Bump version to 0.0.96

This reverts commit 77e5564f4b.

.editorconfig

@@ -0,0 +1,14 @@
+# Check http://editorconfig.org for more information
+# This is the main config file for this project:
+root = true
+
+[*]
+charset = utf-8
+trim_trailing_whitespace = true
+end_of_line = lf
+indent_style = space
+insert_final_newline = true
+indent_size = 2
+
+[*.{rs,py}]
+indent_size = 4

.github/workflows/ci.yaml

@@ -14,7 +14,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          profile: minimal
       - uses: actions/cache@v3
         env:
           cache-name: cache-cargo
@@ -27,7 +27,7 @@ jobs:
             ${{ runner.os }}-build-${{ env.cache-name }}-
             ${{ runner.os }}-build-
             ${{ runner.os }}-
-      - run: cargo build --release
+      - run: cargo build --all --release
 
   cargo_fmt:
     name: "cargo fmt"
@@ -36,7 +36,10 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          profile: minimal
+          toolchain: nightly-2022-11-01
+          override: true
+          components: rustfmt
       - uses: actions/cache@v3
         env:
           cache-name: cache-cargo
@@ -49,7 +52,7 @@ jobs:
             ${{ runner.os }}-build-${{ env.cache-name }}-
             ${{ runner.os }}-build-
             ${{ runner.os }}-
-      - run: cargo fmt --check
+      - run: cargo fmt --all --check
 
   cargo_clippy:
     name: "cargo clippy"
@@ -58,7 +61,10 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          profile: minimal
+          toolchain: nightly-2022-11-01
+          override: true
+          components: clippy
       - uses: actions/cache@v3
         env:
           cache-name: cache-cargo
@@ -71,7 +77,7 @@ jobs:
             ${{ runner.os }}-build-${{ env.cache-name }}-
             ${{ runner.os }}-build-
             ${{ runner.os }}-
-      - run: cargo clippy -- -D warnings
+      - run: cargo clippy --all -- -D warnings
 
   cargo_test:
     name: "cargo test"
@@ -80,7 +86,9 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          profile: minimal
+          toolchain: nightly-2022-11-01
+          override: true
       - uses: actions/cache@v3
         env:
           cache-name: cache-cargo
@@ -93,7 +101,7 @@ jobs:
             ${{ runner.os }}-build-${{ env.cache-name }}-
             ${{ runner.os }}-build-
             ${{ runner.os }}-
-      - run: cargo test
+      - run: cargo test --all
 
   maturin_build:
     name: "maturin build"
@@ -102,7 +110,9 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          profile: minimal
+          toolchain: nightly-2022-11-01
+          override: true
       - uses: actions/setup-python@v4
         with:
           python-version: "3.10"

.github/workflows/flake8-to-ruff.yaml

@@ -0,0 +1,298 @@
+name: "[flake8-to-ruff] Release"
+
+on: workflow_dispatch
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+env:
+  PACKAGE_NAME: flake8-to-ruff
+  CRATE_NAME: flake8_to_ruff
+  PYTHON_VERSION: "3.7" # to build abi3 wheels
+
+jobs:
+  macos-x86_64:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          default: true
+      - name: Build wheels - x86_64
+        uses: messense/maturin-action@v1
+        with:
+          target: x86_64
+          args: --release --out dist --sdist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - name: Install built wheel - x86_64
+        run: |
+          pip install dist/${{ env.CRATE_NAME }}-*.whl --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+  macos-universal:
+    runs-on: macos-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          default: true
+      - name: Build wheels - universal2
+        uses: messense/maturin-action@v1
+        with:
+          args: --release --universal2 --out dist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - name: Install built wheel - universal2
+        run: |
+          pip install dist/${{ env.CRATE_NAME }}-*universal2.whl --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  windows:
+    runs-on: windows-latest
+    strategy:
+      matrix:
+        target: [x64, x86]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: ${{ matrix.target }}
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          default: true
+      - name: Build wheels
+        uses: messense/maturin-action@v1
+        with:
+          target: ${{ matrix.target }}
+          args: --release --out dist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - name: Install built wheel
+        shell: bash
+        run: |
+          python -m pip install dist/${{ env.CRATE_NAME }}-*.whl --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  linux:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target: [x86_64, i686]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: Build wheels
+        uses: messense/maturin-action@v1
+        with:
+          target: ${{ matrix.target }}
+          manylinux: auto
+          args: --release --out dist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - name: Install built wheel
+        if: matrix.target == 'x86_64'
+        run: |
+          pip install dist/${{ env.CRATE_NAME }}-*.whl --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  linux-cross:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target: [aarch64, armv7, s390x, ppc64le, ppc64]
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+      - name: Build wheels
+        uses: messense/maturin-action@v1
+        with:
+          target: ${{ matrix.target }}
+          manylinux: auto
+          args: --no-default-features --release --out dist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - uses: uraimo/run-on-arch-action@v2.0.5
+        if: matrix.target != 'ppc64'
+        name: Install built wheel
+        with:
+          arch: ${{ matrix.target }}
+          distro: ubuntu20.04
+          githubToken: ${{ github.token }}
+          install: |
+            apt-get update
+            apt-get install -y --no-install-recommends python3 python3-pip
+            pip3 install -U pip
+          run: |
+            pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  musllinux:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        target:
+          - x86_64-unknown-linux-musl
+          - i686-unknown-linux-musl
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: Build wheels
+        uses: messense/maturin-action@v1
+        with:
+          target: ${{ matrix.target }}
+          manylinux: musllinux_1_2
+          args: --release --out dist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - name: Install built wheel
+        if: matrix.target == 'x86_64-unknown-linux-musl'
+        uses: addnab/docker-run-action@v3
+        with:
+          image: alpine:latest
+          options: -v ${{ github.workspace }}:/io -w /io
+          run: |
+            apk add py3-pip
+            pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links /io/dist/ --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  musllinux-cross:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        platform:
+          - target: aarch64-unknown-linux-musl
+            arch: aarch64
+          - target: armv7-unknown-linux-musleabihf
+            arch: armv7
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: ${{ env.PYTHON_VERSION }}
+      - name: Build wheels
+        uses: messense/maturin-action@v1
+        with:
+          target: ${{ matrix.platform.target }}
+          manylinux: musllinux_1_2
+          args: --release --out dist -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+          maturin-version: "v0.13.0"
+      - uses: uraimo/run-on-arch-action@master
+        name: Install built wheel
+        with:
+          arch: ${{ matrix.platform.arch }}
+          distro: alpine_latest
+          githubToken: ${{ github.token }}
+          install: |
+            apk add py3-pip
+          run: |
+            pip3 install ${{ env.PACKAGE_NAME }} --no-index --find-links dist/ --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  pypy:
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest]
+        target: [x86_64, aarch64]
+        python-version:
+          - "3.7"
+          - "3.8"
+          - "3.9"
+        exclude:
+          - os: macos-latest
+            target: aarch64
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-python@v4
+        with:
+          python-version: pypy${{ matrix.python-version }}
+      - name: Build wheels
+        uses: messense/maturin-action@v1
+        with:
+          maturin-version: "v0.13.0"
+          target: ${{ matrix.target }}
+          manylinux: auto
+          args: --release --out dist -i pypy${{ matrix.python-version }} -m ./crates/${{ env.CRATE_NAME }}/Cargo.toml
+      - name: Install built wheel
+        if: matrix.target == 'x86_64'
+        run: |
+          pip install dist/${{ env.CRATE_NAME }}-*.whl --force-reinstall
+      - name: Upload wheels
+        uses: actions/upload-artifact@v2
+        with:
+          name: wheels
+          path: dist
+
+  release:
+    name: Release
+    runs-on: ubuntu-latest
+    needs:
+      - macos-universal
+      - macos-x86_64
+      - windows
+      - linux
+      - linux-cross
+      - musllinux
+      - musllinux-cross
+      - pypy
+    steps:
+      - uses: actions/download-artifact@v2
+        with:
+          name: wheels
+      - uses: actions/setup-python@v4
+      - name: Publish to PyPi
+        env:
+          TWINE_USERNAME: __token__
+          TWINE_PASSWORD: ${{ secrets.FLAKE8_TO_RUFF_TOKEN }}
+        run: |
+          pip install --upgrade twine
+          twine upload --skip-existing *

.github/workflows/ruff.yaml

@@ -1,8 +1,6 @@
-name: Release
+name: "[ruff] Release"
 
 on:
-  pull_request:
-    branches: [main]
   create:
     tags:
       - v*
@@ -297,7 +295,7 @@ jobs:
       - name: Publish to PyPi
         env:
           TWINE_USERNAME: __token__
-          TWINE_PASSWORD: ${{ secrets.PYPI_TOKEN }}
+          TWINE_PASSWORD: ${{ secrets.RUFF_TOKEN }}
         run: |
           pip install --upgrade twine
           twine upload --skip-existing *

.pre-commit-config.yaml

@@ -1,5 +1,10 @@
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.40
+    rev: v0.0.96
     hooks:
-      - id: lint
+      - id: ruff
+
+  - repo: https://github.com/abravalheri/validate-pyproject
+    rev: v0.10.1
+    hooks:
+      - id: validate-pyproject

CODE_OF_CONDUCT.md

@@ -0,0 +1,128 @@
+# Contributor Covenant Code of Conduct
+
+## Our Pledge
+
+We as members, contributors, and leaders pledge to make participation in our
+community a harassment-free experience for everyone, regardless of age, body
+size, visible or invisible disability, ethnicity, sex characteristics, gender
+identity and expression, level of experience, education, socio-economic status,
+nationality, personal appearance, race, religion, or sexual identity
+and orientation.
+
+We pledge to act and interact in ways that contribute to an open, welcoming,
+diverse, inclusive, and healthy community.
+
+## Our Standards
+
+Examples of behavior that contributes to a positive environment for our
+community include:
+
+* Demonstrating empathy and kindness toward other people
+* Being respectful of differing opinions, viewpoints, and experiences
+* Giving and gracefully accepting constructive feedback
+* Accepting responsibility and apologizing to those affected by our mistakes,
+  and learning from the experience
+* Focusing on what is best not just for us as individuals, but for the
+  overall community
+
+Examples of unacceptable behavior include:
+
+* The use of sexualized language or imagery, and sexual attention or
+  advances of any kind
+* Trolling, insulting or derogatory comments, and personal or political attacks
+* Public or private harassment
+* Publishing others' private information, such as a physical or email
+  address, without their explicit permission
+* Other conduct which could reasonably be considered inappropriate in a
+  professional setting
+
+## Enforcement Responsibilities
+
+Community leaders are responsible for clarifying and enforcing our standards of
+acceptable behavior and will take appropriate and fair corrective action in
+response to any behavior that they deem inappropriate, threatening, offensive,
+or harmful.
+
+Community leaders have the right and responsibility to remove, edit, or reject
+comments, commits, code, wiki edits, issues, and other contributions that are
+not aligned to this Code of Conduct, and will communicate reasons for moderation
+decisions when appropriate.
+
+## Scope
+
+This Code of Conduct applies within all community spaces, and also applies when
+an individual is officially representing the community in public spaces.
+Examples of representing our community include using an official e-mail address,
+posting via an official social media account, or acting as an appointed
+representative at an online or offline event.
+
+## Enforcement
+
+Instances of abusive, harassing, or otherwise unacceptable behavior may be
+reported to the community leaders responsible for enforcement at
+charlie.r.marsh@gmail.com.
+All complaints will be reviewed and investigated promptly and fairly.
+
+All community leaders are obligated to respect the privacy and security of the
+reporter of any incident.
+
+## Enforcement Guidelines
+
+Community leaders will follow these Community Impact Guidelines in determining
+the consequences for any action they deem in violation of this Code of Conduct:
+
+### 1. Correction
+
+**Community Impact**: Use of inappropriate language or other behavior deemed
+unprofessional or unwelcome in the community.
+
+**Consequence**: A private, written warning from community leaders, providing
+clarity around the nature of the violation and an explanation of why the
+behavior was inappropriate. A public apology may be requested.
+
+### 2. Warning
+
+**Community Impact**: A violation through a single incident or series
+of actions.
+
+**Consequence**: A warning with consequences for continued behavior. No
+interaction with the people involved, including unsolicited interaction with
+those enforcing the Code of Conduct, for a specified period of time. This
+includes avoiding interactions in community spaces as well as external channels
+like social media. Violating these terms may lead to a temporary or
+permanent ban.
+
+### 3. Temporary Ban
+
+**Community Impact**: A serious violation of community standards, including
+sustained inappropriate behavior.
+
+**Consequence**: A temporary ban from any sort of interaction or public
+communication with the community for a specified period of time. No public or
+private interaction with the people involved, including unsolicited interaction
+with those enforcing the Code of Conduct, is allowed during this period.
+Violating these terms may lead to a permanent ban.
+
+### 4. Permanent Ban
+
+**Community Impact**: Demonstrating a pattern of violation of community
+standards, including sustained inappropriate behavior,  harassment of an
+individual, or aggression toward or disparagement of classes of individuals.
+
+**Consequence**: A permanent ban from any sort of public interaction within
+the community.
+
+## Attribution
+
+This Code of Conduct is adapted from the [Contributor Covenant][homepage],
+version 2.0, available at
+https://www.contributor-covenant.org/version/2/0/code_of_conduct.html.
+
+Community Impact Guidelines were inspired by [Mozilla's code of conduct
+enforcement ladder](https://github.com/mozilla/diversity).
+
+[homepage]: https://www.contributor-covenant.org
+
+For answers to common questions about this code of conduct, see the FAQ at
+https://www.contributor-covenant.org/faq. Translations are available at
+https://www.contributor-covenant.org/translations.

CONTRIBUTING.md

@@ -0,0 +1,111 @@
+# Contributing to ruff
+
+Welcome! We're happy to have you here. Thank you in advance for your contribution to ruff.
+
+## The basics
+
+ruff welcomes contributions in the form of Pull Requests. For small changes (e.g., bug fixes), feel
+free to submit a PR. For larger changes (e.g., new lint rules, new functionality, new configuration
+options), consider submitting an [Issue](https://github.com/charliermarsh/ruff/issues) outlining
+your proposed change.
+
+### Prerequisites
+
+ruff is written in Rust (1.63.0). You'll need to install the
+[Rust toolchain](https://www.rust-lang.org/tools/install) for development.
+
+You'll also need [Insta](https://insta.rs/docs/) to update snapshot tests:
+
+```shell
+cargo install cargo-insta
+```
+
+### Development
+
+After cloning the repository, run ruff locally with:
+
+```shell
+cargo run resources/test/fixtures --no-cache
+```
+
+Prior to opening a pull request, ensure that your code has been auto-formatted, and that it passes
+both the lint and test validation checks:
+
+```shell
+cargo fmt     # Auto-formatting...
+cargo clippy  # Linting...
+cargo test    # Testing...
+```
+
+These checks will run on GitHub Actions when you open your Pull Request, but running them locally
+will save you time and expedite the merge process.
+
+Your Pull Request will be reviewed by a maintainer, which may involve a few rounds of iteration
+prior to merging.
+
+### Example: Adding a new lint rule
+
+There are three phases to adding a new lint rule:
+
+1. Define the rule in `src/checks.rs`.
+2. Define the _logic_ for triggering the rule in `src/check_ast.rs` (for AST-based checks)
+   or `src/check_lines.rs` (for text-based checks).
+3. Add a test fixture.
+
+To define the rule, open up `src/checks.rs`. You'll need to define both a `CheckCode` and
+`CheckKind`. As an example, you can grep for `E402` and `ModuleImportNotAtTopOfFile`, and follow the
+pattern implemented therein.
+
+To trigger the rule, you'll likely want to augment the logic in `src/check_ast.rs`, which defines
+the Python AST visitor, responsible for iterating over the abstract syntax tree and collecting
+lint-rule violations as it goes. Grep for the `Check::new` invocations to understand how other,
+similar rules are implemented.
+
+To add a test fixture, create a file under `resources/test/fixtures`, named to match the `CheckCode`
+you defined earlier (e.g., `E402.py`). This file should contain a variety of violations and
+non-violations designed to evaluate and demonstrate the behavior of your lint rule. Run ruff locally
+with (e.g.) `cargo run resources/test/fixtures/E402.py`. Once you're satisfied with the output,
+codify the behavior as a snapshot test by adding a new function to the `mod tests` section of
+`src/linter.rs`, like so:
+
+```rust
+#[test]
+fn e402() -> Result<()> {
+    let mut checks = check_path(
+        Path::new("./resources/test/fixtures/E402.py"),
+        &settings::Settings::for_rule(CheckCode::E402),
+        &fixer::Mode::Generate,
+    )?;
+    checks.sort_by_key(|check| check.location);
+    insta::assert_yaml_snapshot!(checks);
+    Ok(())
+}
+```
+
+Then, run `cargo test`. Your test will fail, but you'll be prompted to follow-up with
+`cargo insta review`. Accept the generated snapshot, then commit the snapshot file alongside the
+rest of your changes.
+
+### Example: Adding a new configuration option
+
+ruff's user-facing settings live in two places: first, the command-line options defined with
+[clap](https://docs.rs/clap/latest/clap/) via the `Cli` struct in `src/main.rs`; and second, the
+`Config` struct defined `src/pyproject.rs`, which is responsible for extracting user-defined
+settings from a `pyproject.toml` file.
+
+Ultimately, these two sources of configuration are merged into the `Settings` struct defined
+in `src/settings.rs`, which is then threaded through the codebase.
+
+To add a new configuration option, you'll likely want to _both_ add a CLI option to `src/main.rs`
+_and_ a `pyproject.toml` parameter to `src/pyproject.rs`. If you want to pattern-match against an
+existing example, grep for `dummy_variable_rgx`, which defines a regular expression to match against
+acceptable unused variables (e.g., `_`).
+
+## Release process
+
+As of now, ruff has an ad hoc release process: releases are cut with high frequency via GitHub
+Actions, which automatically generates the appropriate wheels across architectures and publishes
+them to [PyPI](https://pypi.org/project/ruff/).
+
+ruff follows the [semver](https://semver.org/) versioning standard. However, as pre-1.0 software,
+even patch releases may contain [non-backwards-compatible changes](https://semver.org/#spec-item-4).

