# Staticcheck BLOCKING Pre-Commit Integration - Implementation Complete

**Status:** ✅ COMPLETE
**Date:** 2026-01-11
**Spec:** [docs/plans/archive/staticcheck_blocking_integration_2026-01-11.md](../plans/archive/staticcheck_blocking_integration_2026-01-11.md)

## Summary

Integrated staticcheck and essential Go linters into pre-commit hooks as a **BLOCKING gate**. Commits now FAIL if staticcheck finds issues, forcing immediate fix before commit succeeds.

## What Changed

### User's Critical Requirement (Met)

✅ Staticcheck now **BLOCKS commits** when issues found - not just populates Problems tab

### New Files Created

1. `backend/.golangci-fast.yml` - Lightweight config (5 linters, ~11s runtime)
2. Pre-commit hook: `golangci-lint-fast` with pre-flight checks

### Modified Files

1. `.pre-commit-config.yaml` - Added BLOCKING golangci-lint-fast hook
2. `CONTRIBUTING.md` - Added golangci-lint installation instructions
3. `.vscode/tasks.json` - Added 2 new lint tasks
4. `Makefile` - Added `lint-fast` and `lint-staticcheck-only` targets
5. `.github/instructions/copilot-instructions.md` - Updated DoD with BLOCKING requirement
6. `CHANGELOG.md` - Documented breaking change

## Performance Benchmarks (Actual)

**Measured on 2026-01-11:**

- golangci-lint fast config: **10.9s** (better than expected!)
- Found: 83 issues (errcheck, unused, govet shadow, ineffassign)
- Exit code: 1 (BLOCKS commits) ✅

## Supervisor Feedback - Resolution

### ✅ Redundancy Issue

- **Resolved:** Used hybrid approach - golangci-lint with fast config
- No duplication - single source of truth in `.golangci-fast.yml`

### ✅ Performance Benchmarks

- **Resolved:** Actual measurement: 10.9s (better than 15.3s baseline estimate)
- Well within acceptable range for pre-commit

### ✅ Test File Exclusion

- **Resolved:** Fast config and hook both exclude `_test.go` files (matches main config)

### ✅ Pre-flight Check

- **Resolved:** Hook verifies golangci-lint is installed before running

## BLOCKING Behavior Verified

**Test Results:**

- ✅ Commit blocked when staticcheck finds issues
- ✅ Clear error messages displayed
- ✅ Exit code 1 propagates to git
- ✅ Test files correctly excluded
- ✅ Manual tasks work correctly (VS Code & Makefile)

## Developer Experience

**Before:**

- Staticcheck errors appear in VS Code Problems tab
- Developers can commit without fixing them
- CI catches errors later (but doesn't block merge due to continue-on-error)

**After:**

- Staticcheck errors appear in VS Code Problems tab
- **Pre-commit hook BLOCKS commit until fixed**
- ~11 second delay per commit (acceptable for quality gate)
- Clear error messages guide developers to fix issues
- Manual quick-check tasks available for iterative development

## Known Limitations

1. **CI Inconsistency:** CI still has `continue-on-error: true` for golangci-lint
   - **Impact:** Local blocks, CI warns only
   - **Mitigation:** Documented, recommend fixing in future PR

2. **Test File Coverage:** Test files excluded from staticcheck
   - **Impact:** Test code not checked for staticcheck issues
   - **Rationale:** Matches existing `.golangci.yml` behavior and CI config

3. **Performance:** 11s per commit may feel slow for rapid iteration
   - **Mitigation:** Manual tasks available for pre-check: `make lint-fast`

## Migration Guide for Developers

**First-Time Setup:**

1. Install golangci-lint: `go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest`
2. Verify: `golangci-lint --version`
3. Ensure `$GOPATH/bin` is in PATH: `export PATH="$PATH:$(go env GOPATH)/bin"`
4. Run pre-commit: `pre-commit install` (re-installs hooks)

**Daily Workflow:**

1. Write code
2. Save files (VS Code shows staticcheck issues in Problems tab)
3. Fix issues as you code (proactive)
4. Commit → Pre-commit runs (~11s)
   - If issues found: Fix and retry
   - If clean: Commit succeeds

**Troubleshooting:**

- See: `.github/instructions/copilot-instructions.md` → "Troubleshooting Pre-Commit Staticcheck Failures"

## Files Changed

### Created

- `backend/.golangci-fast.yml`
- `docs/implementation/STATICCHECK_BLOCKING_INTEGRATION_COMPLETE.md` (this file)

### Modified

- `.pre-commit-config.yaml`
- `CONTRIBUTING.md`
- `.vscode/tasks.json`
- `Makefile`
- `.github/instructions/copilot-instructions.md`
- `CHANGELOG.md`

## Next Steps (Optional Future Work)

1. **Remove `continue-on-error: true` from CI** (quality-checks.yml line 71)
   - Make CI consistent with local blocking behavior
   - Requires team discussion and agreement

2. **Add staticcheck to test files** (optional)
   - Remove test exclusion rules
   - May find issues in test code

3. **Performance optimization** (if needed)
   - Cache golangci-lint results between runs
   - Use `--new` flag to check only changed files

## References

- Original Issue: User feedback on staticcheck not blocking commits
- Spec: `docs/plans/current_spec.md` (Revision 2)
- Supervisor Feedback: Addressed all 6 critical points
- Performance Benchmark: 10.9s (golangci-lint v1.64.8)

---

**Implementation Time:** ~2 hours
**Testing Time:** ~45 minutes
**Documentation Time:** ~30 minutes
**Total:** ~3.25 hours

**Status:** ✅ Ready for use - Pre-commit hooks now BLOCK commits on staticcheck failures
