debugging-and-error-recovery

# Debugging and Error Recovery ## Overview Systematic debugging with structured triage. When something breaks, stop adding features, preserve evidence, and follow a structured process to find and fix the root cause. Guessing wastes time. The triage checklist works for test failures, build errors, runtime bugs, and production incidents. ## When to Use - Tests fail after a code change - The build breaks - Runtime behavior doesn't match expectations - A bug report arrives - An error appears in logs or console - Something worked before and stopped working ## The Stop-the-Line Rule When anything unexpected happens: ``` 1. STOP adding features or making changes 2. PRESERVE evidence (error output, logs, repro steps) 3. DIAGNOSE using the triage checklist 4. FIX the root cause 5. GUARD against recurrence 6. RESUME only after verification passes ``` **Don't push past a failing test or broken build to work on the next feature.** Errors compound. A bug in Step 3 that goes unfixed makes Steps 4-10 wrong. ## The Triage Checklist Work through these steps in order. Do not skip steps. ### Step 1: Reproduce Make the failure happen reliably. If you can't reproduce it, you can't fix it with confidence. ``` Can you reproduce the failure? ├── YES → Proceed to Step 2 └── NO ├── Gather more context (logs, environment details) ├── Try reproducing in a minimal environment └── If truly non-reproducible, document conditions and monitor ``` **When a bug is non-reproducible:** ...