Bump version to 0.0.114

This reverts commit 77e5564f4b.

.cargo/config.toml

@@ -0,0 +1,2 @@
+[alias]
+dev = "run --package ruff_dev --bin ruff_dev"

.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

@@ -2,19 +2,19 @@ name: CI
 
 on:
   push:
-    branches: [ main ]
+    branches: [main]
   pull_request:
-    branches: [ main ]
+    branches: [main]
 
 jobs:
   cargo_build:
     name: "cargo build"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: stable
+          profile: minimal
       - uses: actions/cache@v3
         env:
           cache-name: cache-cargo
@@ -27,16 +27,19 @@ 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"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - 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
@@ -49,16 +52,19 @@ 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"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - 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
@@ -71,16 +77,18 @@ 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"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - 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
@@ -93,19 +101,21 @@ jobs:
             ${{ runner.os }}-build-${{ env.cache-name }}-
             ${{ runner.os }}-build-
             ${{ runner.os }}-
-      - run: cargo test
+      - run: cargo test --all
 
   maturin_build:
     name: "maturin build"
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - 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'
+          python-version: "3.10"
       - run: pip install maturin
       - uses: actions/cache@v3
         env:

.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: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          default: true
+      - name: Build wheels - x86_64
+        uses: messense/maturin-action@v1
+        with:
+          target: x86_64
+          args: --release --out dist --sdist -m ./${{ 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: ${{ env.PYTHON_VERSION }}
+          architecture: x64
+      - name: Install Rust toolchain
+        uses: actions-rs/toolchain@v1
+        with:
+          toolchain: stable
+          profile: minimal
+          default: true
+      - name: Build wheels - universal2
+        uses: messense/maturin-action@v1
+        with:
+          args: --release --universal2 --out dist -m ./${{ 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: ${{ matrix.target }}
+          args: --release --out dist -m ./${{ 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: ${{ matrix.target }}
+          manylinux: auto
+          args: --release --out dist -m ./${{ 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: ${{ matrix.target }}
+          manylinux: auto
+          args: --no-default-features --release --out dist -m ./${{ 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: ${{ matrix.target }}
+          manylinux: musllinux_1_2
+          args: --release --out dist -m ./${{ 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: ${{ matrix.platform.target }}
+          manylinux: musllinux_1_2
+          args: --release --out dist -m ./${{ 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 ./${{ env.CRATE_NAME }}/Cargo.toml
+      - name: Install built wheel
+        if: matrix.target == 'x86_64'
+        run: |
+          pip install dist/${{ 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

@@ -1,7 +1,6 @@
-name: Release
+name: "[ruff] Release"
 
 on:
-  push:
   create:
     tags:
       - v*
@@ -15,7 +14,7 @@ env:
   PYTHON_VERSION: "3.7" # to build abi3 wheels
 
 jobs:
-  macos:
+  macos-x86_64:
     runs-on: macos-latest
     steps:
       - uses: actions/checkout@v3
@@ -38,6 +37,25 @@ jobs:
       - name: Install built wheel - x86_64
         run: |
           pip install dist/${{ env.PACKAGE_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:
@@ -128,7 +146,7 @@ jobs:
         with:
           target: ${{ matrix.target }}
           manylinux: auto
-          args: --release --out dist
+          args: --no-default-features --release --out dist
           maturin-version: "v0.13.0"
       - uses: uraimo/run-on-arch-action@v2.0.5
         if: matrix.target != 'ppc64'
@@ -228,9 +246,9 @@ jobs:
         os: [ubuntu-latest, macos-latest]
         target: [x86_64, aarch64]
         python-version:
-          - '3.7'
-          - '3.8'
-          - '3.9'
+          - "3.7"
+          - "3.8"
+          - "3.9"
         exclude:
           - os: macos-latest
             target: aarch64
@@ -260,7 +278,8 @@ jobs:
     name: Release
     runs-on: ubuntu-latest
     needs:
-      - macos
+      - macos-universal
+      - macos-x86_64
       - windows
       - linux
       - linux-cross
@@ -276,7 +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 *

.gitignore

@@ -1,5 +1,5 @@
 # Local cache
-.cache
+.ruff_cache
 resources/test/cpython
 
 ###

.pre-commit-config.yaml

@@ -0,0 +1,10 @@
+repos:
+  - repo: https://github.com/charliermarsh/ruff-pre-commit
+    rev: v0.0.114
+    hooks:
+      - 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 +1,108 @@
+# 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. 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 +nightly fmt --all     # Auto-formatting...
+cargo +nightly clippy --all  # Linting...
+cargo +nightly test --all    # 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 four 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),
+   `src/check_tokens.rs` (for token-based checks), or `src/check_lines.rs` (for text-based checks).
+3. Add a test fixture.
+4. Update the generated files (documentation and generated code).
+
+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. If you need to inspect the AST, you can run `cargo dev print-ast`
+with a Python file. 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 --no-cache`. Once you're satisfied with the
+output, codify the behavior as a snapshot test by adding a new `testcase` macro to the `mod tests`
+section of `src/linter.rs`, like so:
+
+```rust
+#[test_case(CheckCode::A001, Path::new("A001.py"); "A001")]
+...
+```
+
+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.
+
+Finally, to update the documentation, run `cargo dev generate-rules-table` from the repo root. To
+update the generated prefix map, run `cargo dev generate-check-code-prefix`. Both of these commands
+should be run whenever a new check is added to the codebase.
+
+### 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

@@ -1,35 +1,84 @@
+[workspace]
+members = [
+  "flake8_to_ruff",
+  "ruff_dev",
+]
+
 [package]
 name = "ruff"
-version = "0.0.20"
+version = "0.0.114"
 edition = "2021"
 
 [lib]
 name = "ruff"
 
 [dependencies]
-anyhow = { version = "1.0.60" }
+anyhow = { version = "1.0.66" }
 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" }
+bitflags = { version = "1.3.2" }
+chrono = { version = "0.4.21", default-features = false, features = ["clock"] }
+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 = "0.10.5" }
+libcst = { git = "https://github.com/charliermarsh/LibCST", rev = "a13ec97dd4eb925bde4d426c6e422582793b260c" }
 log = { version = "0.4.17" }
+nohash-hasher = { version = "0.2.0" }
 notify = { version = "4.0.17" }
+num-bigint = { version = "0.4.3" }
+once_cell = { version = "1.16.0" }
+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 = "97a9d9de687227595932d6c8a04014dcfc892ff4" }
-serde = { version = "1.0.143", features = ["derive"] }
-serde_json = { version = "1.0.83" }
+ropey = { version = "1.5.0", features = ["cr_lines", "simd"], default-features = false }
+rustpython-ast = { features = ["unparse"], git = "https://github.com/RustPython/RustPython.git", rev = "27bf82a2251d7e6ac6cd75e6ad51be12a53d84bb" }
+rustpython-common = { git = "https://github.com/RustPython/RustPython.git", rev = "27bf82a2251d7e6ac6cd75e6ad51be12a53d84bb" }
+rustpython-parser = { features = ["lalrpop"], git = "https://github.com/RustPython/RustPython.git", rev = "27bf82a2251d7e6ac6cd75e6ad51be12a53d84bb" }
+serde = { version = "1.0.147", features = ["derive"] }
+serde_json = { version = "1.0.87" }
+strum = { version = "0.24.1", features = ["strum_macros"] }
+strum_macros = { version = "0.24.3" }
+textwrap = { version = "0.16.0" }
+titlecase = { version = "2.2.1" }
 toml = { 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" }
+criterion = { version = "0.4.0" }
+insta = { version = "1.19.1", features = ["yaml"] }
+test-case = { version = "2.2.2" }
+
+[features]
+default = ["update-informer"]
+update-informer = ["dep:update-informer"]
+
 [profile.release]
 panic = "abort"
 lto = "thin"
 codegen-units = 1
 opt-level = 3
+
+[profile.dev.package.insta]
+opt-level = 3
+
+[profile.dev.package.similar]
+opt-level = 3
+
+[[bench]]
+name = "source_code_locator"
+harness = false

