[pylint] Implement swap-with-temporary-variable (PLR1712) by Bnyro · Pull Request #22205 · astral-sh/ruff (original) (raw)

added rule

Implementing or modifying a lint rule

preview

Related to preview mode features

labels

Dec 29, 2025

ntBre changed the title[pylint]: Implement consider-swap-variables (PLR1712) [pylint] Implement swap-with-temporary-variable (PLR1712)

Jan 2, 2026

Bnyro deleted the temporary-variable-swap branch

February 19, 2026 23:35

knutwannheden pushed a commit to openrewrite/ruff that referenced this pull request

Feb 20, 2026

…al-sh#22205)

Summary

This PR implements the consider-swap-variables rule from pylint. Basically it tries to find code parts that swap two variables with each other using a temporary variable.

Example code:

temp = x
x = y
y = temp

can be simplified to

x, y = y, x

related:

https://pylint.readthedocs.io/en/latest/user_guide/messages/refactor/consider-swap-variables.html

• astral-sh#970

Test Plan

I've added new snapshots tests.

PS: Since this is my first contribution here and I'm not too familiar with the codebase, suggestions are very welcome! The implementation might also not be 100% memory-optimized yet, since we use clone a few times.

ntBre mentioned this pull request

Feb 26, 2026

ntBre added a commit that referenced this pull request

Feb 26, 2026

… (PLR1712) (#22205)"

This is an alternative to #23588, checking the ecosystem results in comparison.

ntBre added a commit that referenced this pull request

Feb 26, 2026

Summary

The huge number of changes in #22205 (comment) should have obviously been a red flag, but I think it would be nice if CI failed when new ecosystem panics were introduced. This PR adds a check for diagnostic lines that start with panic: Panicked at crates/, raises a ToolError if any are found in the results from the comparison executable, and then also exits non-zero if any errors are returned.

If exiting non-zero is going too far, we could also just raise the ToolError, as that will at least trigger this message, which was not the case on the PLR1712 PR:

https://github.com/astral-sh/ruff/blob/f14edd8661e2803254f89265548c7487f47a09f6/python/ruff-ecosystem/ruff_ecosystem/check.py#L103-L106

Another option would be not to exit zero if Ruff panics, even if --exit-zero is used, but I saw that ty has the same behavior and assumed that that was intentional.

Test Plan

Local testing on the 0.15.3 tag showing that ruff-ecosystem exited non-zero. I can also introduce a panic into a lint rule to test this in CI

ntBre mentioned this pull request

Feb 26, 2026

ntBre added a commit that referenced this pull request

Mar 4, 2026

Summary

The huge number of changes in #22205 (comment) should have obviously been a red flag, but I think it would be nice if CI failed when new ecosystem panics were introduced. This PR adds a check for diagnostic lines that start with panic: Panicked at crates/, raises a ToolError if any are found in the results from the comparison executable, and then also exits non-zero if any errors are returned fails the CI run if the corresponding error message was printed.

After trying this out in CI, I opted not to change the script's exit code itself because that suppressed the ecosystem comment. It feels a little hackier this way but preserves the behavior I wanted of both failing CI and still getting the ecosystem comment to help with debugging.

Test Plan

Local testing on the 0.15.3 tag showing that ruff-ecosystem exited non-zero and some manual testing in CI, as you can see below.

nicopauss pushed a commit to Intersec/lib-common that referenced this pull request

Apr 1, 2026

Released on 2026-03-19.

• Display output severity in preview (#23845)

• Don't show noqa hover for non-Python documents (#24040)

• [pycodestyle] Recognize pyrefly: as a pragma comment (E501) (#24019)

• Don't return code actions for non-Python documents (#23905)

• Add company AI policy to contributing guide (#24021)

• Document editor features for Markdown code formatting (#23924)

• [pylint] Improve phrasing (PLC0208) (#24033)

• Use PEP 639 license information (#19661)

• @tmimmanuel

• @DimitriPapadopoulos

• @amyreese

• @statxc

• @dylwil3

• @hunterhogan

• @renovate

Released on 2026-03-12.

