880513a013
This PR adjusts the logic for skipping formatting so that a `fmt: skip` can affect multiple statements if they lie on the same line. Specifically, a `fmt: skip` comment will now suppress all the statements in the suite in which it appears whose range intersects the line containing the skip directive. For example: ```python x=[ '1' ];x=2 # fmt: skip ``` remains unchanged after formatting. (Note that compound statements are somewhat special and were handled in a previous PR - see #20633). Closes #17331 and #11430. Simplest to review commit by commit - the key diffs of interest are the commit introducing the core logic, and the diff between the snapshots introduced in the last commit (compared to the second commit). # Implementation On `main` we format a suite of statements by iterating through them. If we meet a statement with a leading or trailing (own-line)`fmt: off` comment, then we suppress formatting until we meet a `fmt: on` comment. Otherwise we format the statement using its own formatting rule. How are `fmt: skip` comments handled then? They are handled internally to the formatting of each statement. Specifically, calling `.fmt` on a statement node will first check to see if there is a trailing, end-of-line `fmt: skip` (or `fmt: off`/`yapf: off`), and if so then write the node with suppressed formatting. In this PR we move the responsibility for handling `fmt: skip` into the formatting logic of the suite itself. This is done as follows: - Before beginning to format the suite, we do a pass through the statements and collect the data of ranges with skipped formatting. More specifically, we create a map with key given by the _first_ skipped statement in a block and value a pair consisting of the _last_ skipped statement and the _range_ to write verbatim. - We iterate as before, but if we meet a statement that is a key in the map constructed above, we pause to write the associated range verbatim. We then advance the iterator to the last statement in the block and proceed as before. ## Addendum on range formatting We also had to make some changes to range formatting in order to support this new behavior. For example, we want to make sure that ```python <RANGE_START>x=1<RANGE_END>;x=2 # fmt: skip ``` formats verbatim, rather than becoming ```python x = 1;x=2 # fmt: skip ``` Recall that range formatting proceeds in two steps: 1. Find the smallest enclosing node containing the range AND that has enough info to format the range (so it may be larger than you think, e.g. a docstring has enclosing node given by the suite, not the string itself.) 2. Carve out the formatted range from the result of formatting that enclosing node. We had to modify (1), since the suite knows how to format skipped nodes, but nodes may not "know" they are skipped. To do this we altered the `visit_body` bethod of the `FindEnclosingNode` visitor: now we iterate through the statements and check for skipped ranges intersecting the format range. If we find them, we return without descending. The result is to consider the statement containing the suite as the enclosing node in this case.
Ruff
An extremely fast Python linter and code formatter, written in Rust.
Linting the CPython codebase from scratch.
- ⚡️ 10-100x faster than existing linters (like Flake8) and formatters (like Black)
- 🐍 Installable via
pip - 🛠️
pyproject.tomlsupport - 🤝 Python 3.14 compatibility
- ⚖️ Drop-in parity with Flake8, isort, and Black
- 📦 Built-in caching, to avoid re-analyzing unchanged files
- 🔧 Fix support, for automatic error correction (e.g., automatically remove unused imports)
- 📏 Over 800 built-in rules, with native re-implementations of popular Flake8 plugins, like flake8-bugbear
- ⌨️ First-party editor integrations for VS Code and more
- 🌎 Monorepo-friendly, with hierarchical and cascading configuration
Ruff aims to be orders of magnitude faster than alternative tools while integrating more functionality behind a single, common interface.
Ruff can be used to replace Flake8 (plus dozens of plugins), Black, isort, pydocstyle, pyupgrade, autoflake, and more, all while executing tens or hundreds of times faster than any individual tool.
Ruff is extremely actively developed and used in major open-source projects like:
...and many more.
Ruff is backed by Astral, the creators of uv and ty.
Read the launch post, or the original project announcement.
Testimonials
Sebastián Ramírez, creator of FastAPI:
Ruff is so fast that sometimes I add an intentional bug in the code just to confirm it's actually running and checking the code.
Nick Schrock, founder of Elementl, co-creator of GraphQL:
Why is Ruff a gamechanger? Primarily because it is nearly 1000x faster. Literally. Not a typo. On our largest module (dagster itself, 250k LOC) pylint takes about 2.5 minutes, parallelized across 4 cores on my M1. Running ruff against our entire codebase takes .4 seconds.
Bryan Van de Ven, co-creator of Bokeh, original author of Conda:
Ruff is ~150-200x faster than flake8 on my machine, scanning the whole repo takes ~0.2s instead of ~20s. This is an enormous quality of life improvement for local dev. It's fast enough that I added it as an actual commit hook, which is terrific.
Timothy Crosley, creator of isort:
Just switched my first project to Ruff. Only one downside so far: it's so fast I couldn't believe it was working till I intentionally introduced some errors.
Tim Abbott, lead developer of Zulip (also here):
This is just ridiculously fast...
ruffis amazing.
Table of Contents
For more, see the documentation.
Getting Started
For more, see the documentation.
Installation
Ruff is available as ruff on PyPI.
