[feature]: Implement workflow-specific concurrency groups to fix matrix aggregation

[devantler]

Context

Issue #1903 shows recurring CI matrix aggregation failures caused by concurrency race conditions.

Root Cause

Multiple workflows (CI-KSail, CI-Go) sharing the same concurrency group cancel each other's jobs.

Solution

Update concurrency group to be workflow-specific:

concurrency:
  group: "ci-ksail-${{ github.workflow }}-${{ github.ref }}"
  cancel-in-progress: true

Implementation

1. Update .github/workflows/ci.yaml concurrency config
2. Apply pattern to other workflows
3. Monitor next 5-10 merge queue runs
4. Document pattern in workflow best practices

Acceptance Criteria

• Concurrency groups include workflow name
• No cross-workflow cancellations
• Matrix aggregation false failures eliminated
• Pattern documented for future workflows

Timeline

1 week

Related

#1903 (parent investigation)

[github-actions]

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[botantler]

🎯 Agentic Issue Triage

Summary: This is a well-defined feature request to implement workflow-specific concurrency groups across all GitHub Actions workflows to eliminate CI matrix aggregation failures caused by cross-workflow concurrency conflicts.

📋 Issue Analysis

Type: Feature Request / Infrastructure Improvement
Component: GitHub Actions Workflows (CI/CD)
Priority: High (blocks merges, wastes CI resources)
Related Issues: #1903 (parent investigation), #2001 (matrix aggregation bug)

Current State:

• ✅ .github/workflows/ci.yaml already updated with workflow-specific concurrency (line 10)
• ⏳ Pattern needs to be applied to other workflows
• ⏳ Pattern needs documentation in workflow best practices

Impact:

• Prevents false CI failures from cross-workflow cancellations
• Reduces wasted CI resources (jobs cancelled mid-execution)
• Eliminates manual intervention needed to re-trigger merge queue runs

✅ Implementation Checklist

The issue already provides clear implementation steps. Here's a consolidated checklist:

1. Update Workflow Files

Apply this pattern to all remaining workflows:

concurrency:
  group: "${{ github.workflow }}-${{ github.ref }}"
  cancel-in-progress: true

Files to check/update:

• .github/workflows/ci.yaml (already done - verified line 10)
• .github/workflows/cd.yaml
• .github/workflows/maintenance.yaml
• .github/workflows/publish-pages.yaml
• .github/workflows/release.yaml
• .github/workflows/test-pages.yaml
• .github/workflows/todos.yaml
• Any agentic workflow files (.md files with workflow definitions)

2. Create Documentation

Add .github/copilot/instructions/concurrency-best-practices.md or similar documentation file with:

• ✅ Correct pattern (workflow-specific groups)
• ❌ Anti-pattern (shared concurrency groups)
• Event-specific considerations (merge_group, pull_request, push)
• Debugging checklist for concurrency issues

3. Validation

• Verify all workflows have workflow-specific concurrency groups
• Test with 5-10 merge queue runs (as specified in acceptance criteria)
• Confirm no cross-workflow cancellations occur
• Verify matrix aggregation false failures are eliminated

🔍 Debugging & Resources

Quick Diagnosis Commands

# List all workflow concurrency configurations
grep -r "concurrency:" .github/workflows/

# Check for workflows missing workflow name in group
grep -A2 "concurrency:" .github/workflows/*.yaml | grep -v "github.workflow"

# Test concurrent workflow runs
gh run list --workflow="CI - KSail" --limit 5
gh run list --workflow="CI - Go" --limit 5

Key Patterns to Understand

Why this matters:

• Multiple workflows triggered on same commit (e.g., merge_group) use the same github.ref
• Without workflow-specific groups, they share the same concurrency key
• GitHub's cancel-in-progress cancels jobs from one workflow when another starts
• Result: False "failure" status even though no tests actually failed

The Fix:
Including ${{ github.workflow }} in the concurrency group ensures each workflow has independent concurrency control.

Helpful Resources

• GitHub Actions Concurrency Documentation
• Understanding Merge Queues
• Issue CI Failure DoctorRecurring merge_group concurrency race causing false CI failures #1903 - Detailed root cause analysis
• Issue CI Failure DoctorMatrix job aggregation failure despite all sub-jobs succeeding #2001 - Related matrix aggregation issue (different cause)

💡 Additional Considerations

Testing Strategy

1. Before Testing: Audit all workflow files for concurrency configurations
2. During Testing: Monitor 5-10 merge queue runs with multiple workflows triggering simultaneously
3. Success Criteria:
   • No cancelled jobs with "failure" conclusion
   • Each workflow completes independently
   • Matrix jobs aggregate correctly

Future Improvements

Consider documenting:

• When to use cancel-in-progress: false (e.g., for release workflows)
• Event-specific concurrency patterns
• How to debug concurrency-related failures
• Automated validation (CI check to ensure all workflows follow the pattern)

Labels Applied: github_actions, next

Recommended Priority: This should be prioritized as it directly addresses a recurring infrastructure issue (#1903) that blocks PRs and wastes CI resources.

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