benches/source_code_locator.rs

@@ -0,0 +1,18 @@
+use std::path::Path;
+
+use criterion::{black_box, criterion_group, criterion_main, Criterion};
+use ropey::Rope;
+use ruff::fs;
+
+fn criterion_benchmark(c: &mut Criterion) {
+    let contents = fs::read_file(Path::new("resources/test/fixtures/D.py")).unwrap();
+    c.bench_function("rope", |b| {
+        b.iter(|| {
+            let rope = Rope::from_str(black_box(&contents));
+            rope.line_to_char(black_box(4));
+        })
+    });
+}
+
+criterion_group!(benches, criterion_benchmark);
+criterion_main!(benches);

flake8_to_ruff/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "flake8-to-ruff"
+version = "0.0.114-dev.0"
+edition = "2021"
+
+[lib]
+name = "flake8_to_ruff"
+
+[dependencies]
+anyhow = { version = "1.0.66" }
+clap = { version = "4.0.1", features = ["derive"] }
+configparser = { version = "3.0.2" }
+once_cell = { version = "1.16.0" }
+regex = { version = "1.6.0" }
+ruff = { path = "..", default-features = false }
+serde = { version = "1.0.147", features = ["derive"] }
+serde_json = { version = "1.0.87" }
+toml = { version = "0.5.9" }
+
+[dev-dependencies]
+
+[features]

flake8_to_ruff/README.md

@@ -0,0 +1,98 @@
+# 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 `flake8-to-ruff`:
+
+```shell
+flake8-to-ruff path/to/setup.cfg
+flake8-to-ruff path/to/tox.ini
+flake8-to-ruff path/to/.flake8
+```
+
+`flake8-to-ruff` will print the relevant `pyproject.toml` sections to standard output, like so:
+
+```toml
+[tool.ruff]
+exclude = [
+    '.svn',
+    'CVS',
+    '.bzr',
+    '.hg',
+    '.git',
+    '__pycache__',
+    '.tox',
+    '.idea',
+    '.mypy_cache',
+    '.venv',
+    'node_modules',
+    '_state_machine.py',
+    'test_fstring.py',
+    'bad_coding2.py',
+    'badsyntax_*.py',
+]
+select = [
+    'A',
+    'E',
+    'F',
+    'Q',
+]
+ignore = []
+
+[tool.ruff.flake8-quotes]
+inline-quotes = 'single'
+
+[tool.ruff.pep8-naming]
+ignore-names = [
+    'foo',
+    'bar',
+]
+```
+
+### Plugins
+
+`flake8-to-ruff` will attempt to infer any activated plugins based on the settings provided in your
+configuration file.
+
+For example, if your `.flake8` file includes a `docstring-convention` property, `flake8-to-ruff`
+will enable the appropriate [`flake8-docstrings`](https://pypi.org/project/flake8-docstrings/)
+checks.
+
+Alternatively, you can manually specify plugins on the command-line:
+
+```shell
+flake8-to-ruff path/to/.flake8 --plugin flake8-builtins --plugin flake8-quotes
+```
+
+## 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.)
+
+## 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).

flake8_to_ruff/examples/poetry.ini

@@ -0,0 +1,36 @@
+[flake8]
+min_python_version = 3.7.0
+max-line-length = 88
+ban-relative-imports = true
+# flake8-use-fstring: https://github.com/MichaelKim0407/flake8-use-fstring#--percent-greedy-and---format-greedy
+format-greedy = 1
+inline-quotes = double
+enable-extensions = TC, TC1
+type-checking-strict = true
+eradicate-whitelist-extend = ^-.*;
+extend-ignore =
+    # E203: Whitespace before ':' (pycqa/pycodestyle#373)
+    E203,
+    # SIM106: Handle error-cases first
+    SIM106,
+    # ANN101: Missing type annotation for self in method
+    ANN101,
+    # ANN102: Missing type annotation for cls in classmethod
+    ANN102,
+    # PIE781: assign-and-return
+    PIE781,
+    # PIE798 no-unnecessary-class: Consider using a module for namespacing instead
+    PIE798,
+per-file-ignores =
+    # TC002: Move third-party import '...' into a type-checking block
+    __init__.py:TC002,
+    # ANN201: Missing return type annotation for public function
+    tests/test_*:ANN201
+    tests/**/test_*:ANN201
+extend-exclude =
+    # Frozen and not subject to change in this repo:
+    get-poetry.py,
+    install-poetry.py,
+    # External to the project's coding standards:
+    tests/fixtures/*,
+    tests/**/fixtures/*,

flake8_to_ruff/examples/python-discord.ini

@@ -0,0 +1,19 @@
+[flake8]
+max-line-length=120
+docstring-convention=all
+import-order-style=pycharm
+application_import_names=bot,tests
+exclude=.cache,.venv,.git,constants.py
+extend-ignore=
+    B311,W503,E226,S311,T000,E731
+    # Missing Docstrings
+    D100,D104,D105,D107,
+    # Docstring Whitespace
+    D203,D212,D214,D215,
+    # Docstring Quotes
+    D301,D302,
+    # Docstring Content
+    D400,D401,D402,D404,D405,D406,D407,D408,D409,D410,D411,D412,D413,D414,D416,D417
+    # Type Annotations
+    ANN002,ANN003,ANN101,ANN102,ANN204,ANN206,ANN401
+per-file-ignores=tests/*:D,ANN

flake8_to_ruff/examples/requests.ini

@@ -0,0 +1,6 @@
+[flake8]
+ignore = E203, E501, W503
+per-file-ignores =
+    requests/__init__.py:E402, F401
+    requests/compat.py:E402, F401
+    tests/compat.py:F401

