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pre-commit/action
=================

A GitHub action to run [pre-commit](https://pre-commit.com)

## How to

### Setup

To use this action, make a file `.github/workflows/pre-commit.yml`.  The following template will get you started:

```yaml
name: pre-commit

on:
  pull_request:
  push:
    branches: [master]

jobs:
  pre-commit:
    runs-on: ubuntu-latest
    steps:
    - uses: actions/checkout@v2
    - uses: actions/setup-python@v2
    - uses: pre-commit/action@v2.0.0
```

This does a few things:

- Clones the code
- Installs python
- Sets up the `pre-commit` cache

### With custom invocations

By default, this action runs all the hooks against all the files.  `extra_args`
lets users specify a single hook id and/or options to pass to `pre-commit run`.

Here's a sample step configuration that only runs the `flake8` hook against all
the files (use the template above except for the `pre-commit` action):

```yaml
    - uses: pre-commit/action@v2.0.0
      with:
        extra_args: flake8 --all-files
```

### In private repositories

This action also provides an additional behaviour when used in private
repositories. When configured with a GitHub token, the action will push back
fixes to the pull request branch.

Using the template above, you'll need to make two replacements for individual actions:

First is the checkout step, which needs to use unlimited fetch depth for
pushing:

```yaml
    - uses: actions/checkout@v2
      with:
        fetch-depth: 0
```

Next is passing the token to the pre-commit action:

```yaml
    - uses: pre-commit/action@v2.0.0
      with:
        token: ${{ secrets.GITHUB_TOKEN }}
```

Note that `secrets.GITHUB_TOKEN` is [automatically provisioned](https://docs.github.com/en/free-pro-team@latest/actions/reference/authentication-in-a-workflow#about-the-github_token-secret) and will not
require any special configuration.

While you could _technically_ configure this for a public repository (using a
personal access token), I can't think of a way to do this safely without
exposing a privileged token to pull requests – If you have any ideas, please
leave an [issue](https://github.com/pre-commit/action/issues)!