README.md

Ruff

An extremely fast Python linter, written in Rust.

Linting the CPython codebase from scratch.

• ⚡️ 10-100x faster than existing linters
• 🐍 Installable via pip
• 🤝 Python 3.11 compatibility
• 🛠️ pyproject.toml support
• 📦 Built-in caching, to avoid re-analyzing unchanged files
• 🔧 Autofix support, for automatic error correction (e.g., automatically remove unused imports)
• ⚖️ Near-parity with the built-in Flake8 rule set
• 🔌 Native re-implementations of dozens of 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 a variety of plugins), isort, pydocstyle, yesqa, eradicate, pyupgrade, and autoflake, all while executing tens or hundreds of times faster than any individual tool.

Ruff goes beyond the responsibilities of a traditional linter, instead functioning as an advanced code transformation tool capable of upgrading type annotations, rewriting class definitions, sorting imports, and more.

Ruff is extremely actively developed and used in major open-source projects like:

• pandas
• FastAPI
• Apache Airflow
• Bokeh
• Zulip
• Dagster
• Pydantic
• Sphinx
• Hatch
• Jupyter
• Synapse (Matrix)
• Saleor
• Polars
• Ibis
• OpenBB
• Cryptography (PyCA)
• SnowCLI (Snowflake)

Read the launch blog post.

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:

This is just ridiculously fast... ruff is amazing.

Table of Contents

1. Installation and Usage
2. Configuration
3. Supported Rules
   1. Pyflakes (F)
   2. pycodestyle (E, W)
   3. mccabe (C90)
   4. isort (I)
   5. pydocstyle (D)
   6. pyupgrade (UP)
   7. pep8-naming (N)
   8. flake8-2020 (YTT)
   9. flake8-annotations (ANN)
   10. flake8-bandit (S)
   11. flake8-blind-except (BLE)
   12. flake8-boolean-trap (FBT)
   13. flake8-bugbear (B)
   14. flake8-builtins (A)
   15. flake8-comprehensions (C4)
   16. flake8-debugger (T10)
   17. flake8-errmsg (EM)
   18. flake8-implicit-str-concat (ISC)
   19. flake8-import-conventions (ICN)
   20. flake8-print (T20)
   21. flake8-pytest-style (PT)
   22. flake8-quotes (Q)
   23. flake8-return (RET)
   24. flake8-simplify (SIM)
   25. flake8-tidy-imports (TID)
   26. flake8-unused-arguments (ARG)
   27. flake8-datetimez (DTZ)
   28. eradicate (ERA)
   29. pandas-vet (PD)
   30. pygrep-hooks (PGH)
   31. Pylint (PLC, PLE, PLR, PLW)
   32. flake8-pie (PIE)
   33. flake8-commas (COM)
   34. flake8-no-pep420 (INP)
   35. flake8-executable (EXE)
   36. flake8-type-checking (TYP)
   37. tryceratops (TRY)
   38. Ruff-specific rules (RUF)
4. Editor Integrations
5. FAQ
6. Contributing
7. Releases
8. Benchmarks
9. Reference
10. License

Installation and Usage

Installation

Ruff is available as ruff on PyPI:

pip install ruff

For macOS Homebrew and Linuxbrew users, Ruff is also available as ruff on Homebrew:

brew install ruff

For Conda users, Ruff is also available as ruff on conda-forge:

conda install -c conda-forge ruff

For Arch Linux users, Ruff is also available as ruff on the official repositories:

pacman -S ruff

Usage

To run Ruff, try any of the following:

ruff path/to/code/to/lint.py  # Run Ruff over `lint.py`
ruff path/to/code/            # Run Ruff over all files in `/path/to/code` (and any subdirectories)
ruff path/to/code/*.py        # Run Ruff over all `.py` files in `/path/to/code`

You can run Ruff in --watch mode to automatically re-run on-change:

ruff path/to/code/ --watch

Ruff also works with pre-commit:

- repo: https://github.com/charliermarsh/ruff-pre-commit
  # Ruff version.
  rev: 'v0.0.229'
  hooks:
    - id: ruff

Configuration

Ruff is configurable both via pyproject.toml and the command line. For a full list of configurable options, see the API reference.

If left unspecified, the default configuration is equivalent to:

[tool.ruff]
line-length = 88

# Enable Pyflakes `E` and `F` codes by default.
select = ["E", "F"]
ignore = []

# Exclude a variety of commonly ignored directories.
exclude = [
    ".bzr",
    ".direnv",
    ".eggs",
    ".git",
    ".hg",
    ".mypy_cache",
    ".nox",
    ".pants.d",
    ".ruff_cache",
    ".svn",
    ".tox",
    ".venv",
    "__pypackages__",
    "_build",
    "buck-out",
    "build",
    "dist",
    "node_modules",
    "venv",
]
per-file-ignores = {}

# Allow unused variables when underscore-prefixed.
dummy-variable-rgx = "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"

# Assume Python 3.10.
target-version = "py310"

[tool.ruff.mccabe]
# Unlike Flake8, default to a complexity level of 10.
max-complexity = 10

As an example, the following would configure Ruff to: (1) avoid enforcing line-length violations (E501); (2) never remove unused imports (F401); and (3) ignore import-at-top-of-file violations (E402) in __init__.py files:

[tool.ruff]
# Enable Pyflakes and pycodestyle rules.
select = ["E", "F"]

# Never enforce `E501` (line length violations).
ignore = ["E501"]

# Never try to fix `F401` (unused imports).
unfixable = ["F401"]

# Ignore `E402` (import violations) in all `__init__.py` files, and in `path/to/file.py`.
[tool.ruff.per-file-ignores]
"__init__.py" = ["E402"]
"path/to/file.py" = ["E402"]

Plugin configurations should be expressed as subsections, e.g.:

[tool.ruff]
# Add "Q" to the list of enabled codes.
select = ["E", "F", "Q"]

[tool.ruff.flake8-quotes]
docstring-quotes = "double"

Ruff mirrors Flake8's rule code system, in which each rule code consists of a one-to-three letter prefix, followed by three digits (e.g., F401). The prefix indicates that "source" of the rule (e.g., F for Pyflakes, E for pycodestyle, ANN for flake8-annotations). The set of enabled rules is determined by the select and ignore options, which support both the full code (e.g., F401) and the prefix (e.g., F).

As a special-case, Ruff also supports the ALL code, which enables all rules. Note that some of the pydocstyle rules conflict (e.g., D203 and D211) as they represent alternative docstring formats. Enabling ALL without further configuration may result in suboptimal behavior, especially for the pydocstyle plugin.

As an alternative to pyproject.toml, Ruff will also respect a ruff.toml file, which implements an equivalent schema (though the [tool.ruff] hierarchy can be omitted). For example, the pyproject.toml described above would be represented via the following ruff.toml:

# Enable Pyflakes and pycodestyle rules.
select = ["E", "F"]

# Never enforce `E501` (line length violations).
ignore = ["E501"]

# Always autofix, but never try to fix `F401` (unused imports).
fix = true
unfixable = ["F401"]

# Ignore `E402` (import violations) in all `__init__.py` files, and in `path/to/file.py`.
[per-file-ignores]
"__init__.py" = ["E402"]
"path/to/file.py" = ["E402"]

For a full list of configurable options, see the API reference.

Some common configuration settings can be provided via the command-line:

ruff path/to/code/ --select F401 --select F403

See ruff --help for more:

Ruff: An extremely fast Python linter.

Usage: ruff [OPTIONS] [FILES]...

Arguments:
  [FILES]...

Options:
      --config <CONFIG>
          Path to the `pyproject.toml` or `ruff.toml` file to use for configuration
  -v, --verbose
          Enable verbose logging
  -q, --quiet
          Print lint violations, but nothing else
  -s, --silent
          Disable all logging (but still exit with status code "1" upon detecting lint violations)
  -e, --exit-zero
          Exit with status code "0", even upon detecting lint violations
  -w, --watch
          Run in watch mode by re-running whenever files change
      --fix
          Attempt to automatically fix lint violations
      --fix-only
          Fix any fixable lint violations, but don't report on leftover violations. Implies `--fix`
      --diff
          Avoid writing any fixed files back; instead, output a diff for each changed file to stdout
  -n, --no-cache
          Disable cache reads
      --isolated
          Ignore all configuration files
      --select <RULE_CODE>
          Comma-separated list of rule codes to enable (or ALL, to enable all rules)
      --extend-select <RULE_CODE>
          Like --select, but adds additional rule codes on top of the selected ones
      --ignore <RULE_CODE>
          Comma-separated list of rule codes to disable
      --extend-ignore <RULE_CODE>
          Like --ignore, but adds additional rule codes on top of the ignored ones
      --exclude <FILE_PATTERN>
          List of paths, used to omit files and/or directories from analysis
      --extend-exclude <FILE_PATTERN>
          Like --exclude, but adds additional files and directories on top of those already excluded
      --fixable <RULE_CODE>
          List of rule codes to treat as eligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
      --unfixable <RULE_CODE>
          List of rule codes to treat as ineligible for autofix. Only applicable when autofix itself is enabled (e.g., via `--fix`)
      --per-file-ignores <PER_FILE_IGNORES>
          List of mappings from file pattern to code to exclude
      --format <FORMAT>
          Output serialization format for violations [env: RUFF_FORMAT=] [possible values: text, json, junit, grouped, github, gitlab, pylint]
      --stdin-filename <STDIN_FILENAME>
          The name of the file when passing it through stdin
      --cache-dir <CACHE_DIR>
          Path to the cache directory [env: RUFF_CACHE_DIR=]
      --show-source
          Show violations with source code
      --respect-gitignore
          Respect file exclusions via `.gitignore` and other standard ignore files
      --force-exclude
          Enforce exclusions, even for paths passed to Ruff directly on the command-line
      --update-check
          Enable or disable automatic update checks
      --dummy-variable-rgx <DUMMY_VARIABLE_RGX>
          Regular expression matching the name of dummy variables
      --target-version <TARGET_VERSION>
          The minimum Python version that should be supported
      --line-length <LINE_LENGTH>
          Set the line-length for length-associated rules and automatic formatting
      --add-noqa
          Enable automatic additions of `noqa` directives to failing lines
      --clean
          Clear any caches in the current directory or any subdirectories
      --explain <EXPLAIN>
          Explain a rule
      --show-files
          See the files Ruff will be run against with the current settings
      --show-settings
          See the settings Ruff will use to lint a given Python file
  -h, --help
          Print help information
  -V, --version
          Print version information

pyproject.toml discovery

Similar to ESLint, Ruff supports hierarchical configuration, such that the "closest" pyproject.toml file in the directory hierarchy is used for every individual file, with all paths in the pyproject.toml file (e.g., exclude globs, src paths) being resolved relative to the directory containing the pyproject.toml file.

There are a few exceptions to these rules:

1. In locating the "closest" pyproject.toml file for a given path, Ruff ignores any pyproject.toml files that lack a [tool.ruff] section.
2. If a configuration file is passed directly via --config, those settings are used for across files. Any relative paths in that configuration file (like exclude globs or src paths) are resolved relative to the current working directory.
3. If no pyproject.toml file is found in the filesystem hierarchy, Ruff will fall back to using a default configuration. If a user-specific configuration file exists at ${config_dir}/ruff/pyproject.toml, that file will be used instead of the default configuration, with ${config_dir} being determined via the dirs crate, and all relative paths being again resolved relative to the current working directory.
4. Any pyproject.toml-supported settings that are provided on the command-line (e.g., via --select) will override the settings in every resolved configuration file.

Unlike ESLint, Ruff does not merge settings across configuration files; instead, the "closest" configuration file is used, and any parent configuration files are ignored. In lieu of this implicit cascade, Ruff supports an extend field, which allows you to inherit the settings from another pyproject.toml file, like so:

# Extend the `pyproject.toml` file in the parent directory.
extend = "../pyproject.toml"
# But use a different line length.
line-length = 100

All of the above rules apply equivalently to ruff.toml files. If Ruff detects both a ruff.toml and pyproject.toml file, it will defer to the ruff.toml.

