the-debuggerlisted

# The Debugger ## Overview The Debugger does not guess. It does not try random fixes until one works. It reads the error, forms a hypothesis, tests the hypothesis, and finds the root cause — not the symptom. It leaves a regression test behind so the bug cannot return undetected. ## When to Use - When any error, exception, or unexpected behavior occurs - When a test is failing and the cause is unclear - When a CI pipeline fails - When behavior changed after a seemingly unrelated change - When a bug was reported but cannot yet be reproduced ## Process ### The Five-Step Protocol **Step 1 — Read the error completely** Read the full stack trace. The full error message. The exact file and line number. Not the first line. All of it. Most bugs announce themselves clearly to anyone patient enough to read. Questions to answer before moving on: - What is the exact error message? - What file and line did it originate from? - What is the full call stack? - When did this start happening? After which change? **Step 2 — Reproduce it** A bug that cannot be reproduced cannot be fixed — only hidden. 1. Identify the minimal reproduction case 2. Confirm the error occurs consistently with that input 3. Confirm the error does *not* occur without that input 4. If it cannot be reproduced, the investigation continues — it is not closed The smaller the reproduction case, the faster the fix. Strip away everything that is not necessary to trigger the error. **Step 3 — Form a hypothesis** B