Cargo.toml

@@ -1,6 +1,11 @@
+[workspace]
+members = [
+  "crates/flake8_to_ruff",
+]
+
 [package]
 name = "ruff"
-version = "0.0.44"
+version = "0.0.96"
 edition = "2021"
 
 [lib]
@@ -9,32 +14,51 @@ name = "ruff"
 [dependencies]
 anyhow = { version = "1.0.60" }
 bincode = { version = "1.3.3" }
-cacache = { version = "10.0.1" }
 chrono = { version = "0.4.21" }
-clap = { version = "3.2.16", features = ["derive"] }
-clearscreen = { version = "1.0.10" }
+clap = { version = "4.0.1", features = ["derive"] }
 colored = { version = "2.0.0" }
 common-path = { version = "1.0.0" }
 dirs = { version = "4.0.0" }
 fern = { version = "0.6.1" }
 filetime = { version = "0.2.17" }
 glob = { version = "0.3.0" }
-itertools = { version = "0.10.3" }
+itertools = { version = "0.10.5" }
+libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "32a044c127668df44582f85699358e67803b0d73" }
 log = { version = "0.4.17" }
 notify = { version = "4.0.17" }
+num-bigint = { version = "0.4.3" }
 once_cell = { version = "1.13.1" }
-path-absolutize = { version = "3.0.13", features = ["once_cell_cache"] }
+path-absolutize = { version = "3.0.14", features = ["once_cell_cache", "use_unix_paths_on_wasm"] }
 rayon = { version = "1.5.3" }
 regex = { version = "1.6.0" }
-rustpython-parser = { features = ["lalrpop"], git = "https://github.com/charliermarsh/RustPython.git", rev = "7d21c6923a506e79cc041708d83cef925efd33f4" }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "77b821a1941019fe34f73ce17cea013ae1b98fd0" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "77b821a1941019fe34f73ce17cea013ae1b98fd0" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "77b821a1941019fe34f73ce17cea013ae1b98fd0" }
 serde = { version = "1.0.143", features = ["derive"] }
 serde_json = { version = "1.0.83" }
+strum = { version = "0.24.1", features = ["strum_macros"] }
+strum_macros = { version = "0.24.3" }
+textwrap = { version = "0.15.1" }
+titlecase = { version = "2.2.1" }
 toml = { version = "0.5.9" }
 update-informer = { version = "0.5.0", default_features = false, features = ["pypi"], optional = true }
 walkdir = { version = "2.3.2" }
 
+[target.'cfg(not(target_family = "wasm"))'.dependencies]
+cacache = { version = "10.0.1" } # uses async-std
+clearscreen = { version = "1.0.10" } # uses which
+
+# https://docs.rs/getrandom/0.2.7/getrandom/#webassembly-support
+# For (future) wasm-pack support
+[target.'cfg(all(target_family = "wasm", target_os = "unknown"))'.dependencies]
+getrandom = { version = "0.2.7", features = ["js"] }
+
 [dev-dependencies]
+assert_cmd = { version = "2.0.4" }
+codegen = { version = "0.2.0" }
+criterion = { version = "0.4.0" }
 insta = { version = "1.19.1", features = ["yaml"] }
+test-case = { version = "2.2.2" }
 
 [features]
 default = ["update-informer"]
@@ -51,3 +75,7 @@ opt-level = 3
 
 [profile.dev.package.similar]
 opt-level = 3
+
+[[bench]]
+name = "source_code_locator"
+harness = false

README.md

@@ -1,4 +1,4 @@
-# ruff
+# Ruff
 
 [![image](https://img.shields.io/pypi/v/ruff.svg)](https://pypi.python.org/pypi/ruff)
 [![image](https://img.shields.io/pypi/l/ruff.svg)](https://pypi.python.org/pypi/ruff)
@@ -20,17 +20,49 @@ An extremely fast Python linter, written in Rust.
 - 🤝 Python 3.10 compatibility
 - 🛠️ `pyproject.toml` support
 - 📦 [ESLint](https://eslint.org/docs/latest/user-guide/command-line-interface#caching)-inspired cache support
-- 🔧 [ESLint](https://eslint.org/docs/latest/user-guide/command-line-interface#caching)-inspired `--fix` support
-- 👀 [TypeScript](https://www.typescriptlang.org/docs/handbook/configuring-watch.html)-inspired `--watch` support
-- ⚖️ [Near-complete parity](#Parity-with-Flake8) with the built-in Flake8 rule set
+- 🔧 [ESLint](https://eslint.org/docs/latest/user-guide/command-line-interface#--fix)-inspired autofix support (e.g., automatically remove unused imports)
+- 👀 [TypeScript](https://www.typescriptlang.org/docs/handbook/configuring-watch.html)-inspired `--watch` support, for continuous file monitoring
+- ⚖️ [Near-parity](#how-does-ruff-compare-to-flake8) with the built-in Flake8 rule set
+- 🔌 Native re-implementations of popular Flake8 plugins, like [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/) ([`pydocstyle`](https://pypi.org/project/pydocstyle/))
+
+Ruff aims to be orders of magnitude faster than alternative tools while integrating more
+functionality behind a single, common interface. Ruff can be used to replace Flake8 (plus a variety
+of plugins), [`pydocstyle`](https://pypi.org/project/pydocstyle/), [`yesqa`](https://github.com/asottile/yesqa),
+and even a subset of [`pyupgrade`](https://pypi.org/project/pyupgrade/) and [`autoflake`](https://pypi.org/project/autoflake/)
+all while executing tens or hundreds of times faster than any individual tool.
 
 Read the [launch blog post](https://notes.crmarsh.com/python-tooling-could-be-much-much-faster).
 
-## Installation and usage
+## Table of Contents
+
+1. [Installation and Usage](#installation-and-usage)
+2. [Configuration](#configuration)
+3. [Supported Rules](#supported-rules)
+   1. [Pyflakes](#pyflakes)
+   2. [pycodestyle (error)](#pycodestyle-error)
+   3. [pycodestyle (warning)](#pycodestyle-warning)
+   4. [pydocstyle](#pydocstyle)
+   5. [pyupgrade](#pyupgrade)
+   6. [pep8-naming](#pep8-naming)
+   7. [flake8-comprehensions](#flake8-comprehensions)
+   8. [flake8-bugbear](#flake8-bugbear)
+   9. [flake8-builtins](#flake8-builtins)
+   10. [flake8-print](#flake8-print)
+   11. [flake8-quotes](#flake8-quotes)
+   12. [Meta rules](#meta-rules)
+5. [Editor Integrations](#editor-integrations)
+6. [FAQ](#faq)
+7. [Development](#development)
+8. [Releases](#releases)
+9. [Benchmarks](#benchmarks)
+10. [License](#license)
+11. [Contributing](#contributing)
+
+## Installation and Usage
 
 ### Installation
 
-Available as [ruff](https://pypi.org/project/ruff/) on PyPI:
+Available as [`ruff`](https://pypi.org/project/ruff/) on PyPI:
 
 ```shell
 pip install ruff
@@ -38,7 +70,7 @@ pip install ruff
 
 ### Usage
 
-To run ruff, try any of the following:
+To run Ruff, try any of the following:
 
 ```shell
 ruff path/to/code/to/check.py
@@ -46,89 +78,116 @@ ruff path/to/code/
 ruff path/to/code/*.py
 ```
 
-You can run ruff in `--watch` mode to automatically re-run on-change:
+You can run Ruff in `--watch` mode to automatically re-run on-change:
 
 ```shell
 ruff path/to/code/ --watch
 ```
 
-ruff also works with [pre-commit](https://pre-commit.com):
+Ruff also works with [pre-commit](https://pre-commit.com):
 
 ```yaml
 repos:
   - repo: https://github.com/charliermarsh/ruff-pre-commit
-    rev: v0.0.40
+    rev: v0.0.96
     hooks:
-      - id: lint
+      - id: ruff
 ```
 
+<!-- TODO(charlie): Remove this message a few versions after v0.0.86. -->
+_Note: prior to `v0.0.86`, `ruff-pre-commit` used `lint` (rather than `ruff`) as the hook ID._
+
 ## Configuration
 
-ruff is configurable both via `pyproject.toml` and the command line.
+Ruff is configurable both via `pyproject.toml` and the command line.
 
-For example, you could configure ruff to only enforce a subset of rules with:
+For example, you could configure Ruff to only enforce a subset of rules with:
 
 ```toml
 [tool.ruff]
 line-length = 88
-select = [
-    "F401",
-    "F403",
-]
+select = ["E", "F"]
+ignore = ["E501"]
+per-file-ignores = {"__init__.py" = ["F401"], "path/to/file.py" = ["F401"]}
 ```
 
-Alternatively, on the command-line:
+Plugin configurations should be expressed as subsections, e.g.:
+
+```toml
+[tool.ruff]
+line-length = 88
+
+[tool.ruff.flake8-quotes]
+docstring-quotes = "double"
+```
+
+Alternatively, common configuration settings can be provided via the command-line:
 
 ```shell
-ruff path/to/code/ --select F401 F403
+ruff path/to/code/ --select F401 --select F403
 ```
 
 See `ruff --help` for more:
 
 ```shell
-ruff (v0.0.44) 0.0.44
-An extremely fast Python linter.
+ruff: An extremely fast Python linter.
 
-USAGE:
-    ruff [OPTIONS] <FILES>...
+Usage: ruff [OPTIONS] <FILES>...
 
-ARGS:
-    <FILES>...
+Arguments:
+  <FILES>...
 
