An extremely fast Python linter, written in Rust.
Linting the CPython codebase from scratch.
- ⚡️ 10-100x faster than existing linters
- 🐍 Installable via
pip - 🤝 Python 3.10 compatibility
- 🛠️
pyproject.tomlsupport - 📦 ESLint-inspired cache support
- 🔧 ESLint-inspired
--fixsupport - 👀 TypeScript-inspired
--watchsupport
ruff is a proof-of-concept and not yet intended for production use. It supports only a small subset of the Flake8 rules, and may crash on your codebase.
Read the launch blog post.
Available as ruff on PyPI:
pip install ruffTo run ruff, try any of the following:
ruff path/to/code/to/check.py
ruff path/to/code/
ruff path/to/code/*.pyYou can run ruff in --watch mode to automatically re-run on-change:
ruff path/to/code/ --watchruff also works with Pre-Commit (requires Cargo on system):
repos:
- repo: https://github.com/charliermarsh/ruff
rev: v0.0.28
hooks:
- id: lintruff is configurable both via pyproject.toml and the command line.
For example, you could configure ruff to only enforce a subset of rules with:
[tool.ruff]
line-length = 88
select = [
"F401",
"F403",
]Alternatively, on the command-line:
ruff path/to/code/ --select F401 F403See ruff --help for more:
ruff (v0.0.28)
An extremely fast Python linter.
USAGE:
ruff [OPTIONS] <FILES>...
ARGS:
<FILES>...
OPTIONS:
-e, --exit-zero Exit with status code "0", even upon detecting errors
-f, --fix Attempt to automatically fix lint errors
-h, --help Print help information
--ignore <IGNORE>... Comma-separated list of error codes to ignore
-n, --no-cache Disable cache reads
-q, --quiet Disable all logging (but still exit with status code "1" upon
detecting errors)
--select <SELECT>... Comma-separated list of error codes to enable
-v, --verbose Enable verbose logging
-w, --watch Run in watch mode by re-running whenever files changeruff is intended to be compatible with Black, and should be
compatible out-of-the-box as long as the line-length setting is consistent between the two.
As a project, ruff is designed to be used alongside Black and, as such, will defer implementing lint rules that are obviated by Black (e.g., stylistic rules).
| Code | Name | Message |
|---|---|---|
| E402 | ModuleImportNotAtTopOfFile | Module level import not at top of file |
| E501 | LineTooLong | Line too long |
| E711 | NoneComparison | Comparison to None should be cond is None |
| E712 | TrueFalseComparison | Comparison to True should be cond is True |
| E713 | NotInTest | Test for membership should be not in |
| E714 | NotIsTest | Test for object identity should be is not |
| E731 | DoNotAssignLambda | Do not assign a lambda expression, use a def |
| E902 | IOError | No such file or directory: ... |
| F401 | UnusedImport | ... imported but unused |
| F403 | ImportStarUsage | Unable to detect undefined names |
| F541 | FStringMissingPlaceholders | f-string without any placeholders |
| F631 | AssertTuple | Assert test is a non-empty tuple, which is always True |
| F634 | IfTuple | If test is a tuple, which is always True |
| F704 | YieldOutsideFunction | a yield or yield from statement outside of a function/method |
| F706 | ReturnOutsideFunction | a return statement outside of a function/method |
| F707 | DefaultExceptNotLast | an except: block as not the last exception handler |
| F821 | UndefinedName | Undefined name ... |
| F822 | UndefinedExport | Undefined name ... in __all__ |
| F823 | UndefinedLocal | Local variable ... referenced before assignment |
| F831 | DuplicateArgumentName | Duplicate argument name in function definition |
| F841 | UnusedVariable | Local variable ... is assigned to but never used |
| F901 | RaiseNotImplemented | raise NotImplemented should be raise NotImplementedError |
| R001 | UselessObjectInheritance | Class ... inherits from object |
| R002 | NoAssertEquals | assertEquals is deprecated, use assertEqual instead |
ruff is written in Rust (1.63.0). You'll need to install the Rust toolchain for development.
Assuming you have cargo installed, you can run:
cargo run resources/test/fixtures
cargo fmt
cargo clippy
cargo testruff is distributed on PyPI, and published via maturin.
See: .github/workflows/release.yaml.
First, clone CPython. It's a large and diverse Python codebase, which makes it a good target for benchmarking.
