Oct 9, 2018 21:19 · 218 words · 2 minute read Architecture

Escaping the Technical Debt Cycle

A talk by Michael Feathers: Escaping the Technical Debt Cycle

In the talk, he urges against most numeric metrics. He praises the Open/Closed Principle as one important way to avoid adding unhealthy debt:

In object-oriented programming, the open/closed principle states “software entities (classes, modules, functions, etc.) should be open for extension, but closed for modification”; that is, such an entity can allow its behaviour to be extended without modifying its source code.

Bob Martin defines it more clearly:

You should be able to extend the behavior of a system without having to modify that system.

The rest of SOLID can also be helpful, but Feathers spoke most about Open/Closed.

He recommended refactoring code to make adding the new feature easy, rather than just modifying the code for the new behavior.

Single responsibility principle seems closely related: techniques for solving open/closed can also help with SRP. By providing an extension point, you keep a class or function focused on a single responsibility and allow the other responsibility to be injected in an open manner.

Single responsibility principle is broken in a lot of tech debt laden code. Code that changes together belongs together.

This video about SRP by Uncle Bob is a good explanation of the issues and the way to think about SRP.

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