-OPTIONS:
-    -e, --exit-zero
-            Exit with status code "0", even upon detecting errors
-        --exclude <EXCLUDE>...
-            List of paths, used to exclude files and/or directories from checks
-        --extend-exclude <EXTEND_EXCLUDE>...
-            Like --exclude, but adds additional files and directories on top of the excluded ones
-    -f, --fix
-            Attempt to automatically fix lint errors
-        --format <FORMAT>
-            Output serialization format for error messages [default: text] [possible values: text,
-            json]
-    -h, --help
-            Print help information
-        --ignore <IGNORE>...
-            List of error codes to ignore
-    -n, --no-cache
-            Disable cache reads
-    -q, --quiet
-            Disable all logging (but still exit with status code "1" upon detecting errors)
-        --select <SELECT>...
-            List of error codes to enable
-        --show-files
-            See the files ruff will be run against with the current configuration options
-        --show-settings
-            See ruff's settings
-    -v, --verbose
-            Enable verbose logging
-    -V, --version
-            Print version information
-    -w, --watch
-            Run in watch mode by re-running whenever files change
+Options:
+      --config <CONFIG>
+          Path to the `pyproject.toml` file to use for configuration
+  -v, --verbose
+          Enable verbose logging
+  -q, --quiet
+          Disable all logging (but still exit with status code "1" upon detecting errors)
+  -e, --exit-zero
+          Exit with status code "0", even upon detecting errors
+  -w, --watch
+          Run in watch mode by re-running whenever files change
+  -f, --fix
+          Attempt to automatically fix lint errors
+  -n, --no-cache
+          Disable cache reads
+      --select <SELECT>
+          List of error codes to enable
+      --extend-select <EXTEND_SELECT>
+          Like --select, but adds additional error codes on top of the selected ones
+      --ignore <IGNORE>
+          List of error codes to ignore
+      --extend-ignore <EXTEND_IGNORE>
+          Like --ignore, but adds additional error codes on top of the ignored ones
+      --exclude <EXCLUDE>
+          List of paths, used to exclude files and/or directories from checks
+      --extend-exclude <EXTEND_EXCLUDE>
+          Like --exclude, but adds additional files and directories on top of the excluded ones
+      --per-file-ignores <PER_FILE_IGNORES>
+          List of mappings from file pattern to code to exclude
+      --format <FORMAT>
+          Output serialization format for error messages [default: text] [possible values: text, json]
+      --show-files
+          See the files ruff will be run against with the current settings
+      --show-settings
+          See ruff's settings
+      --add-noqa
+          Enable automatic additions of noqa directives to failing lines
+      --dummy-variable-rgx <DUMMY_VARIABLE_RGX>
+          Regular expression matching the name of dummy variables
+      --target-version <TARGET_VERSION>
+          The minimum Python version that should be supported
+      --stdin-filename <STDIN_FILENAME>
+          The name of the file when passing it through stdin
+  -h, --help
+          Print help information
+  -V, --version
+          Print version information
 ```
 
+### Excluding files
+
 Exclusions are based on globs, and can be either:
 
 - Single-path patterns, like `.mypy_cache` (to exclude any directory named `.mypy_cache` in the
@@ -138,99 +197,470 @@ Exclusions are based on globs, and can be either:
   (to exclude any Python files in `directory`). Note that these paths are relative to the
   project root (e.g., the directory containing your `pyproject.toml`).
 
-### Compatibility with Black
+### Ignoring errors
 
-ruff is compatible with [Black](https://github.com/psf/black) out-of-the-box, as long as
+To omit a lint check entirely, add it to the "ignore" list via `--ignore` or `--extend-ignore`,
+either  on the command-line or in your `project.toml` file.
+
+To ignore an error in-line, Ruff uses a `noqa` system similar to [Flake8](https://flake8.pycqa.org/en/3.1.1/user/ignoring-errors.html).
+To ignore an individual error, add `# noqa: {code}` to the end of the line, like so:
+
+```python
+# Ignore F841.
+x = 1  # noqa: F841
+
+# Ignore E741 and F841.
+i = 1  # noqa: E741, F841
+
+# Ignore _all_ errors.
+x = 1  # noqa
+```
+
+Note that, for multi-line strings, the `noqa` directive should come at the end of the string, and
+will apply to the entire body, like so:
+
+```python
+"""Lorem ipsum dolor sit amet.
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501
+```
+
+Ruff supports several workflows to aid in `noqa` management.
+
+First, Ruff provides a special error code, `M001`, to enforce that your `noqa` directives are
+"valid", in that the errors they _say_ they ignore are actually being triggered on that line (and
+thus suppressed). **You can run `ruff /path/to/file.py --extend-select M001` to flag unused `noqa`
+directives.**
+
+Second, Ruff can _automatically remove_ unused `noqa` directives via its autofix functionality.
+**You can run `ruff /path/to/file.py --extend-select M001 --fix` to automatically remove unused
+`noqa` directives.**
+
+Third, Ruff can _automatically add_ `noqa` directives to all failing lines. This is useful when
+migrating a new codebase to Ruff. **You can run `ruff /path/to/file.py --add-noqa` to automatically
+add `noqa` directives to all failing lines, with the appropriate error codes.**
+
+## Supported Rules
+
+By default, Ruff enables all `E` and `F` error codes, which correspond to those built-in to Flake8.
+
+The 🛠 emoji indicates that a rule is automatically fixable by the `--fix` command-line option.
+
+### Pyflakes
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| F401 | UnusedImport | `...` imported but unused | 🛠 |
+| F402 | ImportShadowedByLoopVar | Import `...` from line 1 shadowed by loop variable |  |
+| F403 | ImportStarUsed | `from ... import *` used; unable to detect undefined names |  |
+| F404 | LateFutureImport | `from __future__` imports must occur at the beginning of the file |  |
+| F405 | ImportStarUsage | `...` may be undefined, or defined from star imports: `...` |  |
+| F406 | ImportStarNotPermitted | `from ... import *` only allowed at module level |  |
+| F407 | FutureFeatureNotDefined | Future feature `...` is not defined |  |
+| F541 | FStringMissingPlaceholders | f-string without any placeholders |  |
+| F601 | MultiValueRepeatedKeyLiteral | Dictionary key literal repeated |  |
+| F602 | MultiValueRepeatedKeyVariable | Dictionary key `...` repeated |  |
+| F621 | ExpressionsInStarAssignment | Too many expressions in star-unpacking assignment |  |
+| F622 | TwoStarredExpressions | Two starred expressions in assignment |  |
+| F631 | AssertTuple | Assert test is a non-empty tuple, which is always `True` |  |
+| F632 | IsLiteral | Use `==` and `!=` to compare constant literals |  |
+| F633 | InvalidPrintSyntax | Use of `>>` is invalid with `print` function |  |
+| F634 | IfTuple | If test is a tuple, which is always `True` |  |
+| F701 | BreakOutsideLoop | `break` outside loop |  |
+| F702 | ContinueOutsideLoop | `continue` not properly in loop |  |
+| F704 | YieldOutsideFunction | `yield` or `yield from` statement outside of a function |  |
+| F706 | ReturnOutsideFunction | `return` statement outside of a function/method |  |
+| F707 | DefaultExceptNotLast | An `except:` block as not the last exception handler |  |
+| F722 | ForwardAnnotationSyntaxError | Syntax error in forward annotation: `...` |  |
+| F821 | UndefinedName | Undefined name `...` |  |
+| F822 | UndefinedExport | Undefined name `...` in `__all__` |  |
+| F823 | UndefinedLocal | Local variable `...` referenced before assignment |  |
+| F831 | DuplicateArgumentName | Duplicate argument name in function definition |  |
+| F841 | UnusedVariable | Local variable `...` is assigned to but never used |  |
+| F901 | RaiseNotImplemented | `raise NotImplemented` should be `raise NotImplementedError` |  |
+
+### pycodestyle (error)
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| E402 | ModuleImportNotAtTopOfFile | Module level import not at top of file |  |
+| E501 | LineTooLong | Line too long (89 > 88 characters) |  |
+| E711 | NoneComparison | Comparison to `None` should be `cond is None` |  |
+| E712 | TrueFalseComparison | Comparison to `True` should be `cond is True` |  |
+| E713 | NotInTest | Test for membership should be `not in` |  |
+| E714 | NotIsTest | Test for object identity should be `is not` |  |
+| E721 | TypeComparison | Do not compare types, use `isinstance()` |  |
+| E722 | DoNotUseBareExcept | Do not use bare `except` |  |
+| E731 | DoNotAssignLambda | Do not assign a lambda expression, use a def |  |
+| E741 | AmbiguousVariableName | Ambiguous variable name: `...` |  |
+| E742 | AmbiguousClassName | Ambiguous class name: `...` |  |
+| E743 | AmbiguousFunctionName | Ambiguous function name: `...` |  |
+| E902 | IOError | IOError: `...` |  |
+| E999 | SyntaxError | SyntaxError: `...` |  |
+
+### pycodestyle (warning)
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| W292 | NoNewLineAtEndOfFile | No newline at end of file |  |
+| W605 | InvalidEscapeSequence | Invalid escape sequence: '\c' |  |
+
+### pydocstyle
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| D100 | PublicModule | Missing docstring in public module |  |
+| D101 | PublicClass | Missing docstring in public class |  |
+| D102 | PublicMethod | Missing docstring in public method |  |
+| D103 | PublicFunction | Missing docstring in public function |  |
+| D104 | PublicPackage | Missing docstring in public package |  |
+| D105 | MagicMethod | Missing docstring in magic method |  |
+| D106 | PublicNestedClass | Missing docstring in public nested class |  |
+| D107 | PublicInit | Missing docstring in `__init__` |  |
+| D200 | FitsOnOneLine | One-line docstring should fit on one line |  |
+| D201 | NoBlankLineBeforeFunction | No blank lines allowed before function docstring (found 1) | 🛠 |
+| D202 | NoBlankLineAfterFunction | No blank lines allowed after function docstring (found 1) | 🛠 |
+| D203 | OneBlankLineBeforeClass | 1 blank line required before class docstring | 🛠 |
+| D204 | OneBlankLineAfterClass | 1 blank line required after class docstring | 🛠 |
+| D205 | BlankLineAfterSummary | 1 blank line required between summary line and description | 🛠 |
+| D206 | IndentWithSpaces | Docstring should be indented with spaces, not tabs |  |
+| D207 | NoUnderIndentation | Docstring is under-indented | 🛠 |
+| D208 | NoOverIndentation | Docstring is over-indented | 🛠 |
+| D209 | NewLineAfterLastParagraph | Multi-line docstring closing quotes should be on a separate line | 🛠 |
+| D210 | NoSurroundingWhitespace | No whitespaces allowed surrounding docstring text | 🛠 |
+| D211 | NoBlankLineBeforeClass | No blank lines allowed before class docstring | 🛠 |
+| D212 | MultiLineSummaryFirstLine | Multi-line docstring summary should start at the first line |  |
+| D213 | MultiLineSummarySecondLine | Multi-line docstring summary should start at the second line |  |
+| D214 | SectionNotOverIndented | Section is over-indented ("Returns") | 🛠 |
+| D215 | SectionUnderlineNotOverIndented | Section underline is over-indented ("Returns") | 🛠 |
+| D300 | UsesTripleQuotes | Use """triple double quotes""" |  |
+| D400 | EndsInPeriod | First line should end with a period |  |
+| D402 | NoSignature | First line should not be the function's signature |  |
+| D403 | FirstLineCapitalized | First word of the first line should be properly capitalized |  |
+| D404 | NoThisPrefix | First word of the docstring should not be 'This' |  |
+| D405 | CapitalizeSectionName | Section name should be properly capitalized ("returns") | 🛠 |
+| D406 | NewLineAfterSectionName | Section name should end with a newline ("Returns") | 🛠 |
+| D407 | DashedUnderlineAfterSection | Missing dashed underline after section ("Returns") | 🛠 |
+| D408 | SectionUnderlineAfterName | Section underline should be in the line following the section's name ("Returns") | 🛠 |
+| D409 | SectionUnderlineMatchesSectionLength | Section underline should match the length of its name ("Returns") | 🛠 |
+| D410 | BlankLineAfterSection | Missing blank line after section ("Returns") | 🛠 |
+| D411 | BlankLineBeforeSection | Missing blank line before section ("Returns") | 🛠 |
+| D412 | NoBlankLinesBetweenHeaderAndContent | No blank lines allowed between a section header and its content ("Returns") | 🛠 |
+| D413 | BlankLineAfterLastSection | Missing blank line after last section ("Returns") | 🛠 |
+| D414 | NonEmptySection | Section has no content ("Returns") |  |
+| D415 | EndsInPunctuation | First line should end with a period, question mark, or exclamation point |  |
+| D416 | SectionNameEndsInColon | Section name should end with a colon ("Returns") | 🛠 |
+| D417 | DocumentAllArguments | Missing argument descriptions in the docstring: `x`, `y` |  |
+| D418 | SkipDocstring | Function decorated with `@overload` shouldn't contain a docstring |  |
+| D419 | NonEmpty | Docstring is empty |  |
+
+### pyupgrade
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| U001 | UselessMetaclassType | `__metaclass__ = type` is implied | 🛠 |
+| U002 | UnnecessaryAbspath | `abspath(__file__)` is unnecessary in Python 3.9 and later | 🛠 |
+| U003 | TypeOfPrimitive | Use `str` instead of `type(...)` | 🛠 |
+| U004 | UselessObjectInheritance | Class `...` inherits from object | 🛠 |
+| U005 | DeprecatedUnittestAlias | `assertEquals` is deprecated, use `assertEqual` instead | 🛠 |
+| U006 | UsePEP585Annotation | Use `list` instead of `List` for type annotations | 🛠 |
+| U007 | UsePEP604Annotation | Use `X \| Y` for type annotations | 🛠 |
+| U008 | SuperCallWithParameters | Use `super()` instead of `super(__class__, self)` | 🛠 |
+
+### pep8-naming
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| N801 | InvalidClassName | Class name `...` should use CapWords convention  |  |
+| N802 | InvalidFunctionName | Function name `...` should be lowercase |  |
+| N803 | InvalidArgumentName | Argument name `...` should be lowercase |  |
+| N804 | InvalidFirstArgumentNameForClassMethod | First argument of a class method should be named `cls` |  |
+| N805 | InvalidFirstArgumentNameForMethod | First argument of a method should be named `self` |  |
+| N806 | NonLowercaseVariableInFunction | Variable `...` in function should be lowercase |  |
+| N807 | DunderFunctionName | Function name should not start and end with `__` |  |
+| N811 | ConstantImportedAsNonConstant | Constant `...` imported as non-constant `...` |  |
