name: Check if PR has fixups

on:
  pull_request:

jobs:
  find-fixups:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
        with:
          fetch-depth: 0
      - run: |
          set -e -o pipefail

          git rev-list 'HEAD^..HEAD' \
            | while read -r COMMIT; do
            printf 'pondering commit %s\n' "$COMMIT"
            git show -s "$COMMIT"
            if git show -s --format='%s' "$COMMIT" | grep -q '^fixup! '; then
              exit 1
            fi
          done
          printf 'ready to merge!\n'