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

flake8_to_ruff/src/converter.rs

@@ -0,0 +1,482 @@
+use std::collections::{BTreeSet, HashMap};
+
+use anyhow::Result;
+use ruff::checks_gen::CheckCodePrefix;
+use ruff::flake8_quotes::settings::Quote;
+use ruff::settings::options::Options;
+use ruff::settings::pyproject::Pyproject;
+use ruff::{flake8_annotations, flake8_quotes, pep8_naming};
+
+use crate::plugin::Plugin;
+use crate::{parser, plugin};
+
+pub fn convert(
+    flake8: &HashMap<String, Option<String>>,
+    plugins: Option<Vec<Plugin>>,
+) -> Result<Pyproject> {
+    // Extract all referenced check code prefixes, to power plugin inference.
+    let mut referenced_codes: BTreeSet<CheckCodePrefix> = Default::default();
+    for (key, value) in flake8 {
+        if let Some(value) = value {
+            match key.as_str() {
+                "select" | "ignore" | "extend-select" | "extend_select" | "extend-ignore"
+                | "extend_ignore" => {
+                    referenced_codes.extend(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "per-file-ignores" | "per_file_ignores" => {
+                    if let Ok(per_file_ignores) =
+                        parser::parse_files_to_codes_mapping(value.as_ref())
+                    {
+                        for (_, codes) in parser::collect_per_file_ignores(per_file_ignores) {
+                            referenced_codes.extend(codes);
+                        }
+                    }
+                }
+                _ => {}
+            }
+        }
+    }
+
+    // Check if the user has specified a `select`. If not, we'll add our own
+    // default `select`, and populate it based on user plugins.
+    let mut select = flake8
+        .get("select")
+        .and_then(|value| {
+            value
+                .as_ref()
+                .map(|value| BTreeSet::from_iter(parser::parse_prefix_codes(value)))
+        })
+        .unwrap_or_else(|| {
+            plugin::resolve_select(
+                flake8,
+                &plugins.unwrap_or_else(|| {
+                    plugin::infer_plugins_from_options(flake8)
+                        .into_iter()
+                        .chain(plugin::infer_plugins_from_codes(&referenced_codes))
+                        .collect()
+                }),
+            )
+        });
+    let mut ignore = flake8
+        .get("ignore")
+        .and_then(|value| {
+            value
+                .as_ref()
+                .map(|value| BTreeSet::from_iter(parser::parse_prefix_codes(value)))
+        })
+        .unwrap_or_default();
+
+    // Parse each supported option.
+    let mut options: Options = Default::default();
+    let mut flake8_annotations: flake8_annotations::settings::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" => {
+                    // No-op (handled above).
+                    select.extend(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "ignore" => {
+                    // No-op (handled above).
+                }
+                "extend-select" | "extend_select" => {
+                    // Unlike Flake8, use a single explicit `select`.
+                    select.extend(parser::parse_prefix_codes(value.as_ref()));
+                }
+                "extend-ignore" | "extend_ignore" => {
+                    // Unlike Flake8, use a single explicit `ignore`.
+                    ignore.extend(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-annotations
+                "suppress-none-returning" | "suppress_none_returning" => {
+                    match parser::parse_bool(value.as_ref()) {
+                        Ok(bool) => flake8_annotations.suppress_none_returning = Some(bool),
+                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    }
+                }
+                "suppress-dummy-args" | "suppress_dummy_args" => {
+                    match parser::parse_bool(value.as_ref()) {
+                        Ok(bool) => flake8_annotations.suppress_dummy_args = Some(bool),
+                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    }
+                }
+                "mypy-init-return" | "mypy_init_return" => {
+                    match parser::parse_bool(value.as_ref()) {
+                        Ok(bool) => flake8_annotations.mypy_init_return = Some(bool),
+                        Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                    }
+                }
+                "allow-star-arg-any" | "allow_star_arg_any" => {
+                    match parser::parse_bool(value.as_ref()) {
+                        Ok(bool) => flake8_annotations.allow_star_arg_any = Some(bool),
+                        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 parser::parse_bool(value.as_ref()) {
+                    Ok(bool) => flake8_quotes.avoid_escape = Some(bool),
+                    Err(e) => eprintln!("Unable to parse '{key}' property: {e}"),
+                },
+                // 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()));
+                }
+                // flake8-docstrings
+                "docstring-convention" => {
+                    // No-op (handled above).
+                }
+                // Unknown
+                _ => eprintln!("Skipping unsupported property: {key}"),
+            }
+        }
+    }
+
+    // Deduplicate and sort.
+    options.select = Some(Vec::from_iter(select));
+    options.ignore = Some(Vec::from_iter(ignore));
+    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::checks_gen::CheckCodePrefix;
+    use ruff::flake8_quotes;
+    use ruff::settings::options::Options;
+    use ruff::settings::pyproject::Pyproject;
+
+    use crate::converter::convert;
+    use crate::plugin::Plugin;
+
+    #[test]
+    fn it_converts_empty() -> Result<()> {
+        let actual = convert(&HashMap::from([]), None)?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: None,
+            flake8_quotes: None,
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_dashes() -> Result<()> {
+        let actual = convert(
+            &HashMap::from([("max-line-length".to_string(), Some("100".to_string()))]),
+            Some(vec![]),
+        )?;
+        let expected = Pyproject::new(Options {
+            line_length: Some(100),
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: None,
+            flake8_quotes: None,
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_underscores() -> Result<()> {
+        let actual = convert(
+            &HashMap::from([("max_line_length".to_string(), Some("100".to_string()))]),
+            Some(vec![]),
+        )?;
+        let expected = Pyproject::new(Options {
+            line_length: Some(100),
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: None,
+            flake8_quotes: None,
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_ignores_parse_errors() -> Result<()> {
+        let actual = convert(
+            &HashMap::from([("max_line_length".to_string(), Some("abc".to_string()))]),
+            Some(vec![]),
+        )?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: None,
+            flake8_quotes: None,
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_plugin_options() -> Result<()> {
+        let actual = convert(
+            &HashMap::from([("inline-quotes".to_string(), Some("single".to_string()))]),
+            Some(vec![]),
+        )?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: 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,
+            }),
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_converts_docstring_conventions() -> Result<()> {
+        let actual = convert(
+            &HashMap::from([(
+                "docstring-convention".to_string(),
+                Some("numpy".to_string()),
+            )]),
+            Some(vec![Plugin::Flake8Docstrings]),
+        )?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::D100,
+                CheckCodePrefix::D101,
+                CheckCodePrefix::D102,
+                CheckCodePrefix::D103,
+                CheckCodePrefix::D104,
+                CheckCodePrefix::D105,
+                CheckCodePrefix::D106,
+                CheckCodePrefix::D200,
+                CheckCodePrefix::D201,
+                CheckCodePrefix::D202,
+                CheckCodePrefix::D204,
+                CheckCodePrefix::D205,
+                CheckCodePrefix::D206,
+                CheckCodePrefix::D207,
+                CheckCodePrefix::D208,
+                CheckCodePrefix::D209,
+                CheckCodePrefix::D210,
+                CheckCodePrefix::D211,
+                CheckCodePrefix::D214,
+                CheckCodePrefix::D215,
+                CheckCodePrefix::D300,
+                CheckCodePrefix::D400,
+                CheckCodePrefix::D403,
+                CheckCodePrefix::D404,
+                CheckCodePrefix::D405,
+                CheckCodePrefix::D406,
+                CheckCodePrefix::D407,
+                CheckCodePrefix::D408,
+                CheckCodePrefix::D409,
+                CheckCodePrefix::D410,
+                CheckCodePrefix::D411,
+                CheckCodePrefix::D412,
+                CheckCodePrefix::D414,
+                CheckCodePrefix::D418,
+                CheckCodePrefix::D419,
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: None,
+            flake8_quotes: None,
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+
+    #[test]
+    fn it_infers_plugins_if_omitted() -> Result<()> {
+        let actual = convert(
+            &HashMap::from([("inline-quotes".to_string(), Some("single".to_string()))]),
+            None,
+        )?;
+        let expected = Pyproject::new(Options {
+            line_length: None,
+            src: None,
+            fix: None,
+            exclude: None,
+            extend_exclude: None,
+            select: Some(vec![
+                CheckCodePrefix::E,
+                CheckCodePrefix::F,
+                CheckCodePrefix::Q,
+                CheckCodePrefix::W,
+            ]),
+            extend_select: None,
+            ignore: Some(vec![]),
+            extend_ignore: None,
+            per_file_ignores: None,
+            dummy_variable_rgx: None,
+            target_version: None,
+            flake8_annotations: 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,
+            }),
+            isort: None,
+            pep8_naming: None,
+        });
+        assert_eq!(actual, expected);
+
+        Ok(())
+    }
+}

flake8_to_ruff/src/lib.rs

@@ -0,0 +1,5 @@
+#![allow(clippy::collapsible_if, clippy::collapsible_else_if)]
+
+pub mod converter;
+mod parser;
+pub mod plugin;

