check_pr_dependency.yml

name: Check for Dependencies in PR

on:
  pull_request:
    types: [opened, reopened, edited, labeled, unlabeled, synchronize]

jobs:
  check-dependency:
    runs-on: ubuntu-latest
    steps:
      - name: Check PR dependencies and merge status
        # Check if dependent PRs are merged before allowing this PR to merge
        run: |
          set -e

          # Function to check if a PR is merged
          check_pr_merged() {
            local pr_ref=$1
            local repo=""
            local pr_number=""

            # Parse PR reference - supports multiple formats:
            # 1. #123 (same repo)
            # 2. owner/repo#123 (different repo)
            # 3. https://github.com/owner/repo/pull/123 (GitHub URL)
            if [[ "$pr_ref" =~ ^https://github\.com/([^/]+/[^/]+)/pull/([0-9]+)$ ]]; then
              # GitHub URL format: https://github.com/owner/repo/pull/123
              repo="${BASH_REMATCH[1]}"
              pr_number="${BASH_REMATCH[2]}"
            elif [[ "$pr_ref" =~ ^([^#]+)#([0-9]+)$ ]]; then
              # Cross-repository reference: owner/repo#123
              repo="${BASH_REMATCH[1]}"
              pr_number="${BASH_REMATCH[2]}"
            elif [[ "$pr_ref" =~ ^#([0-9]+)$ ]]; then
              # Same repository reference: #123
              repo="$GITHUB_REPOSITORY"
              pr_number="${BASH_REMATCH[1]}"
            else
              echo "::error::Invalid PR reference format: $pr_ref"
              return 1
            fi

            echo "Checking PR #$pr_number in repository $repo..."

            local api_response=$(curl -s -H "Authorization: token $GITHUB_TOKEN" \
              "https://api.github.com/repos/$repo/pulls/$pr_number")

            if echo "$api_response" | jq -e '.message == "Not Found"' >/dev/null 2>&1; then
              echo "::error::Referenced PR $repo#$pr_number does not exist or is not accessible"
              return 1
            fi

            local merged=$(echo "$api_response" | jq -r '.merged')
            local state=$(echo "$api_response" | jq -r '.state')

            if [ "$merged" = "true" ]; then
              echo "✓ PR $repo#$pr_number is merged"
              return 0
            elif [ "$state" = "open" ]; then
              echo "::error::PR $repo#$pr_number is still open and not merged"
              return 1
            elif [ "$state" = "closed" ]; then
              echo "::error::PR $repo#$pr_number is closed but not merged"
              return 1
            else
              echo "::error::PR $repo#$pr_number has unknown state: $state"
              return 1
            fi
          }

          # Function to extract PR dependencies from text
          extract_dependencies() {
            local text=$1
            # Match patterns like:
            # - "depends on #123"
            # - "depends on owner/repo#123"
            # - "depends on https://github.com/owner/repo/pull/123"
            # - "requires #456"
            # - "requires owner/repo#456"
            # - "requires https://github.com/owner/repo/pull/456"
            echo "$text" | grep -iEo "(depends on|requires):?\s+(https://github\.com/[a-zA-Z0-9._-]+/[a-zA-Z0-9._-]+/pull/[0-9]+|[a-zA-Z0-9._-]+/[a-zA-Z0-9._-]+#[0-9]+|#[0-9]+)" | \
              sed -E 's/(depends on|requires):?\s+//i' | sort -u
          }

          # Extract PR body and check for dependencies
          PR_BODY=$(cat $GITHUB_EVENT_PATH | jq -r '.pull_request.body // ""')

          echo "Checking PR description for dependencies..."
          DEPENDENCIES=$(extract_dependencies "$PR_BODY")

          TOTAL_FAILED_CHECKS=0

          if [ -n "$DEPENDENCIES" ]; then
            echo "Found PR dependencies in description:"
            echo "$DEPENDENCIES"

            while IFS= read -r dependency; do
              if [ -n "$dependency" ]; then
                if ! check_pr_merged "$dependency"; then
                  TOTAL_FAILED_CHECKS=$((TOTAL_FAILED_CHECKS + 1))
                fi
              fi
            done <<< "$DEPENDENCIES"
          else
            echo "No PR dependencies found in description."
          fi

          # Also check commit messages for dependencies
          echo "Checking commit messages for dependencies..."
          COMMITS_URL=$(cat $GITHUB_EVENT_PATH | jq -r '.pull_request.commits_url')
          COMMIT_MESSAGES=$(curl -s -H "Authorization: token $GITHUB_TOKEN" "$COMMITS_URL" | jq -r '.[].commit.message' | tr '\n' ' ')

          COMMIT_DEPENDENCIES=$(extract_dependencies "$COMMIT_MESSAGES")

          if [ -n "$COMMIT_DEPENDENCIES" ]; then
            echo "Found PR dependencies in commit messages:"
            echo "$COMMIT_DEPENDENCIES"

            while IFS= read -r dependency; do
              if [ -n "$dependency" ]; then
                if ! check_pr_merged "$dependency"; then
                  TOTAL_FAILED_CHECKS=$((TOTAL_FAILED_CHECKS + 1))
                fi
              fi
            done <<< "$COMMIT_DEPENDENCIES"
          else
            echo "No PR dependencies found in commit messages."
          fi

          # Final check - block if any dependencies are unmerged
          if [ $TOTAL_FAILED_CHECKS -gt 0 ]; then
            echo "::error::This PR has $TOTAL_FAILED_CHECKS unmerged dependencies. Please wait for dependent PRs to be merged before merging this PR."
            exit 1
          else
            echo "✅ All PR dependencies are satisfied. This PR can proceed to merge."
          fi

        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}