Invoke Ruff directly with uvx:
uvx ruff check # Lint all files in the current directory.
uvx ruff format # Format all files in the current directory.
Or install Ruff with uv (recommended), pip, or pipx:
# With uv.
uv tool install ruff@latest # Install Ruff globally.
uv add --dev ruff # Or add Ruff to your project.
# With pip.
pip install ruff
# With pipx.
pipx install ruff
Starting with version 0.5.0, Ruff can be installed with our standalone installers:
# On macOS and Linux.
curl -LsSf https://astral.sh/ruff/install.sh | sh
# On Windows.
powershell -c "irm https://astral.sh/ruff/install.ps1 | iex"
# For a specific version.
curl -LsSf https://astral.sh/ruff/0.14.11/install.sh | sh
powershell -c "irm https://astral.sh/ruff/0.14.11/install.ps1 | iex"
You can also install Ruff via Homebrew, Conda, and with a variety of other package managers.
Usage
To run Ruff as a linter, try any of the following:
ruff check # Lint all files in the current directory (and any subdirectories).
ruff check path/to/code/ # Lint all files in `/path/to/code` (and any subdirectories).
ruff check path/to/code/*.py # Lint all `.py` files in `/path/to/code`.
ruff check path/to/code/to/file.py # Lint `file.py`.
ruff check @arguments.txt # Lint using an input file, treating its contents as newline-delimited command-line arguments.
Or, to run Ruff as a formatter:
ruff format # Format all files in the current directory (and any subdirectories).
ruff format path/to/code/ # Format all files in `/path/to/code` (and any subdirectories).
ruff format path/to/code/*.py # Format all `.py` files in `/path/to/code`.
ruff format path/to/code/to/file.py # Format `file.py`.
ruff format @arguments.txt # Format using an input file, treating its contents as newline-delimited command-line arguments.
Ruff can also be used as a pre-commit hook via ruff-pre-commit:
- repo: https://github.com/astral-sh/ruff-pre-commit
# Ruff version.
rev: v0.14.11
hooks:
# Run the linter.
- id: ruff-check
args: [ --fix ]
# Run the formatter.
- id: ruff-format
Ruff can also be used as a VS Code extension or with various other editors.
Ruff can also be used as a GitHub Action via
ruff-action:
name: Ruff
on: [ push, pull_request ]
jobs:
ruff:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: astral-sh/ruff-action@v3
Configuration
Ruff can be configured through a pyproject.toml, ruff.toml, or .ruff.toml file (see:
Configuration, or Settings
for a complete list of all configuration options).
If left unspecified, Ruff's default configuration is equivalent to the following ruff.toml file:
# Exclude a variety of commonly ignored directories.
exclude = [
".bzr",
".direnv",
".eggs",
".git",
".git-rewrite",
".hg",
".ipynb_checkpoints",
".mypy_cache",
".nox",
".pants.d",
".pyenv",
".pytest_cache",
".pytype",
".ruff_cache",
".svn",
".tox",
".venv",
".vscode",
"__pypackages__",
"_build",
"buck-out",
"build",
"dist",
"node_modules",
"site-packages",
"venv",
]
# Same as Black.
line-length = 88
indent-width = 4
# Assume Python 3.9
target-version = "py39"
[lint]
# Enable Pyflakes (`F`) and a subset of the pycodestyle (`E`) codes by default.
select = ["E4", "E7", "E9", "F"]
ignore = []
# Allow fix for all enabled rules (when `--fix`) is provided.
fixable = ["ALL"]
unfixable = []
# Allow unused variables when underscore-prefixed.
dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"
[format]
# Like Black, use double quotes for strings.
quote-style = "double"
# Like Black, indent with spaces, rather than tabs.
indent-style = "space"
# Like Black, respect magic trailing commas.
skip-magic-trailing-comma = false
# Like Black, automatically detect the appropriate line ending.
line-ending = "auto"
Note that, in a pyproject.toml, each section header should be prefixed with tool.ruff. For
example, [lint] should be replaced with [tool.ruff.lint].
Some configuration options can be provided via dedicated command-line arguments, such as those related to rule enablement and disablement, file discovery, and logging level:
ruff check --select F401 --select F403 --quiet
The remaining configuration options can be provided through a catch-all --config argument:
ruff check --config "lint.per-file-ignores = {'some_file.py' = ['F841']}"
To opt in to the latest lint rules, formatter style changes, interface updates, and more, enable
preview mode by setting preview = true in your configuration
file or passing --preview on the command line. Preview mode enables a collection of unstable
features that may change prior to stabilization.
See ruff help for more on Ruff's top-level commands, or ruff help check and ruff help format
for more on the linting and formatting commands, respectively.
Rules
Ruff supports over 800 lint rules, many of which are inspired by popular tools like Flake8, isort, pyupgrade, and others. Regardless of the rule's origin, Ruff re-implements every rule in Rust as a first-party feature.
By default, Ruff enables Flake8's F rules, along with a subset of the E rules, omitting any
stylistic rules that overlap with the use of a formatter, like ruff format or
Black.
If you're just getting started with Ruff, the default rule set is a great place to start: it catches a wide variety of common errors (like unused imports) with zero configuration.