Python file discovery

When passed a path on the command-line, Ruff will automatically discover all Python files in that path, taking into account the exclude and extend-exclude settings in each directory's pyproject.toml file.

By default, Ruff will also skip any files that are omitted via .ignore, .gitignore, .git/info/exclude, and global gitignore files (see: respect-gitignore).

Files that are passed to ruff directly are always linted, regardless of the above criteria. For example, ruff /path/to/excluded/file.py will always lint file.py.

Ignoring errors

To omit a lint rule entirely, add it to the "ignore" list via ignore or extend-ignore, either on the command-line or in your pyproject.toml file.

To ignore a violation inline, Ruff uses a noqa system similar to Flake8. To ignore an individual violation, add # noqa: {code} to the end of the line, like so:

# Ignore F841.
x = 1  # noqa: F841

# Ignore E741 and F841.
i = 1  # noqa: E741, F841

# Ignore _all_ violations.
x = 1  # noqa

Note that, for multi-line strings, the noqa directive should come at the end of the string, and will apply to the entire string, like so:

"""Lorem ipsum dolor sit amet.

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
"""  # noqa: E501

To ignore all violations across an entire file, Ruff supports Flake8's # flake8: noqa directive (or, equivalently, # ruff: noqa). Adding either of those directives to any part of a file will disable enforcement across the entire file.

For targeted exclusions across entire files (e.g., "Ignore all F841 violations in /path/to/file.py"), see the per-file-ignores configuration setting.

"Action Comments"

Ruff respects isort's "Action Comments" (# isort: skip_file, # isort: on, # isort: off, # isort: skip, and # isort: split), which enable selectively enabling and disabling import sorting for blocks of code and other inline configuration.

See the isort documentation for more.

Automating noqa Directives

Ruff supports several workflows to aid in noqa management.

First, Ruff provides a special rule code, RUF100, to enforce that your noqa directives are "valid", in that the violations they say they ignore are actually being triggered on that line (and thus suppressed). You can run ruff /path/to/file.py --extend-select RUF100 to flag unused noqa directives.

Second, Ruff can automatically remove unused noqa directives via its autofix functionality. You can run ruff /path/to/file.py --extend-select RUF100 --fix to automatically remove unused noqa directives.

Third, Ruff can automatically add noqa directives to all failing lines. This is useful when migrating a new codebase to Ruff. You can run ruff /path/to/file.py --add-noqa to automatically add noqa directives to all failing lines, with the appropriate rule codes.

Supported Rules

Regardless of the rule's origin, Ruff re-implements every rule in Rust as a first-party feature.

By default, Ruff enables all E and F rule codes, which correspond to those built-in to Flake8.

The 🛠 emoji indicates that a rule is automatically fixable by the --fix command-line option.

Pyflakes (F)

For more, see Pyflakes on PyPI.

Code	Name	Message	Fix
F401	unused-import	{name} imported but unused; consider adding to __all__ or using a redundant alias	🛠
F402	import-shadowed-by-loop-var	Import {name} from line {line} shadowed by loop variable
F403	import-star-used	from {name} import * used; unable to detect undefined names
F404	late-future-import	from __future__ imports must occur at the beginning of the file
F405	import-star-usage	{name} may be undefined, or defined from star imports: {sources}
F406	import-star-not-permitted	from {name} import * only allowed at module level
F407	future-feature-not-defined	Future feature {name} is not defined
F501	percent-format-invalid-format	'...' % ... has invalid format string: {message}
F502	percent-format-expected-mapping	'...' % ... expected mapping but got sequence
F503	percent-format-expected-sequence	'...' % ... expected sequence but got mapping
F504	percent-format-extra-named-arguments	'...' % ... has unused named argument(s): {message}	🛠
F505	percent-format-missing-argument	'...' % ... is missing argument(s) for placeholder(s): {message}
F506	percent-format-mixed-positional-and-named	'...' % ... has mixed positional and named placeholders
F507	percent-format-positional-count-mismatch	'...' % ... has {wanted} placeholder(s) but {got} substitution(s)
F508	percent-format-star-requires-sequence	'...' % ... * specifier requires sequence
F509	percent-format-unsupported-format-character	'...' % ... has unsupported format character '{char}'
F521	string-dot-format-invalid-format	'...'.format(...) has invalid format string: {message}
F522	string-dot-format-extra-named-arguments	'...'.format(...) has unused named argument(s): {message}	🛠
F523	string-dot-format-extra-positional-arguments	'...'.format(...) has unused arguments at position(s): {message}
F524	string-dot-format-missing-arguments	'...'.format(...) is missing argument(s) for placeholder(s): {message}
F525	string-dot-format-mixing-automatic	'...'.format(...) mixes automatic and manual numbering
F541	f-string-missing-placeholders	f-string without any placeholders	🛠
F601	multi-value-repeated-key-literal	Dictionary key literal {name} repeated	🛠
F602	multi-value-repeated-key-variable	Dictionary key {name} repeated	🛠
F621	expressions-in-star-assignment	Too many expressions in star-unpacking assignment
F622	two-starred-expressions	Two starred expressions in assignment
F631	assert-tuple	Assert test is a non-empty tuple, which is always True
F632	is-literal	Use == to compare constant literals	🛠
F633	invalid-print-syntax	Use of >> is invalid with print function
F634	if-tuple	If test is a tuple, which is always True
F701	break-outside-loop	break outside loop
F702	continue-outside-loop	continue not properly in loop
F704	yield-outside-function	{keyword} statement outside of a function
F706	return-outside-function	return statement outside of a function/method
F707	default-except-not-last	An except block as not the last exception handler
F722	forward-annotation-syntax-error	Syntax error in forward annotation: {body}
F811	redefined-while-unused	Redefinition of unused {name} from line {line}
F821	undefined-name	Undefined name {name}
F822	undefined-export	Undefined name {name} in __all__
F823	undefined-local	Local variable {name} referenced before assignment
F841	unused-variable	Local variable {name} is assigned to but never used	🛠
F842	unused-annotation	Local variable {name} is annotated but never used
F901	raise-not-implemented	raise NotImplemented should be raise NotImplementedError	🛠

pycodestyle (E, W)

For more, see pycodestyle on PyPI.

Error (E)

Code	Name	Message	Fix
E101	mixed-spaces-and-tabs	Indentation contains mixed spaces and tabs
E401	multiple-imports-on-one-line	Multiple imports on one line
E402	module-import-not-at-top-of-file	Module level import not at top of file
E501	line-too-long	Line too long ({length} > {limit} characters)
E711	none-comparison	Comparison to None should be cond is None	🛠
E712	true-false-comparison	Comparison to True should be cond is True	🛠
E713	not-in-test	Test for membership should be not in	🛠
E714	not-is-test	Test for object identity should be is not	🛠
E721	type-comparison	Do not compare types, use isinstance()
E722	do-not-use-bare-except	Do not use bare except
E731	do-not-assign-lambda	Do not assign a lambda expression, use a def	🛠
E741	ambiguous-variable-name	Ambiguous variable name: {name}
E742	ambiguous-class-name	Ambiguous class name: {name}
E743	ambiguous-function-name	Ambiguous function name: {name}
E902	io-error	{message}
E999	syntax-error	SyntaxError: {message}

Warning (W)

Code	Name	Message	Fix
W292	no-new-line-at-end-of-file	No newline at end of file	🛠
W505	doc-line-too-long	Doc line too long ({length} > {limit} characters)
W605	invalid-escape-sequence	Invalid escape sequence: '{char}'	🛠

mccabe (C90)

For more, see mccabe on PyPI.

Code	Name	Message	Fix
C901	function-is-too-complex	{name} is too complex ({complexity})

isort (I)

For more, see isort on PyPI.

Code	Name	Message	Fix
I001	unsorted-imports	Import block is un-sorted or un-formatted	🛠
I002	missing-required-import	Missing required import: {name}	🛠

pydocstyle (D)

For more, see pydocstyle on PyPI.

Code	Name	Message	Fix
D100	public-module	Missing docstring in public module
D101	public-class	Missing docstring in public class
D102	public-method	Missing docstring in public method
D103	public-function	Missing docstring in public function
D104	public-package	Missing docstring in public package
D105	magic-method	Missing docstring in magic method
D106	public-nested-class	Missing docstring in public nested class
D107	public-init	Missing docstring in __init__
D200	fits-on-one-line	One-line docstring should fit on one line	🛠
D201	no-blank-line-before-function	No blank lines allowed before function docstring (found {num_lines})	🛠
D202	no-blank-line-after-function	No blank lines allowed after function docstring (found {num_lines})	🛠
D203	one-blank-line-before-class	1 blank line required before class docstring	🛠
D204	one-blank-line-after-class	1 blank line required after class docstring	🛠
D205	blank-line-after-summary	1 blank line required between summary line and description	🛠
D206	indent-with-spaces	Docstring should be indented with spaces, not tabs
D207	no-under-indentation	Docstring is under-indented	🛠
D208	no-over-indentation	Docstring is over-indented	🛠
D209	new-line-after-last-paragraph	Multi-line docstring closing quotes should be on a separate line	🛠
D210	no-surrounding-whitespace	No whitespaces allowed surrounding docstring text	🛠
D211	no-blank-line-before-class	No blank lines allowed before class docstring	🛠
D212	multi-line-summary-first-line	Multi-line docstring summary should start at the first line
D213	multi-line-summary-second-line	Multi-line docstring summary should start at the second line
D214	section-not-over-indented	Section is over-indented ("{name}")	🛠
D215	section-underline-not-over-indented	Section underline is over-indented ("{name}")	🛠
D300	uses-triple-quotes	Use """triple double quotes"""
D301	uses-r-prefix-for-backslashed-content	Use r""" if any backslashes in a docstring
D400	ends-in-period	First line should end with a period	🛠
D401	non-imperative-mood	First line of docstring should be in imperative mood: "{first_line}"
D402	no-signature	First line should not be the function's signature
D403	first-line-capitalized	First word of the first line should be properly capitalized
D404	no-this-prefix	First word of the docstring should not be "This"
D405	capitalize-section-name	Section name should be properly capitalized ("{name}")	🛠
D406	new-line-after-section-name	Section name should end with a newline ("{name}")	🛠
D407	dashed-underline-after-section	Missing dashed underline after section ("{name}")	🛠
D408	section-underline-after-name	Section underline should be in the line following the section's name ("{name}")	🛠
D409	section-underline-matches-section-length	Section underline should match the length of its name ("{name}")	🛠
D410	blank-line-after-section	Missing blank line after section ("{name}")	🛠
D411	blank-line-before-section	Missing blank line before section ("{name}")	🛠
D412	no-blank-lines-between-header-and-content	No blank lines allowed between a section header and its content ("{name}")	🛠
D413	blank-line-after-last-section	Missing blank line after last section ("{name}")	🛠
D414	non-empty-section	Section has no content ("{name}")
D415	ends-in-punctuation	First line should end with a period, question mark, or exclamation point	🛠
D416	section-name-ends-in-colon	Section name should end with a colon ("{name}")	🛠
D417	document-all-arguments	Missing argument description in the docstring: {name}
D418	skip-docstring	Function decorated with @overload shouldn't contain a docstring
D419	non-empty	Docstring is empty

pyupgrade (UP)

For more, see pyupgrade on PyPI.

