ci: Concurrency control for merge-queue

.github/workflows/cicd-main.yml

@@ -25,7 +25,7 @@ on:
   workflow_dispatch:
 
 concurrency:
-  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}-${{ github.event.label.name || 'main' }}-${{ github.event_name }}
+  group: ${{ github.workflow }}-${{ github.head_ref || github.ref || github.event.pull_request.number }}
   cancel-in-progress: true
 
 permissions:
@@ -211,9 +211,12 @@ jobs:
         id: sha
         env:
           IS_PR: ${{ startsWith(github.ref, 'refs/heads/pull-request/') }}
+          IS_MERGE_GROUP: ${{ github.event_name == 'merge_group' }}
         run: |
           if [[ "$IS_PR" == "true" ]]; then
             SHA=${{ fromJSON(steps.get-pr-info.outputs.pr-info || '{}').merge_commit_sha }}
+          elif [[ "$IS_MERGE_GROUP" == "true" ]]; then
+            SHA=${{ github.event.merge_group.head_sha }}
           else
             SHA=${GITHUB_SHA}
           fi
@@ -548,8 +551,8 @@ jobs:
           GITHUB_RUN_ID: ${{ github.run_id }}
           SKIPPING_IS_ALLOWED: ${{ needs.pre-flight.outputs.docs_only == 'true' || needs.pre-flight.outputs.is_deployment_workflow == 'true' || needs.pre-flight.outputs.is_merge_group == 'true' || needs.pre-flight.outputs.is_ci_workload == 'true' }}
         run: |
-          FAILED_JOBS=$(gh run view $GITHUB_RUN_ID --json jobs --jq '[.jobs[] | select(.status == "completed" and .conclusion == "failure")] | length') || echo 0
-          SKIPPED_JOBS=$(gh run view $GITHUB_RUN_ID --json jobs --jq '[.jobs[] | select(.status == "completed" and .conclusion == "skipped")] | length') || echo 0
+          FAILED_JOBS=$(gh run view $GITHUB_RUN_ID --json jobs --jq '[.jobs[] | select(.status == "completed" and .conclusion == "failure" and .name != "merge-queue-notification")] | length') || echo 0
+          SKIPPED_JOBS=$(gh run view $GITHUB_RUN_ID --json jobs --jq '[.jobs[] | select(.status == "completed" and .conclusion == "skipped" and .name != "merge-queue-notification")] | length') || echo 0
 
           if [ "${FAILED_JOBS:-0}" -eq 0 ] && ([ "${SKIPPED_JOBS:-0}" -eq 0 ] || [ "$SKIPPING_IS_ALLOWED" == "true" ]); then
               echo "✅ All previous jobs completed successfully"
@@ -641,6 +644,34 @@ jobs:
             .coverage
           include-hidden-files: true
 
+  merge-queue-notification:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'merge_group'
+    permissions:
+      pull-requests: write
+    steps:
+      - name: Extract PR number from merge group
+        id: get-pr-number
+        run: |
+          # Extract PR number from merge group head_ref (format: refs/heads/gh-readonly-queue/main/pr-<number>-<sha>)
+          PR_NUMBER=$(echo "${{ github.event.merge_group.head_ref }}" | sed -n 's/.*\/pr-\([0-9]*\)-.*/\1/p')
+          echo "pr_number=$PR_NUMBER" >> $GITHUB_OUTPUT
+
+      - name: Comment on PR with action run URL
+        uses: actions/github-script@v7
+        with:
+          github-token: ${{ secrets.PAT }}
+          script: |
+            const prNumber = ${{ steps.get-pr-number.outputs.pr_number }};
+            const runUrl = `https://github.com/${{ github.repository }}/actions/runs/${{ github.run_id }}`;
+
+            await github.rest.issues.createComment({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: prNumber,
+              body: `🔄 Merge queue validation started!\n\nYou can track the progress here: ${runUrl}`
+            });
+
   cleanup-taint-node:
     runs-on: ${{ needs.is-not-external-contributor.outputs.selected_runner }}
     needs: