auto-merge-on-approval.yml

# ------------------------------------------------------------------------------------
#  Auto-merge on Approval Workflow
#
#  Purpose: Automatically enable auto-merge for PRs when configurable approval
#           and readiness conditions are met. GitHub handles the actual merge
#           when all status checks pass.
#
#  Configuration: All settings are loaded from .github/.env.shared for centralized
#  management across all workflows.
#
#  Triggers:
#  - Pull request reviews (submitted)
#  - Pull request state changes (ready_for_review, review_request_removed)
#
#  Auto-merge Rules (configurable via .env.shared):
#  - Minimum number of approvals
#  - No requested reviewers remaining (if configured)
#  - No "Changes Requested" reviews
#  - PR ready for review (not draft, no WIP indicators)
#  - Bot PRs handled separately (if configured)
#
#  Maintainer: @mrz1836
#
# ------------------------------------------------------------------------------------

name: Auto-merge on Approval

# ————————————————————————————————————————————————————————————————
# Trigger Configuration
# ————————————————————————————————————————————————————————————————
on:
  pull_request_review:
    types: [submitted]
  pull_request:
    types: [ready_for_review, review_request_removed]

# ————————————————————————————————————————————————————————————————
# Permissions
# ————————————————————————————————————————————————————————————————
permissions:
  contents: read
  pull-requests: read

# ————————————————————————————————————————————————————————————————
# Concurrency Control
# ————————————————————————————————————————————————————————————————
concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true

# ————————————————————————————————————————————————————————————————
# Environment Variables
# ————————————————————————————————————————————————————————————————
# Note: Configuration variables are loaded from .github/.env.shared

jobs:
  # ----------------------------------------------------------------------------------
  # Load Environment Variables from .env.shared
  # ----------------------------------------------------------------------------------
  load-env:
    name: 🌍 Load Environment Variables
    runs-on: ubuntu-latest
    outputs:
      env-json: ${{ steps.load-env.outputs.env-json }}
    steps:
      # ————————————————————————————————————————————————————————————————
      # Check out code to access env file
      # ————————————————————————————————————————————————————————————————
      - name: 📥 Checkout code (sparse)
        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
        with:
          sparse-checkout: |
            .github/.env.shared
            .github/actions/load-env

      # ————————————————————————————————————————————————————————————————
      # Load and parse environment file
      # ————————————————————————————————————————————————————————————————
      - name: 🌍 Load environment variables
        uses: ./.github/actions/load-env
        id: load-env

  # ----------------------------------------------------------------------------------
  # Process Auto-merge
  # ----------------------------------------------------------------------------------
  process-auto-merge:
    name: 🤖 Process Auto-merge
    needs: [load-env]
    runs-on: ubuntu-latest
    permissions:
      contents: write
      pull-requests: write
    outputs:
      action-taken: ${{ steps.process.outputs.action }}
      pr-number: ${{ github.event.pull_request.number }}

    steps:
      # ————————————————————————————————————————————————————————————————
      # Extract configuration from env-json
      # ————————————————————————————————————————————————————————————————
      - name: 🔧 Extract configuration
        id: config
        env:
          ENV_JSON: ${{ needs.load-env.outputs.env-json }}
        run: |
          echo "📋 Extracting auto-merge configuration from environment..."

          # Extract all needed variables
          MIN_APPROVALS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_MIN_APPROVALS')
          REQUIRE_ALL_REVIEWS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_REQUIRE_ALL_REQUESTED_REVIEWS')
          MERGE_TYPES=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_ALLOWED_MERGE_TYPES')
          DELETE_BRANCH=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_DELETE_BRANCH')
          SKIP_DRAFT=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_SKIP_DRAFT')
          SKIP_WIP=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_SKIP_WIP')
          WIP_LABELS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_WIP_LABELS')
          COMMENT_ON_ENABLE=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_COMMENT_ON_ENABLE')
          COMMENT_ON_DISABLE=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_COMMENT_ON_DISABLE')
          LABELS_TO_ADD=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_LABELS_TO_ADD')
          SKIP_BOT_PRS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_SKIP_BOT_PRS')
          PREFERRED_TOKEN=$(echo "$ENV_JSON" | jq -r '.PREFERRED_GITHUB_TOKEN')

