precommit_checks.yml

# This action is triggered when a pull request review is submitted.
# It will run precommit checks only when the pull request is approved.
# Reference: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#running-a-workflow-when-a-pull-request-is-approved

name: Run Precommit Checks on PR Approval

on:
    workflow_dispatch:
    push:
        branches:
          - main
    pull_request_review:
        types: [submitted]

jobs:
    # This job runs the precommit checks on the changed files.
    run_precommit_checks:

        # Ensures the job only runs when the PR review state is "approved".
        if: github.event.review.state == 'approved'
        runs-on: ubuntu-22.04

        steps:
            # Checkout the repository to the GitHub Actions runner.
            - name: Checkout Repository
              uses: actions/checkout@v4

            # Set up the desired Python environment.
            - name: Setup Python Environment
              uses: actions/setup-python@v4
              with:
                python-version: '3.10.13'
                cache: 'pip'

            # Install the required dependencies for local repos in the precommit hooks
            - name: Install Dependencies
              run: pip install -r .github/workflows/requirements.txt

            # Determine which python files have changed in the PR.
            - name: Get Changed Files
              id: changed-files
              uses: tj-actions/changed-files@v36
              with:
                files: '*.py'

            # Run the precommit hooks only on the changed files.
            - name: Execute Precommit Hooks on Changed Files in PR
              uses: pre-commit/action@v3.0.0
              with:
                extra_args: --files ${{ steps.changed-files.outputs.all_changed_files }}