Clean Code

The twelve change-shape smells

Shotgun Surgery · Feature Envy · Data Clumps · Long Method · Divergent Change · Duplicated Code · Large Class · Long Parameter List · Primitive Obsession · Message Chains · Dead Code · Speculative Generality

You know each one and its refactoring. The value is the checklist, not the definitions — without the names a diff "looks fine"; with them you find the shape. Run all twelve against any change you review or write.

The smell catalog has four layers

Each examines a different unit, so each sees what the others miss.