          # Validate required configuration
          if [[ -z "$MIN_APPROVALS" ]] || [[ "$MIN_APPROVALS" == "null" ]]; then
            MIN_APPROVALS="1"  # Default to 1 approval
          fi

          # Set as environment variables for all subsequent steps
          echo "MIN_APPROVALS=$MIN_APPROVALS" >> $GITHUB_ENV
          echo "REQUIRE_ALL_REVIEWS=$REQUIRE_ALL_REVIEWS" >> $GITHUB_ENV
          echo "MERGE_TYPES=$MERGE_TYPES" >> $GITHUB_ENV
          echo "DELETE_BRANCH=$DELETE_BRANCH" >> $GITHUB_ENV
          echo "SKIP_DRAFT=$SKIP_DRAFT" >> $GITHUB_ENV
          echo "SKIP_WIP=$SKIP_WIP" >> $GITHUB_ENV
          echo "WIP_LABELS=$WIP_LABELS" >> $GITHUB_ENV
          echo "COMMENT_ON_ENABLE=$COMMENT_ON_ENABLE" >> $GITHUB_ENV
          echo "COMMENT_ON_DISABLE=$COMMENT_ON_DISABLE" >> $GITHUB_ENV
          echo "LABELS_TO_ADD=$LABELS_TO_ADD" >> $GITHUB_ENV
          echo "SKIP_BOT_PRS=$SKIP_BOT_PRS" >> $GITHUB_ENV

          # Determine default merge type
          DEFAULT_MERGE_TYPE=$(echo "$MERGE_TYPES" | cut -d',' -f1)
          if [[ -z "$DEFAULT_MERGE_TYPE" ]]; then
            DEFAULT_MERGE_TYPE="squash"
          fi
          echo "DEFAULT_MERGE_TYPE=$DEFAULT_MERGE_TYPE" >> $GITHUB_ENV

          # Log configuration
          echo "🔍 Configuration loaded:"
          echo "  ✅ Min approvals: $MIN_APPROVALS"
          echo "  👥 Require all reviews: $REQUIRE_ALL_REVIEWS"
          echo "  🔀 Merge types: $MERGE_TYPES (default: $DEFAULT_MERGE_TYPE)"
          echo "  🗑️ Delete branch: $DELETE_BRANCH"
          echo "  📝 Skip draft: $SKIP_DRAFT"
          echo "  🚧 Skip WIP: $SKIP_WIP"
          echo "  🏷️ WIP labels: $WIP_LABELS"
          echo "  💬 Comment on enable: $COMMENT_ON_ENABLE"
          echo "  💬 Comment on disable: $COMMENT_ON_DISABLE"
          echo "  🏷️ Labels to add: $LABELS_TO_ADD"
          echo "  🤖 Skip bot PRs: $SKIP_BOT_PRS"

          if [[ "$PREFERRED_TOKEN" == "GH_PAT_TOKEN" && -n "${{ secrets.GH_PAT_TOKEN }}" ]]; then
            echo "  🔑 Token: Personal Access Token (PAT)"
          else
            echo "  🔑 Token: Default GITHUB_TOKEN"
          fi

      # ————————————————————————————————————————————————————————————————
      # Process the PR for auto-merge
      # ————————————————————————————————————————————————————————————————
      - name: 🔍 Check conditions and enable auto-merge
        id: process
        uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7.0.1
        with:
          github-token: ${{ secrets.GH_PAT_TOKEN || secrets.GITHUB_TOKEN }}
          script: |
            const { owner, repo } = context.repo;
            const prNumber = context.payload.pull_request.number;

            console.log(`🔍 Checking auto-merge conditions for PR #${prNumber}`);
            console.log('════════════════════════════════════════════════════════════════');

            // Get fresh PR data
            const { data: pr } = await github.rest.pulls.get({
              owner,
              repo,
              pull_number: prNumber,
            });

            console.log(`📋 PR #${prNumber}: "${pr.title}"`);
            console.log(`👤 Author: ${pr.user.login} (${pr.user.type})`);

            // ————————————————————————————————————————————————————————————————
            // Check if we should skip bot PRs
            // ————————————————————————————————————————————————————————————————
            const isBot = pr.user.type === 'Bot' || pr.user.login.endsWith('[bot]');
            if (isBot && process.env.SKIP_BOT_PRS === 'true') {
              console.log('🤖 Skipping bot PR (handled by separate workflow)');
              core.setOutput('action', 'skip-bot');
              return;
            }

