Stats
Actions
Tags
Help us improve
Share bugs, ideas, or general feedback.
From sdlc
Automates git bisect to pinpoint the commit introducing a regression by running tests during binary search, showing diff and blame info, and generating analysis reports.
npx claudepluginhub jmagly/aiwg --plugin sdlcHow this skill is triggered — by the user, by Claude, or both
Slash command
/sdlc:regression-bisectThe summary Claude sees in its skill listing — used to decide when to auto-load this skill
Automatically identify the commit that introduced a regression using git bisect.
Pinpoints the commit introducing a bug or regression using git bisect binary search. For performance regressions, recent test failures, or issues that previously worked.
Analyzes bugs, test failures, and error logs to perform root cause analysis using top-down tracing or git bisect. Generates minimal diff patches and regression tests with structured reports.
Using bisect/git bisect to isolate failure to exact commit or code path.
Share bugs, ideas, or general feedback.
Automatically identify the commit that introduced a regression using git bisect.
This skill automates regression root cause analysis by:
When triggered, this skill:
Validates prerequisites:
Executes git bisect:
Analyzes breaking commit:
Provides context:
Documents findings:
bisect_manual:
mode: interactive
good_commit: v1.2.0 # Known good state
bad_commit: HEAD # Known bad state
test_command: "npm test -- auth.test.ts"
workflow:
- git bisect start
- git bisect bad HEAD
- git bisect good v1.2.0
- git bisect run npm test -- auth.test.ts
bisect_automated:
mode: automated
detect_good: auto # Use last passing CI build
detect_bad: auto # Use current failing state
test_command: "npm test"
timeout: 600 # 10 minutes per commit test
auto_detection:
- check_ci_history
- find_last_green_build
- set_as_good_commit
- use_current_as_bad
bisect_custom:
mode: custom
test_script: scripts/regression-test.sh
success_exit_code: 0
failure_exit_code: 1
test_script_template: |
#!/bin/bash
# Custom regression test
npm run build || exit 1
npm test -- specific-test.ts || exit 1
./validate-output.sh || exit 1
exit 0
# Regression Bisect Report
**Date**: 2026-01-28
**Issue**: Authentication fails on login
**Analyzer**: regression-bisect skill
## Executive Summary
**Breaking Commit**: abc123def456
**Author**: John Developer <john@example.com>
**Date**: 2026-01-15 14:32:00
**Bisect Duration**: 8 commits tested, 12 minutes
**Root Cause**: Token validation logic changed to require `iss` claim
## Bisect Results
### Commit Range
- **Good**: v1.2.0 (2026-01-10) - 50 commits ago
- **Bad**: HEAD (2026-01-28) - Current state
- **Breaking**: abc123def456 (2026-01-15) - 25 commits into range
### Bisect Log
| Commit | Status | Test Result | Duration |
|--------|--------|-------------|----------|
| abc123 | ❌ Bad | auth.test.ts failed | 45s |
| def789 | ❌ Bad | auth.test.ts failed | 42s |
| ghi012 | ✅ Good | all tests passed | 48s |
| jkl345 | ✅ Good | all tests passed | 46s |
| mno678 | ❌ Bad | auth.test.ts failed | 44s |
| **pqr901** | **❌ Breaking** | **First failure** | **43s** |
| stu234 | ✅ Good | all tests passed | 47s |
| vwx567 | ✅ Good | all tests passed | 45s |
## Breaking Commit Analysis
### Commit Details
commit pqr901xyz Author: John Developer john@example.com Date: Mon Jan 15 14:32:00 2026 +0000
feat(auth): add JWT issuer validation
- Require `iss` claim in JWT tokens
- Validate issuer against whitelist
- Update token generation to include issuer
Closes #456
### Files Changed
| File | Changes | Impact |
|------|---------|--------|
| src/auth/validate-token.ts | +15/-5 | High - Core validation logic |
| src/auth/generate-token.ts | +8/-2 | Medium - Token generation |
| test/auth/token.test.ts | +25/-0 | Low - Test updates |
### Diff Analysis
```diff
diff --git a/src/auth/validate-token.ts b/src/auth/validate-token.ts
index abc123..def456 100644
--- a/src/auth/validate-token.ts
+++ b/src/auth/validate-token.ts
@@ -15,6 +15,11 @@ export function validateToken(token: string): TokenPayload {
throw new Error('Invalid token signature');
}
+ // NEW: Require issuer claim
+ if (!payload.iss) {
+ throw new Error('Token missing issuer claim');
+ }
+
return payload;
}
Breaking Change: The new validation requires iss claim, but existing tokens don't include it.
