release-branch-checks.yml

name: Release branch checks

on:
  pull_request:
    branches: [ "customdc_stable" ]
  # Required for merge queue to work: https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/configuring-pull-request-merges/managing-a-merge-queue#triggering-merge-group-checks-with-github-actions
  merge_group:
    branches: [ "customdc_stable" ]

jobs:
  verify_all_commits_are_already_in_master:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
        with:
          # Fetch all history for accurate comparison
          fetch-depth: 0
          # Check out the PR branch
          ref: ${{ github.event.pull_request.head.ref }}
          repository: ${{ github.event.pull_request.head.repo.full_name }}

      - name: Verify that all commits are already in the master branch
        run: |
          git remote add dc https://github.com/datacommonsorg/website.git
          git fetch dc
          MASTER_BRANCH="dc/master"

          # Get the list of commits in the source branch that are not in the master branch.
          # Exclude merge commits only if this is the final run in the merge queue.
          # This way the only merge commits that end up in the final commit history
          # are the ones added by GitHub when merging PRs.
          if [[ ${{ github.event_name }}  == 'merge_group' ]]; then
            MISSING_COMMITS=$(git log --pretty="%H - %s" --no-merges $MASTER_BRANCH..HEAD --)
          else
            MISSING_COMMITS=$(git log --pretty="%H - %s" $MASTER_BRANCH..HEAD --)
          fi

          if [[ -n "$MISSING_COMMITS" ]]; then
            echo ""
            echo "ERROR: The following commits are not present in $MASTER_BRANCH:"
            echo ""
            echo "$MISSING_COMMITS"
            echo ""
            echo "PRs to release branches should only contain commits that are already in master."
            echo "To fix this PR, reset its branch locally to a commit at or behind https://github.com/datacommonsorg/website/commits/master/ and then force-push it."
            echo "Note that a release branch PR should be based on master and not the previous version of the release branch, which contains merge commits."
            exit 1
          fi

          echo "All commits are present in $MASTER_BRANCH"