CHANGELOG.md

Changelog

0.16.4

Released on 2026-08-20.

Preview features

[flake8-use-pathlib] Add autofix for PTH116 (#26460)
[refurb] Restrict delete-full-slice to lists (FURB131) (#27711)
[refurb] Skip FURB101 and FURB103 when the open argument is a file descriptor (#27643)

Bug fixes

Fix InvalidInstruction on Windows CPUs that do not support POPCNT (#27803)
[pyflakes] Emit semantic syntax errors in string type definitions as F722 (#27835)
[pylint] Allow os._exit imports in import-private-name (PLC2701) (#27738)

Rule changes

[syntax-errors] Align mixed t-string/bytes error message with CPython 3.14 (#27766)
[ruff] Add ctypes.LittleEndianStructure and related types to existing exception (RUF012) (#27753)
[syntax-errors] Detect duplicate keyword arguments (#17804)
[syntax-errors] Detect parameters declared nonlocal (#27628)

Server

Offer display-only fixes and mark safe fixes preferred (#27807)
Support pull diagnostics for notebook cells (#27779)

Documentation

Add default indicator to rules table (#27724)
Fix broken link to Python docs (#27757)

Other changes

Fix s390x stacker assembly in release builds (#27776)
Guarantee minimum stack size when parsing a module, standalone expression, and suites (#25464)
Reduce configuration deserialization code size (#27924)
Check packed AST index bounds (#27849)

Contributors

0.16.3

Released on 2026-08-13.

Preview features

[pylint] Fix false negatives on negative numbers (PLR6104) (#27251)
[pyupgrade] Add rule to replace while 1 with while True (UP048) (#27190)

Bug fixes

[flake8-bandit] Also check keyword arguments (S602, S603, S607, S609) (#27687)
[pylint] Allow continue in finally on Python 3.8 (#27626)
[pylint] Fix PLE1307 false positive with bools (#27651)
[pylint] Fix false positives and negatives with %b format character (PLE1300, PLE1307) (#27560)
[pylint] Improve handling of concatenated strings (PLE1300) (#27659)

Rule changes

[numpy] Make np.chararray autofix backwards-compatible (NPY201) (#27527)

Performance

Enable PGO for Linux x86-64 Ruff releases (#27570)
Enable PGO for Linux ARM64 Ruff releases (#27574)
Enable PGO for Windows x86-64 Ruff releases (#27573)
Enable PGO for macOS ARM64 Ruff releases (#27572)
Reduce Expr size to 64 bytes (#27591)

CLI

Hyperlink rule codes in ruff check --statistics output (#27646)

Documentation

[ruff] Also suggest asyncio.TaskGroup (RUF006) (#27461)

Other changes

Use mimalloc v3 (#27586)

Contributors

0.16.2

Released on 2026-08-06.

Bug fixes

[flake8-pyi] Avoid false positives on singledispatch functions (PYI041) (#27335)

Server

Register formatting capabilities dynamically to exclude TOML files (#27332)

Contributors

0.16.1

Released on 2026-07-30.

Preview features

Add an option to opt out of human-readable names (#27160)
[flake8-pytest-style] Make fixes safe by default and unsafe only when comments are present (PT018) (#27201)
[pyupgrade] Skip fix when a defaulted TypeVar precedes a non-defaulted one (UP040, UP046, UP047) (#27133)
[ruff] Fix false positive with unpacked arguments (RUF065) (#26959)

Bug fixes

Bump gen-lsp-types to gracefully handle unknown enumeration values in LSP messages (#27230)
[flake8-bugbear] Mark range as immutable (B008) (#27247)
[flake8-comprehensions] NFKC-normalize keyword names in C408 fix (#26813)
[flake8-return] Fix false positive when variable is read in finally clause (RET504) (#25441)
[pydocstyle] Skip section detection inside RST directive bodies (D214, D405, D413) (#23635)
[refurb] Parenthesize yield arguments in the FURB192 fix (#27192)

Rule changes

[flake8-pytest-style] Mark PT022 fixes as unsafe (#26440)
[refurb] Mark fixes that remove unknown separators as unsafe (FURB105) (#27200)

Server

Fix indexing of excluded nested Ruff workspaces (#27303)
Lint TOML files in the LSP (#26862)

Documentation

Cover pycon Markdown formatting (#27153)
[flake8-bandit] Document TYPE_CHECKING exception (S101) (#27004)
[flake8-import-conventions] Document that extend-aliases can override default aliases (#27191)
[pylint] Add missing fix safety gotchas for non-augmented-assignment (PLR6104) (#27250)

Other changes

Reduce syntax error noise by swallowing dedents like indents (#27170)
Vendor latest annotate-snippets (#27033)

Contributors

0.16.0

Released on 2026-07-23.

