In this post, I want to cover the topic of OCP vs YAGNI - contradictions between the Open/Closed Principle and the You aren’t gonna need it one. OCP Let’s start with a refresher for what OCP is. The Open/Closed principle states that: Software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification. It was first introduced by Bertrand Meyer in his canonical Object-Oriented Software Construction book.| Enterprise Craftsmanship