ruff/changelogs/0.9.x.md

Changelog 0.9.x

0.9.0

Check out the blog post for a migration guide and overview of the changes!

Breaking changes

Ruff now formats your code according to the 2025 style guide. As a result, your code might now get formatted differently. See the formatter section for a detailed list of changes.

This release doesn’t remove or remap any existing stable rules.

Stabilization

The following rules have been stabilized and are no longer in preview:

• stdlib-module-shadowing (A005). This rule has also been renamed: previously, it was called builtin-module-shadowing.
• builtin-lambda-argument-shadowing (A006)
• slice-to-remove-prefix-or-suffix (FURB188)
• boolean-chained-comparison (PLR1716)
• decimal-from-float-literal (RUF032)
• post-init-default (RUF033)
• useless-if-else (RUF034)

The following behaviors have been stabilized:

• pytest-parametrize-names-wrong-type (PT006): Detect pytest.parametrize calls outside decorators and calls with keyword arguments.
• module-import-not-at-top-of-file (E402): Ignore pytest.importorskip calls between import statements.
• mutable-dataclass-default (RUF008) and function-call-in-dataclass-default-argument (RUF009): Add support for attrs.
• bad-version-info-comparison (PYI006): Extend the rule to check non-stub files.

The following fixes or improvements to fixes have been stabilized:

• redundant-numeric-union (PYI041)
• duplicate-union-members (PYI016)

Formatter

This release introduces the new 2025 stable style (#13371), stabilizing the following changes:

• Format expressions in f-string elements (#7594)
• Alternate quotes for strings inside f-strings (#13860)
• Preserve the casing of hex codes in f-string debug expressions (#14766)
• Choose the quote style for each string literal in an implicitly concatenated f-string rather than for the entire string (#13539)
• Automatically join an implicitly concatenated string into a single string literal if it fits on a single line (#9457)
• Remove the ISC001 incompatibility warning (#15123)
• Prefer parenthesizing the assert message over breaking the assertion expression (#9457)
• Automatically parenthesize over-long if guards in match case clauses (#13513)
• More consistent formatting for match case patterns (#6933)
• Avoid unnecessary parentheses around return type annotations (#13381)
• Keep the opening parentheses on the same line as the if keyword for comprehensions where the condition has a leading comment (#12282)
• More consistent formatting for with statements with a single context manager for Python 3.8 or older (#10276)
• Correctly calculate the line-width for code blocks in docstrings when using max-doc-code-line-length = "dynamic" (#13523)

Preview features

• [flake8-bugbear] Implement class-as-data-structure (B903) (#9601)
• [flake8-type-checking] Apply quoted-type-alias more eagerly in TYPE_CHECKING blocks and ignore it in stubs (TC008) (#15180)
• [pylint] Ignore eq-without-hash in stub files (PLW1641) (#15310)
• [pyupgrade] Split UP007 into two individual rules: UP007 for Union and UP045 for Optional (UP007, UP045) (#15313)
• [ruff] New rule that detects classes that are both an enum and a dataclass (RUF049) (#15299)
• [ruff] Recode RUF025 to RUF037 (RUF037) (#15258)

Rule changes

• [flake8-builtins] Ignore stdlib-module-shadowing in stub files(A005) (#15350)
• [flake8-return] Add support for functions returning typing.Never (RET503) (#15298)

Server

• Improve the observability by removing the need for the "trace" value to turn on or off logging. The server logging is solely controlled using the logLevel server setting which defaults to info. This addresses the issue where users were notified about an error and told to consult the log, but it didn’t contain any messages. (#15232)
• Ignore diagnostics from other sources for code action requests (#15373)

CLI

• Improve the error message for --config key=value when the key is for a table and it’s a simple value