Code	Name	Message	Fix
UP001	useless-metaclass-type	__metaclass__ = type is implied	🛠
UP003	type-of-primitive	Use {} instead of type(...)	🛠
UP004	useless-object-inheritance	Class {name} inherits from object	🛠
UP005	deprecated-unittest-alias	{alias} is deprecated, use {target}	🛠
UP006	use-pep585-annotation	Use {} instead of {} for type annotations	🛠
UP007	use-pep604-annotation	Use X | Y for type annotations	🛠
UP008	super-call-with-parameters	Use super() instead of super(__class__, self)	🛠
UP009	pep3120-unnecessary-coding-comment	UTF-8 encoding declaration is unnecessary	🛠
UP010	unnecessary-future-import	Unnecessary __future__ import {import} for target Python version	🛠
UP011	lru-cache-without-parameters	Unnecessary parameters to functools.lru_cache	🛠
UP012	unnecessary-encode-utf8	Unnecessary call to encode as UTF-8	🛠
UP013	convert-typed-dict-functional-to-class	Convert {name} from TypedDict functional to class syntax	🛠
UP014	convert-named-tuple-functional-to-class	Convert {name} from NamedTuple functional to class syntax	🛠
UP015	redundant-open-modes	Unnecessary open mode parameters	🛠
UP016	remove-six-compat	Unnecessary six compatibility usage	🛠
UP017	datetime-timezone-utc	Use datetime.UTC alias	🛠
UP018	native-literals	Unnecessary call to {literal_type}	🛠
UP019	typing-text-str-alias	typing.Text is deprecated, use str	🛠
UP020	open-alias	Use builtin open	🛠
UP021	replace-universal-newlines	universal_newlines is deprecated, use text	🛠
UP022	replace-stdout-stderr	Sending stdout and stderr to pipe is deprecated, use capture_output	🛠
UP023	rewrite-c-element-tree	cElementTree is deprecated, use ElementTree	🛠
UP024	os-error-alias	Replace aliased errors with OSError	🛠
UP025	rewrite-unicode-literal	Remove unicode literals from strings	🛠
UP026	rewrite-mock-import	mock is deprecated, use unittest.mock	🛠
UP027	rewrite-list-comprehension	Replace unpacked list comprehension with a generator expression	🛠
UP028	rewrite-yield-from	Replace yield over for loop with yield from	🛠
UP029	unnecessary-builtin-import	Unnecessary builtin import: {import}	🛠
UP030	format-literals	Use implicit references for positional format fields	🛠
UP031	printf-string-formatting	Use format specifiers instead of percent format	🛠
UP032	f-string	Use f-string instead of format call	🛠
UP033	functools-cache	Use @functools.cache instead of @functools.lru_cache(maxsize=None)	🛠
UP034	extraneous-parentheses	Avoid extraneous parentheses	🛠

pep8-naming (N)

For more, see pep8-naming on PyPI.

Code	Name	Message	Fix
N801	invalid-class-name	Class name {name} should use CapWords convention
N802	invalid-function-name	Function name {name} should be lowercase
N803	invalid-argument-name	Argument name {name} should be lowercase
N804	invalid-first-argument-name-for-class-method	First argument of a class method should be named cls
N805	invalid-first-argument-name-for-method	First argument of a method should be named self
N806	non-lowercase-variable-in-function	Variable {name} in function should be lowercase
N807	dunder-function-name	Function name should not start and end with __
N811	constant-imported-as-non-constant	Constant {name} imported as non-constant {asname}
N812	lowercase-imported-as-non-lowercase	Lowercase {name} imported as non-lowercase {asname}
N813	camelcase-imported-as-lowercase	Camelcase {name} imported as lowercase {asname}
N814	camelcase-imported-as-constant	Camelcase {name} imported as constant {asname}
N815	mixed-case-variable-in-class-scope	Variable {name} in class scope should not be mixedCase
N816	mixed-case-variable-in-global-scope	Variable {name} in global scope should not be mixedCase
N817	camelcase-imported-as-acronym	Camelcase {name} imported as acronym {asname}
N818	error-suffix-on-exception-name	Exception name {name} should be named with an Error suffix

flake8-2020 (YTT)

For more, see flake8-2020 on PyPI.

Code	Name	Message	Fix
YTT101	sys-version-slice3-referenced	sys.version[:3] referenced (python3.10), use sys.version_info
YTT102	sys-version2-referenced	sys.version[2] referenced (python3.10), use sys.version_info
YTT103	sys-version-cmp-str3	sys.version compared to string (python3.10), use sys.version_info
YTT201	sys-version-info0-eq3-referenced	sys.version_info[0] == 3 referenced (python4), use >=
YTT202	six-py3-referenced	six.PY3 referenced (python4), use not six.PY2
YTT203	sys-version-info1-cmp-int	sys.version_info[1] compared to integer (python4), compare sys.version_info to tuple
YTT204	sys-version-info-minor-cmp-int	sys.version_info.minor compared to integer (python4), compare sys.version_info to tuple
YTT301	sys-version0-referenced	sys.version[0] referenced (python10), use sys.version_info
YTT302	sys-version-cmp-str10	sys.version compared to string (python10), use sys.version_info
YTT303	sys-version-slice1-referenced	sys.version[:1] referenced (python10), use sys.version_info

flake8-annotations (ANN)

For more, see flake8-annotations on PyPI.

Code	Name	Message	Fix
ANN001	missing-type-function-argument	Missing type annotation for function argument {name}
ANN002	missing-type-args	Missing type annotation for *{name}
ANN003	missing-type-kwargs	Missing type annotation for **{name}
ANN101	missing-type-self	Missing type annotation for {name} in method
ANN102	missing-type-cls	Missing type annotation for {name} in classmethod
ANN201	missing-return-type-public-function	Missing return type annotation for public function {name}
ANN202	missing-return-type-private-function	Missing return type annotation for private function {name}
ANN204	missing-return-type-special-method	Missing return type annotation for special method {name}	🛠
ANN205	missing-return-type-static-method	Missing return type annotation for staticmethod {name}
ANN206	missing-return-type-class-method	Missing return type annotation for classmethod {name}
ANN401	dynamically-typed-expression	Dynamically typed expressions (typing.Any) are disallowed in {name}

flake8-bandit (S)

For more, see flake8-bandit on PyPI.

Code	Name	Message	Fix
S101	assert-used	Use of assert detected
S102	exec-used	Use of exec detected
S103	bad-file-permissions	os.chmod setting a permissive mask {mask:#o} on file or directory
S104	hardcoded-bind-all-interfaces	Possible binding to all interfaces
S105	hardcoded-password-string	Possible hardcoded password: "{}"
S106	hardcoded-password-func-arg	Possible hardcoded password: "{}"
S107	hardcoded-password-default	Possible hardcoded password: "{}"
S108	hardcoded-temp-file	Probable insecure usage of temporary file or directory: "{}"
S113	request-without-timeout	Probable use of requests call with timeout set to {value}
S324	hashlib-insecure-hash-function	Probable use of insecure hash functions in hashlib: "{}"
S501	request-with-no-cert-validation	Probable use of {string} call with verify=False disabling SSL certificate checks
S506	unsafe-yaml-load	Probable use of unsafe loader {name} with yaml.load. Allows instantiation of arbitrary objects. Consider yaml.safe_load.
S508	snmp-insecure-version	The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
S509	snmp-weak-cryptography	You should not use SNMPv3 without encryption. noAuthNoPriv & authNoPriv is insecure.
S701	jinja2-autoescape-false	Using jinja2 templates with autoescape=False is dangerous and can lead to XSS. Ensure autoescape=True or use the select_autoescape function.

flake8-blind-except (BLE)

For more, see flake8-blind-except on PyPI.

Code	Name	Message	Fix
BLE001	blind-except	Do not catch blind exception: {name}

flake8-boolean-trap (FBT)

For more, see flake8-boolean-trap on PyPI.

Code	Name	Message	Fix
FBT001	boolean-positional-arg-in-function-definition	Boolean positional arg in function definition
FBT002	boolean-default-value-in-function-definition	Boolean default value in function definition
FBT003	boolean-positional-value-in-function-call	Boolean positional value in function call

flake8-bugbear (B)

For more, see flake8-bugbear on PyPI.

Code	Name	Message	Fix
B002	unary-prefix-increment	Python does not support the unary prefix increment
B003	assignment-to-os-environ	Assigning to os.environ doesn't clear the environment
B004	unreliable-callable-check	Using hasattr(x, '__call__') to test if x is callable is unreliable. Use callable(x) for consistent results.
B005	strip-with-multi-characters	Using .strip() with multi-character strings is misleading the reader
B006	mutable-argument-default	Do not use mutable data structures for argument defaults
B007	unused-loop-control-variable	Loop control variable {name} not used within the loop body	🛠
B008	function-call-argument-default	Do not perform function call {name} in argument defaults
B009	get-attr-with-constant	Do not call getattr with a constant attribute value. It is not any safer than normal property access.	🛠
B010	set-attr-with-constant	Do not call setattr with a constant attribute value. It is not any safer than normal property access.	🛠
B011	do-not-assert-false	Do not assert False (python -O removes these calls), raise AssertionError()	🛠
B012	jump-statement-in-finally	{name} inside finally blocks cause exceptions to be silenced
B013	redundant-tuple-in-exception-handler	A length-one tuple literal is redundant. Write except {name} instead of except ({name},).	🛠
B014	duplicate-handler-exception	Exception handler with duplicate exception: {name}	🛠
B015	useless-comparison	Pointless comparison. This comparison does nothing but waste CPU instructions. Either prepend assert or remove it.
B016	cannot-raise-literal	Cannot raise a literal. Did you intend to return it or raise an Exception?
B017	no-assert-raises-exception	assertRaises(Exception) should be considered evil
B018	useless-expression	Found useless expression. Either assign it to a variable or remove it.
B019	cached-instance-method	Use of functools.lru_cache or functools.cache on methods can lead to memory leaks
B020	loop-variable-overrides-iterator	Loop control variable {name} overrides iterable it iterates
B021	f-string-docstring	f-string used as docstring. This will be interpreted by python as a joined string rather than a docstring.
B022	useless-contextlib-suppress	No arguments passed to contextlib.suppress. No exceptions will be suppressed and therefore this context manager is redundant
B023	function-uses-loop-variable	Function definition does not bind loop variable {name}
B024	abstract-base-class-without-abstract-method	{name} is an abstract base class, but it has no abstract methods
B025	duplicate-try-block-exception	try-except block with duplicate exception {name}
B026	star-arg-unpacking-after-keyword-arg	Star-arg unpacking after a keyword argument is strongly discouraged
B027	empty-method-without-abstract-decorator	{name} is an empty method in an abstract base class, but has no abstract decorator
B904	raise-without-from-inside-except	Within an except clause, raise exceptions with raise ... from err or raise ... from None to distinguish them from errors in exception handling
B905	zip-without-explicit-strict	zip() without an explicit strict= parameter

flake8-builtins (A)

For more, see flake8-builtins on PyPI.

Code	Name	Message	Fix
A001	builtin-variable-shadowing	Variable {name} is shadowing a python builtin
A002	builtin-argument-shadowing	Argument {name} is shadowing a python builtin
A003	builtin-attribute-shadowing	Class attribute {name} is shadowing a python builtin

flake8-comprehensions (C4)

For more, see flake8-comprehensions on PyPI.

Code	Name	Message	Fix
C400	unnecessary-generator-list	Unnecessary generator (rewrite as a list comprehension)	🛠
C401	unnecessary-generator-set	Unnecessary generator (rewrite as a set comprehension)	🛠
C402	unnecessary-generator-dict	Unnecessary generator (rewrite as a dict comprehension)	🛠
C403	unnecessary-list-comprehension-set	Unnecessary list comprehension (rewrite as a set comprehension)	🛠
C404	unnecessary-list-comprehension-dict	Unnecessary list comprehension (rewrite as a dict comprehension)	🛠
C405	unnecessary-literal-set	Unnecessary {obj_type} literal (rewrite as a set literal)	🛠
C406	unnecessary-literal-dict	Unnecessary {obj_type} literal (rewrite as a dict literal)	🛠
C408	unnecessary-collection-call	Unnecessary {obj_type} call (rewrite as a literal)	🛠
C409	unnecessary-literal-within-tuple-call	Unnecessary {literal} literal passed to tuple() (rewrite as a tuple literal)	🛠
C410	unnecessary-literal-within-list-call	Unnecessary {literal} literal passed to list() (remove the outer call to list())	🛠
C411	unnecessary-list-call	Unnecessary list call (remove the outer call to list())	🛠
C413	unnecessary-call-around-sorted	Unnecessary {func} call around sorted()	🛠
C414	unnecessary-double-cast-or-process	Unnecessary {inner} call within {outer}()
C415	unnecessary-subscript-reversal	Unnecessary subscript reversal of iterable within {func}()
C416	unnecessary-comprehension	Unnecessary {obj_type} comprehension (rewrite using {obj_type}())	🛠
C417	unnecessary-map	Unnecessary map usage (rewrite using a generator expression)

flake8-debugger (T10)

For more, see flake8-debugger on PyPI.

