Dealing with legacy problems

We have been discussing all the issues with legacy code. Now it is time to tackle solving those issues. The first thing we must do is bring sanity to the targeted legacy code, and then we can begin testing and eventually fix the code and bring it back from death.

Safe refactoring

The term refactoring is often used incorrectly. When refactoring, you are merely changing the structure of the code. If the logic and/or signature of the code in question changes, then this does not qualify as refactoring. This is a change; most likely a breaking change.

If I'm changing the structure of the code (refactoring), then I don't ever change its behavior at the same time. If I'm changing the interface by which some logic is invoked, I never change the logic itself at the same time.

– Kent Beck

A safe refactoring is one that is guaranteed to not accidentally break the code. Other changes that aren't intended to actually change the behavior of the code but could do it accidentally...