• Add support for lazy import parsing (#23755)

• Add support for star-unpacking of comprehensions (PEP 798) (#23788)

• Reject semantic syntax errors for lazy imports (#23757)

• Drop a few rules from the preview default set (#23879)

• [airflow] Flag Variable.get() calls outside of task execution context (AIR003) (#23584)

• [airflow] Flag runtime-varying values in DAG/task constructor arguments (AIR304) (#23631)

• [flake8-bugbear] Implement delattr-with-constant (B043) (#23737)

• [flake8-tidy-imports] Add TID254 to enforce lazy imports (#23777)

• [flake8-tidy-imports] Allow users to ban lazy imports with TID254 (#23847)

• [isort] Retain lazy keyword when sorting imports (#23762)

• [pyupgrade] Add from __future__ import annotations automatically (UP006) (#23260)

• [refurb] Support newline parameter in FURB101 for Python 3.13+ (#23754)

• [ruff] Add os-path-commonprefix (RUF071) (#23814)

• [ruff] Add unsafe fix for os-path-commonprefix (RUF071) (#23852)

• [ruff] Limit RUF036 to typing contexts; make it unsafe for non-typing-only (#23765)

• [ruff] Use starred unpacking for RUF017 in Python 3.15+ (#23789)

• Fix --add-noqa creating unwanted leading whitespace (#23773)

• Fix --add-noqa breaking shebangs (#23577)

• [formatter] Fix lambda body formatting for multiline calls and subscripts (#23866)

• [formatter] Preserve required annotation parentheses in annotated assignments (#23865)

• [formatter] Preserve type-expression parentheses in the formatter (#23867)

• [flake8-annotations] Fix stack overflow in ANN401 on quoted annotations with escape sequences (#23912)

• [pep8-naming] Check naming conventions in match pattern bindings (N806, N815, N816) (#23899)

• [perflint] Fix comment duplication in fixes (PERF401, PERF403) (#23729)

• [pyupgrade] Properly trigger super change in nested class (UP008) (#22677)

• [ruff] Avoid syntax errors in RUF036 fixes (#23764)

• [flake8-bandit] Flag S501 with requests.request (#23873)

• [flake8-executable] Fix WSL detection in non-Docker containers (#22879)

• [flake8-print] Ignore pprint calls with stream= (#23787)

• Update docs for Markdown code block formatting (#23871)

• [flake8-bugbear] Fix misleading description for B904 (#23731)

• @zsol

• @carljm

• @ntBre

• @Bortlesboat

• @sososonia-cyber

• @chirizxc

• @leandrobbraga

• @11happy

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• @amyreese

• @xvchris

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• @Dev-iL

Released on 2026-03-05.

• Discover Markdown files by default in preview mode (#23434)

• [perflint] Extend PERF102 to comprehensions and generators (#23473)

• [refurb] Fix FURB101 and FURB103 false positives when I/O variable is used later (#23542)

• [ruff] Add fix for none-not-at-end-of-union (RUF036) (#22829)

• [ruff] Fix false positive for re.split with empty string pattern (RUF055) (#23634)

• [fastapi] Handle callable class dependencies with __call__ method (FAST003) (#23553)

• [pydocstyle] Fix numpy section ordering (D420) (#23685)

• [pyflakes] Fix false positive for names shadowing re-exports (F811) (#23356)

• [pyupgrade] Avoid inserting redundant None elements in UP045 (#23459)

• Document extension mapping for Markdown code formatting (#23574)

• Update default Python version examples (#23605)

• Publish releases to Astral mirror (#23616)

• @amyreese

• @stakeswky

• @chirizxc

• @anishgirianish

• @bxff

• @zsol

• @charliermarsh

• @ntBre

• @kar-ganap

Released on 2026-02-26.

This is a follow-up release to 0.15.3 that resolves a panic when the new rule PLR1712 was enabled with any rule that analyzes definitions, such as many of the ANN or D rules.

• Fix panic on access to definitions after analyzing definitions (#23588)

• [pyflakes] Suppress false positive in F821 for names used before del in stub files (#23550)

• Clarify first-party import detection in Ruff (#23591)

• Fix incorrect import-heading example (#23568)

• @stakeswky

• @ntBre

• @thejcannon

• @GeObts

Released on 2026-02-26.

• Drop explicit support for .qmd file extension (#23572)

  This can now be enabled instead by setting the extension option:

  # ruff.toml
  extension = { qmd = "markdown" }
  
  # pyproject.toml
  [tool.ruff]
  extension = { qmd = "markdown" }

• Include configured extensions in file discovery (#23400)

• [flake8-bandit] Allow suspicious imports in TYPE_CHECKING blocks (S401-S415) (#23441)

• [flake8-bugbear] Allow B901 in pytest hook wrappers (#21931)

• [flake8-import-conventions] Add missing conventions from upstream (ICN001, ICN002) (#21373)

• [pydocstyle] Add rule to enforce docstring section ordering (D420) (#23537)

• [pylint] Implement swap-with-temporary-variable (PLR1712) (#22205)

