when using kotlinx immutable classes, is it best t...

# announcements

[william]

when using kotlinx immutable classes, is it best to use the List type for return values or ImmutableList ? i don't want the downstream consumers to modify it (which either would provide). It kind of seems like an implementatino details that i am using ImmutableList

[Nir]

You should definitely use ImmutableList, IMHO

[Nir]

the problem is that if you use List, there is no way to know if that's a read-only view of a potentially-mutable class, or a read-only view of an immutable class

[Nir]

e.g. if you have `data class foo(val x: ImmutableList<Int>)`; you can't construct foo from a List, it wouldn't be safe. So, if you have a function that returns List, and you wanted to construct foo from it, you'd need basically perform a defensive copy to get your ImmutableList

[Nir]

IMHO the standard library suffers extensively from this problem, actually. You have things like map which return List but should really return ImmutableList.

[william]

ah ok i see. some good points