            // ————————————————————————————————————————————————————————————————
            // Check basic PR conditions
            // ————————————————————————————————————————————————————————————————
            const isDraft = pr.draft;
            const title = pr.title || '';
            const labels = pr.labels.map(l => l.name);

            if (isDraft && process.env.SKIP_DRAFT === 'true') {
              console.log('📝 PR is draft - skipping auto-merge');
              core.setOutput('action', 'skip-draft');
              return;
            }

            // Check for WIP indicators
            if (process.env.SKIP_WIP === 'true') {
              const titleHasWip = /\b(wip|work.in.progress)\b/i.test(title);
              const wipLabels = process.env.WIP_LABELS.split(',').map(l => l.trim());
              const hasWipLabel = labels.some(label => wipLabels.includes(label));

              if (titleHasWip || hasWipLabel) {
                console.log('🚧 PR has WIP indicators - skipping auto-merge');
                core.setOutput('action', 'skip-wip');
                return;
              }
            }

            // ————————————————————————————————————————————————————————————————
            // Check review conditions
            // ————————————————————————————————————————————————————————————————
            const { data: reviews } = await github.rest.pulls.listReviews({
              owner,
              repo,
              pull_number: prNumber,
            });

            // Get latest review per user
            const latestReviews = {};
            reviews.forEach(review => {
              const userId = review.user.id;
              if (!latestReviews[userId] || review.submitted_at > latestReviews[userId].submitted_at) {
                latestReviews[userId] = review;
              }
            });

            const currentReviews = Object.values(latestReviews);
            const approvals = currentReviews.filter(r => r.state === 'APPROVED').length;
            const changesRequested = currentReviews.filter(r => r.state === 'CHANGES_REQUESTED').length;
            const requestedReviewers = (pr.requested_reviewers || []).length;
            const minApprovals = parseInt(process.env.MIN_APPROVALS);

            console.log(`👥 Reviews: ${approvals} approvals, ${changesRequested} changes requested, ${requestedReviewers} pending`);
            console.log(`✅ Required approvals: ${minApprovals}`);

            // ————————————————————————————————————————————————————————————————
            // Determine if we should enable auto-merge
            // ————————————————————————————————————————————————————————————————
            let shouldEnableAutoMerge = approvals >= minApprovals && changesRequested === 0;

            if (process.env.REQUIRE_ALL_REVIEWS === 'true' && requestedReviewers > 0) {
              shouldEnableAutoMerge = false;
            }

            if (!shouldEnableAutoMerge) {
              if (approvals < minApprovals) {
                console.log(`⏳ Needs ${minApprovals - approvals} more approval(s)`);
              }
              if (changesRequested > 0) {
                console.log('🚫 Has "Changes Requested" reviews');
              }
              if (process.env.REQUIRE_ALL_REVIEWS === 'true' && requestedReviewers > 0) {
                console.log(`⏳ Has ${requestedReviewers} pending reviewer request(s)`);
              }
              core.setOutput('action', 'conditions-not-met');
              return;
            }

            // ————————————————————————————————————————————————————————————————
            // Check if this is a disable event
            // ————————————————————————————————————————————————————————————————
            if (context.eventName === 'pull_request_review' &&
                context.payload.review &&
                context.payload.review.state === 'CHANGES_REQUESTED') {

              // Try to disable auto-merge
              try {
                const { execSync } = require('child_process');
                execSync(`gh pr merge --disable-auto "${pr.html_url}"`, {
                  env: {
                    ...process.env,
                    GH_TOKEN: '${{ secrets.GH_PAT_TOKEN || secrets.GITHUB_TOKEN }}'
                  },
                  stdio: 'inherit'
                });

                console.log('🛑 Auto-merge disabled due to "Changes Requested" review');

                if (process.env.COMMENT_ON_DISABLE === 'true') {
                  await github.rest.issues.createComment({
                    owner,
                    repo,
                    issue_number: prNumber,
                    body: `🛑 **Auto-merge disabled**\n\nChanges were requested in a review. Auto-merge will be re-enabled when conditions are met again.`
                  });
                }

                core.setOutput('action', 'disabled-changes-requested');
              } catch (error) {
                console.log('ℹ️ Could not disable auto-merge (may not have been enabled)');
              }
              return;
            }

