changelog.yml

name: Update Changelog on Merge

on:
  pull_request:
    types: [closed]
    branches:
      - main

jobs:
  update-changelog:
    if: github.event.pull_request.merged == true
    runs-on: ubuntu-latest
    
    steps:
      - name: Checkout code
        uses: actions/checkout@v4
        with:
          fetch-depth: 0
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Get latest merge commit
        id: merge-info
        run: |
          # Get the latest merge commit message
          MERGE_MSG=$(git log --merges -1 --pretty=format:'%s')
          MERGE_HASH=$(git log --merges -1 --pretty=format:'%h')
          MERGE_DATE=$(git log --merges -1 --pretty=format:'%ad' --date=short)
          
          echo "merge_msg=$MERGE_MSG" >> $GITHUB_OUTPUT
          echo "merge_hash=$MERGE_HASH" >> $GITHUB_OUTPUT
          echo "merge_date=$MERGE_DATE" >> $GITHUB_OUTPUT

      - name: Extract PR number and details
        id: pr-info
        run: |
          # Check if GitHub CLI is installed
          if ! command -v gh &> /dev/null; then
            echo "ERROR: GitHub CLI (gh) is not installed or not available in PATH"
            echo "Please ensure GitHub CLI is installed in the runner environment"
            exit 1
          fi
          
          # Extract PR number from merge commit message
          PR_NUM=$(echo "${{ steps.merge-info.outputs.merge_msg }}" | grep -oP '#\K\d+' || echo "")
          
          if [ ! -z "$PR_NUM" ]; then
            # Get PR details using GitHub CLI
            PR_TITLE=$(gh pr view $PR_NUM --json title --jq .title || echo "")
            PR_BODY=$(gh pr view $PR_NUM --json body --jq .body || echo "")
            
            echo "pr_number=$PR_NUM" >> $GITHUB_OUTPUT
            echo "pr_title=$PR_TITLE" >> $GITHUB_OUTPUT
            echo "pr_body<<EOF" >> $GITHUB_OUTPUT
            echo "$PR_BODY" >> $GITHUB_OUTPUT
            echo "EOF" >> $GITHUB_OUTPUT
          fi
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Update changelog
        run: |
          # Check if CHANGELOG.md exists
          if [ ! -f "CHANGELOG.md" ]; then
            echo "ERROR: CHANGELOG.md file not found"
            echo "Please ensure CHANGELOG.md exists in the repository root"
            exit 1
          fi
          
          # Create backup of current changelog
          cp CHANGELOG.md CHANGELOG.md.bak
          
          # Extract changelog sections
          UNRELEASED_START=$(grep -n "## \[Unreleased\]" CHANGELOG.md | cut -d: -f1)
          
          # Check if Unreleased section exists
          if [ -z "$UNRELEASED_START" ]; then
            echo "ERROR: '## [Unreleased]' section not found in CHANGELOG.md"
            echo "Please ensure CHANGELOG.md follows the Keep a Changelog format with an Unreleased section"
            exit 1
          fi
          NEXT_VERSION_START=$(tail -n +$((UNRELEASED_START + 1)) CHANGELOG.md | grep -n "## \[" | head -1 | cut -d: -f1)
          
          if [ ! -z "$NEXT_VERSION_START" ]; then
            NEXT_VERSION_LINE=$((UNRELEASED_START + NEXT_VERSION_START))
          else
            NEXT_VERSION_LINE=$(wc -l < CHANGELOG.md)
            NEXT_VERSION_LINE=$((NEXT_VERSION_LINE + 1))
          fi
          
          # Generate changelog entry based on commit messages
          TEMP_FILE=$(mktemp)
          
          # Get commits from the merge
          COMMITS=$(git log --oneline ${{ steps.merge-info.outputs.merge_hash }}^..${{ steps.merge-info.outputs.merge_hash }} --no-merges)
          
          # Categorize changes
          ADDED=""
          CHANGED=""
          FIXED=""
          
          while IFS= read -r commit; do
            if [[ $commit == *"feat:"* ]] || [[ $commit == *"add:"* ]]; then
              CHANGE=$(echo "$commit" | sed 's/^[a-f0-9]* //' | sed 's/^feat: //' | sed 's/^add: //')
              ADDED="$ADDED\n- $CHANGE"
            elif [[ $commit == *"fix:"* ]]; then
              CHANGE=$(echo "$commit" | sed 's/^[a-f0-9]* //' | sed 's/^fix: //')
              FIXED="$FIXED\n- $CHANGE"
            elif [[ $commit == *"refactor:"* ]] || [[ $commit == *"update:"* ]]; then
              CHANGE=$(echo "$commit" | sed 's/^[a-f0-9]* //' | sed 's/^refactor: //' | sed 's/^update: //')
              CHANGED="$CHANGED\n- $CHANGE"
            else
              # Default to changed for other commits
              CHANGE=$(echo "$commit" | sed 's/^[a-f0-9]* //')
              CHANGED="$CHANGED\n- $CHANGE"
            fi
          done <<< "$COMMITS"
          
          # Build the new unreleased section
          {
            head -n $UNRELEASED_START CHANGELOG.md
            echo ""
            if [ ! -z "$ADDED" ]; then
              echo "### Added"
              echo -e "$ADDED"
              echo ""
            fi
            if [ ! -z "$CHANGED" ]; then
              echo "### Changed"
              echo -e "$CHANGED"
              echo ""
            fi
            if [ ! -z "$FIXED" ]; then
              echo "### Fixed"
              echo -e "$FIXED"
              echo ""
            fi
            echo "### Deprecated"
            echo ""
            echo "### Removed"
            echo ""
            echo "### Security"
            echo ""
            tail -n +$NEXT_VERSION_LINE CHANGELOG.md
          } > $TEMP_FILE
          
          mv $TEMP_FILE CHANGELOG.md

      - name: Commit changelog updates
        run: |
          git config --local user.email "action@github.com"
          git config --local user.name "GitHub Action"
          
          if git diff --quiet CHANGELOG.md; then
            echo "No changes to commit"
          else
            git add CHANGELOG.md
            git commit -m "chore: update changelog for merge ${{ steps.merge-info.outputs.merge_hash }}"
            git push
          fi