name: Release Notes

on:
  pull_request:
    branches:
      - "*"
    types:
      - opened
      - reopened
      - synchronize
      - labeled
      - unlabeled

permissions:
  contents: read

defaults:
  run:
    shell: bash

jobs:
  release-notes:
    name: Release Notes
    runs-on: ubuntu-latest
    steps:
      - name: Skip release notes check
        if: contains(github.event.pull_request.labels.*.name, 'no-changelog')
        run: echo "Release notes check skipped by the no-changelog label."

      - name: git checkout
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-changelog') }}
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Check for a release note
        if: ${{ !contains(github.event.pull_request.labels.*.name, 'no-changelog') }}
        env:
          BASE_SHA: ${{ github.event.pull_request.base.sha }}
          HEAD_SHA: ${{ github.event.pull_request.head.sha }}
          RELEASE_NOTES_FILE: docs/release-notes/release-notes-next.md
        run: |
          if git diff --unified=0 "$BASE_SHA...$HEAD_SHA" -- \
              "$RELEASE_NOTES_FILE" |
              awk '
                /^@@/ { in_hunk = 1; next }
                in_hunk && /^\+/ {
                  line = substr($0, 2)
                  if (line ~ /[^[:space:]]/) found = 1
                }
                END { exit found ? 0 : 1 }
              '
          then
            exit 0
          fi

          echo "::error file=$RELEASE_NOTES_FILE::Add a release note or apply the no-changelog label."
          exit 1