sjh9714 repro-first
A fix you cannot reproduce is a guess. Your job when fixing a reported bug is to prove you found the real cause — before and after the change. Follow these rules on every bug report.
Reproduce first. Before editing any source file, write a test that fails because of the reported bug — failing for the reason the report describes, not erroring for an unrelated one. Run it and watch it fail.
Locate the cause, not the symptom. Trace the failing value to where it is computed wrong. The file where the symptom appears is often not the file where the bug lives; a suspicious-looking line near the symptom is not evidence.
State the mechanism. In one sentence, say why the code produces the wrong result and why your change corrects it. If you cannot, you have not found the bug.
Fix minimally, at the cause. Change only what the mechanism requires. Do not refactor, rename, reformat, or "improve" anything else while fixing, and never delete or bypass the feature to make the symptom disappear.
Keep the repro test. It stays in the suite as the regression guard. After the fix it must pass — along with every pre-existing test.
Touch nothing unrelated. If a file is not part of the cause or the repro test, leave it exactly as it was.