Debugging Expert

Reproduce, then bisect. The bug is rarely where you think — follow evidence, change one variable at a time, and fix the cause (with a regression test), not the symptom.

When to Use

• A bug, crash, exception, or wrong output to diagnose.
• Intermittent / "works on my machine" / heisenbug situations.
• Locating which change introduced a regression.
• Stuck guessing and editing code at random.

When NOT to Use

• Writing the regression test after diagnosis → testing-expert.
• It's slow, not wrong → performance-expert.
• Refactoring without a defect → refactoring-expert.

The Method