pyrefly-pre-commit

A pre-commit hook for Pyrefly.

Note

This pre-commit hook changed significantly from version 0.0.1 to version 0.42.0. See the Migration from 0.0.1 section for how to upgrade.

Usage

There are two ways to use the pyrefly-check hook. Add one of the following to your project's .pre-commit-config.yaml:

Option 1: System Install

Use an already-installed pyrefly so your CLI/CI/IDE versions stay in sync:

repos:
  - repo: https://github.com/facebook/pyrefly-pre-commit
    rev: 0.44.2  # Note: this is the version of the pre-commit hook, NOT the pyrefly version used for type checking
    hooks:
      - id: pyrefly-check
        name: Pyrefly (type checking)
        pass_filenames: false  # Recommended to do full repo checks. However, you can change this to `true` to only check changed files
        language: system  # Use system-installed pyrefly

This expects pyrefly to already be available on your PATH (e.g., installed via your project's dependencies). The hook will be able to see your project's other installed dependencies when type checking.

Option 2: Managed Install

Let pre-commit manage the pyrefly installation:

repos:
  - repo: https://github.com/facebook/pyrefly-pre-commit
    rev: 0.44.2  # The pyrefly version to use
    hooks:
      - id: pyrefly-check
        name: Pyrefly (type checking)
        pass_filenames: false
        additional_dependencies: [ ... ]  # Your project's dependencies

Note that you must list all of your project's dependencies (aside from pyrefly, which is bundled with the hook) in additional_dependencies for type checking to work correctly.

Examples

See the examples/ directory for complete working examples of both approaches:

• examples/system-hook/ - demonstrates system install
• examples/specific-version-hook/ - demonstrates managed install

Installation

Once the hook is set up, install and run:

pip install pre-commit  # or: uvx pre-commit
pre-commit install
pre-commit run --all-files

Behavior and Defaults

• We run pyrefly check at the repo root and ignore filenames from pre-commit (pass_filenames: false), since Pyrefly checks project state rather than individual files.
• The hook targets stages: [pre-commit, pre-merge-commit, pre-push, manual] so you can run it locally and in CI.
• You can skip temporarily with SKIP=pyrefly-check git commit -m "...".
• Add args to pass flags to Pyrefly, e.g. ["--ignore=missing-source"]. See full config options here: https://pyrefly.org/en/docs/configuration/

CI Example

Use the official pre-commit/action to run the hook in GitHub Actions:

name: pre-commit
on:
  pull_request:
  push:
    branches: [ main ]
jobs:
  pre-commit:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-python@v5
        with:
          python-version: "3.12"
      - uses: pre-commit/[email protected]
        with:
          extra_args: --all-files

Migration from 0.0.1

In version 0.0.1, this repository offered two hooks, pyrefly-typecheck-system and pyrefly-typecheck-specific-version. Since 0.42.0, these hooks have been consolidated into a single pyrefly-check hook.

To migrate from pyrefly-typecheck-system, change:

repos:
  - repo: https://github.com/facebook/pyrefly-pre-commit
    rev: 0.0.1
    hooks:
      - id: pyrefly-typecheck-system
        name: Pyrefly (type checking)
        pass_filenames: false

to:

repos:
  - repo: https://github.com/facebook/pyrefly-pre-commit
    rev: 0.44.2
    hooks:
      - id: pyrefly-check
        name: Pyrefly (type checking)
        pass_filenames: false
        language: system

To migrate from pyrefly-typecheck-specific-version, change:

repos:
  - repo: https://github.com/facebook/pyrefly-pre-commit
    rev: 0.0.1
    hooks:
      - id: pyrefly-typecheck-specific-version
        name: Pyrefly (type checking)
        pass_filenames: false
        additional_dependencies:
          - pyrefly==0.44.2

to:

repos:
  - repo: https://github.com/facebook/pyrefly-pre-commit
    rev: 0.44.2
    hooks:
      - id: pyrefly-check
        name: Pyrefly (type checking)
        pass_filenames: false

Note that if you were using pyrefly-typecheck-specific-version with a version of pyrefly older than 0.42.0, you'll need to upgrade to 0.42.0 or newer.

License

MIT