Changelog

0.12.2

Preview features

[flake8-pyi] Expand Optional[A] to A | None (PYI016) (#18572)
[pyupgrade] Mark UP008 fix safe if no comments are in range (#18683)

Bug fixes

[flake8-comprehensions] Fix C420 to prepend whitespace when needed (#18616)
[perflint] Fix PERF403 panic on attribute or subscription loop variable (#19042)
[pydocstyle] Fix D413 infinite loop for parenthesized docstring (#18930)
[pylint] Fix PLW0108 autofix introducing a syntax error when the lambda's body contains an assignment expression (#18678)
[refurb] Fix false positive on empty tuples (FURB168) (#19058)
[ruff] Allow more field calls from attrs (RUF009) (#19021)
[ruff] Fix syntax error introduced for an empty string followed by a u-prefixed string (UP025) (#18899)

Rule changes

[flake8-executable] Allow uvx in shebang line (EXE003) (#18967)
[pandas] Avoid flagging PD002 if pandas is not imported (#18963)
[pyupgrade] Avoid PEP-604 unions with typing.NamedTuple (UP007, UP045) (#18682)

Documentation

Document link between import-outside-top-level (PLC0415) and lint.flake8-tidy-imports.banned-module-level-imports (#18733)
Fix description of the format.skip-magic-trailing-comma example (#19095)
[airflow] Make AIR302 example error out-of-the-box (#18988)
[airflow] Make AIR312 example error out-of-the-box (#18989)
[flake8-annotations] Make ANN401 example error out-of-the-box (#18974)
[flake8-async] Make ASYNC100 example error out-of-the-box (#18993)
[flake8-async] Make ASYNC105 example error out-of-the-box (#19002)
[flake8-async] Make ASYNC110 example error out-of-the-box (#18975)
[flake8-async] Make ASYNC210 example error out-of-the-box (#18977)
[flake8-async] Make ASYNC220, ASYNC221, and ASYNC222 examples error out-of-the-box (#18978)
[flake8-async] Make ASYNC251 example error out-of-the-box (#18990)
[flake8-bandit] Make S201 example error out-of-the-box (#19017)
[flake8-bandit] Make S604 and S609 examples error out-of-the-box (#19049)
[flake8-bugbear] Make B028 example error out-of-the-box (#19054)
[flake8-bugbear] Make B911 example error out-of-the-box (#19051)
[flake8-datetimez] Make DTZ011 example error out-of-the-box (#19055)
[flake8-datetimez] Make DTZ901 example error out-of-the-box (#19056)
[flake8-pyi] Make PYI032 example error out-of-the-box (#19061)
[flake8-pyi] Make example error out-of-the-box (PYI014, PYI015) (#19097)
[flake8-pyi] Make example error out-of-the-box (PYI042) (#19101)
[flake8-pyi] Make example error out-of-the-box (PYI059) (#19080)
[flake8-pyi] Make example error out-of-the-box (PYI062) (#19079)
[flake8-pytest-style] Make example error out-of-the-box (PT023) (#19104)
[flake8-pytest-style] Make example error out-of-the-box (PT030) (#19105)
[flake8-quotes] Make example error out-of-the-box (Q003) (#19106)
[flake8-simplify] Make example error out-of-the-box (SIM110) (#19113)
[flake8-simplify] Make example error out-of-the-box (SIM113) (#19109)
[flake8-simplify] Make example error out-of-the-box (SIM401) (#19110)
[pyflakes] Fix backslash in docs (F621) (#19098)
[pylint] Fix PLC0415 example (#18970)

0.12.1

Preview features

[flake8-errmsg] Extend EM101 to support byte strings (#18867)
[flake8-use-pathlib] Add autofix for PTH202 (#18763)
[pygrep-hooks] Add AsyncMock methods to invalid-mock-access (PGH005) (#18547)
[pylint] Ignore __init__.py files in (PLC0414) (#18400)
[ruff] Trigger RUF037 for empty string and byte strings (#18862)
[formatter] Fix missing blank lines before decorated classes in .pyi files (#18888)

