Is there any way Either could be declared with a c...

# arrow

[dave08]

Is there any way Either could be declared with a compose stability annotation (it doesn't require any dependency to the runtime, there's a seperate annotation module for kmp...). It seems like compose thinks Either is unstable...!

[Alejandro Serrano.Mena]

sure thing! could you provide some pointers on how to do this?

[dave08]

https://developer.android.com/develop/ui/compose/performance/stability

[dave08]

This is the dependency:

androidx-compose-runtime-annotation = { group = "androidx.compose.runtime", name = "runtime-annotation", version = "1.10.0" }

(I think that version is the current stable one)

[dave08]

Thanks!

[stojan]

You can use a stability configuration file to fix this on your end:

<https://developer.android.com/develop/ui/compose/performance/stability/fix#configuration-file>

[dave08]

Interesting! I didn't notice that one... but it still would be nice to have this (maybe provided like that in the arrow compose module, since the dep is already there... would that work @stojan?) to avoid all arrow users to have to maintain their own list...

[stojan]

This is what Compose recommends for multi-module and/or libraries:

<https://developer.android.com/develop/ui/compose/performance/stability/fix#multiple-modules>

I typically deal with Either on the ViewModel level, and keep my views dumb -> Meaning Either gets transformed to some other class that represents the UI (in case of a Left this is still just a class, but it's rendered as an error view in the UI).

Do you often have either as part of the UI models?

[Alejandro Serrano.Mena]

unfortunately, it seems that there's no annotation for "parametric stabilty" in Compose. Because the right thing here is to make Either<A, B> immutable or stable only if the types inside are immutable or stable, respectively

[Alejandro Serrano.Mena]

so it seems the only option is marking your data types containing Either manually, as far as I understand

[dave08]

Yeah, I guess... although, normally functional programming doesn't really encourage mutable states, no?

[Alejandro Serrano.Mena]

still, we cannot mark it as @Immutable or @Stable, because there's a risk of being wrong

[dave08]

Yeah, I guess, maybe I should really avoid using them in compose uis then. It's always a risk that another programmer might not understand how to use Either in an immutable way and shoot himself in the foot if I mark it immutable myself.

[Alejandro Serrano.Mena]

I think it's OK if you use an Either inside another class, and you mark that one as stable