Bug fixes

• [eradicate] Ignore metadata blocks directly followed by normal blocks (ERA001) (#15330)
• [flake8-django] Recognize other magic methods (DJ012) (#15365)
• [pycodestyle] Avoid false positives related to type aliases (E252) (#15356)
• [pydocstyle] Avoid treating newline-separated sections as sub-sections (D405) (#15311)
• [pyflakes] Remove call when removing final argument from format (F523) (#15309)
• [refurb] Mark fix as unsafe when the right-hand side is a string (FURB171) (#15273)
• [ruff] Treat ) as a regex metacharacter (RUF043, RUF055) (#15318)
• [ruff] Parenthesize the int-call argument when removing the int call would change semantics (RUF046) (#15277)

0.9.1

Preview features

• [pycodestyle] Run too-many-newlines-at-end-of-file on each cell in notebooks (W391) (#15308)
• [ruff] Omit diagnostic for shadowed private function parameters in used-dummy-variable (RUF052) (#15376)

Rule changes

• [flake8-bugbear] Improve assert-raises-exception message (B017) (#15389)

Formatter

• Preserve trailing end-of line comments for the last string literal in implicitly concatenated strings (#15378)

Server

• Fix a bug where the server and client notebooks were out of sync after reordering cells (#15398)

Bug fixes

• [flake8-pie] Correctly remove wrapping parentheses (PIE800) (#15394)
• [pyupgrade] Handle comments and multiline expressions correctly (UP037) (#15337)

0.9.2

Preview features

• [airflow] Fix typo "security_managr" to "security_manager" (AIR303) (#15463)
• [airflow] extend and fix AIR302 rules (#15525)
• [fastapi] Handle parameters with Depends correctly (FAST003) (#15364)
• [flake8-pytest-style] Implement pytest.warns diagnostics (PT029, PT030, PT031) (#15444)
• [flake8-pytest-style] Test function parameters with default arguments (PT028) (#15449)
• [flake8-type-checking] Avoid false positives for | in TC008 (#15201)

Rule changes

• [flake8-todos] Allow VSCode GitHub PR extension style links in missing-todo-link (TD003) (#15519)
• [pyflakes] Show syntax error message for F722 (#15523)

Formatter

• Fix curly bracket spacing around f-string expressions containing curly braces (#15471)
• Fix joining of f-strings with different quotes when using quote style Preserve (#15524)

Server

• Avoid indexing the same workspace multiple times (#15495)
• Display context for ruff.configuration errors (#15452)

Configuration

• Remove flatten to improve deserialization error messages (#15414)

Bug fixes

• Parse triple-quoted string annotations as if parenthesized (#15387)
• [fastapi] Update Annotated fixes (FAST002) (#15462)
• [flake8-bandit] Check for builtins instead of builtin (S102, PTH123) (#15443)
• [flake8-pathlib] Fix --select for os-path-dirname (PTH120) (#15446)
• [ruff] Fix false positive on global keyword (RUF052) (#15235)

0.9.3

Preview features

• [airflow] Argument fail_stop in DAG has been renamed as fail_fast (AIR302) (#15633)
• [airflow] Extend AIR303 with more symbols (#15611)
• [flake8-bandit] Report all references to suspicious functions (S3) (#15541)
• [flake8-pytest-style] Do not emit diagnostics for empty for loops (PT012, PT031) (#15542)
• [flake8-simplify] Avoid double negations (SIM103) (#15562)
• [pyflakes] Fix infinite loop with unused local import in __init__.py (F401) (#15517)
• [pylint] Do not report methods with only one EM101-compatible raise (PLR6301) (#15507)
• [pylint] Implement redefined-slots-in-subclass (W0244) (#9640)
• [pyupgrade] Add rules to use PEP 695 generics in classes and functions (UP046, UP047) (#15565, #15659)
• [refurb] Implement for-loop-writes (FURB122) (#10630)
• [ruff] Implement needless-else clause (RUF047) (#15051)
• [ruff] Implement starmap-zip (RUF058) (#15483)

