v0.4.1

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Preview features

• [pylint] Implement invalid-hash-returned (PLE0309) (#​10961)
• [pylint] Implement invalid-index-returned (PLE0305) (#​10962)

Bug fixes

• [pylint] Allow NoReturn-like functions for __str__, __len__, etc. (PLE0307) (#​11017)
• Parser: Use empty range when there's "gap" in token source (#​11032)
• [ruff] Ignore stub functions in unused-async (RUF029) (#​11026)
• Parser: Expect indented case block instead of match stmt (#​11033)

v0.4.0

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A new, hand-written parser

Ruff's new parser is >2x faster, which translates to a 20-40% speedup for all linting and formatting invocations.
There's a lot to say about this exciting change, so check out the blog post for more details!

See #​10036 for implementation details.

A new language server in Rust

With this release, we also want to highlight our new language server. ruff server is a Rust-powered language
server that comes built-in with Ruff. It can be used with any editor that supports the Language Server Protocol (LSP).
It uses a multi-threaded, lock-free architecture inspired by rust-analyzer and it will open the door for a lot
of exciting features. It’s also faster than our previous Python-based language server
-- but you probably guessed that already.

ruff server is only in alpha, but it has a lot of features that you can try out today:

• Lints Python files automatically and shows quick-fixes when available
• Formats Python files, with support for range formatting
• Comes with commands for quickly performing actions: ruff.applyAutofix, ruff.applyFormat, and ruff.applyOrganizeImports
• Supports source.fixAll and source.organizeImports source actions
• Automatically reloads your project configuration when you change it

To setup ruff server with your editor, refer to the README.md.

Preview features

• [pycodestyle] Do not trigger E3 rules on defs following a function/method with a dummy body (#​10704)
• [pylint] Implement invalid-bytes-returned (E0308) (#​10959)
• [pylint] Implement invalid-length-returned (E0303) (#​10963)
• [pylint] Implement self-cls-assignment (W0642) (#​9267)
• [pylint] Omit stubs from invalid-bool and invalid-str-return-type (#​11008)
• [ruff] New rule unused-async (RUF029) to detect unneeded async keywords on functions (#​9966)

Rule changes

• [flake8-bandit] Allow urllib.request.urlopen calls with static Request argument (S310) (#​10964)
• [flake8-bugbear] Treat raise NotImplemented-only bodies as stub functions (B006) (#​10990)
• [flake8-slots] Respect same-file Enum subclasses (SLOT000) (#​11006)
• [pylint] Support inverted comparisons (PLR1730) (#​10920)

Linter

• Improve handling of builtin symbols in linter rules (#​10919)
• Improve display of rules in --show-settings (#​11003)
• Improve inference capabilities of the BuiltinTypeChecker (#​10976)
• Resolve classes and functions relative to script name (#​10965)
• Improve performance of RuleTable::any_enabled (#​10971)

Server

This section is devoted to updates for our new language server, written in Rust.

• Enable ruff-specific source actions (#​10916)
• Refreshes diagnostics for open files when file configuration is changed (#​10988)
• Important errors are now shown as popups (#​10951)
• Introduce settings for directly configuring the linter and formatter (#​10984)
• Resolve configuration for each document individually (#​10950)
• Write a setup guide for Neovim (#​10987)

Configuration

• Add RUFF_OUTPUT_FILE environment variable support (#​10992)

Bug fixes

• Avoid non-augmented-assignment for reversed, non-commutative operators (PLR6104) (#​10909)
• Limit commutative non-augmented-assignments to primitive data types (PLR6104) (#​10912)
• Respect per-file-ignores for RUF100 on blanket # noqa (#​10908)
• Consider if expression for parenthesized with items parsing (#​11010)
• Consider binary expr for parenthesized with items parsing (#​11012)
• Reset FOR_TARGET context for all kinds of parentheses (#​11009)

v0.3.7

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Preview features

• [flake8-bugbear] Implement loop-iterator-mutation (B909) (#​9578)
• [pylint] Implement rule to prefer augmented assignment (PLR6104) (#​9932)

Bug fixes

• Avoid TOCTOU errors in cache initialization (#​10884)
• [pylint] Recode nan-comparison rule to W0177 (#​10894)
• [pylint] Reverse min-max logic in if-stmt-min-max (#​10890)

v0.3.6

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Preview features

• [pylint] Implement bad-staticmethod-argument (PLW0211) (#​10781)
• [pylint] Implement if-stmt-min-max (PLR1730, PLR1731) (#​10002)
• [pyupgrade] Replace str,Enum multiple inheritance with StrEnum UP042 (#​10713)
• [refurb] Implement if-expr-instead-of-or-operator (FURB110) (#​10687)
• [refurb] Implement int-on-sliced-str (FURB166) (#​10650)
• [refurb] Implement write-whole-file (FURB103) (#​10802)
• [refurb] Support itemgetter in reimplemented-operator (FURB118) (#​10526)
• [flake8_comprehensions] Add sum/min/max to unnecessary comprehension check (C419) (#​10759)

Rule changes

• [pydocstyle] Require capitalizing docstrings where the first sentence is a single word (D403) (#​10776)
• [pycodestyle] Ignore annotated lambdas in class scopes (E731) (#​10720)
• [flake8-pyi] Various improvements to PYI034 (#​10807)
• [flake8-slots] Flag subclasses of call-based typing.NamedTuples as well as subclasses of collections.namedtuple() (SLOT002) (#​10808)
• [pyflakes] Allow forward references in class bases in stub files (F821) (#​10779)
• [pygrep-hooks] Improve blanket-noqa error message (PGH004) (#​10851)

CLI

• Support FORCE_COLOR env var (#​10839)

Configuration

• Support negated patterns in [extend-]per-file-ignores (#​10852)

Bug fixes

• [flake8-import-conventions] Accept non-aliased (but correct) import in unconventional-import-alias (ICN001) (#​10729)
• [flake8-quotes] Add semantic model flag when inside f-string replacement field (#​10766)
• [pep8-naming] Recursively resolve TypeDicts for N815 violations (#​10719)
• [flake8-quotes] Respect Q00* ignores in flake8-quotes rules (#​10728)
• [flake8-simplify] Show negated condition in needless-bool diagnostics (SIM103) (#​10854)
• [ruff] Use within-scope shadowed bindings in asyncio-dangling-task (RUF006) (#​10793)
• [flake8-pytest-style] Fix single-tuple conversion in pytest-parametrize-values-wrong-type (PT007) (#​10862)
• [flake8-return] Ignore assignments to annotated variables in unnecessary-assign (RET504) (#​10741)
• [refurb] Do not allow any keyword arguments for read-whole-file in rb mode (FURB101) (#​10803)
• [pylint] Don't recommend decorating staticmethods with @singledispatch (PLE1519, PLE1520) (#​10637)
• [pydocstyle] Use section name range for all section-related docstring diagnostics (#​10740)
• Respect # noqa directives on __all__ openers (#​10798)