Code	Name	Message	Fix
T100	debugger	Trace found: {name} used

flake8-errmsg (EM)

For more, see flake8-errmsg on PyPI.

Code	Name	Message	Fix
EM101	raw-string-in-exception	Exception must not use a string literal, assign to variable first
EM102	f-string-in-exception	Exception must not use an f-string literal, assign to variable first
EM103	dot-format-in-exception	Exception must not use a .format() string directly, assign to variable first

flake8-implicit-str-concat (ISC)

For more, see flake8-implicit-str-concat on PyPI.

Code	Name	Message	Fix
ISC001	single-line-implicit-string-concatenation	Implicitly concatenated string literals on one line
ISC002	multi-line-implicit-string-concatenation	Implicitly concatenated string literals over continuation line
ISC003	explicit-string-concatenation	Explicitly concatenated string should be implicitly concatenated

flake8-import-conventions (ICN)

For more, see flake8-import-conventions on GitHub.

Code	Name	Message	Fix
ICN001	import-alias-is-not-conventional	{name} should be imported as {asname}

flake8-print (T20)

For more, see flake8-print on PyPI.

Code	Name	Message	Fix
T201	print-found	print found	🛠
T203	p-print-found	pprint found	🛠

flake8-pytest-style (PT)

For more, see flake8-pytest-style on PyPI.

Code	Name	Message	Fix
PT001	incorrect-fixture-parentheses-style	Use @pytest.fixture{expected_parens} over @pytest.fixture{actual_parens}	🛠
PT002	fixture-positional-args	Configuration for fixture {function} specified via positional args, use kwargs
PT003	extraneous-scope-function	scope='function' is implied in @pytest.fixture()
PT004	missing-fixture-name-underscore	Fixture {function} does not return anything, add leading underscore
PT005	incorrect-fixture-name-underscore	Fixture {function} returns a value, remove leading underscore
PT006	parametrize-names-wrong-type	Wrong name(s) type in @pytest.mark.parametrize, expected {expected}	🛠
PT007	parametrize-values-wrong-type	Wrong values type in @pytest.mark.parametrize expected {values} of {row}
PT008	patch-with-lambda	Use return_value= instead of patching with lambda
PT009	unittest-assertion	Use a regular assert instead of unittest-style {assertion}	🛠
PT010	raises-without-exception	set the expected exception in pytest.raises()
PT011	raises-too-broad	pytest.raises({exception}) is too broad, set the match parameter or use a more specific exception
PT012	raises-with-multiple-statements	pytest.raises() block should contain a single simple statement
PT013	incorrect-pytest-import	Found incorrect import of pytest, use simple import pytest instead
PT015	assert-always-false	Assertion always fails, replace with pytest.fail()
PT016	fail-without-message	No message passed to pytest.fail()
PT017	assert-in-except	Found assertion on exception {name} in except block, use pytest.raises() instead
PT018	composite-assertion	Assertion should be broken down into multiple parts
PT019	fixture-param-without-value	Fixture {name} without value is injected as parameter, use @pytest.mark.usefixtures instead
PT020	deprecated-yield-fixture	@pytest.yield_fixture is deprecated, use @pytest.fixture
PT021	fixture-finalizer-callback	Use yield instead of request.addfinalizer
PT022	useless-yield-fixture	No teardown in fixture {name}, use return instead of yield	🛠
PT023	incorrect-mark-parentheses-style	Use @pytest.mark.{mark_name}{expected_parens} over @pytest.mark.{mark_name}{actual_parens}	🛠
PT024	unnecessary-asyncio-mark-on-fixture	pytest.mark.asyncio is unnecessary for fixtures	🛠
PT025	erroneous-use-fixtures-on-fixture	pytest.mark.usefixtures has no effect on fixtures	🛠
PT026	use-fixtures-without-parameters	Useless pytest.mark.usefixtures without parameters	🛠

flake8-quotes (Q)

For more, see flake8-quotes on PyPI.

Code	Name	Message	Fix
Q000	bad-quotes-inline-string	Double quotes found but single quotes preferred	🛠
Q001	bad-quotes-multiline-string	Double quote multiline found but single quotes preferred	🛠
Q002	bad-quotes-docstring	Double quote docstring found but single quotes preferred	🛠
Q003	avoid-quote-escape	Change outer quotes to avoid escaping inner quotes	🛠

flake8-return (RET)

For more, see flake8-return on PyPI.

Code	Name	Message	Fix
RET501	unnecessary-return-none	Do not explicitly return None in function if it is the only possible return value	🛠
RET502	implicit-return-value	Do not implicitly return None in function able to return non-None value	🛠
RET503	implicit-return	Missing explicit return at the end of function able to return non-None value	🛠
RET504	unnecessary-assign	Unnecessary variable assignment before return statement
RET505	superfluous-else-return	Unnecessary {branch} after return statement
RET506	superfluous-else-raise	Unnecessary {branch} after raise statement
RET507	superfluous-else-continue	Unnecessary {branch} after continue statement
RET508	superfluous-else-break	Unnecessary {branch} after break statement

flake8-simplify (SIM)

For more, see flake8-simplify on PyPI.

Code	Name	Message	Fix
SIM101	duplicate-isinstance-call	Multiple isinstance calls for {name}, merge into a single call	🛠
SIM102	nested-if-statements	Use a single if statement instead of nested if statements	🛠
SIM103	return-bool-condition-directly	Return the condition {cond} directly	🛠
SIM105	use-contextlib-suppress	Use contextlib.suppress({exception}) instead of try-except-pass
SIM107	return-in-try-except-finally	Don't use return in try/except and finally
SIM108	use-ternary-operator	Use ternary operator {contents} instead of if-else-block	🛠
SIM109	compare-with-tuple	Use {replacement} instead of multiple equality comparisons	🛠
SIM110	convert-loop-to-any	Use {any} instead of for loop	🛠
SIM111	convert-loop-to-all	Use {all} instead of for loop	🛠
SIM112	use-capital-environment-variables	Use capitalized environment variable {expected} instead of {original}	🛠
SIM115	open-file-with-context-handler	Use context handler for opening files
SIM117	multiple-with-statements	Use a single with statement with multiple contexts instead of nested with statements	🛠
SIM118	key-in-dict	Use {key} in {dict} instead of {key} in {dict}.keys()	🛠
SIM201	negate-equal-op	Use {left} != {right} instead of not {left} == {right}	🛠
SIM202	negate-not-equal-op	Use {left} == {right} instead of not {left} != {right}	🛠
SIM208	double-negation	Use {expr} instead of not (not {expr})	🛠
SIM210	if-expr-with-true-false	Use bool({expr}) instead of True if {expr} else False	🛠
SIM211	if-expr-with-false-true	Use not {expr} instead of False if {expr} else True	🛠
SIM212	if-expr-with-twisted-arms	Use {expr_else} if {expr_else} else {expr_body} instead of {expr_body} if not {expr_else} else {expr_else}	🛠
SIM220	a-and-not-a	Use False instead of {name} and not {name}	🛠
SIM221	a-or-not-a	Use True instead of {name} or not {name}	🛠
SIM222	or-true	Use True instead of ... or True	🛠
SIM223	and-false	Use False instead of ... and False	🛠
SIM300	yoda-conditions	Yoda conditions are discouraged, use {suggestion} instead	🛠
SIM401	dict-get-with-default	Use {contents} instead of an if block	🛠

flake8-tidy-imports (TID)

For more, see flake8-tidy-imports on PyPI.

Code	Name	Message	Fix
TID251	banned-api	{name} is banned: {message}
TID252	relative-imports	Relative imports from parent modules are banned

flake8-unused-arguments (ARG)

For more, see flake8-unused-arguments on PyPI.

Code	Name	Message	Fix
ARG001	unused-function-argument	Unused function argument: {name}
ARG002	unused-method-argument	Unused method argument: {name}
ARG003	unused-class-method-argument	Unused class method argument: {name}
ARG004	unused-static-method-argument	Unused static method argument: {name}
ARG005	unused-lambda-argument	Unused lambda argument: {name}

flake8-datetimez (DTZ)

For more, see flake8-datetimez on PyPI.

Code	Name	Message	Fix
DTZ001	call-datetime-without-tzinfo	The use of datetime.datetime() without tzinfo argument is not allowed
DTZ002	call-datetime-today	The use of datetime.datetime.today() is not allowed
DTZ003	call-datetime-utcnow	The use of datetime.datetime.utcnow() is not allowed
DTZ004	call-datetime-utcfromtimestamp	The use of datetime.datetime.utcfromtimestamp() is not allowed
DTZ005	call-datetime-now-without-tzinfo	The use of datetime.datetime.now() without tz argument is not allowed
DTZ006	call-datetime-fromtimestamp	The use of datetime.datetime.fromtimestamp() without tz argument is not allowed
DTZ007	call-datetime-strptime-without-zone	The use of datetime.datetime.strptime() without %z must be followed by .replace(tzinfo=) or .astimezone()
DTZ011	call-date-today	The use of datetime.date.today() is not allowed.
DTZ012	call-date-fromtimestamp	The use of datetime.date.fromtimestamp() is not allowed

eradicate (ERA)

For more, see eradicate on PyPI.

Code	Name	Message	Fix
ERA001	commented-out-code	Found commented-out code	🛠

pandas-vet (PD)

For more, see pandas-vet on PyPI.

Code	Name	Message	Fix
PD002	use-of-inplace-argument	inplace=True should be avoided; it has inconsistent behavior
PD003	use-of-dot-is-null	.isna is preferred to .isnull; functionality is equivalent
PD004	use-of-dot-not-null	.notna is preferred to .notnull; functionality is equivalent
PD007	use-of-dot-ix	.ix is deprecated; use more explicit .loc or .iloc
PD008	use-of-dot-at	Use .loc instead of .at. If speed is important, use numpy.
PD009	use-of-dot-iat	Use .iloc instead of .iat. If speed is important, use numpy.
PD010	use-of-dot-pivot-or-unstack	.pivot_table is preferred to .pivot or .unstack; provides same functionality
PD011	use-of-dot-values	Use .to_numpy() instead of .values
PD012	use-of-dot-read-table	.read_csv is preferred to .read_table; provides same functionality
PD013	use-of-dot-stack	.melt is preferred to .stack; provides same functionality
PD015	use-of-pd-merge	Use .merge method instead of pd.merge function. They have equivalent functionality.
PD901	df-is-a-bad-variable-name	df is a bad variable name. Be kinder to your future self.

pygrep-hooks (PGH)

For more, see pygrep-hooks on GitHub.

Code	Name	Message	Fix
PGH001	no-eval	No builtin eval() allowed
PGH002	deprecated-log-warn	warn is deprecated in favor of warning
PGH003	blanket-type-ignore	Use specific rule codes when ignoring type issues
PGH004	blanket-noqa	Use specific rule codes when using noqa

Pylint (PLC, PLE, PLR, PLW)

For more, see Pylint on PyPI.

Convention (PLC)

Code	Name	Message	Fix
PLC0414	useless-import-alias	Import alias does not rename original package	🛠
PLC3002	unnecessary-direct-lambda-call	Lambda expression called directly. Execute the expression inline instead.