Bug fixes

Avoid generating diagnostics with per-file ignores (#18801)
Handle parenthesized arguments in remove_argument (#18805)
[flake8-logging] Avoid false positive for exc_info=True outside logger.exception (LOG014) (#18737)
[flake8-pytest-style] Enforce pytest import for decorators (#18779)
[flake8-pytest-style] Mark autofix for PT001 and PT023 as unsafe if there's comments in the decorator (#18792)
[flake8-pytest-style] PT001/PT023 fix makes syntax error on parenthesized decorator (#18782)
[flake8-raise] Make fix unsafe if it deletes comments (RSE102) (#18788)
[flake8-simplify] Fix SIM911 autofix creating a syntax error (#18793)
[flake8-simplify] Fix false negatives for shadowed bindings (SIM910, SIM911) (#18794)
[flake8-simplify] Preserve original behavior for except () and bare except (SIM105) (#18213)
[flake8-pyi] Fix PYI041's fix causing TypeError with None | None | ... (#18637)
[perflint] Fix PERF101 autofix creating a syntax error and mark autofix as unsafe if there are comments in the list call expr (#18803)
[perflint] Fix false negative in PERF401 (#18866)
[pylint] Avoid flattening nested min/max when outer call has single argument (PLW3301) (#16885)
[pylint] Fix PLC2801 autofix creating a syntax error (#18857)
[pylint] Mark PLE0241 autofix as unsafe if there's comments in the base classes (#18832)
[pylint] Suppress PLE2510/PLE2512/PLE2513/PLE2514/PLE2515 autofix if the text contains an odd number of backslashes (#18856)
[refurb] Detect more exotic float literals in FURB164 (#18925)
[refurb] Fix FURB163 autofix creating a syntax error for yield expressions (#18756)
[refurb] Mark FURB129 autofix as unsafe if there's comments in the readlines call (#18858)
[ruff] Fix false positives and negatives in RUF010 (#18690)
Fix casing of analyze.direction variant names (#18892)

Rule changes

Fix f-string interpolation escaping in generated fixes (#18882)
[flake8-return] Mark RET501 fix unsafe if comments are inside (#18780)
[flake8-async] Fix detection for large integer sleep durations in ASYNC116 rule (#18767)
[flake8-async] Mark autofix for ASYNC115 as unsafe if the call expression contains comments (#18753)
[flake8-bugbear] Mark autofix for B004 as unsafe if the hasattr call expr contains comments (#18755)
[flake8-comprehension] Mark autofix for C420 as unsafe if there's comments inside the dict comprehension (#18768)
[flake8-comprehensions] Handle template strings for comprehension fixes (#18710)
[flake8-future-annotations] Add autofix (FA100) (#18903)
[pyflakes] Mark F504/F522/F523 autofix as unsafe if there's a call with side effect (#18839)
[pylint] Allow fix with comments and document performance implications (PLW3301) (#18936)
[pylint] Detect more exotic NaN literals in PLW0177 (#18630)
[pylint] Fix PLC1802 autofix creating a syntax error and mark autofix as unsafe if there's comments in the len call (#18836)
[pyupgrade] Extend version detection to include sys.version_info.major (UP036) (#18633)
[ruff] Add lint rule RUF064 for calling chmod with non-octal integers (#18541)
[ruff] Added cls.__dict__.get('__annotations__') check (RUF063) (#18233)
[ruff] Frozen dataclass default should be valid (RUF009) (#18735)

Server

Consider virtual path for various server actions (#18910)

Documentation

Add fix safety sections (#18940,#18841,#18802,#18837,#18800,#18415,#18853,#18842)
Use updated pre-commit id (#18718)
[perflint] Small docs improvement to PERF401 (#18786)
[pyupgrade]: Use super(), not __super__ in error messages (UP008) (#18743)
[flake8-pie] Small docs fix to PIE794 (#18829)
[flake8-pyi] Correct collections-named-tuple example to use PascalCase assignment (#16884)
[flake8-pie] Add note on type checking benefits to unnecessary-dict-kwargs (PIE804) (#18666)
[pycodestyle] Clarify PEP 8 relationship to whitespace-around-operator rules (#18870)

Other changes

Disallow newlines in format specifiers of single quoted f- or t-strings (#18708)
[flake8-logging] Add fix safety section to LOG002 (#18840)
[pyupgrade] Add fix safety section to UP010 (#18838)

0.12.0

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

Breaking changes

Detection of more syntax errors

Ruff now detects version-related syntax errors, such as the use of the match statement on Python versions before 3.10, and syntax errors emitted by CPython's compiler, such as irrefutable match patterns before the final case arm.
New default Python version handling for syntax errors

Ruff will default to the latest supported Python version (3.13) when checking for the version-related syntax errors mentioned above to prevent false positives in projects without a Python version configured. The default in all other cases, like applying lint rules, is unchanged and remains at the minimum supported Python version (3.9).
Updated f-string formatting

Ruff now formats multi-line f-strings with format specifiers to avoid adding a line break after the format specifier. This addresses a change to the Python grammar in version 3.13.4 that made such a line break a syntax error.
rust-toolchain.toml is no longer included in source distributions

The rust-toolchain.toml is used to specify a higher Rust version than Ruff's minimum supported Rust version (MSRV) for development and building release artifacts. However, when present in source distributions, it would also cause downstream package maintainers to pull in the same Rust toolchain, even if their available toolchain was MSRV-compatible.