Rule changes

• [flake8-bugbear] Do not raise error if keyword argument is present and target-python version is less or equals than 3.9 (B903) (#15549)
• [flake8-comprehensions] strip parentheses around generators in unnecessary-generator-set (C401) (#15553)
• [flake8-pytest-style] Rewrite references to .exception (PT027) (#15680)
• [flake8-simplify] Mark fixes as unsafe (SIM201, SIM202) (#15626)
• [flake8-type-checking] Fix some safe fixes being labeled unsafe (TC006,TC008) (#15638)
• [isort] Omit trailing whitespace in unsorted-imports (I001) (#15518)
• [pydoclint] Allow ignoring one line docstrings for DOC rules (#13302)
• [pyflakes] Apply redefinition fixes by source code order (F811) (#15575)
• [pyflakes] Avoid removing too many imports in redefined-while-unused (F811) (#15585)
• [pyflakes] Group redefinition fixes by source statement (F811) (#15574)
• [pylint] Include name of base class in message for redefined-slots-in-subclass (W0244) (#15559)
• [ruff] Update fix for RUF055 to use var == value (#15605)

Formatter

• Fix bracket spacing for single-element tuples in f-string expressions (#15537)
• Fix unstable f-string formatting for expressions containing a trailing comma (#15545)

Performance

• Avoid quadratic membership check in import fixes (#15576)

Server

• Allow unsafe-fixes settings for code actions (#15666)

Bug fixes

• [flake8-bandit] Add missing single-line/dotall regex flag (S608) (#15654)
• [flake8-import-conventions] Fix infinite loop between ICN001 and I002 (ICN001) (#15480)
• [flake8-simplify] Do not emit diagnostics for expressions inside string type annotations (SIM222, SIM223) (#15405)
• [pyflakes] Treat arguments passed to the default= parameter of TypeVar as type expressions (F821) (#15679)
• [pyupgrade] Avoid syntax error when the iterable is a non-parenthesized tuple (UP028) (#15543)
• [ruff] Exempt NewType calls where the original type is immutable (RUF009) (#15588)
• Preserve raw string prefix and escapes in all codegen fixes (#15694)

Documentation

• Generate documentation redirects for lowercase rule codes (#15564)
• TRY300: Add some extra notes on not catching exceptions you didn't expect (#15036)

0.9.4

Preview features

• [airflow] Extend airflow context parameter check for BaseOperator.execute (AIR302) (#15713)
• [airflow] Update AIR302 to check for deprecated context keys (#15144)
• [flake8-bandit] Permit suspicious imports within stub files (S4) (#15822)
• [pylint] Do not trigger PLR6201 on empty collections (#15732)
• [refurb] Do not emit diagnostic when loop variables are used outside loop body (FURB122) (#15757)
• [ruff] Add support for more re patterns (RUF055) (#15764)
• [ruff] Check for shadowed map before suggesting fix (RUF058) (#15790)
• [ruff] Do not emit diagnostic when all arguments to zip() are variadic (RUF058) (#15744)
• [ruff] Parenthesize fix when argument spans multiple lines for unnecessary-round (RUF057) (#15703)

Rule changes

• Preserve quote style in generated code (#15726, #15778, #15794)
• [flake8-bugbear] Exempt NewType calls where the original type is immutable (B008) (#15765)
• [pylint] Honor banned top-level imports by TID253 in PLC0415. (#15628)
• [pyupgrade] Ignore is_typeddict and TypedDict for deprecated-import (UP035) (#15800)

CLI

• Fix formatter warning message for flake8-quotes option (#15788)
• Implement tab autocomplete for ruff config (#15603)

Bug fixes

• [flake8-comprehensions] Do not emit unnecessary-map diagnostic when lambda has different arity (C417) (#15802)
• [flake8-comprehensions] Parenthesize sorted when needed for unnecessary-call-around-sorted (C413) (#15825)
• [pyupgrade] Handle end-of-line comments for quoted-annotation (UP037) (#15824)

