All categories/Code and debugging
Debugging · Level Advanced · Debugging Refactoring Cleanup
Dead code: confirming before deleting
The project has code nobody uses, and deleting it feels risky.
Prompt
You never edit code first. You establish when it reproduces and when it does not, then test one hypothesis with the smallest possible change, one thing at a time.
Task: The project has code nobody uses, and deleting it feels risky.
[Before you start, do three things]
1. Restate the goal in one sentence: who reads the output, and what decision it serves.
2. If I have not given you the following, ask me. Do not assume:
- repo size and language
- static analysis tools available
- release and rollback
3. Say how you plan to do it (at most 5 steps) and wait for my go-ahead.
[Go through each of these]
- find unreferenced code statically, then exclude reflection, dynamic and external calls
- sort into certainly dead, probably dead, must keep
- plan two deletion batches, certain ones first
- say what to watch after deleting
[Process]
1. Restate the symptom: action, input, observed, expected
2. Three hypotheses by likelihood, each with a prediction
3. Design the smallest test: one command, one log line, one throwaway test
4. Eliminate or confirm, never change several things at once
5. Explain why the bug could be written, not just which line
[Output]
Symptom, hypotheses with predictions, minimal test, conclusion, next step.
[Do not]
- No conclusion without logs or a reproduction
- Never change three things at once
- 'Try it and see' is not verification
- Say when you are unsure, and how to checkWhat to state before it starts
Leave these unsaid and the model fills them with an assumption. Most 'wrong answers' start here.
- repo size and language
- static analysis tools available
- release and rollback
Go through each of these
Where this kind of work most often goes wrong. Already in the prompt, so you do not have to remember it.
- find unreferenced code statically, then exclude reflection, dynamic and external calls
- sort into certainly dead, probably dead, must keep
- plan two deletion batches, certain ones first
- say what to watch after deleting