Error (PLE)

Code	Name	Message	Fix
PLE0117	nonlocal-without-binding	Nonlocal name {name} found without binding
PLE0118	used-prior-global-declaration	Name {name} is used prior to global declaration on line {line}
PLE1142	await-outside-async	await should be used within an async function

Refactor (PLR)

Code	Name	Message	Fix
PLR0133	constant-comparison	Two constants compared in a comparison, consider replacing {left_constant} {op} {right_constant}
PLR0206	property-with-parameters	Cannot have defined parameters for properties
PLR0402	consider-using-from-import	Use from {module} import {name} in lieu of alias
PLR1701	consider-merging-isinstance	Merge these isinstance calls: isinstance({obj}, ({types}))
PLR1722	use-sys-exit	Use sys.exit() instead of {name}	🛠
PLR2004	magic-value-comparison	Magic value used in comparison, consider replacing {value} with a constant variable

Warning (PLW)

Code	Name	Message	Fix
PLW0120	useless-else-on-loop	Else clause on loop without a break statement, remove the else and de-indent all the code inside it
PLW0602	global-variable-not-assigned	Using global for {name} but no assignment is done

flake8-pie (PIE)

For more, see flake8-pie on PyPI.

Code	Name	Message	Fix
PIE790	no-unnecessary-pass	Unnecessary pass statement	🛠
PIE794	dupe-class-field-definitions	Class field {name} is defined multiple times	🛠
PIE796	prefer-unique-enums	Enum contains duplicate value: {value}
PIE807	prefer-list-builtin	Prefer list() over useless lambda	🛠

flake8-commas (COM)

For more, see flake8-commas on PyPI.

Code	Name	Message	Fix
COM812	trailing-comma-missing	Trailing comma missing	🛠
COM818	trailing-comma-on-bare-tuple-prohibited	Trailing comma on bare tuple prohibited
COM819	trailing-comma-prohibited	Trailing comma prohibited	🛠

flake8-no-pep420 (INP)

For more, see flake8-no-pep420 on PyPI.

Code	Name	Message	Fix
INP001	implicit-namespace-package	File {filename} is part of an implicit namespace package. Add an __init__.py.

flake8-executable (EXE)

For more, see flake8-executable on PyPI.

Code	Name	Message	Fix
EXE003	shebang-python	Shebang should contain "python"
EXE004	shebang-whitespace	Avoid whitespace before shebang	🛠
EXE005	shebang-newline	Shebang should be at the beginning of the file

flake8-type-checking (TYP)

For more, see flake8-type-checking on PyPI.

Code	Name	Message	Fix
TYP005	empty-type-checking-block	Found empty type-checking block

tryceratops (TRY)

For more, see tryceratops on PyPI.

Code	Name	Message	Fix
TRY004	prefer-type-error	Prefer TypeError exception for invalid type
TRY300	try-consider-else	Consider else block

Ruff-specific rules (RUF)

Code	Name	Message	Fix
RUF001	ambiguous-unicode-character-string	String contains ambiguous unicode character '{confusable}' (did you mean '{representant}'?)	🛠
RUF002	ambiguous-unicode-character-docstring	Docstring contains ambiguous unicode character '{confusable}' (did you mean '{representant}'?)	🛠
RUF003	ambiguous-unicode-character-comment	Comment contains ambiguous unicode character '{confusable}' (did you mean '{representant}'?)	🛠
RUF004	keyword-argument-before-star-argument	Keyword argument {name} must come after starred arguments
RUF005	unpack-instead-of-concatenating-to-collection-literal	Consider {expr} instead of concatenation
RUF100	unused-noqa	Unused blanket noqa directive	🛠

Editor Integrations

VS Code (Official)

Download the Ruff VS Code extension, which supports autofix actions, import sorting, and more.

Language Server Protocol (Official)

Ruff supports the Language Server Protocol via the ruff-lsp Python package, available on PyPI.

ruff-lsp enables Ruff to be used with any editor that supports the Language Server Protocol, including Neovim, Sublime Text, Emacs, and more.

For example, to use ruff-lsp with Neovim, install ruff-lsp from PyPI along with nvim-lspconfig. Then, add something like the following to your init.lua:

-- See: https://github.com/neovim/nvim-lspconfig/tree/54eb2a070a4f389b1be0f98070f81d23e2b1a715#suggested-configuration
local opts = { noremap=true, silent=true }
vim.keymap.set('n', '<space>e', vim.diagnostic.open_float, opts)
vim.keymap.set('n', '[d', vim.diagnostic.goto_prev, opts)
vim.keymap.set('n', ']d', vim.diagnostic.goto_next, opts)
vim.keymap.set('n', '<space>q', vim.diagnostic.setloclist, opts)

-- Use an on_attach function to only map the following keys
-- after the language server attaches to the current buffer
local on_attach = function(client, bufnr)
  -- Enable completion triggered by <c-x><c-o>
  vim.api.nvim_buf_set_option(bufnr, 'omnifunc', 'v:lua.vim.lsp.omnifunc')

  -- Mappings.
  -- See `:help vim.lsp.*` for documentation on any of the below functions
  local bufopts = { noremap=true, silent=true, buffer=bufnr }
  vim.keymap.set('n', 'gD', vim.lsp.buf.declaration, bufopts)
  vim.keymap.set('n', 'gd', vim.lsp.buf.definition, bufopts)
  vim.keymap.set('n', 'K', vim.lsp.buf.hover, bufopts)
  vim.keymap.set('n', 'gi', vim.lsp.buf.implementation, bufopts)
  vim.keymap.set('n', '<C-k>', vim.lsp.buf.signature_help, bufopts)
  vim.keymap.set('n', '<space>wa', vim.lsp.buf.add_workspace_folder, bufopts)
  vim.keymap.set('n', '<space>wr', vim.lsp.buf.remove_workspace_folder, bufopts)
  vim.keymap.set('n', '<space>wl', function()
    print(vim.inspect(vim.lsp.buf.list_workspace_folders()))
  end, bufopts)
  vim.keymap.set('n', '<space>D', vim.lsp.buf.type_definition, bufopts)
  vim.keymap.set('n', '<space>rn', vim.lsp.buf.rename, bufopts)
  vim.keymap.set('n', '<space>ca', vim.lsp.buf.code_action, bufopts)
  vim.keymap.set('n', 'gr', vim.lsp.buf.references, bufopts)
  vim.keymap.set('n', '<space>f', function() vim.lsp.buf.format { async = true } end, bufopts)
end

-- Configure `ruff-lsp`.
local configs = require 'lspconfig.configs'
if not configs.ruff_lsp then
  configs.ruff_lsp = {
    default_config = {
      cmd = { 'ruff-lsp' },
      filetypes = { 'python' },
      root_dir = require('lspconfig').util.find_git_ancestor,
      init_options = {
        settings = {
          args = {}
        }
      }
    }
  }
end
require('lspconfig').ruff_lsp.setup {
  on_attach = on_attach,
}

Upon successful installation, you should see Ruff's diagnostics surfaced directly in your editor:

To use ruff-lsp with other editors, including Sublime Text and Helix, see the ruff-lsp documentation.

Language Server Protocol (Unofficial)

Ruff is also available as the python-lsp-ruff plugin for python-lsp-server, both of which are installable from PyPI:

pip install python-lsp-server python-lsp-ruff

The LSP server can then be used with any editor that supports the Language Server Protocol.

For example, to use python-lsp-ruff with Neovim, add something like the following to your init.lua:

require'lspconfig'.pylsp.setup {
  settings = {
    pylsp = {
      plugins = {
        ruff = {
          enabled = true
        },
        pycodestyle = {
          enabled = false
        },
        pyflakes = {
          enabled = false
        },
        mccabe = {
          enabled = false
        }
      }
    }
  },
}

Vim & Neovim

Ruff can be integrated into any editor that supports the Language Server Protocol via ruff-lsp (see: Language Server Protocol), including Vim and Neovim.

It's recommended that you use ruff-lsp, the officially supported LSP server for Ruff.

However, Ruff is also available as part of the coc-pyright extension for coc.nvim.

With the ALE plugin for (Neo)Vim.

let g:ale_linters = { "python": ["ruff"] }
let g:ale_fixers = {
\       "python": ["black", "ruff"],
\}

Ruff can also be integrated via efm in just a few lines.

tools:
  python-ruff: &python-ruff
    lint-command: 'ruff --config ~/myconfigs/linters/ruff.toml --quiet ${INPUT}'
    lint-stdin: true
    lint-formats:
      - '%f:%l:%c: %m'
    format-command: 'ruff --stdin-filename ${INPUT} --config ~/myconfigs/linters/ruff.toml --fix --exit-zero --quiet -'
    format-stdin: true

For neovim users using null-ls, Ruff is already integrated.

local null_ls = require("null-ls")
local methods = require("null-ls.methods")
local helpers = require("null-ls.helpers")

local function ruff_fix()
    return helpers.make_builtin({
        name = "ruff",
        meta = {
            url = "https://github.com/charliermarsh/ruff/",
            description = "An extremely fast Python linter, written in Rust.",
        },
        method = methods.internal.FORMATTING,
        filetypes = { "python" },
        generator_opts = {
            command = "ruff",
            args = { "--fix", "-e", "-n", "--stdin-filename", "$FILENAME", "-" },
            to_stdin = true
        },
        factory = helpers.formatter_factory
    })
end

null_ls.setup({
    sources = {
        ruff_fix(),
        null_ls.builtins.diagnostics.ruff,
    }
})

PyCharm (External Tool)

Ruff can be installed as an External Tool in PyCharm. Open the Preferences pane, then navigate to "Tools", then "External Tools". From there, add a new tool with the following configuration:

Ruff should then appear as a runnable action:

PyCharm (Unofficial)

Ruff is also available as the Ruff plugin on the IntelliJ Marketplace (maintained by @koxudaxi).

GitHub Actions

GitHub Actions has everything you need to run Ruff out-of-the-box:

name: CI
on: push
jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Install Python
        uses: actions/setup-python@v4
        with:
          python-version: "3.11"
      - name: Install dependencies
        run: |
          python -m pip install --upgrade pip
          pip install ruff
      # Include `--format=github` to enable automatic inline annotations.
      - name: Run Ruff
        run: ruff --format=github .

FAQ

Is Ruff compatible with Black?

Yes. Ruff is compatible with Black out-of-the-box, as long as the line-length setting is consistent between the two.

As a project, Ruff is designed to be used alongside Black and, as such, will defer implementing stylistic lint rules that are obviated by autoformatting.

How does Ruff compare to Flake8?

(Coming from Flake8? Try flake8-to-ruff to automatically convert your existing configuration.)

Ruff can be used as a drop-in replacement for Flake8 when used (1) without or with a small number of plugins, (2) alongside Black, and (3) on Python 3 code.

Under those conditions, Ruff implements every rule in Flake8.

Ruff also re-implements some of the most popular Flake8 plugins and related code quality tools natively, including:

• autoflake (#1647)
• eradicate
• flake8-2020
• flake8-annotations
• flake8-bandit (#1646)
• flake8-blind-except
• flake8-boolean-trap
• flake8-bugbear
• flake8-builtins
• flake8-commas
• flake8-comprehensions
• flake8-datetimez
• flake8-debugger
• flake8-docstrings
• flake8-eradicate
• flake8-errmsg
• flake8-executable
• flake8-implicit-str-concat
• flake8-import-conventions
• flake8-no-pep420
• flake8-pie (#1543)
• flake8-print
• flake8-pytest-style
• flake8-quotes
• flake8-return
• flake8-simplify (#998)
• flake8-super
• flake8-tidy-imports
• isort
• mccabe
• pandas-vet
• pep8-naming
• pydocstyle
• pygrep-hooks (#980)
• pyupgrade (#827)
• yesqa

Note that, in some cases, Ruff uses different rule codes and prefixes than would be found in the originating Flake8 plugins. For example, Ruff uses TID252 to represent the I252 rule from flake8-tidy-imports. This helps minimize conflicts across plugins and allows any individual plugin to be toggled on or off with a single (e.g.) --select TID, as opposed to --select I2 (to avoid conflicts with the isort rules, like I001).

