Refactoring Discipline

Structural change without behavior change. For the GoF pattern catalog, see principle-design-patterns. For naming and function-length aesthetics, see principle-clean-code.

The discipline

Four non-negotiable rules:

• Every step preserves behavior. Tests must pass before and after each step.
• No feature changes during refactoring. Find a bug? Note it — fix it in a separate commit.
• Small steps. Each step is independently reviewable and revertable.
• Green between steps. Run tests after each move. If red, revert immediately.

Smells → moves