cleanup-lint-branches.yml

name: "🧹 Cleanup Lint Branches"

# This workflow automatically cleans up lint/* branches that have been merged or closed.
# It helps maintain a clean repository by removing branches created by the linter workflow
# after their associated pull requests are no longer active.

on:
  # Run daily at 00:00 UTC
  schedule:
    - cron: '0 0 * * *'

  # Allow manual triggering with optional dry-run mode
  workflow_dispatch:
    inputs:
      dry_run:
        description: 'Dry run mode (preview deletions without actually deleting)'
        required: false
        type: boolean
        default: true

permissions:
  contents: write
  pull-requests: read

jobs:
  cleanup:
    name: Clean up merged/closed lint branches
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v4
        with:
          fetch-depth: 0  # Fetch all branches and history
          token: ${{ secrets.GITHUB_TOKEN }}

      - name: Setup GitHub CLI
        run: |
          # Verify gh CLI is available (pre-installed on ubuntu-latest)
          gh --version
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}

      - name: Cleanup lint branches
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          # Default to true (dry-run mode) unless explicitly set to false
          # This ensures safe operation for both scheduled and manual triggers
          DRY_RUN: ${{ github.event.inputs.dry_run == 'false' && 'false' || 'true' }}
          BRANCH_AGE_DAYS: 7
        run: |
          set -e
          set -o pipefail

          echo "🧹 Starting lint branch cleanup..."
          echo "Dry run mode: $DRY_RUN"
          echo "Branch age threshold for orphaned branches: $BRANCH_AGE_DAYS days"
          echo ""

          # Get current date in seconds since epoch
          current_date=$(date +%s)
          age_threshold_seconds=$((BRANCH_AGE_DAYS * 86400))

          # Track statistics
          total_branches=0
          deleted_branches=0
          skipped_branches=0
          error_branches=0

          # Get all remote branches matching the pattern lint/style-fixes-*
          echo "📋 Fetching lint branches..."
          lint_branches=$(git for-each-ref --format='%(refname:short)' 'refs/remotes/origin/lint/style-fixes-*' | sed 's|^origin/||' || echo "")

          if [ -z "$lint_branches" ]; then
            echo "✅ No lint branches found matching 'lint/style-fixes-*'"
            exit 0
          fi

          echo "Found $(echo "$lint_branches" | wc -l) lint branches"
          echo ""

          # Process each branch (using while read to handle special characters safely)
          while IFS= read -r branch; do
            [ -z "$branch" ] && continue
            total_branches=$((total_branches + 1))
            echo "🔍 Processing: $branch"

            # Validate branch name matches expected pattern
            if [[ ! "$branch" =~ ^lint/style-fixes-[0-9]+$ ]]; then
              echo "  ⚠️  Warning: Branch name doesn't match expected pattern, skipping"
              skipped_branches=$((skipped_branches + 1))
              echo ""
              continue
            fi

            # Check if there's a PR for this branch
            pr_number=$(gh pr list --state all --head "$branch" --json number --jq '.[0].number // empty' 2>/dev/null || echo "")

            should_delete=false
            delete_reason=""

            if [ -n "$pr_number" ]; then
              # PR exists, check its state
              echo "  Found PR #$pr_number"

              pr_state=$(gh pr view "$pr_number" --json state --jq '.state' 2>/dev/null || echo "")
              pr_merged=$(gh pr view "$pr_number" --json merged --jq '.merged' 2>/dev/null || echo "false")

              if [ "$pr_merged" = "true" ]; then
                should_delete=true
                delete_reason="PR #$pr_number was merged"
              elif [ "$pr_state" = "CLOSED" ]; then
                should_delete=true
                delete_reason="PR #$pr_number was closed"
              else
                echo "  ⏭️  Skipping: PR #$pr_number is still open"
                skipped_branches=$((skipped_branches + 1))
              fi
            else
              # No PR found - check if branch is old enough to delete
              echo "  No associated PR found (orphaned branch)"

              # Get the last commit date on this branch
              last_commit_date=$(git log -1 --format=%ct "origin/$branch" 2>/dev/null || echo "0")

              if [ "$last_commit_date" != "0" ]; then
                branch_age_seconds=$((current_date - last_commit_date))
                branch_age_days=$((branch_age_seconds / 86400))

                echo "  Branch age: $branch_age_days days"

                if [ $branch_age_seconds -gt $age_threshold_seconds ]; then
                  should_delete=true
                  delete_reason="Orphaned branch older than $BRANCH_AGE_DAYS days (age: $branch_age_days days)"
                else
                  echo "  ⏭️  Skipping: Orphaned branch is only $branch_age_days days old (threshold: $BRANCH_AGE_DAYS days)"
                  skipped_branches=$((skipped_branches + 1))
                fi
              else
                echo "  ⚠️  Warning: Could not determine branch age"
                skipped_branches=$((skipped_branches + 1))
              fi
            fi

            # Delete the branch if appropriate
            if [ "$should_delete" = "true" ]; then
              if [ "$DRY_RUN" = "true" ]; then
                echo "  🔍 [DRY RUN] Would delete: $delete_reason"
                deleted_branches=$((deleted_branches + 1))
              else
                echo "  🗑️  Deleting: $delete_reason"
                # Use git push for safer deletion with validated branch name
                delete_error=$(git push origin --delete "$branch" 2>&1)
                exit_code=$?
                if [ $exit_code -eq 0 ]; then
                  echo "  ✅ Successfully deleted"
                  deleted_branches=$((deleted_branches + 1))
                else
                  echo "  ❌ Failed to delete branch: $delete_error"
                  error_branches=$((error_branches + 1))
                fi
              fi
            fi

            echo ""
          done <<< "$lint_branches"

          # Print summary
          echo "📊 Cleanup Summary"
          echo "=================="
          echo "Total lint branches processed: $total_branches"
          if [ "$DRY_RUN" = "true" ]; then
            echo "Branches that would be deleted: $deleted_branches"
          else
            echo "Branches deleted: $deleted_branches"
          fi
          echo "Branches skipped: $skipped_branches"
          if [ $error_branches -gt 0 ]; then
            echo "Branches with errors: $error_branches"
          fi
          echo ""

          if [ "$DRY_RUN" = "true" ]; then
            echo "✅ Dry run completed - no branches were actually deleted"
          else
            echo "✅ Cleanup completed"
          fi