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RCA-001: Lint Pipeline Failure Blocking Production Deployment

Date: 2026-02-16
Pipeline: #2327825235
Stage Failed: lint:go
Impact: Production deployment blocked at deploy-production stage
Status: RESOLVED
Resolution Commit: 62d021a

Incident Summary

GitLab CI/CD pipeline was failing at the lint:go stage due to multiple errcheck and gosec violations, preventing code from reaching the deploy-production stage.

Root Cause Analysis

What Happened

New code was committed (commits f044ca3 through f0a3e57) that introduced: 1. 6 errcheck violations - Unchecked error returns from json.Encode/Decode/Unmarshal and http.ResponseWriter.Write in test files 2. 2 gosec violations - Security linter flags for subprocess execution (G204) and integer overflow (G115)

Why It Happened

  1. No local linting before commit: Developers committed code without running golangci-lint locally
  2. Test file assumptions: Test files often ignore errors for brevity, but errcheck linter requires explicit acknowledgment
  3. Security linter sensitivity: gosec flags patterns that may be intentional but require explicit annotation

Files Affected

File Line Violation Description
auth_middleware_test.go 199 errcheck json.NewEncoder(w).Encode(claims)
fim_completions_test.go 76, 116, 131 errcheck json.Encoder/Decoder
mcp_server_test.go 110, 160, 198, 235, 256, 282 errcheck json.Unmarshal
rate_limiter_test.go 129 errcheck w.Write
mcp_client.go 107 G204 gosec Subprocess with variable path
voyage_reranker.go 312 G115 gosec Integer overflow in bit shift

Resolution

Changes Made

  1. errcheck fixes (test files):
  2. Added _ = prefix to explicitly ignore errors: _ = json.NewEncoder(w).Encode(resp)
  3. Added proper error handling where appropriate: if err := json.Unmarshal(...); err != nil { t.Fatalf(...) }

  4. Used _, _ = w.Write(...) for ResponseWriter.Write

  5. gosec fixes (production code):

  6. Added // #nosec G204 comment with justification for validated serverPath
  7. Added bounds check (if attempt > 10 { attempt = 10 }) before bit shift to prevent overflow

Verification

cd cortex/cortex-api && golangci-lint run --timeout=5m
# Output: 0 issues.

Prevention Measures

Immediate Actions

  1. ✅ Fixed all lint violations
  2. ✅ Verified with local golangci-lint run
  3. ✅ Committed and pushed fix

Long-term Improvements

Action Owner Priority Status
Add pre-commit hook for golangci-lint DevOps P1 TODO
Document lint patterns in AI-WORKFLOW-GUIDE.md AI P1 TODO
Add lint check to developer onboarding DevOps P2 TODO

Add to .git/hooks/pre-commit:

#!/bin/bash
if command -v golangci-lint &> /dev/null; then
    echo "Running golangci-lint..."
    golangci-lint run --fast
    if [ $? -ne 0 ]; then
        echo "Lint errors found. Please fix before committing."
        exit 1
    fi
fi

Lessons Learned

  1. Always run linters locally before push - Don't rely solely on CI to catch issues
  2. Test files need error handling too - Even if ignored, errors must be explicitly handled
  3. gosec requires annotations - Security-sensitive patterns need // #nosec with justification
  4. Pipeline visibility is critical - Monitor pipeline status after every push

Timeline

Time Event
2026-02-16 Phase 2 commits pushed (f044ca3 - f0a3e57)
2026-02-16 Pipeline #2327825235 failed at lint:go
2026-02-16 RCA initiated, lint errors identified
2026-02-16 Fix committed (62d021a), pushed
2026-02-16 Pipeline expected to pass