Documentation

• Add missing config docstrings (#15803)
• Add references to trio.run_process and anyio.run_process (#15761)
• Use uv init --lib in tutorial (#15718)

0.9.5

Preview features

• Recognize all symbols named TYPE_CHECKING for in_type_checking_block (#15719)
• [flake8-comprehensions] Handle builtins at top of file correctly for unnecessary-dict-comprehension-for-iterable (C420) (#15837)
• [flake8-logging] .exception() and exc_info= outside exception handlers (LOG004, LOG014) (#15799)
• [flake8-pyi] Fix incorrect behaviour of custom-typevar-return-type preview-mode autofix if typing was already imported (PYI019) (#15853)
• [flake8-pyi] Fix more complex cases (PYI019) (#15821)
• [flake8-pyi] Make PYI019 autofixable for .py files in preview mode as well as stubs (#15889)
• [flake8-pyi] Remove type parameter correctly when it is the last (PYI019) (#15854)
• [pylint] Fix missing parens in unsafe fix for unnecessary-dunder-call (PLC2801) (#15762)
• [pyupgrade] Better messages and diagnostic range (UP015) (#15872)
• [pyupgrade] Rename private type parameters in PEP 695 generics (UP049) (#15862)
• [refurb] Also report non-name expressions (FURB169) (#15905)
• [refurb] Mark fix as unsafe if there are comments (FURB171) (#15832)
• [ruff] Classes with mixed type variable style (RUF053) (#15841)
• [airflow] BashOperator has been moved to airflow.providers.standard.operators.bash.BashOperator (AIR302) (#15922)
• [flake8-pyi] Add autofix for unused-private-type-var (PYI018) (#15999)
• [flake8-pyi] Significantly improve accuracy of PYI019 if preview mode is enabled (#15888)

Rule changes

• Preserve triple quotes and prefixes for strings (#15818)
• [flake8-comprehensions] Skip when TypeError present from too many (kw)args for C410,C411, and C418 (#15838)
• [flake8-pyi] Rename PYI019 and improve its diagnostic message (#15885)
• [pep8-naming] Ignore @override methods (N803) (#15954)
• [pyupgrade] Reuse replacement logic from UP046 and UP047 to preserve more comments (UP040) (#15840)
• [ruff] Analyze deferred annotations before enforcing mutable-(data)class-default and function-call-in-dataclass-default-argument (RUF008,RUF009,RUF012) (#15921)
• [pycodestyle] Exempt sys.path += ... calls (E402) (#15980)

Configuration

• Config error only when flake8-import-conventions alias conflicts with isort.required-imports bound name (#15918)
• Workaround Even Better TOML crash related to allOf (#15992)

Bug fixes

• [flake8-comprehensions] Unnecessary list comprehension (rewrite as a set comprehension) (C403) - Handle extraneous parentheses around list comprehension (#15877)
• [flake8-comprehensions] Handle trailing comma in fixes for unnecessary-generator-list/set (C400,C401) (#15929)
• [flake8-pyi] Fix several correctness issues with custom-type-var-return-type (PYI019) (#15851)
• [pep8-naming] Consider any number of leading underscore for N801 (#15988)
• [pyflakes] Visit forward annotations in TypeAliasType as types (F401) (#15829)
• [pylint] Correct min/max auto-fix and suggestion for (PL1730) (#15930)
• [refurb] Handle unparenthesized tuples correctly (FURB122, FURB142) (#15953)
• [refurb] Avoid None | None as well as better detection and fix (FURB168) (#15779)

Documentation

• Add deprecation warning for ruff-lsp related settings (#15850)
• Docs (linter.md): clarify that Python files are always searched for in subdirectories (#15882)
• Fix a typo in non_pep695_generic_class.rs (#15946)
• Improve Docs: Pylint subcategories' codes (#15909)
• Remove non-existing lint.extendIgnore editor setting (#15844)
• Update black deviations (#15928)
• Mention UP049 in UP046 and UP047, add See also section to UP040 (#15956)
• Add instance variable examples to RUF012 (#15982)
• Explain precedence for ignore and select config (#15883)

