
+impl<'a> SourceCodeGenerator<'a> {
+    pub fn new(indent: &'a Indentation, quote: &'a Quote) -> Self {
+        SourceCodeGenerator {
+            // Style preferences.
+            indent,
+            quote,
+            // Internal state.
             buffer: vec![],
-            indentation: 0,
-            new_lines: 0,
+            indent_depth: 0,
+            num_newlines: 0,
             initial: true,
         }
     }
@@ -56,30 +63,30 @@ impl SourceGenerator {
 
     fn newline(&mut self) {
         if !self.initial {
-            self.new_lines = std::cmp::max(self.new_lines, 1);
+            self.num_newlines = std::cmp::max(self.num_newlines, 1);
         }
     }
 
     fn newlines(&mut self, extra: usize) {
         if !self.initial {
-            self.new_lines = std::cmp::max(self.new_lines, 1 + extra);
+            self.num_newlines = std::cmp::max(self.num_newlines, 1 + extra);
         }
     }
 
     fn body<U>(&mut self, stmts: &[Stmt<U>]) {
-        self.indentation += 1;
+        self.indent_depth += 1;
         for stmt in stmts {
             self.unparse_stmt(stmt);
         }
-        self.indentation -= 1;
+        self.indent_depth -= 1;
     }
 
     fn p(&mut self, s: &str) {
-        if self.new_lines > 0 {
-            for _ in 0..self.new_lines {
+        if self.num_newlines > 0 {
+            for _ in 0..self.num_newlines {
                 self.buffer.extend("\n".as_bytes());
             }
-            self.new_lines = 0;
+            self.num_newlines = 0;
         }
         self.buffer.extend(s.as_bytes());
     }
@@ -108,7 +115,7 @@ impl SourceGenerator {
         macro_rules! statement {
             ($body:block) => {{
                 self.newline();
-                self.p(&"    ".repeat(self.indentation));
+                self.p(&self.indent.deref().repeat(self.indent_depth));
                 $body
                 self.initial = false;
             }};
@@ -123,7 +130,7 @@ impl SourceGenerator {
                 ..
             } => {
                 // TODO(charlie): Handle decorators.
-                self.newlines(if self.indentation == 0 { 2 } else { 1 });
+                self.newlines(if self.indent_depth == 0 { 2 } else { 1 });
                 statement!({
                     self.p("def ");
                     self.p(name);
@@ -137,7 +144,7 @@ impl SourceGenerator {
                     self.p(":");
                 });
                 self.body(body);
-                if self.indentation == 0 {
+                if self.indent_depth == 0 {
                     self.newlines(2);
                 }
             }
@@ -149,7 +156,7 @@ impl SourceGenerator {
                 ..
             } => {
                 // TODO(charlie): Handle decorators.
-                self.newlines(if self.indentation == 0 { 2 } else { 1 });
+                self.newlines(if self.indent_depth == 0 { 2 } else { 1 });
                 statement!({
                     self.p("async def ");
                     self.p(name);
@@ -163,7 +170,7 @@ impl SourceGenerator {
                     self.p(":");
                 });
                 self.body(body);
-                if self.indentation == 0 {
+                if self.indent_depth == 0 {
                     self.newlines(2);
                 }
             }
@@ -175,7 +182,7 @@ impl SourceGenerator {
                 ..
             } => {
                 // TODO(charlie): Handle decorators.
-                self.newlines(if self.indentation == 0 { 2 } else { 1 });
+                self.newlines(if self.indent_depth == 0 { 2 } else { 1 });
                 statement!({
                     self.p("class ");
                     self.p(name);
@@ -200,7 +207,7 @@ impl SourceGenerator {
                     self.p(":");
                 });
                 self.body(body);
-                if self.indentation == 0 {
+                if self.indent_depth == 0 {
                     self.newlines(2);
                 }
             }
@@ -788,6 +795,12 @@ impl SourceGenerator {
                     {
                         self.p(&value.to_string().replace("inf", inf_str));
                     }
+                    Constant::Bytes(b) => {
+                        self.p(&bytes::repr(b, self.quote.into()));
+                    }
+                    Constant::Str(s) => {
+                        self.p(&format!("{}", str::repr(s, self.quote.into())));
+                    }
                     _ => self.p(&format!("{value}")),
                 }
             }
@@ -931,7 +944,7 @@ impl SourceGenerator {
     }
 
     fn unparse_formatted<U>(&mut self, val: &Expr<U>, conversion: usize, spec: Option<&Expr<U>>) {
-        let mut generator = SourceGenerator::default();
+        let mut generator = SourceCodeGenerator::new(self.indent, self.quote);
         generator.unparse_expr(val, precedence::TEST + 1);
         let brace = if generator.buffer.starts_with("{".as_bytes()) {
             // put a space to avoid escaping the bracket
@@ -987,10 +1000,10 @@ impl SourceGenerator {
             self.unparse_fstring_body(values, is_spec);
         } else {
             self.p("f");
-            let mut generator = SourceGenerator::default();
+            let mut generator = SourceCodeGenerator::new(self.indent, self.quote);
             generator.unparse_fstring_body(values, is_spec);
             let body = std::str::from_utf8(&generator.buffer).unwrap();
-            self.p(&format!("{}", str::repr(body)));
+            self.p(&format!("{}", str::repr(body, self.quote.into())));
         }
     }
 
