release-draft.yml

name: Generate Release Notes Draft

on:
  pull_request:
    types: [labeled, opened, synchronize]
  workflow_dispatch:
    inputs:
      pr_number:
        description: 'PR number to post the comment on'
        required: true
        type: string
      tag_name:
        description: 'Target tag name (e.g. v1.1.0)'
        required: false
        type: string
      previous_tag:
        description: 'Previous tag name'
        required: false
        type: string

permissions:
  contents: read
  pull-requests: write

jobs:
  draft-notes:
    name: Generate and Post Draft Notes
    runs-on: ubuntu-latest
    if: |
      github.event_name == 'workflow_dispatch' ||
      contains(github.event.pull_request.labels.*.name, 'release')
    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0

      - name: Determine PR and Tag Info
        id: info
        run: |
          if [ "${{ github.event_name }}" = "workflow_dispatch" ]; then
            echo "pr_number=${{ github.event.inputs.pr_number }}" >> $GITHUB_OUTPUT
            echo "tag_name=${{ github.event.inputs.tag_name || 'vNext' }}" >> $GITHUB_OUTPUT
            echo "previous_tag=${{ github.event.inputs.previous_tag }}" >> $GITHUB_OUTPUT
          else
            echo "pr_number=${{ github.event.pull_request.number }}" >> $GITHUB_OUTPUT
            echo "tag_name=vNext" >> $GITHUB_OUTPUT
            echo "previous_tag=" >> $GITHUB_OUTPUT
          fi

      - name: Fetch Latest Tag (fallback)
        id: tags
        run: |
          latest_tag=$(git describe --tags --abbrev=0 2>/dev/null || echo "")
          echo "latest_tag=$latest_tag" >> $GITHUB_OUTPUT

      - name: Generate Release Notes
        id: gen
        run: |
          PR_NUM="${{ steps.info.outputs.pr_number }}"
          TAG_NAME="${{ steps.info.outputs.tag_name }}"
          PREV_TAG="${{ steps.info.outputs.previous_tag || steps.tags.outputs.latest_tag }}"
          
          echo "Generating notes since tag: $PREV_TAG"
          
          # Request release notes generation from GitHub API
          if [ -n "$PREV_TAG" ]; then
            NOTES=$(gh api \
              -X POST \
              /repos/{owner}/{repo}/releases/generate-notes \
              -f tag_name="$TAG_NAME" \
              -f previous_tag_name="$PREV_TAG" \
              --jq '.body')
          else
            NOTES=$(gh api \
              -X POST \
              /repos/{owner}/{repo}/releases/generate-notes \
              -f tag_name="$TAG_NAME" \
              --jq '.body')
          fi
          
          # Write notes to a temp file to avoid multi-line bash env variable issues
          echo "$NOTES" > release_notes.md
          
          # Prepare comment header
          echo -e "## 📝 Draft Release Notes\n\nGenerated automatically from merged PRs since \`$PREV_TAG\`:\n\n$NOTES" > comment.md
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Post comment to Release PR
        run: |
          PR_NUM="${{ steps.info.outputs.pr_number }}"
          gh pr comment "$PR_NUM" --body-file comment.md
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}