Changelog

0.12.0

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

The following rules have been removed:

The following rules have been deprecated:

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

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.

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`ruff`
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[syntax-errors] Raise unsupported syntax error for template strings prior to Python 3.14 (#18664)

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)
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`flake8-pyi`
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`flake8-return`
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`pep8-naming`
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`pycodestyle`
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`pyupgrade`
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`refurb`
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`ruff`
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`ruff`
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`ruff`
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`ruff`
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`pylint`
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Drop confusing second * from glob pattern example for per-file-target-version (#18709)
Update Neovim configuration examples (#18491)
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`pylint`
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`refurb`
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