@@ -1010,3 +1023,139 @@ impl SourceGenerator {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+
+    use anyhow::Result;
+    use rustpython_parser::parser;
+
+    use crate::source_code_generator::SourceCodeGenerator;
+    use crate::source_code_style::{Indentation, Quote};
+
+    fn round_trip(contents: &str) -> Result<String> {
+        let indentation = Indentation::default();
+        let quote = Quote::default();
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let mut generator = SourceCodeGenerator::new(&indentation, &quote);
+        generator.unparse_stmt(stmt);
+        generator.generate().map_err(std::convert::Into::into)
+    }
+
+    fn round_trip_with(indentation: &Indentation, quote: &Quote, contents: &str) -> Result<String> {
+        let program = parser::parse_program(contents, "<filename>")?;
+        let stmt = program.first().unwrap();
+        let mut generator = SourceCodeGenerator::new(indentation, quote);
+        generator.unparse_stmt(stmt);
+        generator.generate().map_err(std::convert::Into::into)
+    }
+
+    #[test]
+    fn quote() -> Result<()> {
+        assert_eq!(round_trip(r#""hello""#)?, r#""hello""#);
+        assert_eq!(round_trip(r#"'hello'"#)?, r#""hello""#);
+        assert_eq!(round_trip(r#"u'hello'"#)?, r#"u"hello""#);
+        assert_eq!(round_trip(r#"r'hello'"#)?, r#""hello""#);
+        assert_eq!(round_trip(r#"b'hello'"#)?, r#"b"hello""#);
+        assert_eq!(round_trip(r#"("abc" "def" "ghi")"#)?, r#""abcdefghi""#);
+        assert_eq!(round_trip(r#""he\"llo""#)?, r#"'he"llo'"#);
+        assert_eq!(round_trip(r#"f'abc{"def"}{1}'"#)?, r#"f'abc{"def"}{1}'"#);
+        assert_eq!(round_trip(r#"f"abc{'def'}{1}""#)?, r#"f'abc{"def"}{1}'"#);
+        Ok(())
+    }
+
+    #[test]
+    fn indent() -> Result<()> {
+        assert_eq!(
+            round_trip(
+                r#"
+if True:
+  pass
+"#
+                .trim(),
+            )?,
+            r#"
+if True:
+    pass
+"#
+            .trim()
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn set_quote() -> Result<()> {
+        assert_eq!(
+            round_trip_with(&Indentation::default(), &Quote::Double, r#""hello""#)?,
+            r#""hello""#
+        );
+        assert_eq!(
+            round_trip_with(&Indentation::default(), &Quote::Single, r#""hello""#)?,
+            r#"'hello'"#
+        );
+        assert_eq!(
+            round_trip_with(&Indentation::default(), &Quote::Double, r#"'hello'"#)?,
+            r#""hello""#
+        );
+        assert_eq!(
+            round_trip_with(&Indentation::default(), &Quote::Single, r#"'hello'"#)?,
+            r#"'hello'"#
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn set_indent() -> Result<()> {
+        assert_eq!(
+            round_trip_with(
+                &Indentation::new("    ".to_string()),
+                &Quote::default(),
+                r#"
+if True:
+  pass
+"#
+                .trim(),
+            )?,
+            r#"
+if True:
+    pass
+"#
+            .trim()
+        );
+        assert_eq!(
+            round_trip_with(
+                &Indentation::new("  ".to_string()),
+                &Quote::default(),
+                r#"
+if True:
+  pass
+"#
+                .trim(),
+            )?,
+            r#"
+if True:
+  pass
+"#
+            .trim()
+        );
+        assert_eq!(
+            round_trip_with(
+                &Indentation::new("\t".to_string()),
+                &Quote::default(),
+                r#"
+if True:
+  pass
+"#
+                .trim(),
+            )?,
+            r#"
+if True:
+	pass
+"#
+            .trim()
+        );
+
+        Ok(())
+    }
+}