+| N812 | LowercaseImportedAsNonLowercase | Lowercase `...` imported as non-lowercase `...` |  |
+| N813 | CamelcaseImportedAsLowercase | Camelcase `...` imported as lowercase `...` |  |
+| N814 | CamelcaseImportedAsConstant | Camelcase `...` imported as constant `...` |  |
+| N815 | MixedCaseVariableInClassScope | Variable `mixedCase` in class scope should not be mixedCase |  |
+| N816 | MixedCaseVariableInGlobalScope | Variable `mixedCase` in global scope should not be mixedCase |  |
+| N817 | CamelcaseImportedAsAcronym | Camelcase `...` imported as acronym `...` |  |
+| N818 | ErrorSuffixOnExceptionName | Exception name `...` should be named with an Error suffix |  |
+
+### flake8-comprehensions
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| C400 | UnnecessaryGeneratorList | Unnecessary generator (rewrite as a `list` comprehension) | 🛠 |
+| C401 | UnnecessaryGeneratorSet | Unnecessary generator (rewrite as a `set` comprehension) | 🛠 |
+| C402 | UnnecessaryGeneratorDict | Unnecessary generator (rewrite as a `dict` comprehension) | 🛠 |
+| C403 | UnnecessaryListComprehensionSet | Unnecessary `list` comprehension (rewrite as a `set` comprehension) | 🛠 |
+| C404 | UnnecessaryListComprehensionDict | Unnecessary `list` comprehension (rewrite as a `dict` comprehension) |  |
+| C405 | UnnecessaryLiteralSet | Unnecessary `(list\|tuple)` literal (rewrite as a `set` literal) | 🛠 |
+| C406 | UnnecessaryLiteralDict | Unnecessary `(list\|tuple)` literal (rewrite as a `dict` literal) |  |
+| C408 | UnnecessaryCollectionCall | Unnecessary `(dict\|list\|tuple)` call (rewrite as a literal) | 🛠 |
+| C409 | UnnecessaryLiteralWithinTupleCall | Unnecessary `(list\|tuple)` literal passed to `tuple()` (remove the outer call to `tuple()`) | 🛠 |
+| C410 | UnnecessaryLiteralWithinListCall | Unnecessary `(list\|tuple)` literal passed to `list()` (rewrite as a `list` literal) | 🛠 |
+| C411 | UnnecessaryListCall | Unnecessary `list` call (remove the outer call to `list()`) | 🛠 |
+| C413 | UnnecessaryCallAroundSorted | Unnecessary `(list\|reversed)` call around `sorted()` |  |
+| C414 | UnnecessaryDoubleCastOrProcess | Unnecessary `(list\|reversed\|set\|sorted\|tuple)` call within `(list\|set\|sorted\|tuple)()` |  |
+| C415 | UnnecessarySubscriptReversal | Unnecessary subscript reversal of iterable within `(reversed\|set\|sorted)()` |  |
+| C416 | UnnecessaryComprehension | Unnecessary `(list\|set)` comprehension (rewrite using `(list\|set)()`) |  |
+| C417 | UnnecessaryMap | Unnecessary `map` usage (rewrite using a `(list\|set\|dict)` comprehension) |  |
+
+### flake8-bugbear
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| B002 | UnaryPrefixIncrement | Python does not support the unary prefix increment. |  |
+| B006 | MutableArgumentDefault | Do not use mutable data structures for argument defaults. |  |
+| B007 | UnusedLoopControlVariable | Loop control variable `i` not used within the loop body. | 🛠 |
+| B011 | DoNotAssertFalse | Do not `assert False` (`python -O` removes these calls), raise `AssertionError()` | 🛠 |
+| B013 | RedundantTupleInExceptionHandler | A length-one tuple literal is redundant. Write `except ValueError:` instead of `except (ValueError,):`. |  |
+| B014 | DuplicateHandlerException | Exception handler with duplicate exception: `ValueError` | 🛠 |
+| B017 | NoAssertRaisesException | `assertRaises(Exception):` should be considered evil. |  |
+| B025 | DuplicateTryBlockException | try-except block with duplicate exception `Exception` |  |
+
+### flake8-builtins
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| A001 | BuiltinVariableShadowing | Variable `...` is shadowing a python builtin |  |
+| A002 | BuiltinArgumentShadowing | Argument `...` is shadowing a python builtin |  |
+| A003 | BuiltinAttributeShadowing | Class attribute `...` is shadowing a python builtin |  |
+
+### flake8-print
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| T201 | PrintFound | `print` found | 🛠 |
+| T203 | PPrintFound | `pprint` found | 🛠 |
+
+### flake8-quotes
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| Q000 | BadQuotesInlineString | Single quotes found but double quotes preferred |  |
+| Q001 | BadQuotesMultilineString | Single quote multiline found but double quotes preferred |  |
+| Q002 | BadQuotesDocstring | Single quote docstring found but double quotes preferred |  |
+| Q003 | AvoidQuoteEscape | Change outer quotes to avoid escaping inner quotes |  |
+
+### Meta rules
+
+| Code | Name | Message | Fix |
+| ---- | ---- | ------- | --- |
+| M001 | UnusedNOQA | Unused `noqa` directive | 🛠 |
+
+## Editor Integrations
+
+### PyCharm
+
+Ruff can be installed as an [External Tool](https://www.jetbrains.com/help/pycharm/configuring-third-party-tools.html)
+in PyCharm. Open the Preferences pane, then navigate to "Tools", then "External Tools". From there,
+add a new tool with the following configuration:
+
+![Install Ruff as an External Tool](https://user-images.githubusercontent.com/1309177/193155720-336e43f0-1a8d-46b4-bc12-e60f9ae01f7e.png)
+
+Ruff should then appear as a runnable action:
+
+![Ruff as a runnable action](https://user-images.githubusercontent.com/1309177/193156026-732b0aaf-3dd9-4549-9b4d-2de6d2168a33.png)
+
+### GitHub Actions
+
+GitHub Actions has everything you need to run Ruff out-of-the-box:
+
+```yaml
+name: CI
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - name: Install Python
+        uses: actions/setup-python@v4
+        with:
+          python-version: "3.10"
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          pip install ruff
+      - name: Run Ruff
+        run: ruff .
+```
+
+## FAQ
+
+### Is Ruff compatible with Black?
+
+Yes. Ruff is compatible with [Black](https://github.com/psf/black) out-of-the-box, as long as
 the `line-length` setting is consistent between the two.
 
-As a project, ruff is designed to be used alongside Black and, as such, will defer implementing
+As a project, Ruff is designed to be used alongside Black and, as such, will defer implementing
 stylistic lint rules that are obviated by autoformatting.
 
-### Parity with Flake8
+### How does Ruff compare to Flake8?
 
-ruff's goal is to achieve feature-parity with Flake8 when used (1) without plugins, (2) alongside
-Black, and (3) on Python 3 code.
+Ruff can be used as a (near) drop-in replacement for Flake8 when used (1) without or with a small
+number of plugins, (2) alongside Black, and (3) on Python 3 code.
 
-**Under those conditions, ruff implements 44 out of 60 rules.** (ruff is missing: 14 rules related
-to string `.format` calls, 1 rule related to docstring parsing, and 1 rule related to redefined
-variables.)
+Under those conditions Ruff is missing 14 rules related to string `.format` calls, 1 rule related
+to docstring parsing, and 1 rule related to redefined variables.
 
-Beyond rule-set parity, ruff suffers from the following limitations vis-à-vis Flake8:
+Ruff re-implements some of the most popular Flake8 plugins and related code quality tools natively,
+including:
 
-1. Flake8 has a plugin architecture and supports writing custom lint rules.
-2. Flake8 supports a wider range of `noqa` patterns, such as per-file ignores defined in `.flake8`.
-3. ruff does not yet support parenthesized context managers.
+- [`pydocstyle`](https://pypi.org/project/pydocstyle/)
+- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
+- [`yesqa`](https://github.com/asottile/yesqa)
+- [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
+- [`flake8-builtins`](https://pypi.org/project/flake8-builtins/)
+- [`flake8-super`](https://pypi.org/project/flake8-super/)
+- [`flake8-print`](https://pypi.org/project/flake8-print/)
+- [`flake8-quotes`](https://pypi.org/project/flake8-quotes/)
+- [`flake8-comprehensions`](https://pypi.org/project/flake8-comprehensions/)
+- [`flake8-bugbear`](https://pypi.org/project/flake8-bugbear/) (10/32)
+- [`pyupgrade`](https://pypi.org/project/pyupgrade/) (10/34)
+- [`autoflake`](https://pypi.org/project/autoflake/) (1/7)
 
-## Rules
+Beyond rule-set parity, Ruff suffers from the following limitations vis-à-vis Flake8:
 
-| Code | Name | Message |
-| ---- | ----- | ------- |
-| E402 | ModuleImportNotAtTopOfFile | Module level import not at top of file |
-| E501 | LineTooLong | Line too long (89 > 88 characters) |
-| E711 | NoneComparison | Comparison to `None` should be `cond is None` |
-| E712 | TrueFalseComparison | Comparison to `True` should be `cond is True` |
-| E713 | NotInTest | Test for membership should be `not in` |
-| E714 | NotIsTest | Test for object identity should be `is not` |
-| E721 | TypeComparison | do not compare types, use `isinstance()` |
-| E722 | DoNotUseBareExcept | Do not use bare `except` |
-| E731 | DoNotAssignLambda | Do not assign a lambda expression, use a def |
-| E741 | AmbiguousVariableName | ambiguous variable name '...' |
-| E742 | AmbiguousClassName | ambiguous class name '...' |
-| E743 | AmbiguousFunctionName | ambiguous function name '...' |
-| E902 | IOError | ... |
-| E999 | SyntaxError | SyntaxError: ... |
-| F401 | UnusedImport | `...` imported but unused |
-| F402 | ImportShadowedByLoopVar | import '...' from line 1 shadowed by loop variable |
-| F403 | ImportStarUsed | `from ... import *` used; unable to detect undefined names |
-| F404 | LateFutureImport | from __future__ imports must occur at the beginning of the file |
-| F405 | ImportStarUsage | '...' may be undefined, or defined from star imports: ... |
-| F406 | ImportStarNotPermitted | `from ... import *` only allowed at module level |
-| F407 | FutureFeatureNotDefined | future feature '...' is not defined |
-| F541 | FStringMissingPlaceholders | f-string without any placeholders |
-| F601 | MultiValueRepeatedKeyLiteral | Dictionary key literal repeated |
-| F602 | MultiValueRepeatedKeyVariable | Dictionary key `...` repeated |
-| F621 | TooManyExpressionsInStarredAssignment | too many expressions in star-unpacking assignment |
-| F622 | TwoStarredExpressions | two starred expressions in assignment |
-| F631 | AssertTuple | Assert test is a non-empty tuple, which is always `True` |
-| F632 | IsLiteral | use ==/!= to compare constant literals |
-| F633 | InvalidPrintSyntax | use of >> is invalid with print function |
-| F634 | IfTuple | If test is a tuple, which is always `True` |
-| F701 | BreakOutsideLoop | `break` outside loop |
-| F702 | ContinueOutsideLoop | `continue` not properly in loop |
-| F704 | YieldOutsideFunction | a `yield` or `yield from` statement outside of a function/method |
-| F706 | ReturnOutsideFunction | a `return` statement outside of a function/method |
-| F707 | DefaultExceptNotLast | an `except:` block as not the last exception handler |
-| F722 | ForwardAnnotationSyntaxError | syntax error in forward annotation '...' |
-| F821 | UndefinedName | Undefined name `...` |
-| F822 | UndefinedExport | Undefined name `...` in `__all__` |
-| F823 | UndefinedLocal | Local variable `...` referenced before assignment |
-| F831 | DuplicateArgumentName | Duplicate argument name in function definition |
-| F841 | UnusedVariable | Local variable `...` is assigned to but never used |
-| F901 | RaiseNotImplemented | `raise NotImplemented` should be `raise NotImplementedError` |
-| R001 | UselessObjectInheritance | Class `...` inherits from object |
-| R002 | NoAssertEquals | `assertEquals` is deprecated, use `assertEqual` instead |
+1. Ruff does not yet support a few Python 3.9 and 3.10 language features, including structural
+   pattern matching and parenthesized context managers.
+2. Flake8 has a plugin architecture and supports writing custom lint rules. (To date, popular Flake8
+   plugins have been re-implemented within Ruff directly.)
+
+### Which tools does Ruff replace?
+
+Today, Ruff can be used to replace Flake8 when used with any of the following plugins:
+
+- [`pep8-naming`](https://pypi.org/project/pep8-naming/)
+- [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
+- [`flake8-builtins`](https://pypi.org/project/flake8-builtins/)
+- [`flake8-super`](https://pypi.org/project/flake8-super/)
+- [`flake8-print`](https://pypi.org/project/flake8-print/)
+- [`flake8-quotes`](https://pypi.org/project/flake8-quotes/)
+- [`flake8-comprehensions`](https://pypi.org/project/flake8-comprehensions/)
+- [`flake8-bugbear`](https://pypi.org/project/flake8-bugbear/) (10/32)
+
+Ruff also implements the functionality that you get from [`yesqa`](https://github.com/asottile/yesqa),
+and a subset of the rules implemented in [`pyupgrade`](https://pypi.org/project/pyupgrade/) (10/34).
+
+If you're looking to use Ruff, but rely on an unsupported Flake8 plugin, free to file an Issue.
+
+### Do I need to install Rust to use Ruff?
+
+Nope! Ruff is available as [`ruff`](https://pypi.org/project/ruff/) on PyPI:
+
+```shell
+pip install ruff
+```
+
+Ruff ships with wheels for all major platforms, which enables `pip` to install Ruff without relying
+on Rust at all.
+
+### Can I write my own plugins for Ruff?
+
+Ruff does not yet support third-party plugins, though a plugin system is within-scope for the
+project. See [#283](https://github.com/charliermarsh/ruff/issues/283) for more.
+
+### Does Ruff support NumPy- or Google-style docstrings?
+
+Yes! To enable a specific docstring convention, start by enabling all `pydocstyle` error codes, and
+then selectively disabling based on your [preferred convention](https://www.pydocstyle.org/en/latest/error_codes.html#default-conventions).
+
+For example, if you're coming from `flake8-docstrings`, the following configuration is equivalent to
+`--docstring-convention=numpy`:
+
+```toml
+[tool.ruff]
+extend-select = ["D"]
+extend-ignore = [
+    "D107",
+    "D203",
+    "D212",
+    "D213",
+    "D402",
+    "D413",
+    "D415",
+    "D416",
+    "D417",
+]
+```
+
+Similarly, the following is equivalent to `--docstring-convention=google`:
+
+```toml
+[tool.ruff]
+extend-select = ["D"]
+extend-ignore = [
+    "D203",
+    "D204",
+    "D213",
+    "D215",
+    "D400",
+    "D404",
+    "D406",
+    "D407",
+    "D408",
+    "D409",
+    "D413",
+]
+```
+
+Similarly, the following is equivalent to `--docstring-convention=pep8`:
+
+```toml
+[tool.ruff]
+extend-select = ["D"]
+extend-ignore = [
+    "D203",
+    "D212",
+    "D213",
+    "D214",
+    "D215",
+    "D404",
+    "D405",
+    "D406",
+    "D407",
+    "D408",
+    "D409",
+    "D410",
+    "D411",
+    "D413",
+    "D415",
+    "D416",
+    "D417",
+]
+```
 
 ## Development
 
-ruff is written in Rust (1.63.0). You'll need to install the [Rust toolchain](https://www.rust-lang.org/tools/install)
+Ruff is written in Rust (1.64.0). You'll need to install the [Rust toolchain](https://www.rust-lang.org/tools/install)
 for development.
 
 Assuming you have `cargo` installed, you can run:
 