flake8_to_ruff/src/main.rs

@@ -0,0 +1,44 @@
+//! 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;
+use flake8_to_ruff::plugin::Plugin;
+
+#[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,
+    /// List of plugins to enable.
+    #[arg(long, value_delimiter = ',')]
+    plugin: Option<Vec<Plugin>>,
+}
+
+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))?;
+
+    // Extract the Flake8 section.
+    let flake8 = config
+        .get("flake8")
+        .expect("Unable to find flake8 section in INI file.");
+
+    // Create the pyproject.toml.
+    let pyproject = converter::convert(flake8, cli.plugin)?;
+    println!("{}", toml::to_string_pretty(&pyproject)?);
+
+    Ok(())
+}

flake8_to_ruff/src/parser.rs

@@ -0,0 +1,382 @@
+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()
+}
+
+/// Parse a boolean.
+pub fn parse_bool(value: &str) -> Result<bool> {
+    match value.trim() {
+        "true" => Ok(true),
+        "false" => Ok(false),
+        _ => Err(anyhow::anyhow!("Unexpected boolean value: {value}")),
+    }
+}
+
+#[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(())
+    }
+}

flake8_to_ruff/src/plugin.rs

@@ -0,0 +1,396 @@
+use std::collections::{BTreeSet, HashMap};
+use std::str::FromStr;
+
+use anyhow::anyhow;
+use ruff::checks_gen::CheckCodePrefix;
+
+#[derive(Debug, Clone, Ord, PartialOrd, Eq, PartialEq)]
+pub enum Plugin {
+    Flake8Bugbear,
+    Flake8Builtins,
+    Flake8Comprehensions,
+    Flake8Docstrings,
+    Flake8Print,
+    Flake8Quotes,
+    Flake8Annotations,
+    PEP8Naming,
+    Pyupgrade,
+}
+
+impl FromStr for Plugin {
+    type Err = anyhow::Error;
+
+    fn from_str(string: &str) -> Result<Self, Self::Err> {
+        match string {
+            "flake8-bugbear" => Ok(Plugin::Flake8Bugbear),
+            "flake8-builtins" => Ok(Plugin::Flake8Builtins),
+            "flake8-comprehensions" => Ok(Plugin::Flake8Comprehensions),
+            "flake8-docstrings" => Ok(Plugin::Flake8Docstrings),
+            "flake8-print" => Ok(Plugin::Flake8Print),
+            "flake8-quotes" => Ok(Plugin::Flake8Quotes),
+            "flake8-annotations" => Ok(Plugin::Flake8Annotations),
+            "pep8-naming" => Ok(Plugin::PEP8Naming),
+            "pyupgrade" => Ok(Plugin::Pyupgrade),
+            _ => Err(anyhow!("Unknown plugin: {}", string)),
+        }
+    }
+}
+
+impl Plugin {
+    pub fn default(&self) -> CheckCodePrefix {
+        match self {
+            Plugin::Flake8Bugbear => CheckCodePrefix::B,
+            Plugin::Flake8Builtins => CheckCodePrefix::A,
+            Plugin::Flake8Comprehensions => CheckCodePrefix::C,
+            Plugin::Flake8Docstrings => CheckCodePrefix::D,
+            Plugin::Flake8Print => CheckCodePrefix::T,
+            Plugin::Flake8Quotes => CheckCodePrefix::Q,
+            Plugin::Flake8Annotations => CheckCodePrefix::ANN,
+            Plugin::PEP8Naming => CheckCodePrefix::N,
+            Plugin::Pyupgrade => CheckCodePrefix::U,
+        }
+    }
+
+    pub fn select(&self, flake8: &HashMap<String, Option<String>>) -> Vec<CheckCodePrefix> {
+        match self {
+            Plugin::Flake8Bugbear => vec![CheckCodePrefix::B],
+            Plugin::Flake8Builtins => vec![CheckCodePrefix::A],
+            Plugin::Flake8Comprehensions => vec![CheckCodePrefix::C],
+            Plugin::Flake8Docstrings => {
+                // Use the user-provided docstring.
+                for key in ["docstring-convention", "docstring_convention"] {
+                    if let Some(Some(value)) = flake8.get(key) {
+                        match DocstringConvention::from_str(value) {
+                            Ok(convention) => return convention.select(),
+                            Err(e) => {
+                                eprintln!("Unexpected '{key}' value: {value} ({e}");
+                                return vec![];
+                            }
+                        }
+                    }
+                }
+                // Default to PEP8.
+                DocstringConvention::PEP8.select()
+            }
+            Plugin::Flake8Print => vec![CheckCodePrefix::T],
+            Plugin::Flake8Quotes => vec![CheckCodePrefix::Q],
+            Plugin::Flake8Annotations => vec![CheckCodePrefix::ANN],
+            Plugin::PEP8Naming => vec![CheckCodePrefix::N],
+            Plugin::Pyupgrade => vec![CheckCodePrefix::U],
+        }
+    }
+}
+
+pub enum DocstringConvention {
+    All,
+    PEP8,
+    NumPy,
+    Google,
+}
+
+impl FromStr for DocstringConvention {
+    type Err = anyhow::Error;
+
+    fn from_str(string: &str) -> Result<Self, Self::Err> {
+        match string {
+            "all" => Ok(DocstringConvention::All),
+            "pep8" => Ok(DocstringConvention::PEP8),
+            "numpy" => Ok(DocstringConvention::NumPy),
+            "google" => Ok(DocstringConvention::Google),
+            _ => Err(anyhow!("Unknown docstring convention: {}", string)),
+        }
+    }
+}
+
+impl DocstringConvention {
+    fn select(&self) -> Vec<CheckCodePrefix> {
+        match self {
+            DocstringConvention::All => vec![CheckCodePrefix::D],
+            DocstringConvention::PEP8 => vec![
+                // All errors except D203, D212, D213, D214, D215, D404, D405, D406, D407, D408,
+                // D409, D410, D411, D413, D415, D416 and D417.
+                CheckCodePrefix::D100,
+                CheckCodePrefix::D101,
+                CheckCodePrefix::D102,
+                CheckCodePrefix::D103,
+                CheckCodePrefix::D104,
+                CheckCodePrefix::D105,
+                CheckCodePrefix::D106,
+                CheckCodePrefix::D107,
+                CheckCodePrefix::D200,
+                CheckCodePrefix::D201,
+                CheckCodePrefix::D202,
+                // CheckCodePrefix::D203,
+                CheckCodePrefix::D204,
+                CheckCodePrefix::D205,
+                CheckCodePrefix::D206,
+                CheckCodePrefix::D207,
+                CheckCodePrefix::D208,
+                CheckCodePrefix::D209,
+                CheckCodePrefix::D210,
+                CheckCodePrefix::D211,
+                // CheckCodePrefix::D212,
+                // CheckCodePrefix::D213,
+                // CheckCodePrefix::D214,
+                // CheckCodePrefix::D215,
+                CheckCodePrefix::D300,
+                CheckCodePrefix::D400,
+                CheckCodePrefix::D402,
+                CheckCodePrefix::D403,
+                // CheckCodePrefix::D404,
+                // CheckCodePrefix::D405,
+                // CheckCodePrefix::D406,
+                // CheckCodePrefix::D407,
+                // CheckCodePrefix::D408,
+                // CheckCodePrefix::D409,
+                // CheckCodePrefix::D410,
+                // CheckCodePrefix::D411,
+                CheckCodePrefix::D412,
+                // CheckCodePrefix::D413,
+                CheckCodePrefix::D414,
+                // CheckCodePrefix::D415,
+                // CheckCodePrefix::D416,
+                // CheckCodePrefix::D417,
+                CheckCodePrefix::D418,
+                CheckCodePrefix::D419,
+            ],
+            DocstringConvention::NumPy => vec![
+                // All errors except D107, D203, D212, D213, D402, D413, D415, D416, and D417.
+                CheckCodePrefix::D100,
+                CheckCodePrefix::D101,
+                CheckCodePrefix::D102,
+                CheckCodePrefix::D103,
+                CheckCodePrefix::D104,
+                CheckCodePrefix::D105,
+                CheckCodePrefix::D106,
+                // CheckCodePrefix::D107,
+                CheckCodePrefix::D200,
+                CheckCodePrefix::D201,
+                CheckCodePrefix::D202,
+                // CheckCodePrefix::D203,
+                CheckCodePrefix::D204,
+                CheckCodePrefix::D205,
+                CheckCodePrefix::D206,
+                CheckCodePrefix::D207,
