refactor

To refactor code without changing behavior, you must enforce parity checks across a defined code surface. This requires direct test coverage, seam validation, and full-suite verification before the restructuring can ship.

Safely extracting or renaming methods in a production codebase requires defining the code surface and applying parity verification. You must pass lint or type-check gates and verify full test coverage before shipping.

Seam validation and test coverage are required before restructuring to prevent accidental behavior changes. They verify that observable output remains stable and ensure the refactor does not introduce regressions.

You can modernize internal implementations while keeping production behavior stable by swapping them under strict parity gates. This approach demands full-suite verification and lint checks to prove no observable output has changed.

This refactoring approach works for deduplicating and moving code by applying behavior-preserving restructuring techniques. It enforces coverage and parity checks across the affected code surface to prevent regressions during the transition.

Behavior-preserving refactoring is limited by its strict requirement for direct test coverage and passing lint or type-check gates. If a code surface lacks tests or fails type validation, the refactor cannot safely ship.