• [ruff] Add unnecessary-assign-before-yield (RUF070) (#23300)

• [ruff] Support file-level noqa in RUF102 (#23535)

• [ruff] Suppress diagnostic for invalid f-strings before Python 3.12 (RUF027) (#23480)

• [flake8-bandit] Don't flag BaseLoader/CBaseLoader as unsafe (S506) (#23510)

• Avoid infinite loop between I002 and PYI025 (#23352)

• [pyflakes] Fix false positive for @overload from lint.typing-modules (F811) (#23357)

• [pyupgrade] Fix false positive for TypeVar default before Python 3.12 (UP046) (#23540)

• [pyupgrade] Fix handling of \N in raw strings (UP032) (#22149)

• Render sub-diagnostics in the GitHub output format (#23455)

• [flake8-bugbear] Tag certain B007 diagnostics as unnecessary (#23453)

• [ruff] Ignore unknown rule codes in RUF100 (#23531)

  These are now flagged by RUF102 instead.

• Fix missing settings links for several linters (#23519)

• Update isort action comments heading (#23515)

• [pydocstyle] Fix double comma in description of D404 (#23440)

• Update the Python module (notably find_ruff_bin) for parity with uv (#23406)

• @zanieb

• @o1x3

• @assadyousuf

• @kar-ganap

• @denyszhak

• @amyreese

• @carljm

• @anishgirianish

• @Bnyro

• @danparizher

• @ntBre

• @gcomneno

• @jaap3

• @stakeswky

Released on 2026-02-19.

• Expand the default rule set (#23385)

  In preview, Ruff now enables a significantly expanded default rule set of 412 rules, up from the stable default set of 59 rules. The new rules are mostly a superset of the stable defaults, with the exception of these rules, which are removed from the preview defaults:

  • multiple-imports-on-one-line (E401)
  • module-import-not-at-top-of-file (E402)
  • module-import-not-at-top-of-file (E701)
  • multiple-statements-on-one-line-semicolon (E702)
  • useless-semicolon (E703)
  • none-comparison (E711)
  • true-false-comparison (E712)
  • not-in-test (E713)
  • not-is-test (E714)
  • type-comparison (E721)
  • lambda-assignment (E731)
  • ambiguous-variable-name (E741)
  • ambiguous-class-name (E742)
  • ambiguous-function-name (E743)
  • undefined-local-with-import-star (F403)
  • undefined-local-with-import-star-usage (F405)
  • undefined-local-with-nested-import-star-usage (F406)
  • forward-annotation-syntax-error (F722)

  If you use preview and prefer the old defaults, you can restore them with configuration like:

  
  # ruff.toml
  
  [lint]
  select = ["E4", "E7", "E9", "F"]
  
  # pyproject.toml
  
  [tool.ruff.lint]
  select = ["E4", "E7", "E9", "F"]

  If you do give them a try, feel free to share your feedback in the GitHub discussion!

• [flake8-pyi] Also check string annotations (PYI041) (#19023)

• [flake8-async] Fix in_async_context logic (#23426)

• [ruff] Fix for RUF102 should delete entire comment (#23380)

• [ruff] Suppress diagnostic for strings with backslashes in interpolations before Python 3.12 (RUF027) (#21069)

• [flake8-bugbear] Fix B023 false positive for immediately-invoked lambdas (#23294)

• [parser] Fix false syntax error for match-like annotated assignments (#23297)

• [parser] Fix indentation tracking after line continuations (#23417)

• [flake8-executable] Allow global flags in uv shebangs (EXE003) (#22582)

• [pyupgrade] Fix handling of typing.{io,re} (UP035) (#23131)

• [ruff] Detect PLC0207 on chained str.split() calls (#23275)

• Remove invalid inline noqa warning (#23270)

• Add extension mapping to configuration file options (#23384)

• Add Q004 to the list of conflicting rules (#23340)

• [ruff] Expand lint.external docs and add sub-diagnostic (RUF100, RUF102) (#23268)

• @dylwil3

• @Jkhall81

• @danparizher

• @dhruvmanila

• @harupy

• @ngnpope

• @amyreese

• @kar-ganap

• @robsdedude

• @shaanmajid

• @ntBre

• @toslunar

Released on 2026-02-12.

