Divergent Change

Divergent Change resembles Shotgun Surgery but is actually the opposite smell. Divergent Change is when many changes are made to a single class. Shotgun Surgery refers to when a single change is made to multiple classes simultaneously.

Signs and Symptoms

You find yourself having to change many unrelated methods when you make changes to a class. For example, when adding a new product type you have to change the methods for finding, displaying, and ordering products.

Reasons for the Problem

Often these divergent modifications are due to poor program structure or "copypasta programming”.

Treatment

• Split up the behavior of the class via Extract Class.

• If different classes have the same behavior, you may want to combine the classes through inheritance (Extract Superclass and Extract Subclass).

Payoff

• Improves code organization.

• Reduces code duplication.

• Simplifies support.