Beyond the defaults, Ruff re-implements some of the most popular Flake8 plugins and related code quality tools, including:
- autoflake
- eradicate
- flake8-2020
- flake8-annotations
- flake8-async
- flake8-bandit (#1646)
- flake8-blind-except
- flake8-boolean-trap
- flake8-bugbear
- flake8-builtins
- flake8-commas
- flake8-comprehensions
- flake8-copyright
- flake8-datetimez
- flake8-debugger
- flake8-django
- flake8-docstrings
- flake8-eradicate
- flake8-errmsg
- flake8-executable
- flake8-future-annotations
- flake8-gettext
- flake8-implicit-str-concat
- flake8-import-conventions
- flake8-logging
- flake8-logging-format
- flake8-no-pep420
- flake8-pie
- flake8-print
- flake8-pyi
- flake8-pytest-style
- flake8-quotes
- flake8-raise
- flake8-return
- flake8-self
- flake8-simplify
- flake8-slots
- flake8-super
- flake8-tidy-imports
- flake8-todos
- flake8-type-checking
- flake8-use-pathlib
- flynt (#2102)
- isort
- mccabe
- pandas-vet
- pep8-naming
- pydocstyle
- pygrep-hooks
- pylint-airflow
- pyupgrade
- tryceratops
- yesqa
For a complete enumeration of the supported rules, see Rules.
Contributing
Contributions are welcome and highly appreciated. To get started, check out the contributing guidelines.
You can also join us on Discord.
Support
Having trouble? Check out the existing issues on GitHub, or feel free to open a new one.
You can also ask for help on Discord.
Acknowledgements
Ruff's linter draws on both the APIs and implementation details of many other tools in the Python ecosystem, especially Flake8, Pyflakes, pycodestyle, pydocstyle, pyupgrade, and isort.
In some cases, Ruff includes a "direct" Rust port of the corresponding tool. We're grateful to the maintainers of these tools for their work, and for all the value they've provided to the Python community.
Ruff's formatter is built on a fork of Rome's rome_formatter,
and again draws on both API and implementation details from Rome,
Prettier, and Black.
Ruff's import resolver is based on the import resolution algorithm from Pyright.
Ruff is also influenced by a number of tools outside the Python ecosystem, like Clippy and ESLint.
Ruff is the beneficiary of a large number of contributors.
Ruff is released under the MIT license.
Who's Using Ruff?
Ruff is used by a number of major open-source projects and companies, including:
- Albumentations
- Amazon (AWS SAM)
- Anki
- Anthropic (Python SDK)
- Apache Airflow
- AstraZeneca (Magnus)
- Babel
- Benchling (Refac)
- Bokeh
- Capital One (datacompy)
- CrowdCent (NumerBlox)
- Cryptography (PyCA)
- CERN (Indico)
- DVC
- Dagger
- Dagster
- Databricks (MLflow)
- Dify
- FastAPI
- Godot
- Gradio
- Great Expectations
- HTTPX
- Hatch
- Home Assistant
- Hugging Face (Transformers, Datasets, Diffusers)
- IBM (Qiskit)
- ING Bank (popmon, probatus)
- Ibis
- ivy
- JAX
- Jupyter
- Kraken Tech
- LangChain
- Litestar
- LlamaIndex
- Matrix (Synapse)
- MegaLinter
- Meltano (Meltano CLI, Singer SDK)
- Microsoft (Semantic Kernel, ONNX Runtime, LightGBM)
- Modern Treasury (Python SDK)
- Mozilla (Firefox)
- Mypy
- Nautobot
- Netflix (Dispatch)
- Neon
- Nokia
- NoneBot
- NumPyro
- ONNX
- OpenBB
- Open Wine Components
- PDM
- PaddlePaddle
- Pandas
- Pillow
- Poetry
- Polars
- PostHog
- Prefect (Python SDK, Marvin)
- PyInstaller
- PyMC
- PyMC-Marketing
- pytest
- PyTorch
- Pydantic
- Pylint
- PyScripter
- PyVista
- Reflex
- River
- Rippling
- Robyn
- Saleor
- Scale AI (Launch SDK)
- SciPy
- Snowflake (SnowCLI)
- Sphinx
- Stable Baselines3
- Starlette
- Streamlit
- The Algorithms
- Vega-Altair
- Weblate
- WordPress (Openverse)
- ZenML
- Zulip
- build (PyPA)
- cibuildwheel (PyPA)
- delta-rs
- featuretools
- meson-python
- nox
- pip
Show Your Support
If you're using Ruff, consider adding the Ruff badge to your project's README.md:
[](https://github.com/astral-sh/ruff)
...or README.rst:
.. image:: https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json
:target: https://github.com/astral-sh/ruff
:alt: Ruff
...or, as HTML:
<a href="https://github.com/astral-sh/ruff"><img src="https://img.shields.io/endpoint?url=https://raw.githubusercontent.com/astral-sh/ruff/main/assets/badge/v2.json" alt="Ruff" style="max-width:100%;"></a>
License
This repository is licensed under the MIT License