0.9.6

Preview features

• [airflow] Add external_task.{ExternalTaskMarker, ExternalTaskSensor} for AIR302 (#16014)
• [flake8-builtins] Make strict module name comparison optional (A005) (#15951)
• [flake8-pyi] Extend fix to Python <= 3.9 for redundant-none-literal (PYI061) (#16044)
• [pylint] Also report when the object isn't a literal (PLE1310) (#15985)
• [ruff] Implement indented-form-feed (RUF054) (#16049)
• [ruff] Skip type definitions for missing-f-string-syntax (RUF027) (#16054)

Rule changes

• [flake8-annotations] Correct syntax for typing.Union in suggested return type fixes for ANN20x rules (#16025)
• [flake8-builtins] Match upstream module name comparison (A005) (#16006)
• [flake8-comprehensions] Detect overshadowed list/set/dict, ignore variadics and named expressions (C417) (#15955)
• [flake8-pie] Remove following comma correctly when the unpacked dictionary is empty (PIE800) (#16008)
• [flake8-simplify] Only trigger SIM401 on known dictionaries (#15995)
• [pylint] Do not report calls when object type and argument type mismatch, remove custom escape handling logic (PLE1310) (#15984)
• [pyupgrade] Comments within parenthesized value ranges should not affect applicability (UP040) (#16027)
• [pyupgrade] Don't introduce invalid syntax when upgrading old-style type aliases with parenthesized multiline values (UP040) (#16026)
• [pyupgrade] Ensure we do not rename two type parameters to the same name (UP049) (#16038)
• [pyupgrade] [ruff] Don't apply renamings if the new name is shadowed in a scope of one of the references to the binding (UP049, RUF052) (#16032)
• [ruff] Update RUF009 to behave similar to B008 and ignore attributes with immutable types (#16048)

Server

• Root exclusions in the server to project root (#16043)

Bug fixes

• [flake8-datetime] Ignore .replace() calls while looking for .astimezone (#16050)
• [flake8-type-checking] Avoid TC004 false positive where the runtime definition is provided by __getattr__ (#16052)

Documentation

• Improve ruff-lsp migration document (#16072)
• Undeprecate ruff.nativeServer (#16039)

0.9.7

Preview features

• Consider __new__ methods as special function type for enforcing class method or static method rules (#13305)
• [airflow] Improve the internal logic to differentiate deprecated symbols (AIR303) (#16013)
• [refurb] Manual timezone monkeypatching (FURB162) (#16113)
• [ruff] Implicit class variable in dataclass (RUF045) (#14349)
• [ruff] Skip singleton starred expressions for incorrectly-parenthesized-tuple-in-subscript (RUF031) (#16083)
• [refurb] Check for subclasses includes subscript expressions (FURB189) (#16155)

Rule changes

• [flake8-debugger] Also flag sys.breakpointhook and sys.__breakpointhook__ (T100) (#16191)
• [pycodestyle] Exempt site.addsitedir(...) calls (E402) (#16251)

Formatter

• Fix unstable formatting of trailing end-of-line comments of parenthesized attribute values (#16187)

Server

• Fix handling of requests received after shutdown message (#16262)
• Ignore source.organizeImports.ruff and source.fixAll.ruff code actions for a notebook cell (#16154)
• Include document specific debug info for ruff.printDebugInformation (#16215)
• Update server to return the debug info as string with ruff.printDebugInformation (#16214)

CLI

• Warn on invalid noqa even when there are no diagnostics (#16178)
• Better error messages while loading configuration extends (#15658)

