@codacy/tools-ruff-0

Table of Contents

• Overview
• Updating patterns
• Updating the Ruff version
• Development
• Notes for maintainers

Overview

Python linter using the Ruff binary. Ruff is an extremely fast Python linter written in Rust that implements rules from Flake8, isort, pyupgrade, and many other tools. Uses the CLI execution strategy.

Updating patterns

# Re-fetch pattern metadata from the Codacy API
pnpm prefetch

# Commit the result
git add src/patterns.json

Pattern IDs follow the format Ruff_F401_unused-import, Ruff_E501_line-too-long, etc.

Updating the Ruff version

1. Update preferredVersion in src/adapter.ts
2. Run pnpm prefetch — Ruff adds new rules frequently
3. Run pnpm test to verify compatibility
4. If the major version changes, create a new adapter package (ruff-1/)

Development

pnpm build    # Build with tsup
pnpm test     # Run tests (requires ruff in PATH or auto-install)

Notes for maintainers

• Preset mappings (src/pattern-mappings.json): prefixes are Ruff rule-code namespaces, so one short prefix covers a whole family. Ruff_ASYNC1 (the checkpoint rules from flake8-async) is claimed by trio and anyio — they implement the same cancellation model, so either is evidence; ASYNC2xx/ASYNC3xx stay universal because they flag blocking calls in any async def. Ruff_ICN001 (conventional import aliases) is claimed by the six plotting/data libraries whose aliases it enforces. ICN002/ICN003 stay universal: their banned-import lists are empty by default, so enabling them would add config that checks nothing.

• Ruff is a standalone Rust binary, downloaded from GitHub releases as a .tar.gz archive.

• Installation uses downloadAndExtract() with stripComponents: 1 because the archive wraps the binary in a directory (e.g. ruff-aarch64-apple-darwin/ruff).

• JSON output via ruff check --output-format json.

• --exit-zero ensures exit code 0 even when findings exist.

• --no-cache disables Ruff's file cache for reproducible results.

• When patterns are specified, a ruff.toml config with select = [...] is generated.

• Config file search order: .ruff.toml, ruff.toml, pyproject.toml. As in Ruff itself, pyproject.toml only counts when it has a [tool.ruff] table.