src/source_code_style.rs

@@ -0,0 +1,200 @@
+//! Detect code style from Python source code.
+
+use std::ops::Deref;
+
+use once_cell::unsync::OnceCell;
+use rustpython_ast::Location;
+use rustpython_parser::lexer;
+use rustpython_parser::lexer::Tok;
+
+use crate::ast::types::Range;
+use crate::pydocstyle::helpers::leading_quote;
+use crate::source_code_locator::SourceCodeLocator;
+use crate::vendor;
+
+pub struct SourceCodeStyleDetector<'a> {
+    contents: &'a str,
+    locator: &'a SourceCodeLocator<'a>,
+    indentation: OnceCell<Indentation>,
+    quote: OnceCell<Quote>,
+}
+
+impl<'a> SourceCodeStyleDetector<'a> {
+    pub fn indentation(&'a self) -> &'a Indentation {
+        self.indentation
+            .get_or_init(|| detect_indentation(self.contents, self.locator).unwrap_or_default())
+    }
+
+    pub fn quote(&'a self) -> &'a Quote {
+        self.quote
+            .get_or_init(|| detect_quote(self.contents, self.locator).unwrap_or_default())
+    }
+
+    pub fn from_contents(contents: &'a str, locator: &'a SourceCodeLocator<'a>) -> Self {
+        Self {
+            contents,
+            locator,
+            indentation: OnceCell::default(),
+            quote: OnceCell::default(),
+        }
+    }
+}
+
+/// The quotation style used in Python source code.
+#[derive(Debug, PartialEq, Eq)]
+pub enum Quote {
+    Single,
+    Double,
+}
+
+impl Default for Quote {
+    fn default() -> Self {
+        Quote::Double
+    }
+}
+
+impl From<&Quote> for vendor::str::Quote {
+    fn from(val: &Quote) -> Self {
+        match val {
+            Quote::Single => vendor::str::Quote::Single,
+            Quote::Double => vendor::str::Quote::Double,
+        }
+    }
+}
+
+/// The indentation style used in Python source code.
+#[derive(Debug, PartialEq, Eq)]
+pub struct Indentation(String);
+
+impl Indentation {
+    pub fn new(indentation: String) -> Self {
+        Self(indentation)
+    }
+}
+
+impl Default for Indentation {
+    fn default() -> Self {
+        Indentation("    ".to_string())
+    }
+}
+
+impl Deref for Indentation {
+    type Target = str;
+
+    fn deref(&self) -> &Self::Target {
+        &self.0
+    }
+}
+
+/// Detect the indentation style of the given tokens.
+fn detect_indentation(contents: &str, locator: &SourceCodeLocator) -> Option<Indentation> {
+    for (_start, tok, end) in lexer::make_tokenizer(contents).flatten() {
+        if let Tok::Indent { .. } = tok {
+            let start = Location::new(end.row(), 0);
+            let whitespace = locator.slice_source_code_range(&Range {
+                location: start,
+                end_location: end,
+            });
+            return Some(Indentation(whitespace.to_string()));
+        }
+    }
+    None
+}
+
+/// Detect the quotation style of the given tokens.
+fn detect_quote(contents: &str, locator: &SourceCodeLocator) -> Option<Quote> {
+    for (start, tok, end) in lexer::make_tokenizer(contents).flatten() {
+        if let Tok::String { .. } = tok {
+            let content = locator.slice_source_code_range(&Range {
+                location: start,
+                end_location: end,
+            });
+            if let Some(pattern) = leading_quote(&content) {
+                if pattern.contains('\'') {
+                    return Some(Quote::Single);
+                } else if pattern.contains('"') {
+                    return Some(Quote::Double);
+                }
+                unreachable!("Expected string to start with a valid quote prefix")
+            }
+        }
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use crate::source_code_style::{detect_indentation, detect_quote, Indentation, Quote};
+    use crate::SourceCodeLocator;
+
+    #[test]
+    fn indentation() {
+        let contents = r#"x = 1"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(detect_indentation(contents, &locator), None);
+
+        let contents = r#"
+if True:
+  pass
+"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            detect_indentation(contents, &locator),
+            Some(Indentation("  ".to_string()))
+        );
+
+        let contents = r#"
+if True:
+    pass
+"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            detect_indentation(contents, &locator),
+            Some(Indentation("    ".to_string()))
+        );
+
+        let contents = r#"
+if True:
+	pass
+"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(
+            detect_indentation(contents, &locator),
+            Some(Indentation("\t".to_string()))
+        );
+
+        // TODO(charlie): Should non-significant whitespace be detected?
+        let contents = r#"
+x = (
+  1,
+  2,
+  3,
+)
+"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(detect_indentation(contents, &locator), None);
+    }
+
+    #[test]
+    fn quote() {
+        let contents = r#"x = 1"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(detect_quote(contents, &locator), None);
+
+        let contents = r#"x = '1'"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(detect_quote(contents, &locator), Some(Quote::Single));
+
+        let contents = r#"x = "1""#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(detect_quote(contents, &locator), Some(Quote::Double));
+
+        let contents = r#"
+def f():
+    """Docstring."""
+    pass
+"#;
+        let locator = SourceCodeLocator::new(contents);
+        assert_eq!(detect_quote(contents, &locator), Some(Quote::Double));
+    }
+}