release-changelog-guard.yml

name: Changelog Guard
on:
  pull_request:

concurrency:
  group: "${{ github.ref_name }}-${{ github.head_ref }}-changelog-guard"
  cancel-in-progress: true

permissions:
  contents: read

jobs:
  check_changelog:
    name: Check CHANGELOG.md modifications
    runs-on: ubuntu-latest
    steps:
    - name: Checkout code
      uses: actions/checkout@8e8c483db84b4bee98b60c0593521ed34d9990e8 # v6.0.1
      with:
        persist-credentials: false
        fetch-depth: 0

    - name: Check if CHANGELOG.md was modified 🚫
      env:
        PR_AUTHOR: ${{ github.actor }}
        BASE_SHA: ${{ github.event.pull_request.base.sha }}
        HEAD_SHA: ${{ github.event.pull_request.head.sha }}
      run: |
        # Allow release-please PRs created by grafana-alloybot[bot] to modify the changelog
        if [ "$PR_AUTHOR" = "grafana-alloybot[bot]" ]; then
          echo "✅ grafana-alloybot PR detected. CHANGELOG.md modifications are allowed."
          exit 0
        fi

        if git diff --name-only "$BASE_SHA"..."$HEAD_SHA" | grep -q "^CHANGELOG.md$"; then
          echo "❌ ERROR: CHANGELOG.md has been modified in this PR."
          echo ""
          echo "The CHANGELOG.md file should not be manually edited. It is automatically generated "
          echo "from Pull Request titles using Conventional Commits and release-please."
          echo ""
          echo "To ensure your PR appears correctly in the changelog:"
          echo "  1. Format your PR title following Conventional Commits (e.g., 'feat: add new feature')"
          echo "  2. See docs/developer/contributing.md for detailed guidelines"
          echo ""
          exit 1
        else
          echo "✅ CHANGELOG.md has not been modified. All good!"
        fi