name: Changelog entry

on:
  pull_request:
    # `edited` and the label events: a retitled or relabelled pull request is checked again.
    types: [opened, reopened, synchronize, edited, labeled, unlabeled]
  # The merge queue reruns required checks. The entry was already checked on the pull request.
  merge_group:
    types: [checks_requested]

permissions:
  contents: read

jobs:
  changelog-entry:
    name: Changelog entry
    # A skipped job counts as a passed required check.
    if: github.event_name == 'merge_group' || !contains(github.event.pull_request.labels.*.name, 'no-changelog')
    runs-on: ubuntu-latest
    timeout-minutes: 5
    steps:
      - name: Already required on the pull request
        if: github.event_name == 'merge_group'
        run: echo "The pull request already had to pass this check before it entered the merge queue."

      - name: Checkout
        if: github.event_name != 'merge_group'
        uses: actions/checkout@v4
        with:
          fetch-depth: 2

      # pull_request.base.sha goes stale when main moves; HEAD^1 is the main this merge checkout was built on.
      - name: Check that a feat, fix or breaking pull request adds a changelog entry
        if: github.event_name != 'merge_group'
        env:
          PR_TITLE: ${{ github.event.pull_request.title }}
        run: |
          git show "HEAD^1:CHANGELOG.md" > "$RUNNER_TEMP/base-CHANGELOG.md"
          node scripts/changelog/check-entry.mjs "$PR_TITLE" "$RUNNER_TEMP/base-CHANGELOG.md" CHANGELOG.md