+                CheckCodePrefix::D208,
+                CheckCodePrefix::D209,
+                CheckCodePrefix::D210,
+                CheckCodePrefix::D211,
+                // CheckCodePrefix::D212,
+                // CheckCodePrefix::D213,
+                CheckCodePrefix::D214,
+                CheckCodePrefix::D215,
+                CheckCodePrefix::D300,
+                CheckCodePrefix::D400,
+                // CheckCodePrefix::D402,
+                CheckCodePrefix::D403,
+                CheckCodePrefix::D404,
+                CheckCodePrefix::D405,
+                CheckCodePrefix::D406,
+                CheckCodePrefix::D407,
+                CheckCodePrefix::D408,
+                CheckCodePrefix::D409,
+                CheckCodePrefix::D410,
+                CheckCodePrefix::D411,
+                CheckCodePrefix::D412,
+                // CheckCodePrefix::D413,
+                CheckCodePrefix::D414,
+                // CheckCodePrefix::D415,
+                // CheckCodePrefix::D416,
+                // CheckCodePrefix::D417,
+                CheckCodePrefix::D418,
+                CheckCodePrefix::D419,
+            ],
+            DocstringConvention::Google => vec![
+                // All errors except D203, D204, D213, D215, D400, D401, D404, D406, D407, D408,
+                // D409 and D413.
+                CheckCodePrefix::D100,
+                CheckCodePrefix::D101,
+                CheckCodePrefix::D102,
+                CheckCodePrefix::D103,
+                CheckCodePrefix::D104,
+                CheckCodePrefix::D105,
+                CheckCodePrefix::D106,
+                CheckCodePrefix::D107,
+                CheckCodePrefix::D200,
+                CheckCodePrefix::D201,
+                CheckCodePrefix::D202,
+                // CheckCodePrefix::D203,
+                // CheckCodePrefix::D204,
+                CheckCodePrefix::D205,
+                CheckCodePrefix::D206,
+                CheckCodePrefix::D207,
+                CheckCodePrefix::D208,
+                CheckCodePrefix::D209,
+                CheckCodePrefix::D210,
+                CheckCodePrefix::D211,
+                CheckCodePrefix::D212,
+                // CheckCodePrefix::D213,
+                CheckCodePrefix::D214,
+                // CheckCodePrefix::D215,
+                CheckCodePrefix::D300,
+                // CheckCodePrefix::D400,
+                CheckCodePrefix::D402,
+                CheckCodePrefix::D403,
+                // CheckCodePrefix::D404,
+                CheckCodePrefix::D405,
+                // CheckCodePrefix::D406,
+                // CheckCodePrefix::D407,
+                // CheckCodePrefix::D408,
+                // CheckCodePrefix::D409,
+                CheckCodePrefix::D410,
+                CheckCodePrefix::D411,
+                CheckCodePrefix::D412,
+                // CheckCodePrefix::D413,
+                CheckCodePrefix::D414,
+                CheckCodePrefix::D415,
+                CheckCodePrefix::D416,
+                CheckCodePrefix::D417,
+                CheckCodePrefix::D418,
+                CheckCodePrefix::D419,
+            ],
+        }
+    }
+}
+
+/// Infer the enabled plugins based on user-provided options.
+///
+/// For example, if the user specified a `mypy-init-return` setting, we should
+/// infer that `flake8-annotations` is active.
+pub fn infer_plugins_from_options(flake8: &HashMap<String, Option<String>>) -> Vec<Plugin> {
+    let mut plugins = BTreeSet::new();
+    for key in flake8.keys() {
+        match key.as_str() {
+            // flake8-docstrings
+            "docstring-convention" | "docstring_convention" => {
+                plugins.insert(Plugin::Flake8Docstrings);
+            }
+            // flake8-builtins
+            "builtins-ignorelist" | "builtins_ignorelist" => {
+                plugins.insert(Plugin::Flake8Builtins);
+            }
+            // flake8-quotes
+            "quotes" | "inline-quotes" | "inline_quotes" => {
+                plugins.insert(Plugin::Flake8Quotes);
+            }
+            "multiline-quotes" | "multiline_quotes" => {
+                plugins.insert(Plugin::Flake8Quotes);
+            }
+            "docstring-quotes" | "docstring_quotes" => {
+                plugins.insert(Plugin::Flake8Quotes);
+            }
+            "avoid-escape" | "avoid_escape" => {
+                plugins.insert(Plugin::Flake8Quotes);
+            }
+            // flake8-annotations
+            "suppress-none-returning" | "suppress_none_returning" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "suppress-dummy-args" | "suppress_dummy_args" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "allow-untyped-defs" | "allow_untyped_defs" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "allow-untyped-nested" | "allow_untyped_nested" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "mypy-init-return" | "mypy_init_return" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "dispatch-decorators" | "dispatch_decorators" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "overload-decorators" | "overload_decorators" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            "allow-star-arg-any" | "allow_star_arg_any" => {
+                plugins.insert(Plugin::Flake8Annotations);
+            }
+            // pep8-naming
+            "ignore-names" | "ignore_names" => {
+                plugins.insert(Plugin::PEP8Naming);
+            }
+            "classmethod-decorators" | "classmethod_decorators" => {
+                plugins.insert(Plugin::PEP8Naming);
+            }
+            "staticmethod-decorators" | "staticmethod_decorators" => {
+                plugins.insert(Plugin::PEP8Naming);
+            }
+            _ => {}
+        }
+    }
+    Vec::from_iter(plugins)
+}
+
+/// Infer the enabled plugins based on the referenced prefixes.
+///
+/// For example, if the user ignores `ANN101`, we should infer that
+/// `flake8-annotations` is active.
+pub fn infer_plugins_from_codes(codes: &BTreeSet<CheckCodePrefix>) -> Vec<Plugin> {
+    [
+        Plugin::Flake8Bugbear,
+        Plugin::Flake8Builtins,
+        Plugin::Flake8Comprehensions,
+        Plugin::Flake8Docstrings,
+        Plugin::Flake8Print,
+        Plugin::Flake8Quotes,
+        Plugin::Flake8Annotations,
+        Plugin::PEP8Naming,
+        Plugin::Pyupgrade,
+    ]
+    .into_iter()
+    .filter(|plugin| {
+        for prefix in codes {
+            if prefix
+                .codes()
+                .iter()
+                .any(|code| plugin.default().codes().contains(code))
+            {
+                return true;
+            }
+        }
+        false
+    })
+    .collect()
+}
+
+/// Resolve the set of enabled `CheckCodePrefix` values for the given plugins.
+pub fn resolve_select(
+    flake8: &HashMap<String, Option<String>>,
+    plugins: &[Plugin],
+) -> BTreeSet<CheckCodePrefix> {
+    // Include default Pyflakes and pycodestyle checks.
+    let mut select = BTreeSet::from([CheckCodePrefix::E, CheckCodePrefix::F, CheckCodePrefix::W]);
+
+    // Add prefix codes for every plugin.
+    for plugin in plugins {
+        select.extend(plugin.select(flake8));
+    }
+
+    select
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::HashMap;
+
+    use crate::plugin::{infer_plugins_from_options, Plugin};
+
+    #[test]
+    fn it_infers_plugins() {
+        let actual = infer_plugins_from_options(&HashMap::from([(
+            "inline-quotes".to_string(),
+            Some("single".to_string()),
+        )]));
+        let expected = vec![Plugin::Flake8Quotes];
+        assert_eq!(actual, expected);
+
+        let actual = infer_plugins_from_options(&HashMap::from([(
+            "staticmethod-decorators".to_string(),
+            Some("[]".to_string()),
+        )]));
+        let expected = vec![Plugin::PEP8Naming];
+        assert_eq!(actual, expected);
+    }
+}