 ```shell
 cargo run resources/test/fixtures
-cargo fmt
-cargo clippy
-cargo test
 ```
 
-## Deployment
+For development, we use [nightly Rust](https://rust-lang.github.io/rustup/concepts/channels.html#working-with-nightly-rust):
 
-ruff is distributed on [PyPI](https://pypi.org/project/ruff/), and published via [`maturin`](https://github.com/PyO3/maturin).
+```shell
+cargo +nightly fmt
+cargo +nightly clippy
+cargo +nightly test
+```
+
+## Releases
+
+Ruff is distributed on [PyPI](https://pypi.org/project/ruff/), and published via [`maturin`](https://github.com/PyO3/maturin).
 
 See: `.github/workflows/release.yaml`.
 
-## Benchmarking
+## Benchmarks
 
 First, clone [CPython](https://github.com/python/cpython). It's a large and diverse Python codebase,
 which makes it a good target for benchmarking.
@@ -307,9 +737,9 @@ hyperfine --ignore-failure --warmup 5 \
 
 In order, these evaluate:
 
-- ruff
+- Ruff
 - Pylint
-- PyFlakes
+- Pyflakes
 - autoflake
 - pycodestyle
 - Flake8
@@ -369,3 +799,8 @@ Summary
 ## License
 
 MIT
+
+## Contributing
+
+Contributions are welcome and hugely appreciated. To get started, check out the
+[contributing guidelines](https://github.com/charliermarsh/ruff/blob/main/CONTRIBUTING.md).

benches/source_code_locator.rs

@@ -0,0 +1,15 @@
+use std::path::Path;
+
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use ruff::fs;
+use ruff::source_code_locator::compute_offsets;
+
+fn criterion_benchmark(c: &mut Criterion) {
+    let contents = fs::read_file(Path::new("resources/test/fixtures/D.py")).unwrap();
+    c.bench_function("compute_offsets", |b| {
+        b.iter(|| compute_offsets(black_box(&contents)))
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);

crates/flake8_to_ruff/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "flake8-to-ruff"
+version = "0.0.96-dev.0"
+edition = "2021"
+
+[lib]
+name = "flake8_to_ruff"
+
+[dependencies]
+anyhow = { version = "1.0.60" }
+clap = { version = "4.0.1", features = ["derive"] }
+configparser = { version = "3.0.2" }
+once_cell = { version = "1.13.1" }
+regex = { version = "1.6.0" }
+ruff = { path = "../..", default-features = false }
+serde = { version = "1.0.143", features = ["derive"] }
+serde_json = { version = "1.0.83" }
+toml = { version = "0.5.9" }
+
+[dev-dependencies]
+
+[features]

crates/flake8_to_ruff/README.md

@@ -0,0 +1,47 @@
+# flake8-to-ruff
+
+Convert existing Flake8 configuration files (`setup.cfg`, `tox.ini`, or `.flake8`) for use with
+[Ruff](https://github.com/charliermarsh/ruff).
+
+Generates a Ruff-compatible `pyproject.toml` section.
+
+## Installation and Usage
+
+### Installation
+
+Available as [`flake8-to-ruff`](https://pypi.org/project/flake8-to-ruff/) on PyPI:
+
+```shell
+pip install flake8-to-ruff
+```
+
+### Usage
+
+To run Ruff, try any of the following:
+
+```shell
+flake8-to-ruff path/to/setup.cfg
+flake8-to-ruff path/to/tox.ini
+flake8-to-ruff path/to/.flake8
+```
+
+## Limitations
+
+1. Ruff only supports a subset of the Flake configuration options. `flake8-to-ruff` will warn on and
+   ignore unsupported options in the `.flake8` file (or equivalent). (Similarly, Ruff has a few
+   configuration options that don't exist in Flake8.)
+2. Ruff will omit any error codes that are unimplemented or unsupported by Ruff, including error
+   codes from unsupported plugins. (See the [Ruff README](https://github.com/charliermarsh/ruff#user-content-how-does-ruff-compare-to-flake8)
+   for the complete list of supported plugins.)
+3. `flake8-to-ruff` does not auto-detect your Flake8 plugins, so any reliance on Flake8 plugins that
+   implicitly enable third-party checks will be ignored. Instead, add those error codes to your
+   `select` or `extend-select` fields, so that `flake8-to-ruff` can pick them up.
+
+## License
+
+MIT
+
+## Contributing
+
+Contributions are welcome and hugely appreciated. To get started, check out the
+[contributing guidelines](https://github.com/charliermarsh/ruff/blob/main/CONTRIBUTING.md).

crates/flake8_to_ruff/pyproject.toml

@@ -0,0 +1,33 @@
+[project]
+name = "flake8-to-ruff"
+keywords = ["automation", "flake8", "pycodestyle", "pyflakes", "pylint", "clippy"]
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Environment :: Console",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Operating System :: OS Independent",
+    "Programming Language :: Python",
+    "Programming Language :: Python :: 3.7",
+    "Programming Language :: Python :: 3.8",
+    "Programming Language :: Python :: 3.9",
+    "Programming Language :: Python :: 3.10",
+    "Programming Language :: Python :: 3 :: Only",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+    "Topic :: Software Development :: Quality Assurance",
+]
+author = "Charlie Marsh"
+author_email = "charlie.r.marsh@gmail.com"
+description = "Convert existing Flake8 configuration to Ruff."
+requires-python = ">=3.7"
+
+[project.urls]
+repository = "https://github.com/charliermarsh/ruff#subdirectory=crates/flake8_to_ruff"
+
+[build-system]
+requires = ["maturin>=0.13,<0.14"]
+build-backend = "maturin"
+
+[tool.maturin]
+bindings = "bin"
+strip = true

crates/flake8_to_ruff/src/converter.rs

@@ -0,0 +1,243 @@
+use std::collections::HashMap;
+
+use anyhow::Result;
+use ruff::flake8_quotes::settings::Quote;
+use ruff::settings::options::Options;
+use ruff::settings::pyproject::Pyproject;
+use ruff::{flake8_quotes, pep8_naming};
+
+use crate::parser;
+
+pub fn convert(config: HashMap<String, HashMap<String, Option<String>>>) -> Result<Pyproject> {
+    // Extract the Flake8 section.
+    let flake8 = config
+        .get("flake8")
+        .expect("Unable to find flake8 section in INI file.");
+
+    // Parse each supported option.
+    let mut options: Options = Default::default();
+    let mut flake8_quotes: flake8_quotes::settings::Options = Default::default();
+    let mut pep8_naming: pep8_naming::settings::Options = Default::default();
+    for (key, value) in flake8 {
+        if let Some(value) = value {
+            match key.as_str() {
+                // flake8
+                "max-line-length" | "max_line_length" => match value.clone().parse::<usize>() {
+                    Ok(line_length) => options.line_length = Some(line_length),
+                    Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                },
+                "select" => {
+                    options.select = Some(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "extend-select" | "extend_select" => {
+                    options.extend_select = Some(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "ignore" => {
+                    options.ignore = Some(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "extend-ignore" | "extend_ignore" => {
+                    options.extend_ignore = Some(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "exclude" => {
+                    options.exclude = Some(parser::parse_strings(value.as_ref()));
+                }
+                "extend-exclude" | "extend_exclude" => {
+                    options.extend_exclude = Some(parser::parse_strings(value.as_ref()));
+                }
+                "per-file-ignores" | "per_file_ignores" => {
+                    match parser::parse_files_to_codes_mapping(value.as_ref()) {
+                        Ok(per_file_ignores) => {
+                            options.per_file_ignores =
+                                Some(parser::collect_per_file_ignores(per_file_ignores))
+                        }
+                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    }
+                }
+                // flake8-quotes
+                "quotes" | "inline-quotes" | "inline_quotes" => match value.trim() {
+                    "'" | "single" => flake8_quotes.inline_quotes = Some(Quote::Single),
+                    "\"" | "double" => flake8_quotes.inline_quotes = Some(Quote::Single),
+                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                },
+                "multiline-quotes" | "multiline_quotes" => match value.trim() {
+                    "'" | "single" => flake8_quotes.multiline_quotes = Some(Quote::Single),
+                    "\"" | "double" => flake8_quotes.multiline_quotes = Some(Quote::Single),
+                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                },
+                "docstring-quotes" | "docstring_quotes" => match value.trim() {
+                    "'" | "single" => flake8_quotes.docstring_quotes = Some(Quote::Single),
+                    "\"" | "double" => flake8_quotes.docstring_quotes = Some(Quote::Single),
+                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                },
+                "avoid-escape" | "avoid_escape" => match value.trim() {
+                    "true" => flake8_quotes.avoid_escape = Some(true),
+                    "false" => flake8_quotes.avoid_escape = Some(false),
+                    _ => eprintln!("Unexpected '{key}' value: {value}"),
+                },
+                // pep8-naming
+                "ignore-names" | "ignore_names" => {
+                    pep8_naming.ignore_names = Some(parser::parse_strings(value.as_ref()));
+                }
+                "classmethod-decorators" | "classmethod_decorators" => {
+                    pep8_naming.classmethod_decorators =
+                        Some(parser::parse_strings(value.as_ref()));
+                }
+                "staticmethod-decorators" | "staticmethod_decorators" => {
+                    pep8_naming.staticmethod_decorators =
+                        Some(parser::parse_strings(value.as_ref()));
+                }
+                // Unknown
+                _ => eprintln!("Skipping unsupported property: {key}"),
+            }
+        }
+    }
+
+    if flake8_quotes != Default::default() {
+        options.flake8_quotes = Some(flake8_quotes);
+    }
+    if pep8_naming != Default::default() {
+        options.pep8_naming = Some(pep8_naming);
+    }
+
+    // Create the pyproject.toml.
+    Ok(Pyproject::new(options))
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashMap;
+
+    use anyhow::Result;
+    use ruff::flake8_quotes;
+    use ruff::settings::options::Options;
+    use ruff::settings::pyproject::Pyproject;
+
+    use crate::converter::convert;
+
+    #[test]
+    fn it_converts_empty() -> Result<()> {
+        let actual = convert(HashMap::from([("flake8".to_string(), HashMap::from([]))]))?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            exclude: None,
+            extend_exclude: None,
+            select: None,
+            extend_select: None,
+            ignore: None,
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_quotes: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_dashes() -> Result<()> {
+        let actual = convert(HashMap::from([(
+            "flake8".to_string(),
+            HashMap::from([("max-line-length".to_string(), Some("100".to_string()))]),
+        )]))?;
+        let expected = Pyproject::new(Options {
+            line_length: Some(100),
+            exclude: None,
+            extend_exclude: None,
+            select: None,
+            extend_select: None,
+            ignore: None,
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_quotes: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_underscores() -> Result<()> {
+        let actual = convert(HashMap::from([(
+            "flake8".to_string(),
+            HashMap::from([("max_line_length".to_string(), Some("100".to_string()))]),
+        )]))?;
+        let expected = Pyproject::new(Options {
+            line_length: Some(100),
+            exclude: None,
+            extend_exclude: None,
+            select: None,
+            extend_select: None,
+            ignore: None,
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_quotes: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_ignores_parse_errors() -> Result<()> {
+        let actual = convert(HashMap::from([(
+            "flake8".to_string(),
+            HashMap::from([("max_line_length".to_string(), Some("abc".to_string()))]),
+        )]))?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            exclude: None,
+            extend_exclude: None,
+            select: None,
+            extend_select: None,
+            ignore: None,
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_quotes: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_extensions() -> Result<()> {
+        let actual = convert(HashMap::from([(
+            "flake8".to_string(),
+            HashMap::from([("inline-quotes".to_string(), Some("single".to_string()))]),
+        )]))?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            exclude: None,
+            extend_exclude: None,
+            select: None,
+            extend_select: None,
+            ignore: None,
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_quotes: Some(flake8_quotes::settings::Options {
+                inline_quotes: Some(flake8_quotes::settings::Quote::Single),
+                multiline_quotes: None,
+                docstring_quotes: None,
+                avoid_escape: None,
+            }),
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+}

crates/flake8_to_ruff/src/lib.rs

@@ -0,0 +1,4 @@
+#![allow(clippy::collapsible_if, clippy::collapsible_else_if)]
+
+pub mod converter;
+mod parser;

crates/flake8_to_ruff/src/main.rs

@@ -0,0 +1,35 @@
+//! Utility to generate Ruff's pyproject.toml section from a Flake8 INI file.
+
+use std::path::PathBuf;
+
+use anyhow::Result;
+use clap::Parser;
+use configparser::ini::Ini;
+use flake8_to_ruff::converter;
+
+#[derive(Parser)]
+#[command(
+    about = "Convert existing Flake8 configuration to Ruff.",
+    long_about = None
+)]
+struct Cli {
+    /// Path to the Flake8 configuration file (e.g., 'setup.cfg', 'tox.ini', or
+    /// '.flake8').
+    #[arg(required = true)]
+    file: PathBuf,
+}
+
+fn main() -> Result<()> {
+    let cli = Cli::parse();
+
+    // Read the INI file.
+    let mut ini = Ini::new_cs();
+    ini.set_multiline(true);
+    let config = ini.load(cli.file).map_err(|msg| anyhow::anyhow!(msg))?;
+
+    // Create the pyproject.toml.
+    let pyproject = converter::convert(config)?;
+    println!("{}", toml::to_string_pretty(&pyproject)?);
+
+    Ok(())
+}

crates/flake8_to_ruff/src/parser.rs

@@ -0,0 +1,373 @@
+use std::collections::BTreeMap;
+use std::str::FromStr;
+
+use anyhow::Result;
+use once_cell::sync::Lazy;
+use regex::Regex;
+use ruff::checks_gen::CheckCodePrefix;
+use ruff::settings::types::PatternPrefixPair;
+
+static COMMA_SEPARATED_LIST_RE: Lazy<Regex> = Lazy::new(|| Regex::new(r"[,\s]").unwrap());
+
+/// Parse a comma-separated list of `CheckCodePrefix` values (e.g.,
+/// "F401,E501").
+pub fn parse_prefix_codes(value: &str) -> Vec<CheckCodePrefix> {
+    let mut codes: Vec<CheckCodePrefix> = vec![];
+    for code in COMMA_SEPARATED_LIST_RE.split(value) {
+        let code = code.trim();
+        if code.is_empty() {
+            continue;
+        }
+        if let Ok(code) = CheckCodePrefix::from_str(code) {
+            codes.push(code);
+        } else {
+            eprintln!("Unsupported prefix code: {code}");
+        }
+    }
+    codes
+}
+
+/// Parse a comma-separated list of strings (e.g., "__init__.py,__main__.py").
+pub fn parse_strings(value: &str) -> Vec<String> {
+    COMMA_SEPARATED_LIST_RE
+        .split(value)
+        .map(|part| part.trim())
+        .filter(|part| !part.is_empty())
+        .map(String::from)
+        .collect()
+}
+
+#[derive(Debug)]
+struct Token {
+    token_name: TokenType,
+    src: String,
+}
+
+#[derive(Debug)]
+enum TokenType {
+    Code,
+    File,
+    Colon,
+    Comma,
+    Ws,
+    Eof,
+}
+
+struct State {
+    seen_sep: bool,
+    seen_colon: bool,
+    filenames: Vec<String>,
+    codes: Vec<String>,
+}
+
+impl State {
+    fn new() -> Self {
+        Self {
+            seen_sep: true,
+            seen_colon: false,
+            filenames: vec![],
+            codes: vec![],
+        }
+    }
+
+    /// Generate the list of `StrCheckCodePair` pairs for the current state.
+    fn parse(&self) -> Vec<PatternPrefixPair> {
+        let mut codes: Vec<PatternPrefixPair> = vec![];
+        for code in &self.codes {
+            match CheckCodePrefix::from_str(code) {
+                Ok(code) => {
+                    for filename in &self.filenames {
+                        codes.push(PatternPrefixPair {
+                            pattern: filename.clone(),
+                            prefix: code.clone(),
+                        });
+                    }
+                }
+                Err(_) => eprintln!("Skipping unrecognized prefix: {}", code),
+            }
+        }
+        codes
+    }
+}
+
+/// Tokenize the raw 'files-to-codes' mapping.
+fn tokenize_files_to_codes_mapping(value: &str) -> Vec<Token> {
+    let mut tokens = vec![];
+    let mut i = 0;
+    while i < value.len() {
+        for (token_re, token_name) in [
+            (
+                Regex::new(r"([A-Z]+[0-9]*)(?:$|\s|,)").unwrap(),
+                TokenType::Code,
+            ),
+            (Regex::new(r"([^\s:,]+)").unwrap(), TokenType::File),
+            (Regex::new(r"(\s*:\s*)").unwrap(), TokenType::Colon),
+            (Regex::new(r"(\s*,\s*)").unwrap(), TokenType::Comma),
+            (Regex::new(r"(\s+)").unwrap(), TokenType::Ws),
+        ] {
+            if let Some(cap) = token_re.captures(&value[i..]) {
+                let mat = cap.get(1).unwrap();
+                if mat.start() == 0 {
+                    tokens.push(Token {
+                        token_name,
+                        src: mat.as_str().to_string().trim().to_string(),
+                    });
+                    i += mat.end();
+                    break;
+                }
+            }
+        }
+    }
+    tokens.push(Token {
+        token_name: TokenType::Eof,
+        src: "".to_string(),
+    });
+    tokens
+}
+
+/// Parse a 'files-to-codes' mapping, mimicking Flake8's internal logic.
+///
+/// See: https://github.com/PyCQA/flake8/blob/7dfe99616fc2f07c0017df2ba5fa884158f3ea8a/src/flake8/utils.py#L45
+pub fn parse_files_to_codes_mapping(value: &str) -> Result<Vec<PatternPrefixPair>> {
+    if value.trim().is_empty() {
+        return Ok(vec![]);
+    }
+    let mut codes: Vec<PatternPrefixPair> = vec![];
+    let mut state = State::new();
+    for token in tokenize_files_to_codes_mapping(value) {
+        if matches!(token.token_name, TokenType::Comma | TokenType::Ws) {
+            state.seen_sep = true;
+        } else if !state.seen_colon {
+            if matches!(token.token_name, TokenType::Colon) {
+                state.seen_colon = true;
+                state.seen_sep = true;
+            } else if state.seen_sep && matches!(token.token_name, TokenType::File) {
+                state.filenames.push(token.src);
+                state.seen_sep = false;
+            } else {
+                return Err(anyhow::anyhow!("Unexpected token: {:?}", token.token_name));
+            }
+        } else {
+            if matches!(token.token_name, TokenType::Eof) {
+                codes.extend(state.parse());
+                state = State::new();
+            } else if state.seen_sep && matches!(token.token_name, TokenType::Code) {