Beyond the rule set, Ruff suffers from the following limitations vis-à-vis Flake8:

1. Ruff does not yet support structural pattern matching.
2. Flake8 has a plugin architecture and supports writing custom lint rules. (Instead, popular Flake8 plugins are re-implemented in Rust as part of Ruff itself.)

There are a few other minor incompatibilities between Ruff and the originating Flake8 plugins:

• Ruff doesn't implement all the "opinionated" lint rules from flake8-bugbear.
• Depending on your project structure, Ruff and isort can differ in their detection of first-party code. (This is often solved by modifying the src property, e.g., to src = ["src"], if your code is nested in a src directory.)

How does Ruff compare to Pylint?

At time of writing, Pylint implements 409 total rules, while Ruff implements 224, of which at least 60 overlap with the Pylint rule set. Subjectively, Pylint tends to implement more rules based on type inference (e.g., validating the number of arguments in a function call).

Like Flake8, Pylint supports plugins (called "checkers"), while Ruff implements all rules natively.

Unlike Pylint, Ruff is capable of automatically fixing its own lint violations.

Pylint parity is being tracked in #970.

Which tools does Ruff replace?

Today, Ruff can be used to replace Flake8 when used with any of the following plugins:

• flake8-2020
• flake8-annotations
• flake8-bandit (#1646)
• flake8-blind-except
• flake8-boolean-trap
• flake8-bugbear
• flake8-builtins
• flake8-commas
• flake8-comprehensions
• flake8-datetimez
• flake8-debugger
• flake8-docstrings
• flake8-eradicate
• flake8-errmsg
• flake8-executable
• flake8-implicit-str-concat
• flake8-import-conventions
• flake8-no-pep420
• flake8-pie (#1543)
• flake8-print
• flake8-pytest-style
• flake8-quotes
• flake8-return
• flake8-simplify (#998)
• flake8-super
• flake8-tidy-imports
• mccabe
• pandas-vet
• pep8-naming
• pydocstyle

Ruff can also replace isort, yesqa, eradicate, pygrep-hooks (#980), and a subset of the rules implemented in pyupgrade (#827).

If you're looking to use Ruff, but rely on an unsupported Flake8 plugin, feel free to file an Issue.

Do I need to install Rust to use Ruff?

Nope! Ruff is available as ruff on PyPI:

pip install ruff

Ruff ships with wheels for all major platforms, which enables pip to install Ruff without relying on Rust at all.

Can I write my own plugins for Ruff?

Ruff does not yet support third-party plugins, though a plugin system is within-scope for the project. See #283 for more.

How does Ruff's import sorting compare to isort?

Ruff's import sorting is intended to be nearly equivalent to isort when used profile = "black". (There are some minor differences in how Ruff and isort break ties between similar imports.)

Like isort, Ruff's import sorting is compatible with Black.

Ruff is less configurable than isort, but supports the known-first-party, known-third-party, extra-standard-library, and src settings, like so:

[tool.ruff]
select = [
    # Pyflakes
    "F",
    # Pycodestyle
    "E",
    "W",
    # isort
    "I001"
]
src = ["src", "tests"]

[tool.ruff.isort]
known-first-party = ["my_module1", "my_module2"]

Does Ruff support Jupyter Notebooks?

Ruff is integrated into nbQA, a tool for running linters and code formatters over Jupyter Notebooks.

After installing ruff and nbqa, you can run Ruff over a notebook like so:

> nbqa ruff Untitled.ipynb
Untitled.ipynb:cell_1:2:5: F841 Local variable `x` is assigned to but never used
Untitled.ipynb:cell_2:1:1: E402 Module level import not at top of file
Untitled.ipynb:cell_2:1:8: F401 `os` imported but unused
Found 3 error(s).
1 potentially fixable with the --fix option.

Does Ruff support NumPy- or Google-style docstrings?

Yes! To enable specific docstring convention, add the following to your pyproject.toml:

[tool.ruff.pydocstyle]
convention = "google"  # Accepts: "google", "numpy", or "pep257".

For example, if you're coming from flake8-docstrings, and your originating configuration uses --docstring-convention=numpy, you'd instead set convention = "numpy" in your pyproject.toml, as above.

Alongside convention, you'll want to explicitly enable the D rule code prefix, like so:

[tool.ruff]
select = [
    "D",
]

[tool.ruff.pydocstyle]
convention = "google"

Setting a convention force-disables any rules that are incompatible with that convention, no matter how they're provided, which avoids accidental incompatibilities and simplifies configuration.

How can I tell what settings Ruff is using to check my code?

Run ruff /path/to/code.py --show-settings to view the resolved settings for a given file.

Contributing

Contributions are welcome and hugely appreciated. To get started, check out the contributing guidelines.

Releases

Ruff is distributed on PyPI, and published via maturin.

See: .github/workflows/release.yaml.

Benchmarks

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/cpython

To benchmark the release build:

cargo build --release && hyperfine --ignore-failure --warmup 10 \
  "./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):     293.8 ms ±   3.2 ms    [User: 2384.6 ms, System: 90.3 ms]
  Range (min … max):   289.9 ms … 301.6 ms    10 runs

  Warning: Ignoring non-zero exit code.

Benchmark 2: ./target/release/ruff ./resources/test/cpython/
  Time (mean ± σ):      48.0 ms ±   3.1 ms    [User: 65.2 ms, System: 124.7 ms]
  Range (min … max):    45.0 ms …  66.7 ms    62 runs

  Warning: Ignoring non-zero exit code.

Summary
  './target/release/ruff ./resources/test/cpython/' ran
    6.12 ± 0.41 times faster than './target/release/ruff ./resources/test/cpython/ --no-cache'

To benchmark against the ecosystem's existing tools:

hyperfine --ignore-failure --warmup 5 \
  "./target/release/ruff ./resources/test/cpython/ --no-cache" \
  "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" \
  "flake8 resources/test/cpython"

Benchmark 1: ./target/release/ruff ./resources/test/cpython/ --no-cache
  Time (mean ± σ):     294.3 ms ±   3.3 ms    [User: 2467.5 ms, System: 89.6 ms]
  Range (min … max):   291.1 ms … 302.8 ms    10 runs

  Warning: Ignoring non-zero exit code.

Benchmark 2: pyflakes resources/test/cpython
  Time (mean ± σ):     15.786 s ±  0.143 s    [User: 15.560 s, System: 0.214 s]
  Range (min … max):   15.640 s … 16.157 s    10 runs

  Warning: Ignoring non-zero exit code.

Benchmark 3: autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython
  Time (mean ± σ):      6.175 s ±  0.169 s    [User: 54.102 s, System: 1.057 s]
  Range (min … max):    5.950 s …  6.391 s    10 runs

Benchmark 4: pycodestyle resources/test/cpython
  Time (mean ± σ):     46.921 s ±  0.508 s    [User: 46.699 s, System: 0.202 s]
  Range (min … max):   46.171 s … 47.863 s    10 runs

  Warning: Ignoring non-zero exit code.

Benchmark 5: flake8 resources/test/cpython
  Time (mean ± σ):     12.260 s ±  0.321 s    [User: 102.934 s, System: 1.230 s]
  Range (min … max):   11.848 s … 12.933 s    10 runs

  Warning: Ignoring non-zero exit code.

Summary
  './target/release/ruff ./resources/test/cpython/ --no-cache' ran
   20.98 ± 0.62 times faster than 'autoflake --recursive --expand-star-imports --remove-all-unused-imports --remove-unused-variables --remove-duplicate-keys resources/test/cpython'
   41.66 ± 1.18 times faster than 'flake8 resources/test/cpython'
   53.64 ± 0.77 times faster than 'pyflakes resources/test/cpython'
  159.43 ± 2.48 times faster than 'pycodestyle resources/test/cpython'

You can run poetry install from ./scripts to create a working environment for the above. All reported benchmarks were computed using the versions specified by ./scripts/pyproject.toml on Python 3.11.

To benchmark Pylint, remove the following files from the CPython repository:

rm Lib/test/bad_coding.py \
  Lib/test/bad_coding2.py \
  Lib/test/bad_getattr.py \
  Lib/test/bad_getattr2.py \
  Lib/test/bad_getattr3.py \
  Lib/test/badcert.pem \
  Lib/test/badkey.pem \
  Lib/test/badsyntax_3131.py \
  Lib/test/badsyntax_future10.py \
  Lib/test/badsyntax_future3.py \
  Lib/test/badsyntax_future4.py \
  Lib/test/badsyntax_future5.py \
  Lib/test/badsyntax_future6.py \
  Lib/test/badsyntax_future7.py \
  Lib/test/badsyntax_future8.py \
  Lib/test/badsyntax_future9.py \
  Lib/test/badsyntax_pep3120.py \
  Lib/test/test_asyncio/test_runners.py \
  Lib/test/test_copy.py \
  Lib/test/test_inspect.py \
  Lib/test/test_typing.py

Then, from resources/test/cpython, run: time pylint -j 0 -E $(git ls-files '*.py'). This will execute Pylint with maximum parallelism and only report errors.

To benchmark Pyupgrade, run the following from resources/test/cpython:

hyperfine --ignore-failure --warmup 5 --prepare "git reset --hard HEAD" \
  "find . -type f -name \"*.py\" | xargs -P 0 pyupgrade --py311-plus"

Benchmark 1: find . -type f -name "*.py" | xargs -P 0 pyupgrade --py311-plus
  Time (mean ± σ):     30.119 s ±  0.195 s    [User: 28.638 s, System: 0.390 s]
  Range (min … max):   29.813 s … 30.356 s    10 runs

Reference

Options

allowed-confusables

A list of allowed "confusable" Unicode characters to ignore when enforcing RUF001, RUF002, and RUF003.

Default value: []

Type: Vec<char>

Example usage:

[tool.ruff]
# Allow minus-sign (U+2212), greek-small-letter-rho (U+03C1), and the asterisk-operator (U+2217),
# which could be confused for "-", "p", and "*", respectively.
allowed-confusables = ["−", "ρ", "∗"]

---

builtins

A list of builtins to treat as defined references, in addition to the system builtins.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff]
builtins = ["_"]

---

cache-dir

A path to the cache directory.

By default, Ruff stores cache results in a .ruff_cache directory in the current project root.

However, Ruff will also respect the RUFF_CACHE_DIR environment variable, which takes precedence over that default.

This setting will override even the RUFF_CACHE_DIR environment variable, if set.

Default value: .ruff_cache

Type: PathBuf

Example usage:

[tool.ruff]
cache-dir = "~/.cache/ruff"

---

dummy-variable-rgx

A regular expression used to identify "dummy" variables, or those which should be ignored when enforcing (e.g.) unused-variable rules. The default expression matches _, __, and _var, but not _var_.

Default value: "^(_+|(_+[a-zA-Z0-9_]*[a-zA-Z0-9]+?))$"

Type: Regex

Example usage:

[tool.ruff]
# Only ignore variables named "_".
dummy-variable-rgx = "^_$"

---

exclude

A list of file patterns to exclude from linting.

Exclusions are based on globs, and can be either:

• Single-path patterns, like .mypy_cache (to exclude any directory named .mypy_cache in the tree), foo.py (to exclude any file named foo.py), or foo_*.py (to exclude any file matching foo_*.py ).
• Relative patterns, like directory/foo.py (to exclude that specific file) or directory/*.py (to exclude any Python files in directory). Note that these paths are relative to the project root (e.g., the directory containing your pyproject.toml).

For more information on the glob syntax, refer to the globset documentation.

Note that you'll typically want to use extend-exclude to modify the excluded paths.

Default value: [".bzr", ".direnv", ".eggs", ".git", ".hg", ".mypy_cache", ".nox", ".pants.d", ".ruff_cache", ".svn", ".tox", ".venv", "__pypackages__", "_build", "buck-out", "build", "dist", "node_modules", "venv"]

Type: Vec<FilePattern>

Example usage:

[tool.ruff]
exclude = [".venv"]

---

extend

A path to a local pyproject.toml file to merge into this configuration. User home directory and environment variables will be expanded.

