Systematic Debugging (root cause first)

증상이 아니라 근본 원인을 찾아 수정

언제 쓰나 · 버그·테스트 실패·이상 동작 발생 시

Bug: {{symptom}}.

Before proposing a fix:
1. Reproduce it with a minimal failing case.
2. Form 2-3 hypotheses for the ROOT cause (not the symptom).
3. Add logging/asserts to confirm which hypothesis is true — show evidence.
4. Only then fix the confirmed cause.
5. Add a regression test that fails before the fix and passes after.

Never patch the symptom without evidence of the cause.