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

Breaking changes

Ruff now enables a much larger set of rules by default (413, up from 59). See the blog post for more details and the new Default Rules page for a full listing of the enabled rules. Note that this is primarily an expansion, but 18 of the more opinionated pycodestyle (E) and pyflakes (F) rules have been removed from the default set: E401, E402, E701, E702, E703, E711, E712, E713, E714, E721, E731, E741, E742, E743, F403, F405, F406, and F722.
Ruff can now format Python code blocks in Markdown files and will do this by default. See the documentation for more details.
Ruff now supports ruff: ignore comments at the ends of lines, like noqa comments, or on the line preceding a diagnostic. For example, these both suppress an unused-import (F401) diagnostic:
```
import math  # ruff: ignore[F401]

# ruff: ignore[F401]
import os
```

Fixes are now shown in check and format --check output:

❯ ruff format --check .
unformatted: File would be reformatted
 --> try.md:1:1
  |
1 | ```python
  - import   math
2 + import math
3 | ```
  |

1 file would be reformatted

This example also shows off the Markdown formatting.

format --check now supports the same output formats as the linter, including the github and gitlab outputs for rendering annotations in CI:
```
❯ ruff format --check --output-format github .
::error title=ruff (unformatted),file=try.md,line=2,col=8,endLine=2,endColumn=10::try.md:2:8: unformatted: File would be reformatted
```
See the CLI help or documentation for the full list of supported formats.
The filename, location, end_location, fix.edits[].location, and fix.edits[].end_location fields in the JSON output format may now be null rather than defaulting to the empty string and row 1, column 1, respectively.

Stabilization

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

airflow3-incompatible-function-signature (AIR303)
missing-copyright-notice (CPY001)
unnecessary-from-float (FURB164)
sorted-min-max (FURB192)
implicit-string-concatenation-in-collection-literal (ISC004)
log-exception-outside-except-handler (LOG004)
invalid-bool-return-type (PLE0304)
too-many-positional-arguments (PLR0917)
stop-iteration-return (PLR1708)
none-not-at-end-of-union (RUF036)
access-annotations-from-class-dict (RUF063)
duplicate-entry-in-dunder-all (RUF068)

The following behaviors have been stabilized:

blind-except (BLE001) is now suppressed when the exception is logged via logging methods other than critical, error and exception.
future-required-type-annotation (FA102) now checks for additional PEP 585-compatible APIs, such as those from collections.abc.
f-string-in-get-text-func-call (INT001), format-in-get-text-func-call (INT002), and printf-in-get-text-func-call (INT003) now check for additional common ways of using the gettext module, such as assigning it to builtins._.
suspicious-url-open-usage (S310) now resolves local string literal bindings to avoid more false positives.
snmp-insecure-version (S508) and snmp-weak-cryptography (S509) now support the recommended API from newer versions of PySNMP.
typing-text-str-alias (UP019) now recognizes typing_extensions.Text in addition to typing.Text.

Preview features

[pyupgrade] Fix false positive with TypeVar default before Python 3.13 (UP040) (#26888)

Bug fixes

[ruff] Fix missing check on unrecognized early bound (RUF016) (#26986)

Rule changes

Insert a space after the colon in Ruff suppression comments (#27123)

Performance

[pyupgrade] Speed up unnecessary-future-import (UP010) (#27047)

Documentation

[ruff] Add missing period in "Why is this bad?" section (RUF200) (#26930)
[flake8-simplify] Clarify os.environ behavior on Windows (SIM112) (#26972)
[pydocstyle] Document fix safety (D400) (#26971)