            // ————————————————————————————————————————————————————————————————
            // Enable auto-merge
            // ————————————————————————————————————————————————————————————————
            try {
              // Check if auto-merge is already enabled
              if (pr.auto_merge) {
                console.log('✅ Auto-merge already enabled');
                core.setOutput('action', 'already-enabled');
                return;
              }

              // Enable auto-merge with the configured merge type
              const { execSync } = require('child_process');
              const mergeType = process.env.DEFAULT_MERGE_TYPE;

              let mergeCommand = `gh pr merge --auto`;
              if (mergeType === 'squash') {
                mergeCommand += ' --squash';
              } else if (mergeType === 'merge') {
                mergeCommand += ' --merge';
              } else if (mergeType === 'rebase') {
                mergeCommand += ' --rebase';
              }

              if (process.env.DELETE_BRANCH === 'true') {
                mergeCommand += ' --delete-branch';
              }

              mergeCommand += ` "${pr.html_url}"`;

              console.log(`🚀 Enabling auto-merge with command: ${mergeCommand}`);

              execSync(mergeCommand, {
                env: {
                  ...process.env,
                  GH_TOKEN: '${{ secrets.GH_PAT_TOKEN || secrets.GITHUB_TOKEN }}'
                },
                stdio: 'inherit'
              });

              console.log('✅ Auto-merge enabled! PR will merge when all status checks pass.');

              // Add comment if configured
              if (process.env.COMMENT_ON_ENABLE === 'true') {
                const mergeTypeText = mergeType === 'squash' ? 'squash and merge' :
                                     mergeType === 'merge' ? 'create a merge commit' :
                                     'rebase and merge';

                await github.rest.issues.createComment({
                  owner,
                  repo,
                  issue_number: prNumber,
                  body: `🤖 **Auto-merge enabled**\n\nThis PR will automatically ${mergeTypeText} when all required status checks pass.\n\n` +
                        `✅ Approvals: ${approvals}/${minApprovals}\n` +
                        `🔍 Changes requested: ${changesRequested}\n` +
                        `⏳ Pending reviews: ${requestedReviewers}`
                });
              }

              // Add labels if configured
              if (process.env.LABELS_TO_ADD) {
                const labelsToAdd = process.env.LABELS_TO_ADD.split(',').map(l => l.trim()).filter(l => l);
                if (labelsToAdd.length > 0) {
                  await github.rest.issues.addLabels({
                    owner,
                    repo,
                    issue_number: prNumber,
                    labels: labelsToAdd
                  });
                  console.log(`🏷️ Added labels: ${labelsToAdd.join(', ')}`);
                }
              }

              core.setOutput('action', 'enabled');

            } catch (error) {
              console.error('❌ Failed to enable auto-merge:', error.message);

              // Comment on failure if configured
              if (process.env.COMMENT_ON_ENABLE === 'true') {
                await github.rest.issues.createComment({
                  owner,
                  repo,
                  issue_number: prNumber,
                  body: `⚠️ **Auto-merge failed**\n\nCould not enable auto-merge: ${error.message}\n\n` +
                        `This might be due to:\n` +
                        `- Branch protection rules\n` +
                        `- Missing permissions\n` +
                        `- Repository settings`
                });
              }

              core.setOutput('action', 'failed');
              throw error;
            }

  # ----------------------------------------------------------------------------------
  # Generate Workflow Summary Report
  # ----------------------------------------------------------------------------------
  summary:
    name: 📊 Generate Summary
    if: always()
    needs: [load-env, process-auto-merge]
    runs-on: ubuntu-latest
    steps:
      # ————————————————————————————————————————————————————————————————
      # Generate a workflow summary report
      # ————————————————————————————————————————————————————————————————
      - name: 📊 Generate workflow summary
        env:
          ENV_JSON: ${{ needs.load-env.outputs.env-json }}
        run: |
          echo "📊 Generating workflow summary..."

