name: Fast forward merge
on:
  pull_request:
    types: [labeled]
    branches:
      - release
      - release-proxy
      - release-compute

jobs:
  fast-forward:
    if: ${{ github.event.label.name == 'fast-forward' }}
    runs-on: ubuntu-22.04

    steps:
      - name: Harden the runner (Audit all outbound calls)
        uses: step-security/harden-runner@0634a2670c59f64b4a01f0f96f84700a4088b9f0 # v2.12.0
        with:
          egress-policy: audit

      - name: Remove fast-forward label to PR
        env:
          GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
        run: |
          gh pr edit ${{ github.event.pull_request.number }} --repo "${GITHUB_REPOSITORY}" --remove-label "fast-forward"

      - name: Fast forwarding
        uses: sequoia-pgp/fast-forward@ea7628bedcb0b0b96e94383ada458d812fca4979
        # See https://docs.github.com/en/graphql/reference/enums#mergestatestatus
        if: ${{ contains(fromJSON('["clean", "unstable"]'), github.event.pull_request.mergeable_state) }}
        with:
          merge: true
          comment: on-error
          github_token: ${{ secrets.CI_ACCESS_TOKEN }}

      - name: Comment if mergeable_state is not clean
        if: ${{ !contains(fromJSON('["clean", "unstable"]'), github.event.pull_request.mergeable_state) }}
        env:
          GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
        run: |
          gh pr comment ${{ github.event.pull_request.number }} \
            --repo "${GITHUB_REPOSITORY}" \
            --body "Not trying to forward pull-request, because \`mergeable_state\` is \`${{ github.event.pull_request.mergeable_state }}\`, not \`clean\` or \`unstable\`."