Removed Rules

The following rules have been removed:

suspicious-xmle-tree-usage (S320)

Deprecated Rules

The following rules have been deprecated:

pandas-df-variable-name

Stabilization

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

for-loop-writes (FURB122)
check-and-remove-from-set (FURB132)
verbose-decimal-constructor (FURB157)
fromisoformat-replace-z (FURB162)
int-on-sliced-str (FURB166)
exc-info-outside-except-handler (LOG014)
import-outside-top-level (PLC0415)
unnecessary-dict-index-lookup (PLR1733)
nan-comparison (PLW0177)
eq-without-hash (PLW1641)
pytest-parameter-with-default-argument (PT028)
pytest-warns-too-broad (PT030)
pytest-warns-with-multiple-statements (PT031)
invalid-formatter-suppression-comment (RUF028)
dataclass-enum (RUF049)
class-with-mixed-type-vars (RUF053)
unnecessary-round (RUF057)
starmap-zip (RUF058)
non-pep604-annotation-optional (UP045)
non-pep695-generic-class (UP046)
non-pep695-generic-function (UP047)
private-type-parameter (UP049)

The following behaviors have been stabilized:

collection-literal-concatenation (RUF005) now recognizes slices, in addition to list literals and variables.
The fix for readlines-in-for (FURB129) is now marked as always safe.
if-else-block-instead-of-if-exp (SIM108) will now further simplify expressions to use or instead of an if expression, where possible.
unused-noqa (RUF100) now checks for file-level noqa comments as well as inline comments.
subprocess-without-shell-equals-true (S603) now accepts literal strings, as well as lists and tuples of literal strings, as trusted input.
boolean-type-hint-positional-argument (FBT001) now applies to types that include bool, like bool | int or typing.Optional[bool], in addition to plain bool annotations.
non-pep604-annotation-union (UP007) has now been split into two rules. UP007 now applies only to typing.Union, while non-pep604-annotation-optional (UP045) checks for use of typing.Optional. UP045 has also been stabilized in this release, but you may need to update existing include, ignore, or noqa settings to accommodate this change.

Preview features

[ruff] Check for non-context-manager use of pytest.raises, pytest.warns, and pytest.deprecated_call (RUF061) (#17368)
[syntax-errors] Raise unsupported syntax error for template strings prior to Python 3.14 (#18664)

Bug fixes

Add syntax error when conversion flag does not immediately follow exclamation mark (#18706)
Add trailing space around readlines (#18542)
Fix \r and \r\n handling in t- and f-string debug texts (#18673)
Hug closing } when f-string expression has a format specifier (#18704)
[flake8-pyi] Avoid syntax error in the case of starred and keyword arguments (PYI059) (#18611)
[flake8-return] Fix RET504 autofix generating a syntax error (#18428)
[pep8-naming] Suppress fix for N804 and N805 if the recommended name is already used (#18472)
[pycodestyle] Avoid causing a syntax error in expressions spanning multiple lines (E731) (#18479)
[pyupgrade] Suppress UP008 if super is shadowed (#18688)
[refurb] Parenthesize lambda and ternary expressions (FURB122, FURB142) (#18592)
[ruff] Handle extra arguments to deque (RUF037) (#18614)
[ruff] Preserve parentheses around deque in fix for unnecessary-empty-iterable-within-deque-call (RUF037) (#18598)
[ruff] Validate arguments before offering a fix (RUF056) (#18631)
[ruff] Skip fix for RUF059 if dummy name is already bound (#18509)
[pylint] Fix PLW0128 to check assignment targets in square brackets and after asterisks (#18665)

Rule changes

Fix false positive on mutations in return statements (B909) (#18408)
Treat ty: comments as pragma comments (#18532)
[flake8-pyi] Apply custom-typevar-for-self to string annotations (PYI019) (#18311)
[pyupgrade] Don't offer a fix for Optional[None] (UP007, UP045) (#18545)
[pyupgrade] Fix super(__class__, self) detection (UP008) (#18478)
[refurb] Make the fix for FURB163 unsafe for log2, log10, *args, and deleted comments (#18645)

Server

Support cancellation requests (#18627)

Documentation

Drop confusing second * from glob pattern example for per-file-target-version (#18709)
Update Neovim configuration examples (#18491)
[pylint] De-emphasize __hash__ = Parent.__hash__ (PLW1641) (#18613)
[refurb] Add a note about float literal handling (FURB157) (#18615)