prettier-label-action.yml

name: Prettier Formatting on Label

# Explicitly set permissions
permissions:
  contents: write
  pull-requests: write

on:
  pull_request:
    types: [labeled]

jobs:
  prettier-format:
    # Only run if the 'prettier' label is added
    if: ${{ contains(github.event.pull_request.labels.*.name, 'prettier') }}
    runs-on: ubuntu-latest
    steps:
      # Checkout the PR branch
      - uses: actions/checkout@v4
        with:
          # Use the full PR head reference
          ref: ${{ github.event.pull_request.head.ref }}
          # Use the full repository name
          repository: ${{ github.event.pull_request.head.repo.full_name }}
          token: ${{ secrets.GITHUB_TOKEN }}
          fetch-depth: 0

      # Setup Node.js (required for Prettier)
      - uses: actions/setup-node@v4
        with:
          node-version: "lts/*"

      # Install Prettier
      - name: Install Prettier
        run: npm install --save-dev --save-exact prettier

      # Run Prettier using the repo's config
      - name: Run Prettier
        run: npx prettier --write .

      # Check if there are any changes
      - name: Check for changes
        id: check-changes
        run: |
          git diff --quiet || echo "changes=true" >> $GITHUB_OUTPUT

      # Commit and push changes if any
      - name: Commit changes
        if: steps.check-changes.outputs.changes == 'true'
        run: |
          git config --local user.email "action@github.com"
          git config --local user.name "GitHub Action"
          git add .
          git commit -m "[chore] automatic prettier formatting"
          git push origin HEAD:${{ github.event.pull_request.head.ref }}

      # Remove the label after formatting
      # todo: label removal is flaky, disabled for now
      # - name: Remove formatting label
      #   if: always()
      #   uses: actions/github-script@v7
      #   with:
      #     github-token: ${{ secrets.GITHUB_TOKEN }}
      #     script: |
      #       github.rest.issues.removeLabel({
      #         owner: context.repo.owner,
      #         repo: context.repo.repo,
      #         issue_number: context.issue.number,
      #         name: 'prettier'
      #       })