git clone --branch 3.10 https://github.com/python/cpython.git resources/test/cpythonAdd this pyproject.toml to the CPython directory:
[tool.linter]
line-length = 88
exclude = [
"Lib/lib2to3/tests/data/bom.py",
"Lib/lib2to3/tests/data/crlf.py",
"Lib/lib2to3/tests/data/different_encoding.py",
"Lib/lib2to3/tests/data/false_encoding.py",
"Lib/lib2to3/tests/data/py2_test_grammar.py",
"Lib/test/bad_coding2.py",
"Lib/test/badsyntax_3131.py",
"Lib/test/badsyntax_pep3120.py",
"Lib/test/encoded_modules/module_iso_8859_1.py",
"Lib/test/encoded_modules/module_koi8_r.py",
"Lib/test/test_fstring.py",
"Lib/test/test_grammar.py",
"Lib/test/test_importlib/test_util.py",
"Lib/test/test_named_expressions.py",
"Lib/test/test_patma.py",
"Lib/test/test_source_encoding.py",
"Tools/c-analyzer/c_parser/parser/_delim.py",
"Tools/i18n/pygettext.py",
"Tools/test2to3/maintest.py",
"Tools/test2to3/setup.py",
"Tools/test2to3/test/test_foo.py",
"Tools/test2to3/test2to3/hello.py",
]Next, to benchmark the release build:
cargo build --release
hyperfine --ignore-failure --warmup 1 \
"./target/release/ruff ./resources/test/cpython/ --no-cache" \
"./target/release/ruff ./resources/test/cpython/"
Benchmark 1: ./target/release/ruff ./resources/test/cpython/ --no-cache
Time (mean ± σ): 353.6 ms ± 7.6 ms [User: 2868.8 ms, System: 171.5 ms]
Range (min … max): 344.4 ms … 367.3 ms 10 runs
Benchmark 2: ./target/release/ruff ./resources/test/cpython/
Time (mean ± σ): 59.6 ms ± 2.5 ms [User: 36.4 ms, System: 345.6 ms]
Range (min … max): 55.9 ms … 67.0 ms 48 runsTo benchmark against the ecosystem's existing tools:
hyperfine --ignore-failure --warmup 5 \
"./target/release/ruff ./resources/test/cpython/ --no-cache" \
"pylint --recursive=y resources/test/cpython/" \
"pyflakes resources/test/cpython" \
"autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython" \
"pycodestyle resources/test/cpython" \
"pycodestyle --select E501 resources/test/cpython" \
"flake8 resources/test/cpython" \
"flake8 --select=F831,F541,F634,F403,F706,F901,E501 resources/test/cpython" \
"python -m scripts.run_flake8 resources/test/cpython" \
"python -m scripts.run_flake8 resources/test/cpython --select=F831,F541,F634,F403,F706,F901,E501"In order, these evaluate:
- ruff
- Pylint
- PyFlakes
- autoflake
- pycodestyle
- pycodestyle, limited to the checks supported by ruff
- Flake8
- Flake8, limited to the checks supported by ruff
- Flake8, with a hack to enable multiprocessing on macOS
- Flake8, with a hack to enable multiprocessing on macOS, limited to the checks supported by ruff
(You can poetry install from ./scripts to create a working environment for the above.)
Benchmark 1: ./target/release/ruff ./resources/test/cpython/ --no-cache
Time (mean ± σ): 469.3 ms ± 16.3 ms [User: 2663.0 ms, System: 972.5 ms]
Range (min … max): 445.2 ms … 494.8 ms 10 runs
Benchmark 2: pylint --recursive=y resources/test/cpython/
Time (mean ± σ): 27.211 s ± 0.097 s [User: 26.405 s, System: 0.799 s]
Range (min … max): 27.056 s … 27.349 s 10 runs
Benchmark 3: pyflakes resources/test/cpython
Time (mean ± σ): 27.309 s ± 0.033 s [User: 27.137 s, System: 0.169 s]
Range (min … max): 27.267 s … 27.372 s 10 runs
Benchmark 4: autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython
Time (mean ± σ): 8.027 s ± 0.024 s [User: 74.255 s, System: 0.953 s]
Range (min … max): 7.969 s … 8.052 s 10 runs
Benchmark 5: pycodestyle resources/test/cpython
Time (mean ± σ): 41.666 s ± 0.266 s [User: 41.531 s, System: 0.132 s]
Range (min … max): 41.295 s … 41.980 s 10 runs
Benchmark 6: pycodestyle --select E501 resources/test/cpython
Time (mean ± σ): 14.547 s ± 0.077 s [User: 14.466 s, System: 0.079 s]
Range (min … max): 14.429 s … 14.695 s 10 runs
Benchmark 7: flake8 resources/test/cpython
Time (mean ± σ): 75.700 s ± 0.152 s [User: 75.254 s, System: 0.440 s]
Range (min … max): 75.513 s … 76.014 s 10 runs
Benchmark 8: flake8 --select=F831,F541,F634,F403,F706,F901,E501 resources/test/cpython
Time (mean ± σ): 75.122 s ± 0.532 s [User: 74.677 s, System: 0.440 s]
Range (min … max): 74.130 s … 75.606 s 10 runs
Benchmark 9: python -m scripts.run_flake8 resources/test/cpython
Time (mean ± σ): 12.794 s ± 0.147 s [User: 90.792 s, System: 0.738 s]
Range (min … max): 12.606 s … 13.030 s 10 runs
Benchmark 10: python -m scripts.run_flake8 resources/test/cpython --select=F831,F541,F634,F403,F706,F901,E501
Time (mean ± σ): 12.487 s ± 0.118 s [User: 90.052 s, System: 0.714 s]
Range (min … max): 12.265 s … 12.665 s 10 runs
Summary
'./target/release/ruff ./resources/test/cpython/ --no-cache' ran
17.10 ± 0.60 times faster than 'autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython'
26.60 ± 0.96 times faster than 'python -m scripts.run_flake8 resources/test/cpython --select=F831,F541,F634,F403,F706,F901,E501'
27.26 ± 1.00 times faster than 'python -m scripts.run_flake8 resources/test/cpython'
30.99 ± 1.09 times faster than 'pycodestyle --select E501 resources/test/cpython'
57.98 ± 2.03 times faster than 'pylint --recursive=y resources/test/cpython/'
58.19 ± 2.02 times faster than 'pyflakes resources/test/cpython'
88.77 ± 3.14 times faster than 'pycodestyle resources/test/cpython'
160.06 ± 5.68 times faster than 'flake8 --select=F831,F541,F634,F403,F706,F901,E501 resources/test/cpython'
161.29 ± 5.61 times faster than 'flake8 resources/test/cpython'MIT