+                state.codes.push(token.src);
+                state.seen_sep = false;
+            } else if state.seen_sep && matches!(token.token_name, TokenType::File) {
+                codes.extend(state.parse());
+                state = State::new();
+                state.filenames.push(token.src);
+                state.seen_sep = false;
+            } else {
+                return Err(anyhow::anyhow!("Unexpected token: {:?}", token.token_name));
+            }
+        }
+    }
+    Ok(codes)
+}
+
+/// Collect a list of `PatternPrefixPair` structs as a `BTreeMap`.
+pub fn collect_per_file_ignores(
+    pairs: Vec<PatternPrefixPair>,
+) -> BTreeMap<String, Vec<CheckCodePrefix>> {
+    let mut per_file_ignores: BTreeMap<String, Vec<CheckCodePrefix>> = BTreeMap::new();
+    for pair in pairs {
+        per_file_ignores
+            .entry(pair.pattern)
+            .or_insert_with(Vec::new)
+            .push(pair.prefix);
+    }
+    per_file_ignores
+}
+
+#[cfg(test)]
+mod tests {
+    use anyhow::Result;
+    use ruff::checks_gen::CheckCodePrefix;
+    use ruff::settings::types::PatternPrefixPair;
+
+    use crate::parser::{parse_files_to_codes_mapping, parse_prefix_codes, parse_strings};
+
+    #[test]
+    fn it_parses_prefix_codes() {
+        let actual = parse_prefix_codes("");
+        let expected: Vec<CheckCodePrefix> = vec![];
+        assert_eq!(actual, expected);
+
+        let actual = parse_prefix_codes(" ");
+        let expected: Vec<CheckCodePrefix> = vec![];
+        assert_eq!(actual, expected);
+
+        let actual = parse_prefix_codes("F401");
+        let expected = vec![CheckCodePrefix::F401];
+        assert_eq!(actual, expected);
+
+        let actual = parse_prefix_codes("F401,");
+        let expected = vec![CheckCodePrefix::F401];
+        assert_eq!(actual, expected);
+
+        let actual = parse_prefix_codes("F401,E501");
+        let expected = vec![CheckCodePrefix::F401, CheckCodePrefix::E501];
+        assert_eq!(actual, expected);
+
+        let actual = parse_prefix_codes("F401, E501");
+        let expected = vec![CheckCodePrefix::F401, CheckCodePrefix::E501];
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn it_parses_strings() {
+        let actual = parse_strings("");
+        let expected: Vec<String> = vec![];
+        assert_eq!(actual, expected);
+
+        let actual = parse_strings(" ");
+        let expected: Vec<String> = vec![];
+        assert_eq!(actual, expected);
+
+        let actual = parse_strings("__init__.py");
+        let expected = vec!["__init__.py".to_string()];
+        assert_eq!(actual, expected);
+
+        let actual = parse_strings("__init__.py,");
+        let expected = vec!["__init__.py".to_string()];
+        assert_eq!(actual, expected);
+
+        let actual = parse_strings("__init__.py,__main__.py");
+        let expected = vec!["__init__.py".to_string(), "__main__.py".to_string()];
+        assert_eq!(actual, expected);
+
+        let actual = parse_strings("__init__.py, __main__.py");
+        let expected = vec!["__init__.py".to_string(), "__main__.py".to_string()];
+        assert_eq!(actual, expected);
+    }
+
+    #[test]
+    fn it_parse_files_to_codes_mapping() -> Result<()> {
+        let actual = parse_files_to_codes_mapping("")?;
+        let expected: Vec<PatternPrefixPair> = vec![];
+        assert_eq!(actual, expected);
+
+        let actual = parse_files_to_codes_mapping(" ")?;
+        let expected: Vec<PatternPrefixPair> = vec![];
+        assert_eq!(actual, expected);
+
+        // Ex) locust
+        let actual = parse_files_to_codes_mapping(
+            "per-file-ignores =
+    locust/test/*: F841
+    examples/*: F841
+    *.pyi: E302,E704"
+                .strip_prefix("per-file-ignores =")
+                .unwrap(),
+        )?;
+        let expected: Vec<PatternPrefixPair> = vec![
+            PatternPrefixPair {
+                pattern: "locust/test/*".to_string(),
+                prefix: CheckCodePrefix::F841,
+            },
+            PatternPrefixPair {
+                pattern: "examples/*".to_string(),
+                prefix: CheckCodePrefix::F841,
+            },
+        ];
+        assert_eq!(actual, expected);
+
+        // Ex) celery
+        let actual = parse_files_to_codes_mapping(
+            "per-file-ignores =
+   t/*,setup.py,examples/*,docs/*,extra/*:
+       D,"
+            .strip_prefix("per-file-ignores =")
+            .unwrap(),
+        )?;
+        let expected: Vec<PatternPrefixPair> = vec![
+            PatternPrefixPair {
+                pattern: "t/*".to_string(),
+                prefix: CheckCodePrefix::D,
+            },
+            PatternPrefixPair {
+                pattern: "setup.py".to_string(),
+                prefix: CheckCodePrefix::D,
+            },
+            PatternPrefixPair {
+                pattern: "examples/*".to_string(),
+                prefix: CheckCodePrefix::D,
+            },
+            PatternPrefixPair {
+                pattern: "docs/*".to_string(),
+                prefix: CheckCodePrefix::D,
+            },
+            PatternPrefixPair {
+                pattern: "extra/*".to_string(),
+                prefix: CheckCodePrefix::D,
+            },
+        ];
+        assert_eq!(actual, expected);
+
+        // Ex) scrapy
+        let actual = parse_files_to_codes_mapping(
+            "per-file-ignores =
+    scrapy/__init__.py:E402
+    scrapy/core/downloader/handlers/http.py:F401
+    scrapy/http/__init__.py:F401
+    scrapy/linkextractors/__init__.py:E402,F401
+    scrapy/selector/__init__.py:F401
+    scrapy/spiders/__init__.py:E402,F401
+    scrapy/utils/url.py:F403,F405
+    tests/test_loader.py:E741"
+                .strip_prefix("per-file-ignores =")
+                .unwrap(),
+        )?;
+        let expected: Vec<PatternPrefixPair> = vec![
+            PatternPrefixPair {
+                pattern: "scrapy/__init__.py".to_string(),
+                prefix: CheckCodePrefix::E402,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/core/downloader/handlers/http.py".to_string(),
+                prefix: CheckCodePrefix::F401,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/http/__init__.py".to_string(),
+                prefix: CheckCodePrefix::F401,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/linkextractors/__init__.py".to_string(),
+                prefix: CheckCodePrefix::E402,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/linkextractors/__init__.py".to_string(),
+                prefix: CheckCodePrefix::F401,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/selector/__init__.py".to_string(),
+                prefix: CheckCodePrefix::F401,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/spiders/__init__.py".to_string(),
+                prefix: CheckCodePrefix::E402,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/spiders/__init__.py".to_string(),
+                prefix: CheckCodePrefix::F401,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/utils/url.py".to_string(),
+                prefix: CheckCodePrefix::F403,
+            },
+            PatternPrefixPair {
+                pattern: "scrapy/utils/url.py".to_string(),
+                prefix: CheckCodePrefix::F405,
+            },
+            PatternPrefixPair {
+                pattern: "tests/test_loader.py".to_string(),
+                prefix: CheckCodePrefix::E741,
+            },
+        ];
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+}

examples/generate_check_code_prefix.rs

@@ -0,0 +1,104 @@
+//! Generate the CheckCodePrefix enum.
+
+use std::collections::{BTreeMap, BTreeSet};
+
+use codegen::{Scope, Type, Variant};
+use itertools::Itertools;
+use ruff::checks::CheckCode;
+use strum::IntoEnumIterator;
+
+fn main() {
+    // Build up a map from prefix to matching CheckCodes.
+    let mut prefix_to_codes: BTreeMap<String, BTreeSet<CheckCode>> = Default::default();
+    for check_code in CheckCode::iter() {
+        let as_ref = check_code.as_ref().to_string();
+        for i in 1..=as_ref.len() {
+            let prefix = as_ref[..i].to_string();
+            let entry = prefix_to_codes
+                .entry(prefix)
+                .or_insert_with(|| Default::default());
+            entry.insert(check_code.clone());
+        }
+    }
+
+    let mut scope = Scope::new();
+
+    // Create the `CheckCodePrefix` definition.
+    let mut gen = scope
+        .new_enum("CheckCodePrefix")
+        .vis("pub")
+        .derive("EnumString")
+        .derive("Debug")
+        .derive("PartialEq")
+        .derive("Eq")
+        .derive("Clone")
+        .derive("Serialize")
+        .derive("Deserialize");
+    for (prefix, _) in &prefix_to_codes {
+        gen = gen.push_variant(Variant::new(prefix.to_string()));
+    }
+
+    // Create the `PrefixSpecificity` definition.
+    scope
+        .new_enum("PrefixSpecificity")
+        .vis("pub")
+        .derive("PartialEq")
+        .derive("Eq")
+        .derive("PartialOrd")
+        .derive("Ord")
+        .push_variant(Variant::new("Category"))
+        .push_variant(Variant::new("Hundreds"))
+        .push_variant(Variant::new("Tens"))
+        .push_variant(Variant::new("Explicit"));
+
+    // Create the `match` statement, to map from definition to relevant codes.
+    let mut gen = scope
+        .new_impl("CheckCodePrefix")
+        .new_fn("codes")
+        .arg_ref_self()
+        .ret(Type::new("Vec<CheckCode>"))
+        .vis("pub")
+        .line("match self {");
+    for (prefix, codes) in &prefix_to_codes {
+        gen = gen.line(format!(
+            "CheckCodePrefix::{prefix} => vec![{}],",
+            codes
+                .iter()
+                .map(|code| format!("CheckCode::{}", code.as_ref()))
+                .join(", ")
+        ));
+    }
+    gen.line("}");
+
+    // Create the `match` statement, to map from definition to specificity.
+    let mut gen = scope
+        .new_impl("CheckCodePrefix")
+        .new_fn("specificity")
+        .arg_ref_self()
+        .ret(Type::new("PrefixSpecificity"))
+        .vis("pub")
+        .line("match self {");
+    for (prefix, _) in &prefix_to_codes {
+        let specificity = match prefix.len() {
+            4 => "Explicit",
+            3 => "Tens",
+            2 => "Hundreds",
+            1 => "Category",
+            _ => panic!("Invalid prefix: {}", prefix),
+        };
+        gen = gen.line(format!(
+            "CheckCodePrefix::{prefix} => PrefixSpecificity::{},",
+            specificity
+        ));
+    }
+    gen.line("}");
+
+    println!("//! File automatically generated by examples/generate_check_code_prefix.rs.");
+    println!();
+    println!("use serde::{{Serialize, Deserialize}};");
+    println!("use strum_macros::EnumString;");
+    println!();
+    println!("use crate::checks::CheckCode;");
+    println!();
+    println!("{}", scope.to_string());
+}

examples/generate_rules_table.rs

@@ -1,19 +1,28 @@
-/// Generate a Markdown-compatible table of supported lint rules.
-use ruff::checks::{CheckCode, ALL_CHECK_CODES};
+//! Generate a Markdown-compatible table of supported lint rules.
+
+use ruff::checks::{CheckCategory, CheckCode};
+use strum::IntoEnumIterator;
 
 fn main() {
-    let mut check_codes: Vec<CheckCode> = ALL_CHECK_CODES.to_vec();
-    check_codes.sort();
+    for check_category in CheckCategory::iter() {
+        println!("### {}", check_category.title());
+        println!();
 
-    println!("| Code | Name | Message |");
-    println!("| ---- | ----- | ------- |");
-    for check_code in check_codes {
-        let check_kind = check_code.kind();
-        println!(
-            "| {} | {} | {} |",
-            check_kind.code().as_str(),
-            check_kind.name(),
-            check_kind.body()
-        );
+        println!("| Code | Name | Message | Fix |");
+        println!("| ---- | ---- | ------- | --- |");
+        for check_code in CheckCode::iter() {
+            if check_code.category() == check_category {
+                let check_kind = check_code.kind();
+                let fix_token = if check_kind.fixable() { "🛠" } else { "" };
+                println!(
+                    "| {} | {} | {} | {} |",
+                    check_kind.code().as_ref(),
+                    check_kind.as_ref(),
+                    check_kind.summary().replace("|", r"\|"),
+                    fix_token
+                );
+            }
+        }
+        println!();
     }
 }

examples/generate_source_code.rs

@@ -0,0 +1,25 @@
+use std::path::PathBuf;
+
+use anyhow::Result;
+use clap::Parser;
+use ruff::code_gen::SourceGenerator;
+use ruff::fs;
+use rustpython_parser::parser;
+
+#[derive(Debug, Parser)]
+struct Cli {
+    #[arg(required = true)]
+    file: PathBuf,
+}
+
+fn main() -> Result<()> {
+    let cli = Cli::parse();
+
+    let contents = fs::read_file(&cli.file)?;
+    let python_ast = parser::parse_program(&contents, &cli.file.to_string_lossy())?;
+    let mut generator = SourceGenerator::new();
+    generator.unparse_suite(&python_ast)?;
+    println!("{}", generator.generate()?);
+
+    Ok(())
+}

examples/print_ast.rs

@@ -1,15 +1,15 @@
-/// Print the AST for a given Python file.
+//! Print the AST for a given Python file.
+
 use std::path::PathBuf;
 
 use anyhow::Result;
-use clap::{Parser, ValueHint};
-use rustpython_parser::parser;
-
+use clap::Parser;
 use ruff::fs;
+use rustpython_parser::parser;
 
 #[derive(Debug, Parser)]
 struct Cli {
-    #[clap(parse(from_os_str), value_hint = ValueHint::FilePath, required = true)]
+    #[arg(required = true)]
     file: PathBuf,
 }
 

examples/print_tokens.rs

@@ -1,15 +1,15 @@
-/// Print the token stream for a given Python file.
+//! Print the token stream for a given Python file.
+
 use std::path::PathBuf;
 
 use anyhow::Result;
-use clap::{Parser, ValueHint};
-use rustpython_parser::lexer;
-
+use clap::Parser;
 use ruff::fs;
+use rustpython_parser::lexer;
 
 #[derive(Debug, Parser)]
 struct Cli {
-    #[clap(parse(from_os_str), value_hint = ValueHint::FilePath, required = true)]
+    #[arg(required = true)]
     file: PathBuf,
 }
 

pyproject.toml

@@ -8,7 +8,6 @@ classifiers = [
     "License :: OSI Approved :: MIT License",
     "Operating System :: OS Independent",
     "Programming Language :: Python",
-    "Programming Language :: Python :: 3.6",
     "Programming Language :: Python :: 3.7",
     "Programming Language :: Python :: 3.8",
     "Programming Language :: Python :: 3.9",

resources/test/fixtures/A001.py

@@ -0,0 +1,27 @@
+import some as sum
+from some import other as int
+
+print = 1
+copyright: 'annotation' = 2
+(complex := 3)
+float = object = 4
+min, max = 5, 6
+
+def bytes():
+    pass
+
+class slice:
+    pass
+
+try:
+    ...
+except ImportError as ValueError:
+    ...
+
+for memoryview, *bytearray in []:
+    pass
+
+with open('file') as str, open('file2') as (all, any):
+    pass
+
+[0 for sum in ()]

resources/test/fixtures/A002.py

@@ -0,0 +1,9 @@
+def func1(str, /, type, *complex, Exception, **getattr):
+    pass
+
+
+async def func2(bytes):
+    pass
+
+
+map([], lambda float: ...)

resources/test/fixtures/A003.py

@@ -0,0 +1,8 @@
+class MyClass:
+    ImportError = 4
+
+    def __init__(self):
+        self.float = 5  # is fine
+
+    def str(self):
+        pass

resources/test/fixtures/B002.py

@@ -0,0 +1,20 @@
+"""
+Should emit:
+B002 - on lines 15 and 20
+"""
+
+
+def this_is_all_fine(n):
+    x = n + 1
+    y = 1 + n
+    z = +x + y
+    return +z
+
+
+def this_is_buggy(n):
+    x = ++n
+    return x
+
+
+def this_is_buggy_too(n):
+    return ++n

resources/test/fixtures/B006_B008.py

@@ -0,0 +1,187 @@
+import collections
+import datetime as dt
+import logging
+import operator
+import random
+import re
+import time
+import types
+from operator import attrgetter, itemgetter, methodcaller
+from types import MappingProxyType
+
+
+# B006
+# Allow immutable literals/calls/comprehensions
+def this_is_okay(value=(1, 2, 3)):
+    ...
+
+
+async def and_this_also(value=tuple()):
+    pass
+
+
+def frozenset_also_okay(value=frozenset()):
+    pass
+
+
+def mappingproxytype_okay(
+    value=MappingProxyType({}), value2=types.MappingProxyType({})
+):
+    pass
+
+
+def re_compile_ok(value=re.compile("foo")):
+    pass
+
+
+def operators_ok(
+    v=operator.attrgetter("foo"),
+    v2=operator.itemgetter("foo"),
+    v3=operator.methodcaller("foo"),
+):
+    pass
+
+
+def operators_ok_unqualified(
+    v=attrgetter("foo"),
+    v2=itemgetter("foo"),
+    v3=methodcaller("foo"),
+):
+    pass
+
+
+def kwonlyargs_immutable(*, value=()):
+    ...
+
+
+# Flag mutable literals/comprehensions
+
+
+def this_is_wrong(value=[1, 2, 3]):
+    ...
+
+
+def this_is_also_wrong(value={}):
+    ...
+
+
+def and_this(value=set()):
+    ...
+
+
+def this_too(value=collections.OrderedDict()):
+    ...
+
+
+async def async_this_too(value=collections.defaultdict()):
+    ...
+
+
+def dont_forget_me(value=collections.deque()):
+    ...
+
+
+# N.B. we're also flagging the function call in the comprehension
+def list_comprehension_also_not_okay(default=[i**2 for i in range(3)]):
+    pass
+
+
+def dict_comprehension_also_not_okay(default={i: i**2 for i in range(3)}):
+    pass
+
+
+def set_comprehension_also_not_okay(default={i**2 for i in range(3)}):
+    pass
+
+
+def kwonlyargs_mutable(*, value=[]):
+    ...
+
+
+# Recommended approach for mutable defaults
+def do_this_instead(value=None):
+    if value is None:
+        value = set()
+
+
+# B008
+# Flag function calls as default args (including if they are part of a sub-expression)
+def in_fact_all_calls_are_wrong(value=time.time()):
+    ...
+
+
+def f(when=dt.datetime.now() + dt.timedelta(days=7)):
+    pass
+
+
+def can_even_catch_lambdas(a=(lambda x: x)()):
+    ...
+
+
+# Recommended approach for function calls as default args
+LOGGER = logging.getLogger(__name__)
+
+
+def do_this_instead_of_calls_in_defaults(logger=LOGGER):
+    # That makes it more obvious that this one value is reused.
+    ...
+
+
+# Handle inf/infinity/nan special case
+def float_inf_okay(value=float("inf")):
+    pass
+
+
+def float_infinity_okay(value=float("infinity")):
+    pass
+
+
+def float_plus_infinity_okay(value=float("+infinity")):
+    pass
+
+
+def float_minus_inf_okay(value=float("-inf")):
+    pass
+
+
+def float_nan_okay(value=float("nan")):
+    pass
+
+
+def float_minus_NaN_okay(value=float("-NaN")):
+    pass
+
+
+def float_infinity_literal(value=float("1e999")):
+    pass
+
+
+# But don't allow standard floats
+def float_int_is_wrong(value=float(3)):
+    pass
+
+
+def float_str_not_inf_or_nan_is_wrong(value=float("3.14")):
+    pass
+
+
+# B006 and B008
+# We should handle arbitrary nesting of these B008.
+def nested_combo(a=[float(3), dt.datetime.now()]):
+    pass
+
+
+# Don't flag nested B006 since we can't guarantee that
+# it isn't made mutable by the outer operation.
+def no_nested_b006(a=map(lambda s: s.upper(), ["a", "b", "c"])):
+    pass
+
+
+# B008-ception.
+def nested_b008(a=random.randint(0, dt.datetime.now().year)):
+    pass
+
+
+# Ignore lambda contents since they are evaluated at call time.
+def foo(f=lambda x: print(x)):
+    f(1)

resources/test/fixtures/B007.py

@@ -0,0 +1,31 @@
+for i in range(10):
+    print(i)
+