Bug fixes

• [flake8-comprehensions] Handle trailing comma in C403 fix (#16110)
• [flake8-pyi] Avoid flagging custom-typevar-for-self on metaclass methods (PYI019) (#16141)
• [pydocstyle] Handle arguments with the same names as sections (D417) (#16011)
• [pylint] Correct ordering of arguments in fix for if-stmt-min-max (PLR1730) (#16080)
• [pylint] Do not offer fix for raw strings (PLE251) (#16132)
• [pyupgrade] Do not upgrade functional TypedDicts with private field names to the class-based syntax (UP013) (#16219)
• [pyupgrade] Handle micro version numbers correctly (UP036) (#16091)
• [pyupgrade] Unwrap unary expressions correctly (UP018) (#15919)
• [refurb] Correctly handle lengths of literal strings in slice-to-remove-prefix-or-suffix (FURB188) (#16237)
• [ruff] Skip RUF001 diagnostics when visiting string type definitions (#16122)

Documentation

• Add FAQ entry for source.* code actions in Notebook (#16212)
• Add SECURITY.md (#16224)

0.9.8

Preview features

• Start detecting version-related syntax errors in the parser (#16090)

Rule changes

• [pylint] Mark fix unsafe (PLW1507) (#16343)
• [pylint] Catch case np.nan/case math.nan in match statements (PLW0177) (#16378)
• [ruff] Add more Pydantic models variants to the list of default copy semantics (RUF012) (#16291)

Server

• Avoid indexing the project if configurationPreference is editorOnly (#16381)
• Avoid unnecessary info at non-trace server log level (#16389)
• Expand ruff.configuration to allow inline config (#16296)
• Notify users for invalid client settings (#16361)

Configuration

• Add per-file-target-version option (#16257)

Bug fixes

• [refurb] Do not consider docstring(s) (FURB156) (#16391)
• [flake8-self] Ignore attribute accesses on instance-like variables (SLF001) (#16149)
• [pylint] Fix false positives, add missing methods, and support positional-only parameters (PLE0302) (#16263)
• [flake8-pyi] Mark PYI030 fix unsafe when comments are deleted (#16322)

Documentation

• Fix example for S611 (#16316)
• Normalize inconsistent markdown headings in docstrings (#16364)
• Document MSRV policy (#16384)

0.9.9

Preview features

• Fix caching of unsupported-syntax errors (#16425)

Bug fixes

• Only show unsupported-syntax errors in editors when preview mode is enabled (#16429)

0.9.10

Preview features

• [ruff] Add new rule RUF059: Unused unpacked assignment (#16449)
• [syntax-errors] Detect assignment expressions before Python 3.8 (#16383)
• [syntax-errors] Named expressions in decorators before Python 3.9 (#16386)
• [syntax-errors] Parenthesized keyword argument names after Python 3.8 (#16482)
• [syntax-errors] Positional-only parameters before Python 3.8 (#16481)
• [syntax-errors] Tuple unpacking in return and yield before Python 3.8 (#16485)
• [syntax-errors] Type parameter defaults before Python 3.13 (#16447)
• [syntax-errors] Type parameter lists before Python 3.12 (#16479)
• [syntax-errors] except* before Python 3.11 (#16446)
• [syntax-errors] type statements before Python 3.12 (#16478)

Bug fixes

• Escape template filenames in glob patterns in configuration (#16407)
• [flake8-simplify] Exempt unittest context methods for SIM115 rule (#16439)
• Formatter: Fix syntax error location in notebooks (#16499)
• [pyupgrade] Do not offer fix when at least one target is global/nonlocal (UP028) (#16451)
• [flake8-builtins] Ignore variables matching module attribute names (A001) (#16454)
• [pylint] Convert code keyword argument to a positional argument in fix for (PLR1722) (#16424)

CLI

• Move rule code from description to check_name in GitLab output serializer (#16437)

Documentation

• [pydocstyle] Clarify that D417 only checks docstrings with an arguments section (#16494)