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",
@@ -19,10 +18,12 @@ classifiers = [
 ]
 author = "Charlie Marsh"
 author_email = "charlie.r.marsh@gmail.com"
-url = "https://github.com/charliermarsh/ruff"
 description = "An extremely fast Python linter, written in Rust."
 requires-python = ">=3.7"
 
+[project.urls]
+repository = "https://github.com/charliermarsh/ruff"
+
 [build-system]
 requires = ["maturin>=0.13,<0.14"]
 build-backend = "maturin"
@@ -31,3 +32,7 @@ build-backend = "maturin"
 bindings = "bin"
 sdist-include = ["Cargo.lock"]
 strip = true
+
+[tool.isort]
+profile = "black"
+known_third_party = ["fastapi", "pydantic", "starlette"]

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/B003.py

@@ -0,0 +1,18 @@
+"""
+Should emit:
+B003 - on line 9
+"""
+
+import os
+from os import environ
+
+os.environ = {}
+environ = {}  # that's fine, assigning a new meaning to the module-level name
+
+
+class Object:
+    os = None
+
+
+o = Object()
+o.os.environ = {}

resources/test/fixtures/B004.py

@@ -0,0 +1,12 @@
+def this_is_a_bug():
+    o = object()
+    if hasattr(o, "__call__"):
+        print("Ooh, callable! Or is it?")
+    if getattr(o, "__call__", False):
+        print("Ooh, callable! Or is it?")
+
+
+def this_is_fine():
+    o = object()
+    if callable(o):
+        print("Ooh, this is actually callable.")

resources/test/fixtures/B005.py

@@ -0,0 +1,26 @@
+s = "qwe"
+s.strip(s)  # no warning
+s.strip("we")  # no warning
+s.strip(".facebook.com")  # warning
+s.strip("e")  # no warning
+s.strip("\n\t ")  # no warning
+s.strip(r"\n\t ")  # warning
+s.lstrip(s)  # no warning
+s.lstrip("we")  # no warning
+s.lstrip(".facebook.com")  # warning
+s.lstrip("e")  # no warning
+s.lstrip("\n\t ")  # no warning
+s.lstrip(r"\n\t ")  # warning
+s.rstrip(s)  # no warning
+s.rstrip("we")  # warning
+s.rstrip(".facebook.com")  # warning
+s.rstrip("e")  # no warning
+s.rstrip("\n\t ")  # no warning
+s.rstrip(r"\n\t ")  # warning
+
+from somewhere import other_type, strip
+
+strip("we")  # no warning
+other_type().lstrip()  # no warning
+other_type().rstrip(["a", "b", "c"])  # no warning
+other_type().strip("a", "b")  # no warning

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/B009_B010.py

@@ -0,0 +1,36 @@
+"""
+Should emit:
+B009 - Line 18, 19, 20, 21, 22
+B010 - Line 33, 34, 35, 36
+"""
+
+# Valid getattr usage
+getattr(foo, bar)
+getattr(foo, "bar", None)
+getattr(foo, "bar{foo}".format(foo="a"), None)
+getattr(foo, "bar{foo}".format(foo="a"))
+getattr(foo, bar, None)
+getattr(foo, "123abc")
+getattr(foo, r"123\abc")
+getattr(foo, "except")
+
+# Invalid usage
+getattr(foo, "bar")
+getattr(foo, "_123abc")
+getattr(foo, "abc123")
+getattr(foo, r"abc123")
+_ = lambda x: getattr(x, "bar")
+
+# Valid setattr usage
+setattr(foo, bar, None)
+setattr(foo, "bar{foo}".format(foo="a"), None)
+setattr(foo, "123abc", None)
+setattr(foo, r"123\abc", None)
+setattr(foo, "except", None)
+_ = lambda x: setattr(x, "bar", 1)
+
+# Invalid usage
+setattr(foo, "bar", None)
+setattr(foo, "_123abc", None)
+setattr(foo, "abc123", None)
+setattr(foo, r"abc123", None)

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/B015.py

@@ -0,0 +1,27 @@
+assert 1 == 1
+
+1 == 1
+
+assert 1 in (1, 2)
+
+1 in (1, 2)
+
+
+if 1 == 2:
+    pass
+
+
+def test():
+    assert 1 in (1, 2)
+
+    1 in (1, 2)
+
+
+data = [x for x in [1, 2, 3] if x in (1, 2)]
+
+
+class TestClass:
+    1 == 1
+
+
+print(1 == 1)

resources/test/fixtures/B016.py

@@ -0,0 +1,11 @@
+"""
+Should emit:
+B016 - on lines 6, 7, and 8
+"""
+
+raise False
+raise 1
+raise "string"
+raise Exception(False)
+raise Exception(1)
+raise Exception("string")

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/B018.py

@@ -0,0 +1,59 @@
+class Foo1:
+    """abc"""
+
+
+class Foo2:
+    """abc"""
+
+    a = 2
+    "str"  # Str (no raise)
+    f"{int}"  # JoinedStr (no raise)
+    1j  # Number (complex)
+    1  # Number (int)
+    1.0  # Number (float)
+    b"foo"  # Binary
+    True  # NameConstant (True)
+    False  # NameConstant (False)
+    None  # NameConstant (None)
+    [1, 2]  # list
+    {1, 2}  # set
+    {"foo": "bar"}  # dict
+
+
+class Foo3:
+    123
+    a = 2
+    "str"
+    1
+
+
+def foo1():
+    """my docstring"""
+
+
+def foo2():
+    """my docstring"""
+    a = 2
+    "str"  # Str (no raise)
+    f"{int}"  # JoinedStr (no raise)
+    1j  # Number (complex)
+    1  # Number (int)
+    1.0  # Number (float)
+    b"foo"  # Binary
+    True  # NameConstant (True)
+    False  # NameConstant (False)
+    None  # NameConstant (None)
+    [1, 2]  # list
+    {1, 2}  # set
+    {"foo": "bar"}  # dict
+
+
+def foo3():
+    123
+    a = 2
+    "str"
+    3
+
+
+def foo4():
+    ...

