Bug Protection: Multi-Layered

Overview

A single validation point is easy to bypass — different code paths, refactoring, or mocks can circumvent it. Real protection requires checks at every layer data passes through.

Core principle: One fix removes the bug. Validation layers make the invalid state structurally impossible; instrumentation makes missed failures diagnosable.

systematic-debugging
  -> fix at source and prove original symptom
  -> bug-protection-multi-layered  (you are here, for high-risk bug classes)
       -> add entry validation / business checks / environment guards
       -> add forensic instrumentation where useful
       -> test-driven-development / manual-testing  (prove protections)
       -> verification-before-completion

When to Use