Make request-traceable surgical edits

These examples and illustrative results are independently authored teaching materials, not measured model results.

Use case

Repair empty-email validation in a file with unrelated username rules and old unused functions. Every teaching edit should trace to the request, not incidental policy/reformatting.

Mechanism

Identify trigger/necessary call paths and preserve surrounding style. Remove orphans created by the fix, recording preexisting unrelated dead code. Include causally necessary cross-file edits instead of a one-file limit. Review diff provenance and regressions, preserving user changes.

Bad example

Fix email while tightening usernames, deleting old functions and reformatting everything as overall improvement.

Good example

Change empty-email behavior/required callers, retain username policy and remove newly unused imports only. Explain each diff’s connection and verify repair/related existing behavior without expanding rules.

Why the change matters

Traceability reduces review surface/unrelated regression. Cleaning new orphans completes the change while retaining unrelated code respects scope.

Observable expectation

Teaching email branch/import changes map to the fix; username policy stays. Shared-type edits need caller evidence. Check the symptom and existing valid usernames; unrun regressions remain unverified.

Limits

Small scope does not mean one line; necessary refactoring can be broader. Minimal diffs must not hide incomplete fixes. Continue authorized work and record unrelated design suggestions separately.