resources/test/fixtures/B019.py

@@ -0,0 +1,108 @@
+"""
+Should emit:
+B019 - on lines 73, 77, 81, 85, 89, 93, 97, 101
+"""
+import functools
+from functools import cache, cached_property, lru_cache
+
+
+def some_other_cache():
+    ...
+
+
+@functools.cache
+def compute_func(self, y):
+    ...
+
+
+class Foo:
+    def __init__(self, x):
+        self.x = x
+
+    def compute_method(self, y):
+        ...
+
+    @some_other_cache
+    def user_cached_instance_method(self, y):
+        ...
+
+    @classmethod
+    @functools.cache
+    def cached_classmethod(cls, y):
+        ...
+
+    @classmethod
+    @cache
+    def other_cached_classmethod(cls, y):
+        ...
+
+    @classmethod
+    @functools.lru_cache
+    def lru_cached_classmethod(cls, y):
+        ...
+
+    @classmethod
+    @lru_cache
+    def other_lru_cached_classmethod(cls, y):
+        ...
+
+    @staticmethod
+    @functools.cache
+    def cached_staticmethod(y):
+        ...
+
+    @staticmethod
+    @cache
+    def other_cached_staticmethod(y):
+        ...
+
+    @staticmethod
+    @functools.lru_cache
+    def lru_cached_staticmethod(y):
+        ...
+
+    @staticmethod
+    @lru_cache
+    def other_lru_cached_staticmethod(y):
+        ...
+
+    @functools.cached_property
+    def some_cached_property(self):
+        ...
+
+    @cached_property
+    def some_other_cached_property(self):
+        ...
+
+    # Remaining methods should emit B019
+    @functools.cache
+    def cached_instance_method(self, y):
+        ...
+
+    @cache
+    def another_cached_instance_method(self, y):
+        ...
+
+    @functools.cache()
+    def called_cached_instance_method(self, y):
+        ...
+
+    @cache()
+    def another_called_cached_instance_method(self, y):
+        ...
+
+    @functools.lru_cache
+    def lru_cached_instance_method(self, y):
+        ...
+
+    @lru_cache
+    def another_lru_cached_instance_method(self, y):
+        ...
+
+    @functools.lru_cache()
+    def called_lru_cached_instance_method(self, y):
+        ...
+
+    @lru_cache()
+    def another_called_lru_cached_instance_method(self, y):
+        ...

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/B026.py

@@ -0,0 +1,21 @@
+"""
+Should emit:
+B026 - on lines 16, 17, 18, 19, 20, 21
+"""
+
+
+def foo(bar, baz, bam):
+    print(bar, baz, bam)
+
+
+bar_baz = ["bar", "baz"]
+
+foo("bar", "baz", bam="bam")
+foo("bar", baz="baz", bam="bam")
+foo(bar="bar", baz="baz", bam="bam")
+foo(bam="bam", *["bar", "baz"])
+foo(bam="bam", *bar_baz)
+foo(baz="baz", bam="bam", *["bar"])
+foo(bar="bar", baz="baz", bam="bam", *[])
+foo(bam="bam", *["bar"], *["baz"])
+foo(*["bar"], bam="bam", *["baz"])

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 +1,6 @@
+x = [2, 3, 1]
+list(x)
+list(sorted(x))
+reversed(sorted(x))
+reversed(sorted(x, key=lambda e: e))
+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

@@ -0,0 +1,32 @@
+"""Top-level docstring."""
+
+__all__ = ["y"]
+__version__: str = "0.1.0"
+
+import a
+
+try:
+    import b
+except ImportError:
+    pass
+else:
+    pass
+
+import c
+
+if x > 0:
+    import d
+else:
+    import e
+
+y = x + 1
+
+import f
+
+
+def foo() -> None:
+    import e
+
+
+if __name__ == "__main__":
+    import g

resources/test/fixtures/E501.py

@@ -0,0 +1,51 @@
+"""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.
+"""
+
+_ = """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"
+
+
+def caller(string: str) -> None:
+    assert string is not None
+
+
+caller(
+    """
+    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+    """,
+)
+
+
+caller(
+    """
+    Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+    """,  # noqa: E501
+)
+
+multiple_strings_per_line = {
+    # OK
+    "Lorem ipsum dolor": "sit amet",
+    # E501 Line too long
+    "Lorem ipsum dolor": "sit amet consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.",
+    # E501 Line too long
+    "Lorem ipsum dolor": """
+sit amet  consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+""",
+    # OK
+    "Lorem ipsum dolor": "sit amet consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.",  # noqa: E501
+    # OK
+    "Lorem ipsum dolor": """
+sit amet  consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
+""",  # noqa: E501
+}

resources/test/fixtures/E711.py

@@ -0,0 +1,50 @@
+#: E711
+if res == None:
+    pass
+#: E711
+if res != None:
+    pass
+#: E711
+if None == res:
+    pass
+#: E711
+if None != res:
+    pass
+#: E711
+if res[1] == None:
+    pass
+#: E711
+if res[1] != None:
+    pass
+#: E711
+if None != res[1]:
+    pass
+#: E711
+if None == res[1]:
+    pass
+
+#: Okay
+if x not in y:
+    pass
+
+if not (X in Y or X is Z):
+    pass
+
+if not (X in Y):
+    pass
+
+if x is not y:
+    pass
+
+if X is not Y is not Z:
+    pass
+
+if TrueElement.get_element(True) == TrueElement.get_element(False):
+    pass
+
+if (True) == TrueElement or x == TrueElement:
+    pass
+
+assert (not foo) in bar
+assert {"x": not foo} in bar
+assert [42, not foo] in bar

resources/test/fixtures/E712.py

@@ -0,0 +1,46 @@
+#: E712
+if res == True:
+    pass
+#: E712
+if res != False:
+    pass
+#: E712
+if True != res:
+    pass
+#: E712
+if False == res:
+    pass
+#: E712
+if res[1] == True:
+    pass
+#: E712
+if res[1] != False:
+    pass
+#: E712
+var = 1 if cond == True else -1 if cond == False else cond
+#: E712
+if (True) == TrueElement or x == TrueElement:
+    pass
+
+#: Okay
+if x not in y:
+    pass
+
+if not (X in Y or X is Z):
+    pass
+
+if not (X in Y):
+    pass
+
+if x is not y:
+    pass
+
+if X is not Y is not Z:
+    pass
+
+if TrueElement.get_element(True) == TrueElement.get_element(False):
+    pass
+
+assert (not foo) in bar
+assert {"x": not foo} in bar
+assert [42, not foo] in bar

resources/test/fixtures/E713.py

@@ -0,0 +1,38 @@
+#: E713
+if not X in Y:
+    pass
+#: E713
+if not X.B in Y:
+    pass
+#: E713
+if not X in Y and Z == "zero":
+    pass
+#: E713
+if X == "zero" or not Y in Z:
+    pass
+#: E713
+if not (X in Y):
+    pass
+
+#: Okay
+if x not in y:
+    pass
+
+if not (X in Y or X is Z):
+    pass
+
+if x is not y:
+    pass
+
+if X is not Y is not Z:
+    pass
+
+if TrueElement.get_element(True) == TrueElement.get_element(False):
+    pass
+
+if (True) == TrueElement or x == TrueElement:
+    pass
+
+assert (not foo) in bar
+assert {"x": not foo} in bar
+assert [42, not foo] in bar

resources/test/fixtures/E714.py

@@ -0,0 +1,38 @@
+#: E714
+if not X is Y:
+    pass
+#: E714
+if not X.B is Y:
+    pass
+#: E714
+if not X is Y is not Z:
+    pass
+
+#: Okay
+if not X is not Y:
+    pass
+
+if x not in y:
+    pass
+
+if not (X in Y or X is Z):
+    pass
+
+if not (X in Y):
+    pass
+
+if x is not y:
+    pass
+
+if X is not Y is not Z:
+    pass
+
+if TrueElement.get_element(True) == TrueElement.get_element(False):
+    pass
+
+if (True) == TrueElement or x == TrueElement:
+    pass
+
+assert (not foo) in bar
+assert {"x": not foo} in bar
+assert [42, not foo] in bar

