commit-lint.yml

name: Commit Lint

on:
  pull_request:
    types: [opened, synchronize, edited]

jobs:
  commit-lint:
    name: Validate PR Title
    runs-on: ubuntu-latest
    permissions:
      contents: read
      pull-requests: write
    steps:
      - name: Skip for release PRs
        if: startsWith(github.event.pull_request.head.ref, 'release/')
        run: echo "⏭️ Skipping commit lint for release PR"

      - uses: actions/checkout@v4
        if: "!startsWith(github.event.pull_request.head.ref, 'release/')"
        with:
          fetch-depth: 0

      - name: Validate or fix PR title
        if: "!startsWith(github.event.pull_request.head.ref, 'release/')"
        env:
          # Forgejo runner has no `gh` CLI — hit the forge's REST.
          FORGE_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          FORGE_API: ${{ github.api_url }}
          REPO: ${{ github.repository }}
          PR_NUMBER: ${{ github.event.pull_request.number }}
          PR_TITLE: ${{ github.event.pull_request.title }}
        run: |
          PATTERN='^([Ff]eat|[Ff]ix|[Dd]ocs|[Ss]tyle|[Rr]efactor|[Pp]erf|[Tt]est|[Bb]uild|[Cc][Ii]|[Cc]hore|[Rr]evert)(\(.+\))?(!)?: .+'

          # 1. Check if PR title already follows conventional commits
          if [[ "$PR_TITLE" =~ $PATTERN ]]; then
            echo "✅ PR title is valid: $PR_TITLE"
            exit 0
          fi

          echo "⚠️  PR title is not conventional: $PR_TITLE"
          echo "Scanning PR commits for a conventional commit message..."

          # 2. Scan PR commits for a conventional commit to use as title
          SUGGESTED=""
          while IFS= read -r MSG; do
            if [[ "$MSG" =~ $PATTERN ]]; then
              SUGGESTED="$MSG"
              break
            fi
          done < <(git log "${{ github.event.pull_request.base.sha }}..${{ github.event.pull_request.head.sha }}" --format="%s" --reverse)

          # 3. If found, update the PR title automatically
          if [ -n "$SUGGESTED" ]; then
            echo "📝 Found conventional commit: $SUGGESTED"
            echo "Updating PR title..."
            export SUGGESTED
            PAYLOAD=$(python3 -c 'import json,os; print(json.dumps({"title":os.environ["SUGGESTED"]}))')
            curl -fsSL -X PATCH \
              -H "Authorization: token ${FORGE_TOKEN}" \
              -H "Content-Type: application/json" \
              -d "${PAYLOAD}" \
              "${FORGE_API}/repos/${REPO}/pulls/${PR_NUMBER}" >/dev/null
            echo "✅ PR title updated to: $SUGGESTED"
            exit 0
          fi

          # 4. No conventional commit found anywhere — fail with guidance
          echo ""
          echo "::error::PR title does not follow Conventional Commits and no conventional commit found in PR history."
          echo ""
          echo "Expected: <type>(<optional scope>): <description>"
          echo "Got:      $PR_TITLE"
          echo ""
          echo "Valid types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert"
          echo ""
          echo "Release impact:"
          echo "  feat:                        -> minor version bump (0.1.0 -> 0.2.0)"
          echo "  fix, perf, refactor, etc.    -> patch version bump (0.2.0 -> 0.2.1)"
          echo "  <type>!: (any type with !)   -> major version bump (0.2.1 -> 1.0.0)"
          echo "  docs, test, ci, chore, style -> changelog only, no version bump"
          exit 1