changelog.yml

name: Changelog Check

on:
  pull_request:
    types: [opened, synchronize, reopened, ready_for_review]
    # Only check PRs that introduce user-visible changes.
    # Draft PRs are exempt until marked ready.

permissions:
  contents: read

jobs:
  check-changelog:
    name: Changelog updated?
    # Skip for draft PRs and for changes that don't need a changelog entry.
    if: github.event.pull_request.draft == false
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Determine if changelog update is needed
        id: check
        run: |
          PR_TITLE="${{ github.event.pull_request.title }}"
          PR_LABELS="${{ toJson(github.event.pull_request.labels.*.name) }}"

          # Types that always need a changelog entry
          if echo "$PR_TITLE" | grep -qiE "^(feat|fix|perf)(\(|:)"; then
            echo "needed=true" >> "$GITHUB_OUTPUT"
            echo "reason=PR title indicates a user-visible change (feat/fix/perf)"
            exit 0
          fi

          # Types that never need a changelog entry
          if echo "$PR_TITLE" | grep -qiE "^(chore|ci|style|refactor|test|docs)(\(|:)"; then
            echo "needed=false" >> "$GITHUB_OUTPUT"
            echo "reason=PR title indicates an internal change (${PR_TITLE%%:*})"
            exit 0
          fi

          # Check for skip-changelog label
          if echo "$PR_LABELS" | grep -qi "skip-changelog"; then
            echo "needed=false" >> "$GITHUB_OUTPUT"
            echo "reason=skip-changelog label present"
            exit 0
          fi

          # Conservative: require changelog for unknown types
          echo "needed=true" >> "$GITHUB_OUTPUT"
          echo "reason=unknown PR type, changelog required by default"

      - name: Verify CHANGELOG.md was modified
        if: steps.check.outputs.needed == 'true'
        run: |
          git fetch origin "${{ github.base_ref }}" --depth=1
          if git diff --name-only "origin/${{ github.base_ref }}...HEAD" | grep -q "^CHANGELOG.md$"; then
            echo "✓ CHANGELOG.md updated"
            exit 0
          fi

          echo ""
          echo "  ERROR: CHANGELOG.md must be updated for this change."
          echo "  Reason: ${{ steps.check.outputs.reason }}"
          echo ""
          echo "  If this change does not need a changelog entry:"
          echo "    1. Add the 'skip-changelog' label to this PR, or"
          echo "    2. Change the PR title to use chore/ci/style/refactor/test/docs"
          echo ""
          exit 1

      - name: Changelog not required (info)
        if: steps.check.outputs.needed == 'false'
        run: |
          echo "✓ Changelog update not required: ${{ steps.check.outputs.reason }}"