diagnosing-bugs

A systematic approach to diagnosing hard bugs involves a structured loop: building a feedback loop, reproducing and minimizing the bug, formulating falsifiable hypotheses, instrumenting, fixing, and regression testing.

To reproduce and minimise a bug, focus on creating a minimal reproducible scenario that still reliably triggers the issue, which narrows down the problem space and makes analysis significantly easier.

Hypothesis testing for performance regressions involves creating falsifiable hypotheses about the cause, then using instrumentation and logging to gather data that either confirms or eliminates each potential theory.

The best way to structure a debugging workflow is through a phase-based approach: build a feedback loop, reproduce and minimise, hypothesise, instrument, fix with regression testing, and end with cleanup and a post-mortem.

Yes, bisection is part of the comprehensive diagnosis loop, allowing you to systematically narrow down commits or changes that introduced the performance regression by repeatedly testing subsets of your codebase.

If your initial bug hypothesis is wrong, the systematic approach encourages creating falsifiable hypotheses, meaning you use the disproven theory to refine your instrumentation and guide the next debugging phase.