Bump ruff from 0.15.21 to 0.16.4

[dependabot]

Bumps ruff from 0.15.21 to 0.16.4.

Release notes

Sourced from ruff's releases.

0.16.4

Release Notes

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

• @​AbhinavMir
• @​eduardorittner
• @​royb3
• @​MichaReiser
• @​carljm
• @​rosstitmarsh
• @​ntBre

... (truncated)

Changelog

Sourced from ruff's 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

• @​AbhinavMir
• @​eduardorittner
• @​royb3
• @​MichaReiser
• @​carljm
• @​rosstitmarsh
• @​ntBre
• @​zaniebot

... (truncated)

Commits

• 11c76bf Bump 0.16.4 (#27937)
• d53c8c5 Isolate playground builds from deployment credentials (#27839)
• cab001e Disable uv preview for releases and pre-commit hooks (#27939)
• f8d575f [ty] Clarify writing guidance for human readers (#27912)
• ca45fae Set --preview and --default-index for the uv-lock hook (#27935)
• 4827bf7 Export UV_DEFAULT_INDEX in release.sh (#27934)
• d1087a4 [ty] Handle assignment expressions in string annotations (#27921)
• 680cce4 [ty] Optimize inherited recursive protocol comparisons (#27922)
• 974d3cb Upgrade ecosystem-analyzer and mypy_primer to the latest upstream pins (#27932)
• b169b40 Install cargo tools locked (#27929)
• Additional commits viewable in compare view

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[github-actions]

Hi @dependabot[bot], thank you for your contribution! 🎉

This PR comes from your fork git-mastery/exercises on branch dependabot/uv/ruff-0.16.4.

Before you request for a review, please ensure that you have tested your changes locally!

Important

The previously recommended way of using ./test-download.py is no longer the best way to test your changes locally.

Please read the following instructions for the latest instructions.

Prerequisites

Ensure that you have the gitmastery app installed locally (instructions)

Testing steps

If you already have a local Git-Mastery root to test, you can skip the following step.

Create a Git-Mastery root locally:

gitmastery setup

Navigate into the Git-Mastery root (defaults to gitmastery-exercises/):

cd gitmastery-exercises/

Edit the .gitmastery.json configuration file. You need to set the following values under the exercises_source key.

{
    # other fields...
    "exercises_source": {
        "username": "git-mastery",
        "repository": "exercises",
        "branch": "dependabot/uv/ruff-0.16.4"
    }
}

Then, you can use the gitmastery app to download and verify your changes locally.

gitmastery download <your new change>
gitmastery verify

Checklist

• (For exercises and hands-ons) I have verified that the downloading behavior works
• (For exercises only) I have verified that the verification behavior is accurate

Important

To any reviewers of this pull request, please use the same instructions above to test the changes.