ruff 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
• @zaniebot
• @ewdurbin
• @woodruffw
• @Sacrimento
• @lakshayxi
• @WhiteFox0-0
• @baltasarblanco

Install ruff 0.16.4

Install prebuilt binaries via shell script

curl --proto '=https' --tlsv1.2 -LsSf https://releases.astral.sh/github/ruff/releases/download/0.16.4/ruff-installer.sh | sh

Install prebuilt binaries via powershell script

powershell -ExecutionPolicy Bypass -c "irm https://releases.astral.sh/github/ruff/releases/download/0.16.4/ruff-installer.ps1 | iex"

Download ruff 0.16.4

File	Platform	Checksum
ruff-aarch64-apple-darwin.tar.gz	Apple Silicon macOS	checksum
ruff-x86_64-apple-darwin.tar.gz	Intel macOS	checksum
ruff-aarch64-pc-windows-msvc.zip	ARM64 Windows	checksum
ruff-i686-pc-windows-msvc.zip	x86 Windows	checksum
ruff-x86_64-pc-windows-msvc.zip	x64 Windows	checksum
ruff-aarch64-unknown-linux-gnu.tar.gz	ARM64 Linux	checksum
ruff-i686-unknown-linux-gnu.tar.gz	x86 Linux	checksum
ruff-powerpc64-unknown-linux-gnu.tar.gz	PPC64 Linux	checksum
ruff-powerpc64le-unknown-linux-gnu.tar.gz	PPC64LE Linux	checksum
ruff-riscv64gc-unknown-linux-gnu.tar.gz	RISCV Linux	checksum
ruff-s390x-unknown-linux-gnu.tar.gz	S390x Linux	checksum
ruff-x86_64-unknown-linux-gnu.tar.gz	x64 Linux	checksum
ruff-armv7-unknown-linux-gnueabihf.tar.gz	ARMv7 Linux	checksum
ruff-aarch64-unknown-linux-musl.tar.gz	ARM64 MUSL Linux	checksum
ruff-i686-unknown-linux-musl.tar.gz	x86 MUSL Linux	checksum
ruff-x86_64-unknown-linux-musl.tar.gz	x64 MUSL Linux	checksum
ruff-arm-unknown-linux-musleabihf.tar.gz	ARMv6 MUSL Linux (Hardfloat)	checksum
ruff-armv7-unknown-linux-musleabihf.tar.gz	ARMv7 MUSL Linux	checksum

Verifying GitHub Artifact Attestations

The artifacts in this release have attestations generated with GitHub Artifact Attestations. These can be verified by using the GitHub CLI:

gh attestation verify <file-path of downloaded artifact> --repo astral-sh/ruff

You can also download the attestation from GitHub and verify against that directly:

gh attestation verify <file-path of downloaded artifact> --bundle <file-path of downloaded attestation>