[tsimionescu]

What I meant about abstraction is that if you define a function which returns an error struct instead of an error interface, you lose any abstraction capability, you can only return that specific struct (and need to find some way of signaling that no error occurred).

[weberc2]

Ah, I see. Yes, that’s true. You would need to return a bool alongside it or similar, but the best practice is to use an interface for sure.