debugginglisted

# Debugging ## The Iron Law Never propose a fix without first identifying the root cause. "Quick fix now, investigate later" is forbidden — it creates harder bugs. ## Process **1. Reproduce** — make the bug consistent. If intermittent, run N times under stress or simulate poor conditions (slow network, low memory) until it triggers reliably. **2. Investigate** — trace backward through the call chain from the symptom. Add diagnostic logging at each component boundary. Compare working vs broken state using a differential table (environment, version, data, timing — what changed?). **3. Hypothesize and test** — one change at a time. If a hypothesis is wrong, fully revert before testing the next. Use `git bisect` to find regressions efficiently. **4. Fix and verify** — create a failing test FIRST, then fix. Run the test. Confirm the original reproduction case passes. No completion claims without fresh verification evidence. ## Three-Fix Threshold After 3 failed fix attempts, STOP. The problem is likely architectural, not a surface bug. Step back and question assumptions about how the system works. Read the actual code path end-to-end instead of spot-checking. ## Escalation: Competing Hypotheses When the cause is unclear across multiple components, use Analysis of Competing Hypotheses: - Generate hypotheses across failure modes: logic error, data issue, state problem, integration failure, resource exhaustion, environment - Investigate each with evidence: Direct (strong),