To resolve the current pyproject.toml file, Ruff will first resolve this base configuration file, then merge in any properties defined in the current configuration file.

Default value: None

Type: Path

Example usage:

[tool.ruff]
# Extend the `pyproject.toml` file in the parent directory.
extend = "../pyproject.toml"
# But use a different line length.
line-length = 100

---

extend-exclude

A list of file patterns to omit from linting, in addition to those specified by exclude.

Exclusions are based on globs, and can be either:

• Single-path patterns, like .mypy_cache (to exclude any directory named .mypy_cache in the tree), foo.py (to exclude any file named foo.py), or foo_*.py (to exclude any file matching foo_*.py ).
• Relative patterns, like directory/foo.py (to exclude that specific file) or directory/*.py (to exclude any Python files in directory). Note that these paths are relative to the project root (e.g., the directory containing your pyproject.toml).

For more information on the glob syntax, refer to the globset documentation.

Default value: []

Type: Vec<FilePattern>

Example usage:

[tool.ruff]
# In addition to the standard set of exclusions, omit all tests, plus a specific file.
extend-exclude = ["tests", "src/bad.py"]

---

extend-ignore

A list of rule codes or prefixes to ignore, in addition to those specified by ignore.

Note that extend-ignore is applied after resolving rules from ignore/select and a less specific rule in extend-ignore would overwrite a more specific rule in select. It is recommended to only use extend-ignore when extending a pyproject.toml file via extend.

Default value: []

Type: Vec<RuleSelector>

Example usage:

[tool.ruff]
# Skip unused variable rules (`F841`).
extend-ignore = ["F841"]

---

extend-select

A list of rule codes or prefixes to enable, in addition to those specified by select.

Note that extend-select is applied after resolving rules from ignore/select and a less specific rule in extend-select would overwrite a more specific rule in ignore. It is recommended to only use extend-select when extending a pyproject.toml file via extend.

Default value: []

Type: Vec<RuleSelector>

Example usage:

[tool.ruff]
# On top of the default `select` (`E`, `F`), enable flake8-bugbear (`B`) and flake8-quotes (`Q`).
extend-select = ["B", "Q"]

---

external

A list of rule codes that are unsupported by Ruff, but should be preserved when (e.g.) validating # noqa directives. Useful for retaining # noqa directives that cover plugins not yet implemented by Ruff.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff]
# Avoiding flagging (and removing) `V101` from any `# noqa`
# directives, despite Ruff's lack of support for `vulture`.
external = ["V101"]

---

fix

Enable autofix behavior by-default when running ruff (overridden by the --fix and --no-fix command-line flags).

Default value: false

Type: bool

Example usage:

[tool.ruff]
fix = true

---

fix-only

Like fix, but disables reporting on leftover violation. Implies fix.

Default value: false

Type: bool

Example usage:

[tool.ruff]
fix-only = true

---

fixable

A list of rule codes or prefixes to consider autofixable.

Default value: ["A", "ANN", "ARG", "B", "BLE", "C", "D", "E", "ERA", "F", "FBT", "I", "ICN", "N", "PGH", "PLC", "PLE", "PLR", "PLW", "Q", "RET", "RUF", "S", "T", "TID", "UP", "W", "YTT"]

Type: Vec<RuleSelector>

Example usage:

[tool.ruff]
# Only allow autofix behavior for `E` and `F` rules.
fixable = ["E", "F"]

---

force-exclude

Whether to enforce exclude and extend-exclude patterns, even for paths that are passed to Ruff explicitly. Typically, Ruff will lint any paths passed in directly, even if they would typically be excluded. Setting force-exclude = true will cause Ruff to respect these exclusions unequivocally.

This is useful for pre-commit, which explicitly passes all changed files to the ruff-pre-commit plugin, regardless of whether they're marked as excluded by Ruff's own settings.

Default value: false

Type: bool

Example usage:

[tool.ruff]
force-exclude = true

---

format

The style in which violation messages should be formatted: "text" (default), "grouped" (group messages by file), "json" (machine-readable), "junit" (machine-readable XML), "github" (GitHub Actions annotations), "gitlab" (GitLab CI code quality report), or "pylint" (Pylint text format).

Default value: "text"

Type: SerializationType

Example usage:

[tool.ruff]
# Group violations by containing file.
format = "grouped"

---

ignore

A list of rule codes or prefixes to ignore. Prefixes can specify exact rules (like F841), entire categories (like F), or anything in between.

When breaking ties between enabled and disabled rules (via select and ignore, respectively), more specific prefixes override less specific prefixes.

Default value: []

Type: Vec<RuleSelector>

Example usage:

[tool.ruff]
# Skip unused variable rules (`F841`).
ignore = ["F841"]

---

ignore-init-module-imports

Avoid automatically removing unused imports in __init__.py files. Such imports will still be +flagged, but with a dedicated message suggesting that the import is either added to the module' +__all__ symbol, or re-exported with a redundant alias (e.g., import os as os).

Default value: false

Type: bool

Example usage:

[tool.ruff]
ignore-init-module-imports = true

---

line-length

The line length to use when enforcing long-lines violations (like E501).

Default value: 88

Type: usize

Example usage:

[tool.ruff]
# Allow lines to be as long as 120 characters.
line-length = 120

---

namespace-packages

Mark the specified directories as namespace packages. For the purpose of module resolution, Ruff will treat those directories as if they contained an __init__.py file.

Default value: []

Type: Vec<PathBuf>

Example usage:

[tool.ruff]
namespace-packages = ["airflow/providers"]

---

per-file-ignores

A list of mappings from file pattern to rule codes or prefixes to exclude, when considering any matching files.

Default value: {}

Type: HashMap<String, Vec<RuleSelector>>

Example usage:

[tool.ruff]
# Ignore `E402` (import violations) in all `__init__.py` files, and in `path/to/file.py`.
[tool.ruff.per-file-ignores]
"__init__.py" = ["E402"]
"path/to/file.py" = ["E402"]

---

required-version

Require a specific version of Ruff to be running (useful for unifying results across many environments, e.g., with a pyproject.toml file).

Default value: None

Type: String

Example usage:

[tool.ruff]
required-version = "0.0.193"

---

respect-gitignore

Whether to automatically exclude files that are ignored by .ignore, .gitignore, .git/info/exclude, and global gitignore files. Enabled by default.

Default value: true

Type: bool

Example usage:

[tool.ruff]
respect_gitignore = false

---

select

A list of rule codes or prefixes to enable. Prefixes can specify exact rules (like F841), entire categories (like F), or anything in between.

When breaking ties between enabled and disabled rules (via select and ignore, respectively), more specific prefixes override less specific prefixes.

Default value: ["E", "F"]

Type: Vec<RuleSelector>

Example usage:

[tool.ruff]
# On top of the defaults (`E`, `F`), enable flake8-bugbear (`B`) and flake8-quotes (`Q`).
select = ["E", "F", "B", "Q"]

---

show-source

Whether to show source code snippets when reporting lint violations (overridden by the --show-source command-line flag).

Default value: false

Type: bool

Example usage:

[tool.ruff]
# By default, always show source code snippets.
show-source = true

---

src

The source code paths to consider, e.g., when resolving first- vs. third-party imports.

As an example: given a Python package structure like:

my_package/
  pyproject.toml
  src/
    my_package/
      __init__.py
      foo.py
      bar.py

The src directory should be included in source (e.g., source = ["src"]), such that when resolving imports, my_package.foo is considered a first-party import.

This field supports globs. For example, if you have a series of Python packages in a python_modules directory, src = ["python_modules/*"] would expand to incorporate all of the packages in that directory. User home directory and environment variables will also be expanded.

Default value: ["."]

Type: Vec<PathBuf>

Example usage:

[tool.ruff]
# Allow imports relative to the "src" and "test" directories.
src = ["src", "test"]

---

target-version

The Python version to target, e.g., when considering automatic code upgrades, like rewriting type annotations. Note that the target version will not be inferred from the current Python version, and instead must be specified explicitly (as seen below).

Default value: "py310"

Type: PythonVersion

Example usage:

[tool.ruff]
# Always generate Python 3.7-compatible code.
target-version = "py37"

---

task-tags

A list of task tags to recognize (e.g., "TODO", "FIXME", "XXX").

Comments starting with these tags will be ignored by commented-out code detection (ERA), and skipped by line-length rules (E501) if ignore-overlong-task-comments is set to true.

Default value: ["TODO", "FIXME", "XXX"]

Type: Vec<String>

Example usage:

[tool.ruff]
task-tags = ["HACK"]

---

typing-modules

A list of modules whose imports should be treated equivalently to members of the typing module.

This is useful for ensuring proper type annotation inference for projects that re-export typing and typing_extensions members from a compatibility module. If omitted, any members imported from modules apart from typing and typing_extensions will be treated as ordinary Python objects.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff]
typing-modules = ["airflow.typing_compat"]

---

unfixable

A list of rule codes or prefixes to consider non-autofix-able.

Default value: []

Type: Vec<RuleSelector>

Example usage:

[tool.ruff]
# Disable autofix for unused imports (`F401`).
unfixable = ["F401"]

---

update-check

Enable or disable automatic update checks (overridden by the --update-check and --no-update-check command-line flags).

Default value: false

Type: bool

Example usage:

[tool.ruff]
update-check = true

---

flake8-annotations

allow-star-arg-any

Whether to suppress ANN401 for dynamically typed *args and **kwargs arguments.

Default value: false

Type: bool

Example usage:

[tool.ruff.flake8-annotations]
allow-star-arg-any = true

---

mypy-init-return

Whether to allow the omission of a return type hint for __init__ if at least one argument is annotated.

Default value: false

Type: bool

Example usage:

[tool.ruff.flake8-annotations]
mypy-init-return = true

---

suppress-dummy-args

Whether to suppress ANN000-level violations for arguments matching the "dummy" variable regex (like _).

Default value: false

Type: bool

Example usage:

[tool.ruff.flake8-annotations]
suppress-dummy-args = true

---

suppress-none-returning

Whether to suppress ANN200-level violations for functions that meet either of the following criteria:

• Contain no return statement.
• Explicit return statement(s) all return None (explicitly or implicitly).

Default value: false

Type: bool

Example usage:

[tool.ruff.flake8-annotations]
suppress-none-returning = true

---

flake8-bandit

hardcoded-tmp-directory

A list of directories to consider temporary.

Default value: ["/tmp", "/var/tmp", "/dev/shm"]

Type: Vec<String>

Example usage:

[tool.ruff.flake8-bandit]
hardcoded-tmp-directory = ["/foo/bar"]

---

hardcoded-tmp-directory-extend

A list of directories to consider temporary, in addition to those specified by hardcoded-tmp-directory.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.flake8-bandit]
extend-hardcoded-tmp-directory = ["/foo/bar"]

---

flake8-bugbear

extend-immutable-calls

Additional callable functions to consider "immutable" when evaluating, e.g., the no-mutable-default-argument rule (B006).

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.flake8-bugbear]
# Allow default arguments like, e.g., `data: List[str] = fastapi.Query(None)`.
extend-immutable-calls = ["fastapi.Depends", "fastapi.Query"]

---

flake8-errmsg

max-string-length

Maximum string length for string literals in exception messages.

Default value: 0

Type: usize

Example usage:

[tool.ruff.flake8-errmsg]
max-string-length = 20

---

flake8-import-conventions

aliases

The conventional aliases for imports. These aliases can be extended by the extend_aliases option.

Default value: {"altair": "alt", "matplotlib.pyplot": "plt", "numpy": "np", "pandas": "pd", "seaborn": "sns"}

Type: FxHashMap<String, String>

Example usage:

[tool.ruff.flake8-import-conventions]
[tool.ruff.flake8-import-conventions.aliases]
# Declare the default aliases.
altair = "alt"
"matplotlib.pyplot" = "plt"
numpy = "np"
pandas = "pd"
seaborn = "sns"

---

extend-aliases

A mapping of modules to their conventional import aliases. These aliases will be added to the aliases mapping.

