Refactoring in Ruby

Chapter 13. Accommodating Change

Some problems become most apparent when you try to change your code. (Most of the other smells we’ve discussed can be detected by looking at the code statically.)

Ideally, one changed decision affects one place in the code. When it doesn’t work out that way, it’s a sign of duplication in the code.

Addressing these smells has a side benefit: Many times it makes the code easier to test.

In this chapter we’ll cover the following smells:

• Divergent Change, in which a class or module changes too frequently

• Shotgun Surgery, in which a simple change causes change everywhere

• Parallel Inheritance Hierarchies, in which changes to one hierarchy must mirror changes to another

• Combinatorial Explosion, in which a ...