purge-pr-cache.yaml

name: Purge closed PR cache
on:
  pull_request:
    types:
      - closed

jobs:
  cleanup:
    runs-on: ubuntu-latest
    permissions:
      actions: write
    steps:
      - name: Cleanup
        env:
          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
          REPO: ${{ github.repository }}
          BRANCH: refs/pull/${{ github.event.pull_request.number }}/merge
        run: |
          set -euo pipefail

          echo "Installing GitHub CLI extension..."
          gh extension install actions/gh-actions-cache

          echo "Fetching list of cache keys..."
          cacheKeysForPR=$(gh actions-cache list -R "$REPO" -B "$BRANCH" -L 100 | cut -f 1)

          if [ -z "$cacheKeysForPR" ]; then
            echo "No caches found to purge."
            exit 0
          fi

          echo "Deleting caches..."
          echo "$cacheKeysForPR" | while read -r cacheKey; do
            if [ -n "$cacheKey" ]; then
              echo "Deleting cache key: $cacheKey"
              gh actions-cache delete "$cacheKey" -R "$REPO" -B "$BRANCH" --confirm || echo "Failed to delete cache key: $cacheKey"
            fi
          done

          echo "Cache purge complete."