• [airflow] Add ruff rules to catch deprecated Airflow imports for Airflow 3.1 (AIR321) (#22376)

• [airflow] Third positional parameter not named ti_key should be flagged for BaseOperatorLink.get_link (AIR303) (#22828)

• [flake8-gettext] Fix false negatives for plural argument of ngettext (INT001, INT002, INT003) (#21078)

• [pyflakes] Fix infinite loop in preview fix for unused-import (F401) (#23038)

• [pygrep-hooks] Detect non-existent mock methods in standalone expressions (PGH005) (#22830)

• [pylint] Allow dunder submodules and improve diagnostic range (PLC2701) (#22804)

• [pyupgrade] Improve diagnostic range for tuples (UP024) (#23013)

• [refurb] Check subscripts in tuple do not use lambda parameters in reimplemented-operator (FURB118) (#23079)

• [ruff] Detect mutable defaults in field calls (RUF008) (#23046)

• [ruff] Ignore std cmath.inf (RUF069) (#23120)

• [ruff] New rule float-equality-comparison (RUF069) (#20585)

• Don't format unlabeled Markdown code blocks (#23106)

• Markdown formatting support in LSP (#23063)

• Support Quarto Markdown language markers (#22947)

• Support formatting pycon Markdown code blocks (#23112)

• Use extension mapping to select Markdown code block language (#22934)

• Avoid false positive for undefined variables in FAST001 (#23224)

• Avoid introducing syntax errors for FAST003 autofix (#23227)

• Avoid suggesting InitVar for __post_init__ that references PEP 695 type parameters (#23226)

• Deduplicate type variables in generic functions (#23225)

• Fix exception handler parenthesis removal for Python 3.14+ (#23126)

• Fix f-string middle panic when parsing t-strings (#23232)

• Wrap RUF020 target for multiline fixes (#23210)

• Wrap UP007 target for multiline fixes (#23208)

• Fix missing diagnostics for last range suppression in file (#23242)

• [pyupgrade] Fix syntax error on string with newline escape and comment (UP037) (#22968)

• Use ruff instead of Ruff as the program name in GitHub output format (#23240)

• [PT006] Fix syntax error when unpacking nested tuples in parametrize fixes (#22441) (#22464)

• [airflow] Catch deprecated attribute access from context key for Airflow 3.0 (AIR301) (#22850)

• [airflow] Capture deprecated arguments and a decorator (AIR301) (#23170)

• [flake8-boolean-trap] Add multiprocessing.Value to excluded functions for FBT003 (#23010)

• [flake8-bugbear] Add a secondary annotation showing the previous occurrence (B033) (#22634)

• [flake8-type-checking] Add sub-diagnostic showing the runtime use of an annotation (TC004) (#23091)

• [isort] Support configurable import section heading comments (#23151)

• [ruff] Improve the diagnostic for RUF012 (#23202)

• Suppress diagnostic output for format --check --silent (#17736)

• Add tabbed shell completion documentation (#23169)

• Explain how to enable Markdown formatting for pre-commit hook (#23077)

• Fixed import in runtime-evaluated-decorators example (#23187)

• Update ruff server contributing guide (#23060)

• Exclude WASM artifacts from GitHub releases (#23221)

• @mkniewallner

• @bxff

• @dylwil3

• @Avasam

• @amyreese

• @charliermarsh

• @Alex-ley-scrub

• @Kalmaegi

• @danparizher

• @AiyionPrime

• @eureka928

• @11happy

• @Jkhall81

• @chirizxc

• @leandrobbraga

• @tvatter

• @anishgirianish

• @shaanmajid

• @ntBre

• @sjyangkevin

Released on 2026-02-03.

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

• Ruff now formats your code according to the 2026 style guide. See the formatter section below or in the blog post for a detailed list of changes.

• The linter now supports block suppression comments. For example, to suppress N803 for all parameters in this function:

  # ruff: disable[N803]
  def foo(
      legacyArg1,
      legacyArg2,
      legacyArg3,
      legacyArg4,
  ): ...
  # ruff: enable[N803]

  See the documentation for more details.

• The ruff:alpine Docker image is now based on Alpine 3.23 (up from 3.21).

• The ruff:debian and ruff:debian-slim Docker images are now based on Debian 13 "Trixie" instead of Debian 12 "Bookworm."

• Binaries for the ppc64 (64-bit big-endian PowerPC) architecture are no longer included in our releases. It should still be possible to build Ruff manually for this platform, if needed.

• Ruff now resolves all extended configuration files before falling back on a default Python version.