Default value: {}

Type: FxHashMap<String, String>

Example usage:

[tool.ruff.flake8-import-conventions]
[tool.ruff.flake8-import-conventions.extend-aliases]
# Declare a custom alias for the `matplotlib` module.
"dask.dataframe" = "dd"

---

flake8-pytest-style

fixture-parentheses

Boolean flag specifying whether @pytest.fixture() without parameters should have parentheses. If the option is set to true (the default), @pytest.fixture() is valid and @pytest.fixture is invalid. If set to false, @pytest.fixture is valid and @pytest.fixture() is invalid.

Default value: true

Type: bool

Example usage:

[tool.ruff.flake8-pytest-style]
fixture-parentheses = true

---

mark-parentheses

Boolean flag specifying whether @pytest.mark.foo() without parameters should have parentheses. If the option is set to true (the default), @pytest.mark.foo() is valid and @pytest.mark.foo is invalid. If set to false, @pytest.fixture is valid and @pytest.mark.foo() is invalid.

Default value: true

Type: bool

Example usage:

[tool.ruff.flake8-pytest-style]
mark-parentheses = true

---

parametrize-names-type

Expected type for multiple argument names in @pytest.mark.parametrize. The following values are supported:

• csv — a comma-separated list, e.g. @pytest.mark.parametrize('name1,name2', ...)
• tuple (default) — e.g. @pytest.mark.parametrize(('name1', 'name2'), ...)
• list — e.g. @pytest.mark.parametrize(['name1', 'name2'], ...)

Default value: tuple

Type: ParametrizeNameType

Example usage:

[tool.ruff.flake8-pytest-style]
parametrize-names-type = "list"

---

parametrize-values-row-type

Expected type for each row of values in @pytest.mark.parametrize in case of multiple parameters. The following values are supported:

• tuple (default) — e.g. @pytest.mark.parametrize(('name1', 'name2'), [(1, 2), (3, 4)])
• list — e.g. @pytest.mark.parametrize(('name1', 'name2'), [[1, 2], [3, 4]])

Default value: tuple

Type: ParametrizeValuesRowType

Example usage:

[tool.ruff.flake8-pytest-style]
parametrize-values-row-type = "list"

---

parametrize-values-type

Expected type for the list of values rows in @pytest.mark.parametrize. The following values are supported:

• tuple — e.g. @pytest.mark.parametrize('name', (1, 2, 3))
• list (default) — e.g. @pytest.mark.parametrize('name', [1, 2, 3])

Default value: list

Type: ParametrizeValuesType

Example usage:

[tool.ruff.flake8-pytest-style]
parametrize-values-type = "tuple"

---

raises-extend-require-match-for

List of additional exception names that require a match= parameter in a pytest.raises() call. This extends the default list of exceptions that require a match= parameter. This option is useful if you want to extend the default list of exceptions that require a match= parameter without having to specify the entire list. Note that this option does not remove any exceptions from the default list.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.flake8-pytest-style]
raises-extend-require-match-for = ["requests.RequestException"]

---

raises-require-match-for

List of exception names that require a match= parameter in a pytest.raises() call.

Default value: ["BaseException", "Exception", "ValueError", "OSError", "IOError", "EnvironmentError", "socket.error"]

Type: Vec<String>

Example usage:

[tool.ruff.flake8-pytest-style]
raises-require-match-for = ["requests.RequestException"]

---

flake8-quotes

avoid-escape

Whether to avoid using single quotes if a string contains single quotes, or vice-versa with double quotes, as per PEP8. This minimizes the need to escape quotation marks within strings.

Default value: true

Type: bool

Example usage:

[tool.ruff.flake8-quotes]
# Don't bother trying to avoid escapes.
avoid-escape = false

---

docstring-quotes

Quote style to prefer for docstrings (either "single" (') or "double" (")).

Default value: "double"

Type: Quote

Example usage:

[tool.ruff.flake8-quotes]
docstring-quotes = "single"

---

inline-quotes

Quote style to prefer for inline strings (either "single" (') or "double" (")).

Default value: "double"

Type: Quote

Example usage:

[tool.ruff.flake8-quotes]
inline-quotes = "single"

---

multiline-quotes

Quote style to prefer for multiline strings (either "single" (') or "double" (")).

Default value: "double"

Type: Quote

Example usage:

[tool.ruff.flake8-quotes]
multiline-quotes = "single"

---

flake8-tidy-imports

ban-relative-imports

Whether to ban all relative imports ("all"), or only those imports that extend into the parent module or beyond ("parents").

Default value: "parents"

Type: Strictness

Example usage:

[tool.ruff.flake8-tidy-imports]
# Disallow all relative imports.
ban-relative-imports = "all"

---

banned-api

Specific modules or module members that may not be imported or accessed. Note that this rule is only meant to flag accidental uses, and can be circumvented via eval or importlib.

Default value: {}

Type: HashMap<String, BannedApi>

Example usage:

[tool.ruff.flake8-tidy-imports]
[tool.ruff.flake8-tidy-imports.banned-api]
"cgi".msg = "The cgi module is deprecated, see https://peps.python.org/pep-0594/#cgi."
"typing.TypedDict".msg = "Use typing_extensions.TypedDict instead."

---

flake8-unused-arguments

ignore-variadic-names

Whether to allow unused variadic arguments, like *args and **kwargs.

Default value: false

Type: bool

Example usage:

[tool.ruff.flake8-unused-arguments]
ignore-variadic-names = true

---

isort

classes

An override list of tokens to always recognize as a Class for order-by-type regardless of casing.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
classes = ["SVC"]

---

combine-as-imports

Combines as imports on the same line. See isort's combine-as-imports option.

Default value: false

Type: bool

Example usage:

[tool.ruff.isort]
combine-as-imports = true

---

constants

An override list of tokens to always recognize as a CONSTANT for order-by-type regardless of casing.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
constants = ["constant"]

---

extra-standard-library

A list of modules to consider standard-library, in addition to those known to Ruff in advance.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
extra-standard-library = ["path"]

---

force-single-line

Forces all from imports to appear on their own line.

Default value: false

Type: bool

Example usage:

[tool.ruff.isort]
force-single-line = true

---

force-sort-within-sections

Don't sort straight-style imports (like import sys) before from-style imports (like from itertools import groupby). Instead, sort the imports by module, independent of import style.

Default value: false

Type: bool

Example usage:

[tool.ruff.isort]
force-sort-within-sections = true

---

force-wrap-aliases

Force import from statements with multiple members and at least one alias (e.g., import A as B) to wrap such that every line contains exactly one member. For example, this formatting would be retained, rather than condensing to a single line:

from .utils import (
    test_directory as test_directory,
    test_id as test_id
)

Note that this setting is only effective when combined with combine-as-imports = true. When combine-as-imports isn't enabled, every aliased import from will be given its own line, in which case, wrapping is not necessary.

Default value: false

Type: bool

Example usage:

[tool.ruff.isort]
force-wrap-aliases = true
combine-as-imports = true

---

known-first-party

A list of modules to consider first-party, regardless of whether they can be identified as such via introspection of the local filesystem.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
known-first-party = ["src"]

---

known-third-party

A list of modules to consider third-party, regardless of whether they can be identified as such via introspection of the local filesystem.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
known-third-party = ["src"]

---

no-lines-before

A list of sections that should not be delineated from the previous section via empty lines.

Default value: []

Type: Option<Vec<ImportType>>

Example usage:

[tool.ruff.isort]
no-lines-before = ["future", "standard-library"]

---

order-by-type

Order imports by type, which is determined by case, in addition to alphabetically.

Default value: true

Type: bool

Example usage:

[tool.ruff.isort]
order-by-type = true

---

relative-imports-order

Whether to place "closer" imports (fewer . characters, most local) before "further" imports (more . characters, least local), or vice versa.

The default ("furthest-to-closest") is equivalent to isort's reverse-relative default (reverse-relative = false); setting this to "closest-to-furthest" is equivalent to isort's reverse-relative = true.

Default value: furthest-to-closest

Type: RelatveImportsOrder

Example usage:

[tool.ruff.isort]
relative-imports-order = "closest-to-furthest"

---

required-imports

Add the specified import line to all files.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
required-imports = ["from __future__ import annotations"]

---

single-line-exclusions

One or more modules to exclude from the single line rule.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
single-line-exclusions = ["os", "json"]

---

split-on-trailing-comma

If a comma is placed after the last member in a multi-line import, then the imports will never be folded into one line.

See isort's split-on-trailing-comma option.

Default value: true

Type: bool

Example usage:

[tool.ruff.isort]
split-on-trailing-comma = false

---

variables

An override list of tokens to always recognize as a var for order-by-type regardless of casing.

Default value: []

Type: Vec<String>

Example usage:

[tool.ruff.isort]
variables = ["VAR"]

---

mccabe

max-complexity

The maximum McCabe complexity to allow before triggering C901 errors.

Default value: 10

Type: usize

Example usage:

[tool.ruff.mccabe]
# Flag errors (`C901`) whenever the complexity level exceeds 5.
max-complexity = 5

---

pep8-naming

classmethod-decorators

A list of decorators that, when applied to a method, indicate that the method should be treated as a class method. For example, Ruff will expect that any method decorated by a decorator in this list takes a cls argument as its first argument.

Default value: ["classmethod"]

Type: Vec<String>

Example usage:

[tool.ruff.pep8-naming]
# Allow Pydantic's `@validator` decorator to trigger class method treatment.
classmethod-decorators = ["classmethod", "pydantic.validator"]

---

ignore-names

A list of names to ignore when considering pep8-naming violations.

Default value: ["setUp", "tearDown", "setUpClass", "tearDownClass", "setUpModule", "tearDownModule", "asyncSetUp", "asyncTearDown", "setUpTestData", "failureException", "longMessage", "maxDiff"]

Type: Vec<String>

Example usage:

[tool.ruff.pep8-naming]
ignore-names = ["callMethod"]

---

staticmethod-decorators

A list of decorators that, when applied to a method, indicate that the method should be treated as a static method. For example, Ruff will expect that any method decorated by a decorator in this list has no self or cls argument.

Default value: ["staticmethod"]

Type: Vec<String>

Example usage:

[tool.ruff.pep8-naming]
# Allow a shorthand alias, `@stcmthd`, to trigger static method treatment.
staticmethod-decorators = ["staticmethod", "stcmthd"]

---

pycodestyle

ignore-overlong-task-comments

Whether or not line-length violations (E501) should be triggered for comments starting with task-tags (by default: ["TODO", "FIXME", and "XXX"]).

Default value: false

Type: bool

Example usage:

[tool.ruff.pycodestyle]
ignore-overlong-task-comments = true

---

max-doc-length

The maximum line length to allow for line-length violations within documentation (W505), including standalone comments.

Default value: None

Type: usize

Example usage:

[tool.ruff.pycodestyle]
max-doc-length = 88

---

pydocstyle

convention

Whether to use Google-style or NumPy-style conventions or the PEP257 defaults when analyzing docstring sections.

Default value: None

Type: Convention

Example usage:

[tool.ruff.pydocstyle]
# Use Google-style docstrings.
convention = "google"

---

pylint

allow-magic-value-types

Constant types to ignore when used as "magic values".

Default value: ["str"]

Type: Vec<ConstantType>

Example usage:

[tool.ruff.pylint]
allow-magic-value-types = ["int"]

---

pyupgrade

keep-runtime-typing

Whether to avoid PEP 585 (List[int] -> list[int]) and PEP 604 (Optional[str] -> str | None) rewrites even if a file imports from __future__ import annotations. Note that this setting is only applicable when the target Python version is below 3.9 and 3.10 respectively.

Default value: false

Type: bool

Example usage:

[tool.ruff.pyupgrade]
# Preserve types, even if a file imports `from __future__ import annotations`.
keep-runtime-typing = true

---

License

MIT