resources/test/fixtures/E721.py

@@ -0,0 +1,54 @@
+#: E721
+if type(res) == type(42):
+    pass
+#: E721
+if type(res) != type(""):
+    pass
+#: E721
+import types
+
+if res == types.IntType:
+    pass
+#: E721
+import types
+
+if type(res) is not types.ListType:
+    pass
+#: E721
+assert type(res) == type(False) or type(res) == type(None)
+#: E721
+assert type(res) == type([])
+#: E721
+assert type(res) == type(())
+#: E721
+assert type(res) == type((0,))
+#: E721
+assert type(res) == type((0))
+#: E721
+assert type(res) != type((1,))
+#: E721
+assert type(res) is type((1,))
+#: E721
+assert type(res) is not type((1,))
+#: E211 E721
+assert type(res) == type(
+    [
+        2,
+    ]
+)
+#: E201 E201 E202 E721
+assert type(res) == type(())
+#: E201 E202 E721
+assert type(res) == type((0,))
+
+#: Okay
+import types
+
+if isinstance(res, int):
+    pass
+if isinstance(res, str):
+    pass
+if isinstance(res, types.MethodType):
+    pass
+if type(a) != type(b) or type(a) == type(ccc):
+    pass

resources/test/fixtures/E722.py

@@ -0,0 +1,33 @@
+#: E722
+try:
+    pass
+except:
+    pass
+#: E722
+try:
+    pass
+except Exception:
+    pass
+except:
+    pass
+#: E722
+try:
+    pass
+except:
+    pass
+#: Okay
+fake_code = """"
+try:
+    do_something()
+except:
+    pass
+"""
+try:
+    pass
+except Exception:
+    pass
+#: Okay
+from . import compute_type
+
+if compute_type(foo) == 5:
+    pass

resources/test/fixtures/E731.py

@@ -0,0 +1,21 @@
+#: E731
+f = lambda x: 2 * x
+#: E731
+f = lambda x: 2 * x
+#: E731
+while False:
+    this = lambda y, z: 2 * x
+
+
+f = object()
+#: E731
+f.method = lambda: "Method"
+
+f = {}
+#: E731
+f["a"] = lambda x: x ** 2
+
+f = []
+f.append(lambda x: x ** 2)
+
+lambda: "no-op"

resources/test/fixtures/E741.py

@@ -0,0 +1,75 @@
+from contextlib import contextmanager
+
+l = 0
+I = 0
+O = 0
+l: int = 0
+
+a, l = 0, 1
+[a, l] = 0, 1
+a, *l = 0, 1, 2
+a = l = 0
+
+o = 0
+i = 0
+
+for l in range(3):
+    pass
+
+
+for a, l in zip(range(3), range(3)):
+    pass
+
+
+def f1():
+    global l
+    l = 0
+
+
+def f2():
+    l = 0
+
+    def f3():
+        nonlocal l
+        l = 1
+
+    f3()
+    return l
+
+
+def f4(l, /, I):
+    return l, I, O
+
+
+def f5(l=0, *, I=1):
+    return l, I
+
+
+def f6(*l, **I):
+    return l, I
+
+
+@contextmanager
+def ctx1():
+    yield 0
+
+
+with ctx1() as l:
+    pass
+
+
+@contextmanager
+def ctx2():
+    yield 0, 1
+
+
+with ctx2() as (a, l):
+    pass
+
+try:
+    pass
+except ValueError as l:
+    pass
+
+if (l := 5) > 0:
+    pass

resources/test/fixtures/E742.py

@@ -0,0 +1,14 @@
+class l:
+    pass
+
+
+class I:
+    pass
+
+
+class O:
+    pass
+
+
+class X:
+    pass

resources/test/fixtures/E743.py

@@ -0,0 +1,15 @@
+def l():
+    pass
+
+
+def I():
+    pass
+
+
+class X:
+    def O(self):
+        pass
+
+
+def x():
+    pass

resources/test/fixtures/E999.py

@@ -0,0 +1,2 @@
+def x():
+

resources/test/fixtures/F401_0.py

@@ -0,0 +1,87 @@
+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/F402.py

@@ -0,0 +1,9 @@
+import os
+import os.path as path
+
+
+for os in range(3):
+    pass
+
+for path in range(3):
+    pass

resources/test/fixtures/F404.py

@@ -0,0 +1,6 @@
+"""Docstring"""
+from __future__ import absolute_import
+
+from collections import namedtuple
+
+from __future__ import print_function

resources/test/fixtures/F405.py

@@ -0,0 +1,11 @@
+from mymodule import *
+
+
+def print_name():
+    print(name)
+
+
+def print_name(name):
+    print(name)
+
+__all__ = ['a']

resources/test/fixtures/F406.py

@@ -0,0 +1,9 @@
+from F634 import *
+
+
+def f():
+    from F634 import *
+
+
+class F:
+    from F634 import *

resources/test/fixtures/F407.py

@@ -0,0 +1,2 @@
+from __future__ import print_function
+from __future__ import non_existent_feature

resources/test/fixtures/F601.py

@@ -0,0 +1,12 @@
+x = {
+    "a": 1,
+    "a": 2,
+    "b": 3,
+    ("a", "b"): 3,
+    ("a", "b"): 4,
+    1.0: 2,
+    1: 0,
+    1: 3,
+    b"123": 1,
+    b"123": 4,
+}

resources/test/fixtures/F602.py

@@ -0,0 +1,7 @@
+a = 1
+b = 2
+x = {
+    a: 1,
+    a: 2,
+    b: 3,
+}

resources/test/fixtures/F622.py

@@ -0,0 +1,3 @@
+*a, *b, c = (1, 2, 3)
+*a, b, c = (1, 2, 3)
+a, b, *c = (1, 2, 3)

resources/test/fixtures/F631.py

@@ -0,0 +1,4 @@
+assert (False, "x")
+assert (False,)
+assert ()
+assert True

resources/test/fixtures/F632.py

@@ -0,0 +1,8 @@
+if x is "abc":
+    pass
+
+if 123 is not y:
+    pass
+
+if "123" is x < 3:
+    pass

resources/test/fixtures/F633.py

@@ -0,0 +1,4 @@
+from __future__ import print_function
+import sys
+
+print >> sys.stderr, "Hello"

resources/test/fixtures/F634.py

@@ -6,3 +6,5 @@ for _ in range(5):
         pass
     elif (3, 4):
         pass
+    elif ():
+        pass

resources/test/fixtures/F701.py

@@ -0,0 +1,23 @@
+for i in range(10):
+    break
+else:
+    break
+
+i = 0
+while i < 10:
+    i += 1
+    break
+
+
+def f():
+    for i in range(10):
+        break
+
+    break
+
+
+class Foo:
+    break
+
+
+break

resources/test/fixtures/F702.py

@@ -0,0 +1,23 @@
+for i in range(10):
+    continue
+else:
+    continue
+
+i = 0
+while i < 10:
+    i += 1
+    continue
+
+
+def f():
+    for i in range(10):
+        continue
+
+    continue
+
+
+class Foo:
+    continue
+
+
+continue

resources/test/fixtures/F704.py

@@ -0,0 +1,10 @@
+def f() -> int:
+    yield 1
+
+
+class Foo:
+    yield 2
+
+
+yield 3
+yield from 3