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

• blocking-http-call-httpx-in-async-function (ASYNC212)
• blocking-path-method-in-async-function (ASYNC240)
• blocking-input-in-async-function (ASYNC250)
• map-without-explicit-strict (B912)
• if-exp-instead-of-or-operator (FURB110)
• single-item-membership-test (FURB171)
• missing-maxsplit-arg (PLC0207)
• unnecessary-lambda (PLW0108)
• unnecessary-empty-iterable-within-deque-call (RUF037)
• in-empty-collection (RUF060)
• legacy-form-pytest-raises (RUF061)
• non-octal-permissions (RUF064)
• invalid-rule-code (RUF102)
• invalid-suppression-comment (RUF103)
• unmatched-suppression-comment (RUF104)
• replace-str-enum (UP042)

The following behaviors have been stabilized:

• The --output-format flag is now respected when running Ruff in --watch mode, and the full output format is now used by default, matching the regular CLI output.
• builtin-attribute-shadowing (A003) now detects the use of shadowed built-in names in additional contexts like decorators, default arguments, and other attribute definitions.
• duplicate-union-member (PYI016) now considers typing.Optional when searching for duplicate union members.
• split-static-string (SIM905) now offers an autofix when the maxsplit argument is provided, even without a sep argument.
• dict-get-with-none-default (SIM910) now applies to more types of key expressions.
• super-call-with-parameters (UP008) now has a safe fix when it will not delete comments.
• unnecessary-default-type-args (UP043) now applies to stub (.pyi) files on Python versions before 3.13.

This release introduces the new 2026 style guide, with the following changes:

• Lambda parameters are now kept on the same line and lambda bodies will be parenthesized to let them break across multiple lines (#21385)

• Parentheses around tuples of exceptions in except clauses will now be removed on Python 3.14 and later (#20768)

• A single empty line is now permitted at the beginning of function bodies (#21110)

• Parentheses are avoided for long as captures in match statements (#21176)

• Extra spaces between escaped quotes and ending triple quotes can now be omitted (#17216)

• Blank lines are now enforced before classes with decorators in stub files (#18888)

• Apply formatting to Markdown code blocks (#22470, #22990, #22996)

  See the documentation for more details.

• Fix suppression indentation matching (#22903)

• Customize where the fix_title sub-diagnostic appears (#23044)

• [FastAPI] Add sub-diagnostic explaining why a fix was unavailable (FAST002) (#22565)

• [flake8-annotations] Don't suggest NoReturn for functions raising NotImplementedError (ANN201, ANN202, ANN205, ANN206) (#21311)

• [pyupgrade] Make fix unsafe if it deletes comments (UP017) (#22873)

• [pyupgrade] Make fix unsafe if it deletes comments (UP020) (#22872)

• [pyupgrade] Make fix unsafe if it deletes comments (UP033) (#22871)

• [refurb] Do not add abc.ABC if already present (FURB180) (#22234)

• [refurb] Make fix unsafe if it deletes comments (FURB110) (#22768)

• [ruff] Add sub-diagnostics with permissions (RUF064) (#22972)

• Identify notebooks by LSP didOpen instead of .ipynb file extension (#22810)

• Add --color CLI option to force colored output (#22806)

• Document - stdin convention in CLI help text (#22817)

• [refurb] Change example to re.search with ^ anchor (FURB167) (#22984)

• Fix link to Sphinx code block directives (#23041)

• [pydocstyle] Clarify which quote styles are allowed (D300) (#22825)

• [flake8-bugbear] Improve docs for no-explicit-stacklevel (B028) (#22538)

• Update MSRV to 1.91 (#22874)

• @danparizher

• @chirizxc

• @amyreese

• @Jkhall81

• @cwkang1998

• @manzt

• @11happy

• @hugovk

• @caiquejjx

• @ntBre

• @akawd

• @konstin

Renovate-Branch: renovate/2024.6-ruff-0.x Change-Id: I8f8e865435fde1fc736fe2528261a604acb46215 Priv-Id: f7e1d99008e3617149c4b639a9a2bbc06212d064

KotlinIsland pushed a commit to KotlinIsland/basedpython that referenced this pull request

May 1, 2026

Summary

The huge number of changes in astral-sh/ruff#22205 (comment) should have obviously been a red flag, but I think it would be nice if CI failed when new ecosystem panics were introduced. This PR adds a check for diagnostic lines that start with panic: Panicked at crates/, raises a ToolError if any are found in the results from the comparison executable, and then also exits non-zero if any errors are returned fails the CI run if the corresponding error message was printed.

After trying this out in CI, I opted not to change the script's exit code itself because that suppressed the ecosystem comment. It feels a little hackier this way but preserves the behavior I wanted of both failing CI and still getting the ecosystem comment to help with debugging.

Test Plan

Local testing on the 0.15.3 tag showing that ruff-ecosystem exited non-zero and some manual testing in CI, as you can see below.

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