+print(i)  # name no longer defined on Python 3; no warning yet
+
+for i in range(10):  # name not used within the loop; B007
+    print(10)
+
+print(i)  # name no longer defined on Python 3; no warning yet
+
+
+for _ in range(10):  # _ is okay for a throw-away variable
+    print(10)
+
+
+for i in range(10):
+    for j in range(10):
+        for k in range(10):  # k not used, i and j used transitively
+            print(i + j)
+
+
+def strange_generator():
+    for i in range(10):
+        for j in range(10):
+            for k in range(10):
+                for l in range(10):
+                    yield i, (j, (k, l))
+
+
+for i, (j, (k, l)) in strange_generator():  # i, k not used
+    print(j, l)

resources/test/fixtures/B011.py

@@ -0,0 +1,10 @@
+"""
+Should emit:
+B011 - on line 8
+B011 - on line 10
+"""
+
+assert 1 != 2
+assert False
+assert 1 != 2, "message"
+assert False, "message"

resources/test/fixtures/B013.py

@@ -0,0 +1,8 @@
+try:
+    pass
+except (ValueError,):
+    pass
+except AttributeError:
+    pass
+except (ImportError, TypeError):
+    pass

resources/test/fixtures/B014.py

@@ -0,0 +1,76 @@
+"""
+Should emit:
+B014 - on lines 11, 17, 28, 42, 49, 56, and 74.
+"""
+
+import binascii
+import re
+
+try:
+    pass
+except (Exception, TypeError):
+    # TypeError is a subclass of Exception, so it doesn't add anything
+    pass
+
+try:
+    pass
+except (OSError, OSError) as err:
+    # Duplicate exception types are useless
+    pass
+
+
+class MyError(Exception):
+    pass
+
+
+try:
+    pass
+except (MyError, MyError):
+    # Detect duplicate non-builtin errors
+    pass
+
+
+try:
+    pass
+except (MyError, Exception) as e:
+    # Don't assume that we're all subclasses of Exception
+    pass
+
+
+try:
+    pass
+except (MyError, BaseException) as e:
+    # But we *can* assume that everything is a subclass of BaseException
+    pass
+
+
+try:
+    pass
+except (re.error, re.error):
+    # Duplicate exception types as attributes
+    pass
+
+
+try:
+    pass
+except (IOError, EnvironmentError, OSError):
+    # Detect if a primary exception and any its aliases are present.
+    #
+    # Since Python 3.3, IOError, EnvironmentError, WindowsError, mmap.error,
+    # socket.error and select.error are aliases of OSError. See PEP 3151 for
+    # more info.
+    pass
+
+
+try:
+    pass
+except (MyException, NotImplemented):
+    # NotImplemented is not an exception, let's not crash on it.
+    pass
+
+
+try:
+    pass
+except (ValueError, binascii.Error):
+    # binascii.Error is a subclass of ValueError.
+    pass

resources/test/fixtures/B017.py

@@ -0,0 +1,36 @@
+"""
+Should emit:
+B017 - on lines 20
+"""
+import asyncio
+import unittest
+
+CONSTANT = True
+
+
+def something_else() -> None:
+    for i in (1, 2, 3):
+        print(i)
+
+
+class Foo:
+    pass
+
+
+class Foobar(unittest.TestCase):
+    def evil_raises(self) -> None:
+        with self.assertRaises(Exception):
+            raise Exception("Evil I say!")
+
+    def context_manager_raises(self) -> None:
+        with self.assertRaises(Exception) as ex:
+            raise Exception("Context manager is good")
+        self.assertEqual("Context manager is good", str(ex.exception))
+
+    def regex_raises(self) -> None:
+        with self.assertRaisesRegex(Exception, "Regex is good"):
+            raise Exception("Regex is good")
+
+    def raises_with_absolute_reference(self):
+        with self.assertRaises(asyncio.CancelledError):
+            Foo()

resources/test/fixtures/B025.py

@@ -0,0 +1,38 @@
+"""
+Should emit:
+B025 - on lines 15, 22, 31
+"""
+
+import pickle
+
+try:
+    a = 1
+except ValueError:
+    a = 2
+finally:
+    a = 3
+
+try:
+    a = 1
+except ValueError:
+    a = 2
+except ValueError:
+    a = 2
+
+try:
+    a = 1
+except pickle.PickleError:
+    a = 2
+except ValueError:
+    a = 2
+except pickle.PickleError:
+    a = 2
+
+try:
+    a = 1
+except (ValueError, TypeError):
+    a = 2
+except ValueError:
+    a = 2
+except (OSError, TypeError):
+    a = 2

resources/test/fixtures/C400.py

@@ -0,0 +1,4 @@
+x = list(x for x in range(3))
+x = list(
+    x for x in range(3)
+)

resources/test/fixtures/C401.py

@@ -0,0 +1,4 @@
+x = set(x for x in range(3))
+x = set(
+    x for x in range(3)
+)

resources/test/fixtures/C402.py

@@ -0,0 +1,5 @@
+dict((x, x) for x in range(3))
+dict(
+    (x, x) for x in range(3)
+)
+dict(((x, x) for x in range(3)), z=3)

resources/test/fixtures/C403.py

@@ -0,0 +1,4 @@
+s = set([x for x in range(3)])
+s = set(
+    [x for x in range(3)]
+)

resources/test/fixtures/C404.py

@@ -0,0 +1,2 @@
+dict([(i, i) for i in range(3)])
+dict([(i, i) for i in range(3)], z=4)

resources/test/fixtures/C405.py

@@ -0,0 +1,5 @@
+s1 = set([1, 2])
+s2 = set((1, 2))
+s3 = set([])
+s4 = set(())
+s5 = set()

resources/test/fixtures/C406.py

@@ -0,0 +1,5 @@
+d1 = dict([(1, 2)])
+d2 = dict(((1, 2),))
+d3 = dict([])
+d4 = dict(())
+d5 = dict()

resources/test/fixtures/C408.py

@@ -0,0 +1,5 @@
+t = tuple()
+l = list()
+d1 = dict()
+d2 = dict(a=1)
+d3 = dict(**d2)

resources/test/fixtures/C409.py

@@ -0,0 +1,10 @@
+t1 = tuple([])
+t2 = tuple([1, 2])
+t3 = tuple((1, 2))
+t4 = tuple([
+    1,
+    2
+])
+t5 = tuple(
+    (1, 2)
+)

resources/test/fixtures/C410.py

@@ -0,0 +1,4 @@
+l1 = list([1, 2])
+l2 = list((1, 2))
+l3 = list([])
+l4 = list(())

resources/test/fixtures/C411.py

@@ -0,0 +1,2 @@
+x = [1, 2, 3]
+list([i for i in x])

resources/test/fixtures/C413.py

@@ -0,0 +1,4 @@
+x = [2, 3, 1]
+list(sorted(x))
+reversed(sorted(x))
+reversed(sorted(x, reverse=True))

resources/test/fixtures/C414.py

@@ -0,0 +1,14 @@
+x = [1, 2, 3]
+list(list(x))
+list(tuple(x))
+tuple(list(x))
+tuple(tuple(x))
+set(set(x))
+set(list(x))
+set(tuple(x))
+set(sorted(x))
+set(reversed(x))
+sorted(list(x))
+sorted(tuple(x))
+sorted(sorted(x))
+sorted(reversed(x))

resources/test/fixtures/C415.py

@@ -0,0 +1,9 @@
+lst = [2, 1, 3]
+a = set(lst[::-1])
+b = reversed(lst[::-1])
+c = sorted(lst[::-1])
+d = sorted(lst[::-1], reverse=True)
+e = set(lst[2:-1])
+f = set(lst[:1:-1])
+g = set(lst[::1])
+h = set(lst[::-2])

resources/test/fixtures/C416.py

@@ -0,0 +1,6 @@
+x = [1, 2, 3]
+[i for i in x]
+{i for i in x}
+
+[i for i in x if i > 1]
+[i for i in x for j in x]

resources/test/fixtures/C417.py

@@ -0,0 +1,6 @@
+nums = [1, 2, 3]
+map(lambda x: x + 1, nums)
+map(lambda x: str(x), nums)
+list(map(lambda x: x * 2, nums))
+set(map(lambda x: x % 2 == 0, nums))
+dict(map(lambda v: (v, v**2), nums))

resources/test/fixtures/D.py

@@ -0,0 +1,534 @@
+# No docstring, so we can test D100
+from functools import wraps
+import os
+from .expected import Expectation
+from typing import overload
+
+
+expectation = Expectation()
+expect = expectation.expect
+
+expect('class_', 'D101: Missing docstring in public class')
+
+
+class class_:
+
+    expect('meta', 'D419: Docstring is empty')
+
+    class meta:
+        """"""
+
+    @expect('D102: Missing docstring in public method')
+    def method(self=None):
+        pass
+
+    def _ok_since_private(self=None):
+        pass
+
+    @overload
+    def overloaded_method(self, a: int) -> str:
+        ...
+
+    @overload
+    def overloaded_method(self, a: str) -> str:
+        """Foo bar documentation."""
+        ...
+
+    def overloaded_method(a):
+        """Foo bar documentation."""
+        return str(a)
+
+    expect('overloaded_method',
+           "D418: Function/ Method decorated with @overload"
+           " shouldn't contain a docstring")
+
+    @property
+    def foo(self):
+        """The foo of the thing, which isn't in imperitive mood."""
+        return "hello"
+
+    @expect('D102: Missing docstring in public method')
+    def __new__(self=None):
+        pass
+
+    @expect('D107: Missing docstring in __init__')
+    def __init__(self=None):
+        pass
+
+    @expect('D105: Missing docstring in magic method')
+    def __str__(self=None):
+        pass
+
+    @expect('D102: Missing docstring in public method')
+    def __call__(self=None, x=None, y=None, z=None):
+        pass
+
+
+@expect('D419: Docstring is empty')
+def function():
+    """ """
+    def ok_since_nested():
+        pass
+
+    @expect('D419: Docstring is empty')
+    def nested():
+        ''
+
+
+def function_with_nesting():
+    """Foo bar documentation."""
+    @overload
+    def nested_overloaded_func(a: int) -> str:
+        ...
+
+    @overload
+    def nested_overloaded_func(a: str) -> str:
+        """Foo bar documentation."""
+        ...
+
+    def nested_overloaded_func(a):
+        """Foo bar documentation."""
+        return str(a)
+
+
+expect('nested_overloaded_func',
+       "D418: Function/ Method decorated with @overload"
+       " shouldn't contain a docstring")
+
+
+@overload
+def overloaded_func(a: int) -> str:
+    ...
+
+
+@overload
+def overloaded_func(a: str) -> str:
+    """Foo bar documentation."""
+    ...
+
+
+def overloaded_func(a):
+    """Foo bar documentation."""
+    return str(a)
+
+
+expect('overloaded_func',
+       "D418: Function/ Method decorated with @overload"
+       " shouldn't contain a docstring")
+
+
+@expect('D200: One-line docstring should fit on one line with quotes '
+        '(found 3)')
+@expect('D212: Multi-line docstring summary should start at the first line')
+def asdlkfasd():
+    """
+    Wrong.
+    """
+
+
+@expect('D201: No blank lines allowed before function docstring (found 1)')
+def leading_space():
+
+    """Leading space."""
+
+
+@expect('D202: No blank lines allowed after function docstring (found 1)')
+def trailing_space():
+    """Leading space."""
+
+    pass
+
+
+@expect('D201: No blank lines allowed before function docstring (found 1)')
+@expect('D202: No blank lines allowed after function docstring (found 1)')
+def trailing_and_leading_space():
+
+    """Trailing and leading space."""
+
+    pass
+
+
+expect('LeadingSpaceMissing',
+       'D203: 1 blank line required before class docstring (found 0)')
+
+
+class LeadingSpaceMissing:
+    """Leading space missing."""
+
+
+expect('WithLeadingSpace',
+       'D211: No blank lines allowed before class docstring (found 1)')
+
+
+class WithLeadingSpace:
+
+    """With leading space."""
+
+
+expect('TrailingSpace',
+       'D204: 1 blank line required after class docstring (found 0)')
+expect('TrailingSpace',
+       'D211: No blank lines allowed before class docstring (found 1)')
+
+
+class TrailingSpace:
+
+    """TrailingSpace."""
+    pass
+
+
+expect('LeadingAndTrailingSpaceMissing',
+       'D203: 1 blank line required before class docstring (found 0)')
+expect('LeadingAndTrailingSpaceMissing',
+       'D204: 1 blank line required after class docstring (found 0)')
+
+
+class LeadingAndTrailingSpaceMissing:
+    """Leading and trailing space missing."""
+    pass
+
+
+@expect('D205: 1 blank line required between summary line and description '
+        '(found 0)')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def multi_line_zero_separating_blanks():
+    """Summary.
+    Description.
+
+    """
+
+
+@expect('D205: 1 blank line required between summary line and description '
+        '(found 2)')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def multi_line_two_separating_blanks():
+    """Summary.
+
+
+    Description.
+
+    """
+
+
+@expect('D213: Multi-line docstring summary should start at the second line')
+def multi_line_one_separating_blanks():
+    """Summary.
+
+    Description.
+
+    """
+
+
+@expect('D207: Docstring is under-indented')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def asdfsdf():
+    """Summary.
+
+Description.
+
+    """
+
+
+@expect('D207: Docstring is under-indented')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def asdsdfsdffsdf():
+    """Summary.
+
+    Description.
+
+"""
+
+
+@expect('D208: Docstring is over-indented')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def asdfsdsdf24():
+    """Summary.
+
+       Description.
+
+    """
+
+
+@expect('D208: Docstring is over-indented')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def asdfsdsdfsdf24():
+    """Summary.
+
+    Description.
+
+        """
+
+
+@expect('D208: Docstring is over-indented')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def asdfsdfsdsdsdfsdf24():
+    """Summary.
+
+        Description.
+
+    """
+
+
+@expect('D209: Multi-line docstring closing quotes should be on a separate '
+        'line')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def asdfljdf24():
+    """Summary.
+
+    Description."""
+
+
+@expect('D210: No whitespaces allowed surrounding docstring text')
+def endswith():
+    """Whitespace at the end. """
+
+
+@expect('D210: No whitespaces allowed surrounding docstring text')
+def around():
+    """ Whitespace at everywhere. """
+
+
+@expect('D210: No whitespaces allowed surrounding docstring text')
+@expect('D213: Multi-line docstring summary should start at the second line')
+def multiline():
+    """ Whitespace at the beginning.
+
+    This is the end.
+    """
+
+
+@expect('D300: Use """triple double quotes""" (found \'\'\'-quotes)')
+def triple_single_quotes_raw():
+    r'''Summary.'''
+
+
+@expect('D300: Use """triple double quotes""" (found \'\'\'-quotes)')
+def triple_single_quotes_raw_uppercase():
+    R'''Summary.'''
+
+
+@expect('D300: Use """triple double quotes""" (found \'-quotes)')
+def single_quotes_raw():
+    r'Summary.'
+
+
+@expect('D300: Use """triple double quotes""" (found \'-quotes)')
+def single_quotes_raw_uppercase():
+    R'Summary.'
+
+
+@expect('D300: Use """triple double quotes""" (found \'-quotes)')
+@expect('D301: Use r""" if any backslashes in a docstring')
+def single_quotes_raw_uppercase_backslash():
+    R'Sum\mary.'
+
+
+@expect('D301: Use r""" if any backslashes in a docstring')
+def double_quotes_backslash():
+    """Sum\\mary."""
+
+
+@expect('D301: Use r""" if any backslashes in a docstring')
+def double_quotes_backslash_uppercase():
+    R"""Sum\\mary."""
+
+
+@expect('D213: Multi-line docstring summary should start at the second line')
+def exceptions_of_D301():
+    """Exclude some backslashes from D301.
+
+    In particular, line continuations \
+    and unicode literals \u0394 and \N{GREEK CAPITAL LETTER DELTA}.
+    They are considered to be intentionally unescaped.
+    """
+
+
+@expect("D400: First line should end with a period (not 'y')")
+@expect("D415: First line should end with a period, question mark, "
+        "or exclamation point (not 'y')")
+def lwnlkjl():
+    """Summary"""
+
+
+@expect("D401: First line should be in imperative mood "
+        "(perhaps 'Return', not 'Returns')")
+def liouiwnlkjl():
+    """Returns foo."""
+
+
+@expect("D401: First line should be in imperative mood; try rephrasing "
+        "(found 'Constructor')")
+def sdgfsdg23245():
+    """Constructor for a foo."""
+
+
+@expect("D401: First line should be in imperative mood; try rephrasing "
+        "(found 'Constructor')")
+def sdgfsdg23245777():
+    """Constructor."""
+
+
+@expect('D402: First line should not be the function\'s "signature"')
+def foobar():
+    """Signature: foobar()."""
+
+
+@expect('D213: Multi-line docstring summary should start at the second line')
+def new_209():
+    """First line.
+
+    More lines.
+    """
+    pass
+
+
+@expect('D213: Multi-line docstring summary should start at the second line')
+def old_209():
+    """One liner.
+
+    Multi-line comments. OK to have extra blank line
+
+    """
+
+
+@expect("D103: Missing docstring in public function")
+def oneliner_d102(): return
+
+
+@expect("D400: First line should end with a period (not 'r')")
+@expect("D415: First line should end with a period, question mark,"
+        " or exclamation point (not 'r')")
+def oneliner_withdoc(): """One liner"""
+
+
+def ignored_decorator(func):   # noqa: D400,D401,D415
+    """Runs something"""
+    func()
+    pass
+
+
+def decorator_for_test(func):   # noqa: D400,D401,D415
+    """Runs something"""
+    func()
+    pass
+
+
+@ignored_decorator
+def oneliner_ignored_decorator(): """One liner"""
+
+
+@decorator_for_test
+@expect("D400: First line should end with a period (not 'r')")
+@expect("D415: First line should end with a period, question mark,"
+        " or exclamation point (not 'r')")
+def oneliner_with_decorator_expecting_errors(): """One liner"""
+
+
+@decorator_for_test
+def valid_oneliner_with_decorator(): """One liner."""
+
+
+@expect("D207: Docstring is under-indented")
+@expect('D213: Multi-line docstring summary should start at the second line')
+def docstring_start_in_same_line(): """First Line.
+
+    Second Line
+    """
+
+
+def function_with_lambda_arg(x=lambda y: y):
+    """Wrap the given lambda."""
+
+
+@expect('D213: Multi-line docstring summary should start at the second line')
+def a_following_valid_function(x=None):
+    """Check for a bug where the previous function caused an assertion.
+
+    The assertion was caused in the next function, so this one is necessary.
+
+    """
+
+
+def outer_function():
+    """Do something."""
+    def inner_function():
+        """Do inner something."""
+        return 0
+
+
+@expect("D400: First line should end with a period (not 'g')")
+@expect("D401: First line should be in imperative mood "
+        "(perhaps 'Run', not 'Runs')")
+@expect("D415: First line should end with a period, question mark, "
+        "or exclamation point (not 'g')")
+def docstring_bad():
+    """Runs something"""
+    pass
+
+
+def docstring_bad_ignore_all():  # noqa
+    """Runs something"""
+    pass
+
+
+def docstring_bad_ignore_one():  # noqa: D400,D401,D415
+    """Runs something"""
+    pass
+
+
+@expect("D401: First line should be in imperative mood "
+        "(perhaps 'Run', not 'Runs')")
+def docstring_ignore_some_violations_but_catch_D401():  # noqa: E501,D400,D415
+    """Runs something"""
+    pass
+
+
+@expect(
+    "D401: First line should be in imperative mood "
+    "(perhaps 'Initiate', not 'Initiates')"
+)
+def docstring_initiates():
+    """Initiates the process."""
+
+
+@expect(
+    "D401: First line should be in imperative mood "
+    "(perhaps 'Initialize', not 'Initializes')"
+)
+def docstring_initializes():
+    """Initializes the process."""
+
+
+@wraps(docstring_bad_ignore_one)
+def bad_decorated_function():
+    """Bad (E501) but decorated"""
+    pass
+
+
+def valid_google_string():  # noqa: D400
+    """Test a valid something!"""
+
+
+@expect("D415: First line should end with a period, question mark, "
+        "or exclamation point (not 'g')")
+def bad_google_string():  # noqa: D400
+    """Test a valid something"""
+
+
+# This is reproducing a bug where AttributeError is raised when parsing class
+# parameters as functions for Google / Numpy conventions.
+class Blah:  # noqa: D203,D213
+    """A Blah.
+
+    Parameters
+    ----------
+    x : int
+
+    """
+
+    def __init__(self, x):
+        pass
+
+
+expect(os.path.normcase(__file__ if __file__[-1] != 'c' else __file__[:-1]),
+       'D100: Missing docstring in public module')

resources/test/fixtures/E402.py

@@ -1,4 +1,8 @@
 """Top-level docstring."""
+
+__all__ = ["y"]
+__version__: str = "0.1.0"
+
 import a
 
 try:

resources/test/fixtures/E501.py

@@ -5,5 +5,12 @@
 Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
 """
 
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501
+
 _ = "---------------------------------------------------------------------------AAAAAAA"
