Skill: cmanfre7/debug-pro (version 1.0.0)

# debug-pro Systematic debugging methodology and language-specific debugging commands. ## The 7-Step Debugging Protocol 1. **Reproduce** — Get it to fail consistently. Document exact steps, inputs, and environment. 2. **Isolate** — Narrow scope. Comment out code, use binary search, check recent commits with `git bisect`. 3. **Hypothesize** — Form a specific, testable theory about the root cause. 4. **Instrument** — Add targeted logging, breakpoints, or assertions. 5. **Verify** — Confirm root cause. If hypothesis was wrong, return to step 3. 6. **Fix** — Apply the minimal correct fix. Resist the urge to refactor while debugging. 7. **Regression Test** — Write a test that catches this bug. Verify it passes. ## Language-Specific Debugging ### JavaScript / TypeScript ```bash # Node.js debugger node --inspect-brk app.js # Chrome DevTools: chrome://inspect # Console debugging console.log(JSON.stringify(obj, null, 2)) console.trace('Call stack here') console.time('perf'); /* code */ console.timeEnd('perf') # Memory leaks node --expose-gc --max-old-space-size=4096 app.js ``` ### Python ```bash # Built-in debugger python -m pdb script.py # Breakpoint in code breakpoint() # Python 3.7+ # Verbose tracing python -X tracemalloc script.py # Profile python -m cProfile -s cumulative script.py ``` ### Swift ```bash # LLDB debugging lldb ./MyApp (lldb) breakpoint set --name main (lldb) run (lldb) po myVariable # Xcode: Product → Profile (Instruments) ``` ### CSS / Layout ```css /* Outline all elements */ * { outline: 1px solid red !important; } /* Debug specific element */ .debug { background: rgba(255,0,0,0.1) !important; } ``` ### Network ```bash # HTTP debugging curl -v https://api.example.com/endpoint curl -w "@curl-format.txt" -o /dev/null -s https://example.com # DNS dig example.com nslookup example.com # Ports lsof -i :3000 netstat -tlnp ``` ### Git Bisect ```bash git bisect start git bisect bad # Current commit is broken git bisect good abc1234 # Known good commit # Git checks out middle commit — test it, then: git bisect good # or git bisect bad # Repeat until root cause commit is found git bisect reset ``` ## Common Error Patterns | Error | Likely Cause | Fix | |-------|-------------|-----| | `Cannot read property of undefined` | Missing null check or wrong data shape | Add optional chaining (`?.`) or validate data | | `ENOENT` | File/directory doesn't exist | Check path, create directory, use `existsSync` | | `CORS error` | Backend missing CORS headers | Add CORS middleware with correct origins | | `Module not found` | Missing dependency or wrong import path | `npm install`, check tsconfig paths | | `Hydration mismatch` (React) | Server/client render different HTML | Ensure consistent rendering, use `useEffect` for client-only | | `Segmentation fault` | Memory corruption, null pointer | Check array bounds, pointer validity | | `Connection refused` | Service not running on expected port | Check if service is up, verify port/host | | `Permission denied` | File/network permission issue | Check chmod, firewall, sudo | ## Quick Diagnostic Commands ```bash # What's using this port? lsof -i :PORT # What's this process doing? ps aux | grep PROCESS # Watch file changes fswatch -r ./src # Disk space df -h # System resource usage top -l 1 | head -10 ```


Security scan verdicts — ClawScan: clean | static analysis: clean | VirusTotal: clean | SkillSpector: clean (LOW)