name: Changelog

on:
  pull_request:

jobs:
  check-changelog:
    name: Check for changelog entry
    runs-on: ubuntu-latest
    # dependabot PRs are automerged if CI passes; we shouldn't block these
    if: github.actor != 'dependabot[bot]'
    env:
      PR_SUBMITTER: ${{ github.actor }}
      PR_NUMBER: ${{ github.event.number }}
      PR_BASE: ${{ github.base_ref }}
    steps:
      - uses: actions/checkout@v4
      - name: Fetch PR base
        run: git fetch --no-tags --prune --depth=1 origin
      - name: Search for added line in changelog
        run: |
          ADDED=$(git diff -U0 "origin/${PR_BASE}" HEAD -- CHANGELOG.md | grep -P '^\+[^\+].+$')
          echo "Added lines in CHANGELOG.md:"
          echo "$ADDED"
          echo "Grepping for PR info:"
          grep "#${PR_NUMBER}\\b.*@${PR_SUBMITTER}\\b" <<< "$ADDED"