          echo "# 🤖 Auto-merge on Approval Summary" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "**⏰ Processed:** $(date -u '+%Y-%m-%d %H:%M:%S UTC')" >> $GITHUB_STEP_SUMMARY
          echo "**📋 PR:** #${{ needs.process-auto-merge.outputs.pr-number }}" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY

          # Determine action taken
          ACTION="${{ needs.process-auto-merge.outputs.action-taken }}"
          case "$ACTION" in
            "enabled")
              ACTION_DESC="✅ Auto-merge enabled"
              ;;
            "already-enabled")
              ACTION_DESC="✅ Auto-merge already enabled"
              ;;
            "disabled-changes-requested")
              ACTION_DESC="🛑 Auto-merge disabled (changes requested)"
              ;;
            "skip-bot")
              ACTION_DESC="🤖 Skipped (bot PR)"
              ;;
            "skip-draft")
              ACTION_DESC="📝 Skipped (draft PR)"
              ;;
            "skip-wip")
              ACTION_DESC="🚧 Skipped (work in progress)"
              ;;
            "conditions-not-met")
              ACTION_DESC="⏳ Conditions not met"
              ;;
            "failed")
              ACTION_DESC="❌ Failed to enable auto-merge"
              ;;
            *)
              ACTION_DESC="❓ Unknown action: $ACTION"
              ;;
          esac

          echo "## 🎯 Action Taken" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "$ACTION_DESC" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY

          echo "### 🔧 Current Configuration" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY

          # Extract configuration for display
          MIN_APPROVALS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_MIN_APPROVALS')
          REQUIRE_ALL_REVIEWS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_REQUIRE_ALL_REQUESTED_REVIEWS')
          MERGE_TYPES=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_ALLOWED_MERGE_TYPES')
          SKIP_DRAFT=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_SKIP_DRAFT')
          SKIP_WIP=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_SKIP_WIP')
          SKIP_BOT_PRS=$(echo "$ENV_JSON" | jq -r '.AUTO_MERGE_SKIP_BOT_PRS')

          echo "| Setting | Value |" >> $GITHUB_STEP_SUMMARY
          echo "|---------|-------|" >> $GITHUB_STEP_SUMMARY
          echo "| Min approvals | $MIN_APPROVALS |" >> $GITHUB_STEP_SUMMARY
          echo "| Require all reviews | $REQUIRE_ALL_REVIEWS |" >> $GITHUB_STEP_SUMMARY
          echo "| Allowed merge types | $MERGE_TYPES |" >> $GITHUB_STEP_SUMMARY
          echo "| Skip draft PRs | $SKIP_DRAFT |" >> $GITHUB_STEP_SUMMARY
          echo "| Skip WIP PRs | $SKIP_WIP |" >> $GITHUB_STEP_SUMMARY
          echo "| Skip bot PRs | $SKIP_BOT_PRS |" >> $GITHUB_STEP_SUMMARY
          echo "" >> $GITHUB_STEP_SUMMARY
          echo "---" >> $GITHUB_STEP_SUMMARY
          echo "🤖 _Automated by GitHub Actions_" >> $GITHUB_STEP_SUMMARY

      # ————————————————————————————————————————————————————————————————
      # Report final workflow status
      # ————————————————————————————————————————————————————————————————
      - name: 📢 Report workflow status
        run: |
          echo "=== 🤖 Auto-merge on Approval Summary ==="
          echo "📋 PR: #${{ needs.process-auto-merge.outputs.pr-number }}"

          ACTION="${{ needs.process-auto-merge.outputs.action-taken }}"
          case "$ACTION" in
            enabled)
              echo "✅ Action: Auto-merge enabled successfully"
              ;;
            already-enabled)
              echo "✅ Action: Auto-merge was already enabled"
              ;;
            disabled-changes-requested)
              echo "🛑 Action: Auto-merge disabled due to changes requested"
              ;;
            skip-*)
              echo "⏭️ Action: Skipped - $ACTION"
              ;;
            conditions-not-met)
              echo "⏳ Action: Waiting for conditions to be met"
              ;;
            failed)
              echo "❌ Action: Failed to enable auto-merge"
              ;;
            *)
              echo "❓ Action: $ACTION"
              ;;
          esac

          echo "🕐 Completed: $(date -u '+%Y-%m-%d %H:%M:%S UTC')"
          echo "✅ Workflow completed!"