 _ = "---------------------------------------------------------------------------亜亜亜亜亜亜亜"

resources/test/fixtures/F401.py

@@ -1,41 +0,0 @@
-from __future__ import all_feature_names
-import os
-import functools
-from datetime import datetime
-from collections import (
-    Counter,
-    OrderedDict,
-    namedtuple,
-)
-import multiprocessing.pool
-import multiprocessing.process
-import logging.config
-import logging.handlers
-from typing import TYPING_CHECK, NamedTuple, Dict, Type, TypeVar, List, Set, Union, cast
-
-from blah import ClassA, ClassB, ClassC
-
-if TYPING_CHECK:
-    from models import Fruit, Nut, Vegetable
-
-
-class X:
-    datetime: datetime
-    foo: Type["NamedTuple"]
-
-    def a(self) -> "namedtuple":
-        x = os.environ["1"]
-        y = Counter()
-        z = multiprocessing.pool.ThreadPool()
-
-
-__all__ = ["ClassA"] + ["ClassB"]
-__all__ += ["ClassC"]
-
-X = TypeVar("X")
-Y = TypeVar("Y", bound="Dict")
-Z = TypeVar("Z", "List", "Set")
-
-a = list["Fruit"]
-b = Union["Nut", None]
-c = cast("Vegetable", b)

resources/test/fixtures/F401_0.py

@@ -0,0 +1,88 @@
+from __future__ import all_feature_names
+import functools, os
+from datetime import datetime
+from collections import (
+    Counter,
+    OrderedDict,
+    namedtuple,
+)
+import multiprocessing.pool
+import multiprocessing.process
+import logging.config
+import logging.handlers
+from typing import (
+    TYPE_CHECKING,
+    NamedTuple,
+    Dict,
+    Type,
+    TypeVar,
+    List,
+    Set,
+    Union,
+    cast,
+)
+from dataclasses import MISSING, field
+
+from blah import ClassA, ClassB, ClassC
+
+if TYPE_CHECKING:
+    from models import Fruit, Nut, Vegetable
+
+
+if TYPE_CHECKING:
+    import shelve
+    import importlib
+
+if TYPE_CHECKING:
+    """Hello, world!"""
+    import pathlib
+
+    z = 1
+
+
+class X:
+    datetime: datetime
+    foo: Type["NamedTuple"]
+
+    def a(self) -> "namedtuple":
+        x = os.environ["1"]
+        y = Counter()
+        z = multiprocessing.pool.ThreadPool()
+
+    def b(self) -> None:
+        import pickle
+
+
+__all__ = ["ClassA"] + ["ClassB"]
+__all__ += ["ClassC"]
+
+X = TypeVar("X")
+Y = TypeVar("Y", bound="Dict")
+Z = TypeVar("Z", "List", "Set")
+
+a = list["Fruit"]
+b = Union["""Nut""", None]
+c = cast("Vegetable", b)
+
+Field = lambda default=MISSING: field(default=default)
+
+
+# Test: access a sub-importation via an alias.
+import pyarrow as pa
+import pyarrow.csv
+
+print(pa.csv.read_csv("test.csv"))
+
+
+# Test: referencing an import via TypeAlias.
+import sys
+
+import numpy as np
+
+if sys.version_info >= (3, 10):
+    from typing import TypeAlias
+else:
+    from typing_extensions import TypeAlias
+
+
+CustomInt: TypeAlias = "np.int8 | np.int16"

resources/test/fixtures/F401_1.py

@@ -0,0 +1,5 @@
+"""Access a sub-importation via an alias."""
+import pyarrow as pa
+import pyarrow.csv
+
+print(pa.csv.read_csv("test.csv"))

resources/test/fixtures/F401_2.py

@@ -0,0 +1,12 @@
+"""Test: referencing an import via TypeAlias."""
+import sys
+
+import numpy as np
+
+if sys.version_info >= (3, 10):
+    from typing import TypeAlias
+else:
+    from typing_extensions import TypeAlias
+
+
+CustomInt: TypeAlias = "np.int8 | np.int16"

resources/test/fixtures/F401_3.py

@@ -0,0 +1,14 @@
+"""Test: referencing an import via TypeAlias (with future annotations)."""
+from __future__ import annotations
+
+import sys
+
+import numpy as np
+
+if sys.version_info >= (3, 10):
+    from typing import TypeAlias
+else:
+    from typing_extensions import TypeAlias
+
+
+CustomInt: TypeAlias = np.int8 | np.int16

resources/test/fixtures/F401_4.py

@@ -0,0 +1,14 @@
+"""Test: referencing an import via TypeAlias (with future annotations and quotes)."""
+from __future__ import annotations
+
+import sys
+
+import numpy as np
+
+if sys.version_info >= (3, 10):
+    from typing import TypeAlias
+else:
+    from typing_extensions import TypeAlias
+
+
+CustomInt: TypeAlias = "np.int8 | np.int16"

resources/test/fixtures/F401_5.py

@@ -0,0 +1,5 @@
+"""Test: removal of multi-segment and aliases imports."""
+from a.b import c
+from d.e import f as g
+import h.i
+import j.k as l

resources/test/fixtures/F404.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 """Docstring"""
 from __future__ import absolute_import
 

resources/test/fixtures/F821_0.py

@@ -89,3 +89,45 @@ A = (
     f'B'
     f'{B}'
 )
+
+
+from typing import Annotated, Literal
+
+
+def arbitrary_callable() -> None:
+    ...
+
+
+class PEP593Test:
+    field: Annotated[
+        int,
+        "base64",
+        arbitrary_callable(),
+        123,
+        (1, 2, 3),
+    ]
+    field_with_stringified_type: Annotated[
+        "PEP593Test",
+        123,
+    ]
+    field_with_undefined_stringified_type: Annotated[
+        "PEP593Test123",
+        123,
+    ]
+    field_with_nested_subscript: Annotated[
+        dict[Literal["foo"], str],
+        123,
+    ]
+    field_with_undefined_nested_subscript: Annotated[
+        dict["foo", "bar"],  # Expected to fail as undefined.
+        123,
+    ]
+
+
+def in_ipython_notebook() -> bool:
+    try:
+        # autoimported by notebooks
+        get_ipython()  # type: ignore[name-defined]
+    except NameError:
+        return False  # not in notebook
+    return True

resources/test/fixtures/F821_1.py

@@ -0,0 +1,30 @@
+"""Test: typing module imports."""
+from foo import cast
+
+# OK
+x = cast("Model")
+
+from typing import cast
+
+
+# F821 Undefined name `Model`
+x = cast("Model", x)
+
+
+import typing
+
+
+# F821 Undefined name `Model`
+x = typing.cast("Model", x)
+
+
+from typing import Pattern
+
+# F821 Undefined name `Model`
+x = Pattern["Model"]
+
+
+from typing.re import Match
+
+# F821 Undefined name `Model`
+x = Match["Model"]

resources/test/fixtures/F821_2.py

@@ -0,0 +1,18 @@
+"""Test: typing_extensions module imports."""
+from foo import Literal
+
+# F821 Undefined name `Model`
+x: Literal["Model"]
+
+from typing_extensions import Literal
+
+
+# OK
+x: Literal["Model"]
+
+
+import typing_extensions
+
+
+# OK
+x: typing_extensions.Literal["Model"]

resources/test/fixtures/F841.py

@@ -10,13 +10,13 @@ except ValueError as e:
     print(e)
 
 
-def f():
+def f1():
     x = 1
     y = 2
     z = x + y
 
 
-def g():
+def f2():
     foo = (1, 2)
     (a, b) = (1, 2)
 
@@ -26,6 +26,12 @@ def g():
     (x, y) = baz = bar
 
 
-def h():
+def f3():
     locals()
     x = 1
+
+
+def f4():
+    _ = 1
+    __ = 1
+    _discarded = 1

resources/test/fixtures/M001.py

@@ -0,0 +1,60 @@
+def f() -> None:
+    # Valid
+    a = 1  # noqa
+
+    # Valid
+    b = 2  # noqa: F841
+
+    # Invalid
+    c = 1  # noqa
+    print(c)
+
+    # Invalid
+    d = 1  # noqa: E501
+
+    # Invalid
+    d = 1  # noqa: F841, E501
+
+    # Invalid (and unimplemented)
+    d = 1  # noqa: F841, W191
+
+
+# Valid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501
+
+# Valid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa
+
+# Invalid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+"""  # noqa: E501, F841
+
+# Invalid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.
+"""  # noqa: E501
+
+# Invalid
+_ = """Lorem ipsum dolor sit amet.
+
+    https://github.com/PyCQA/pycodestyle/pull/258/files#diff-841c622497a8033d10152bfdfb15b20b92437ecdea21a260944ea86b77b51533
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor.
+"""  # noqa

resources/test/fixtures/N801.py

@@ -0,0 +1,34 @@
+class bad:
+    pass
+
+
+class _bad:
+    pass
+
+
+class bad_class:
+    pass
+
+
+class Bad_Class:
+    pass
+
+
+class BAD_CLASS:
+    pass
+
+
+class Good:
+    pass
+
+
+class _Good:
+    pass
+
+
+class GoodClass:
+    pass
+
+
+class GOOD:
+    pass

resources/test/fixtures/N802.py

@@ -0,0 +1,41 @@
+import unittest
+
+
+def Bad():
+    pass
+
+
+def _Bad():
+    pass
+
+
+def BAD():
+    pass
+
+
+def BAD_FUNC():
+    pass
+
+
+def good():
+    pass
+
+
+def _good():
+    pass
+
+
+def good_func():
+    pass
+
+
+def tearDownModule():
+    pass
+
+
+class Test(unittest.TestCase):
+    def tearDown(self):
+        return super().tearDown()
+
+    def testTest(self):
+        assert True

resources/test/fixtures/N803.py

@@ -0,0 +1,7 @@
+def func(a, A):
+    return a, A
+
+
+class Class:
+    def method(self, a, A):
+        return a, A

resources/test/fixtures/N804.py

@@ -0,0 +1,19 @@
+class Class:
+    @classmethod
+    def bad_class_method(this):
+        pass
+
+    @classmethod
+    def good_class_method(cls):
+        pass
+
+    def method(self):
+        pass
+
+    @staticmethod
+    def static_method(x):
+        return x
+
+
+def func(x):
+    return x

resources/test/fixtures/N805.py

@@ -0,0 +1,26 @@
+import random
+
+
+class Class:
+    def bad_method(this):
+        pass
+
+    if random.random(0, 2) == 0:
+
+        def extra_bad_method(this):
+            pass
+
+    def good_method(self):
+        pass
+
+    @classmethod
+    def class_method(cls):
+        pass
+
+    @staticmethod
+    def static_method(x):
+        return x
+
+
+def func(x):
+    return x

resources/test/fixtures/N806.py

@@ -0,0 +1,4 @@
+def f():
+    lower = 0
+    Camel = 0
+    CONSTANT = 0

resources/test/fixtures/N807.py

@@ -0,0 +1,15 @@
+def __bad__():
+    pass
+
+
+def __good():
+    pass
+
+
+def good__():
+    pass
+
+
+class Class:
+    def __good__(self):
+        pass

resources/test/fixtures/N811.py

@@ -0,0 +1,3 @@
+import mod.CONST as const
+from mod import CONSTANT as constant
+from mod import ANOTHER_CONSTANT as another_constant

resources/test/fixtures/N812.py

@@ -0,0 +1,3 @@
+import modl.lowercase as Lower
+from mod import lowercase as Lowercase
+from mod import another_lowercase as AnotherLowercase

resources/test/fixtures/N813.py

@@ -0,0 +1,3 @@
+import mod.Camel as camel
+from mod import CamelCase as camelcase
+from mod import AnotherCamelCase as another_camelcase

resources/test/fixtures/N814.py

@@ -0,0 +1,3 @@
+import mod.Camel as CAMEL
+from mod import CamelCase as CAMELCASE
+from mod import AnotherCamelCase as ANOTHER_CAMELCASE

resources/test/fixtures/N815.py

@@ -0,0 +1,6 @@
+class C:
+    lower = 0
+    CONSTANT = 0
+    mixedCase = 0
+    _mixedCase = 0
+    mixed_Case = 0

resources/test/fixtures/N816.py

@@ -0,0 +1,5 @@
+lower = 0
+CONSTANT = 0
+mixedCase = 0
+_mixedCase = 0
+mixed_Case = 0

resources/test/fixtures/N817.py

@@ -0,0 +1,2 @@
+import mod.CaMel as CM
+from mod import CamelCase as CC

resources/test/fixtures/N818.py

@@ -0,0 +1,10 @@
+class Error(Exception):
+    pass
+
+
+class AnotherError(Exception):
+    pass
+
+
+class C(Exception):
+    pass

resources/test/fixtures/R002.py

@@ -1,3 +0,0 @@
-self.assertEquals (1, 2)
-self.assertEquals(1, 2)
-self.assertEqual(3, 4)

resources/test/fixtures/T201.py

@@ -0,0 +1 @@
+print("Hello, world!")  # T201

resources/test/fixtures/T203.py

@@ -0,0 +1,10 @@
+from pprint import pprint
+
+pprint("Hello, world!")  # T203
+
+
+import pprint
+
+pprint.pprint("Hello, world!")  # T203
+
+pprint.pformat("Hello, world!")

resources/test/fixtures/U001.py

@@ -0,0 +1,13 @@
+class A:
+    __metaclass__ = type
+
+
+class B:
+    __metaclass__ = type
+
+    def __init__(self) -> None:
+        pass
+
+
+class C(metaclass=type):
+    pass

resources/test/fixtures/U002.py

@@ -0,0 +1,15 @@
+from os.path import abspath
+
+x = abspath(__file__)
+
+
+import os
+
+
+y = os.path.abspath(__file__)
+
+
+from os import path
+
+
+z = path.abspath(__file__)

resources/test/fixtures/U003.py

@@ -0,0 +1,5 @@
+type('')
+type(b'')
+type(0)
+type(0.)
+type(0j)

resources/test/fixtures/U005.py

@@ -0,0 +1,10 @@
+import unittest
+
+
+class Suite(unittest.TestCase):
+    def test(self) -> None:
+        self.assertEquals (1, 2)
+        self.assertEquals(1, 2)
+        self.assertEqual(3, 4)
+        self.failUnlessAlmostEqual(1, 1.1)
+        self.assertNotRegexpMatches("a", "b")

resources/test/fixtures/U006.py

@@ -0,0 +1,12 @@
+from typing import List
+
+
+def f(x: List[str]) -> None:
+    ...
+
+
+import typing
+
+
+def f(x: typing.List[str]) -> None:
+    ...

resources/test/fixtures/U007.py

@@ -0,0 +1,40 @@
+from typing import Optional
+
+
+def f(x: Optional[str]) -> None:
+    ...
+
+
+import typing
+
+
+def f(x: typing.Optional[str]) -> None:
+    ...
+
+
+from typing import Union
+
+
+def f(x: Union[str, int, Union[float, bytes]]) -> None:
+    ...
+
+
+import typing
+
+
+def f(x: typing.Union[str, int]) -> None:
+    ...
+
+
+from typing import Union
+
+
+def f(x: "Union[str, int, Union[float, bytes]]") -> None:
+    ...
+
+
+import typing
+
+
+def f(x: "typing.Union[str, int]") -> None:
+    ...

resources/test/fixtures/U008.py

@@ -0,0 +1,65 @@
+class Parent:
+    def method(self):
+        pass
+
+    def wrong(self):
+        pass
+
+
+class Child(Parent):
+    def method(self):
+        parent = super()  # ok
+        super().method()  # ok
+        Parent.method(self)  # ok
+        Parent.super(1, 2)  # ok
+
+    def wrong(self):
+        parent = super(Child, self)  # wrong
+        super(Child, self).method  # wrong
+        super(
+            Child,
+            self,
+        ).method()  # wrong
+
+
+class BaseClass:
+    def f(self):
+        print("f")
+
+
+def defined_outside(self):
+    super(MyClass, self).f()  # CANNOT use super()
+
+
+class MyClass(BaseClass):
+    def normal(self):
+        super(MyClass, self).f()  # can use super()
+        super().f()
+
+    def different_argument(self, other):
+        super(MyClass, other).f()  # CANNOT use super()
+
+    def comprehension_scope(self):
+        [super(MyClass, self).f() for x in [1]]  # CANNOT use super()
+
+    def inner_functions(self):
+        def outer_argument():
+            super(MyClass, self).f()  # CANNOT use super()
+
+        def inner_argument(self):
+            super(MyClass, self).f()  # can use super()
+            super().f()
+
+        outer_argument()
+        inner_argument(self)
+
+    def inner_class(self):
+        class InnerClass:
+            super(MyClass, self).f()  # CANNOT use super()
+
+            def method(inner_self):
+                super(MyClass, self).f()  # CANNOT use super()
+
+        InnerClass().method()
+
+    defined_outside = defined_outside

resources/test/fixtures/W292_0.py

@@ -0,0 +1,2 @@
+def fn() -> None:
+    pass

resources/test/fixtures/W292_1.py

@@ -0,0 +1,2 @@
+def fn() -> None:
+    pass  # noqa: W292

resources/test/fixtures/W292_2.py

@@ -0,0 +1,2 @@
+def fn() -> None:
+    pass

resources/test/fixtures/W605.py

@@ -0,0 +1,35 @@
+#: W605:1:10
+regex = '\.png$'
+
+#: W605:2:1
+regex = '''
+\.png$
+'''
+
+#: W605:2:6
+f(
+    '\_'
+)
+
+#: W605:4:6
+"""
+multi-line
+literal
+with \_ somewhere
+in the middle
+"""
+
+#: Okay
+regex = r'\.png$'
+regex = '\\.png$'
+regex = r'''
+\.png$
+'''
+regex = r'''
+\\.png$
+'''
+s = '\\'
+regex = '\w'  # noqa
+regex = '''
+\w
+'''  # noqa

resources/test/fixtures/__init__.py

@@ -1,3 +1,5 @@
+import os
+
 print(__path__)
 
 __all__ = ["a", "b", "c"]

resources/test/fixtures/canonical_google_examples.py

@@ -0,0 +1,108 @@
+"""A one line summary of the module or program, terminated by a period.
+
+Leave one blank line.  The rest of this docstring should contain an
+overall description of the module or program.  Optionally, it may also
+contain a brief description of exported classes and functions and/or usage
+examples.
+
+  Typical usage example:
+
+  foo = ClassFoo()
+  bar = foo.FunctionBar()
+"""
+# above: "2.8.2 Modules" section example
+# https://google.github.io/styleguide/pyguide.html#382-modules
+
+# Examples from the official "Google Python Style Guide" documentation:
+#     * As HTML: https://google.github.io/styleguide/pyguide.html
+#     * Source Markdown:
+#         https://github.com/google/styleguide/blob/gh-pages/pyguide.md
+
+import os
+from .expected import Expectation
+
+expectation = Expectation()
+expect = expectation.expect
+
+# module docstring expected violations:
+expectation.expected.add((
+    os.path.normcase(__file__),
+    "D213: Multi-line docstring summary should start at the second line"))
+
+
+# "3.8.3 Functions and Methods" section example
+# https://google.github.io/styleguide/pyguide.html#383-functions-and-methods
+@expect("D213: Multi-line docstring summary should start at the second line",
+        arg_count=3)
+@expect("D401: First line should be in imperative mood "
+        "(perhaps 'Fetch', not 'Fetches')", arg_count=3)
+@expect("D406: Section name should end with a newline "
+        "('Raises', not 'Raises:')", arg_count=3)
+@expect("D406: Section name should end with a newline "
+        "('Returns', not 'Returns:')", arg_count=3)
+@expect("D407: Missing dashed underline after section ('Raises')", arg_count=3)
+@expect("D407: Missing dashed underline after section ('Returns')",
+        arg_count=3)
+@expect("D413: Missing blank line after last section ('Raises')", arg_count=3)
+def fetch_bigtable_rows(big_table, keys, other_silly_variable=None):
+    """Fetches rows from a Bigtable.
+
+    Retrieves rows pertaining to the given keys from the Table instance
+    represented by big_table.  Silly things may happen if
+    other_silly_variable is not None.
+
+    Args:
+        big_table: An open Bigtable Table instance.
+        keys: A sequence of strings representing the key of each table row
+            to fetch.
+        other_silly_variable: Another optional variable, that has a much
+            longer name than the other args, and which does nothing.
+
+    Returns:
+        A dict mapping keys to the corresponding table row data
+        fetched. Each row is represented as a tuple of strings. For
+        example:
+
+        {'Serak': ('Rigel VII', 'Preparer'),
+         'Zim': ('Irk', 'Invader'),
+         'Lrrr': ('Omicron Persei 8', 'Emperor')}
+
+        If a key from the keys argument is missing from the dictionary,
+        then that row was not found in the table.
+
+    Raises:
+        IOError: An error occurred accessing the bigtable.Table object.
+    """
+
+
+# "3.8.4 Classes" section example
+# https://google.github.io/styleguide/pyguide.html#384-classes
+@expect("D203: 1 blank line required before class docstring (found 0)")
+@expect("D213: Multi-line docstring summary should start at the second line")
+@expect("D406: Section name should end with a newline "
+        "('Attributes', not 'Attributes:')")
+@expect("D407: Missing dashed underline after section ('Attributes')")
+@expect("D413: Missing blank line after last section ('Attributes')")
+class SampleClass:
+    """Summary of class here.
+
+    Longer class information....
+    Longer class information....
+
+    Attributes:
+        likes_spam: A boolean indicating if we like SPAM or not.
+        eggs: An integer count of the eggs we have laid.
+    """
+
+    @expect("D401: First line should be in imperative mood "
+            "(perhaps 'Init', not 'Inits')", arg_count=2)
+    def __init__(self, likes_spam=False):
+        """Inits SampleClass with blah."""
+        if self:  # added to avoid NameError when run via @expect decorator
+            self.likes_spam = likes_spam
+            self.eggs = 0
+
+    @expect("D401: First line should be in imperative mood "
+            "(perhaps 'Perform', not 'Performs')", arg_count=1)
+    def public_method(self):
+        """Performs operation blah."""