The commit added mandatory iss (issuer) claim validation without:
Impact: All existing user sessions became invalid immediately.
Git history shows related changes:
src/auth/validate-token.ts:
85% John Developer <john@example.com>
10% Jane Reviewer <jane@example.com>
5% Bob Maintainer <bob@example.com>
iss validation optional with feature flagiss claimRecommended: Option B - Feature flag allows gradual rollout
// src/auth/validate-token.ts
export function validateToken(token: string): TokenPayload {
const payload = jwt.verify(token, SECRET_KEY);
if (!payload.sub) {
throw new Error('Invalid token signature');
}
// FIXED: Make issuer validation optional during migration
if (featureFlags.requireIssuer && !payload.iss) {
throw new Error('Token missing issuer claim');
}
return payload;
}
requireIssuer: falseissrequireIssuer: true2026-01-10: v1.2.0 released (working)
2026-01-15: Commit pqr901 merged (breaking change introduced)
2026-01-15: No CI failure (tests didn't catch integration issue)
2026-01-16: Deployed to production
2026-01-16: User reports started (authentication failures)
2026-01-28: Bisect identified root cause
Time to Detection: 13 days Time to Root Cause: Immediate (via bisect)
This regression could have been prevented by:
## Usage Examples
### Basic Regression Bisect
User: "Find which commit broke authentication"
Skill executes:
Output: "Regression Bisect Complete
Breaking Commit: pqr901xyz Author: John Developer Date: 2026-01-15 14:32:00 Message: feat(auth): add JWT issuer validation
Root Cause: Required iss claim without backward compatibility
Files Changed:
Recommendation: Make validation optional with feature flag
Full report: .aiwg/testing/regression-bisect-auth.md"
### Bisect with Custom Test
User: "Bisect the payment processing regression"
Skill asks: "What is a good commit (when it worked)?" User: "v2.1.0"
Skill executes:
Output: "Breaking Commit: def456 Broke payment refund logic Changed: src/payments/refund.ts
Bisected 45 commits in 32 minutes See .aiwg/testing/regression-bisect-payment.md"
### Automatic Good/Bad Detection
User: "When did the API start returning 500 errors?"
Skill analyzes:
Runs bisect automatically.
Output: "Regression introduced in commit abc123 2 days ago by Jane Developer Changed database query logic
Breaking change: Added JOIN without NULL check See full analysis in .aiwg/testing/regression-api-500.md"
## Integration
This skill uses:
- `regression-baseline`: Load known good states
- `project-awareness`: Detect test commands and CI configuration
- `test-coverage`: Identify relevant test suites
- Git tools: For bisect operations and history analysis
## Agent Orchestration
```yaml
agents:
analysis:
agent: debugger
focus: Root cause analysis and blame
testing:
agent: test-engineer
focus: Test execution and validation
documentation:
agent: technical-writer
focus: Report generation
bisect_presets:
auth_regression:
test_command: npm test -- auth.test.ts
timeout: 300
auto_detect_good: true
api_regression:
test_command: npm run test:api
timeout: 600
auto_detect_good: true
performance_regression:
test_command: npm run benchmark
threshold: "response_time < 1000ms"
timeout: 900
timeout_config:
per_commit_test: 600 # 10 minutes
total_bisect: 3600 # 1 hour max
on_timeout: skip_commit # or fail_bisect
If test results are inconsistent:
If commit doesn't build:
If bisect takes too long:
.aiwg/testing/regression-bisect-{issue}.md.aiwg/testing/bisect-logs/.aiwg/working/regression-fixes/