formal.yml

---
name: lint

on: [push, pull_request]

jobs:
  build:
    name: formalities
    runs-on: ubuntu-latest
    strategy:
      fail-fast: false

    steps:
      - uses: actions/checkout@v3
        with:
          ref: "${{ github.event.pull_request.head.sha }}"
          fetch-depth: 0

      - name: Determine branch name
        run: |
          # shellcheck disable=SC2030

          BRANCH="${GITHUB_BASE_REF#refs/heads/}"
          echo "Building for $BRANCH"
          echo "BRANCH=$BRANCH" >>"$GITHUB_ENV"

      - name: Test formalities
        run: |
          # shellcheck disable=SC1091

          source .github/workflows/ci_helpers.sh

          RET=0
          for commit in $(git rev-list HEAD ^origin/"$BRANCH"); do
              info "=== Checking commit '$commit'"
              if git show --format='%P' -s "$commit" | grep -qF ' '; then
                  err "Pull request should not include merge commits"
                  RET=1
              fi

              subject="$(git show -s --format=%s "$commit")"
              if echo "$subject" | grep -q -e '^[0-9A-Za-z,+/_-]\+: ' -e '^Revert '; then
                  success "Commit subject line seems ok ($subject)"
              else
                  err "Commit subject line MUST start with '<package name>: ' ($subject)"
                  RET=1
              fi
          done

          exit $RET