Is there a way to mark a parameter of type `List lt String g

Question

Is there a way to mark a parameter of type `List lt String gt ` as stable

Adam Powell · Answer

it s not stable though slightly smiling face

Leland Richardson [G] · Answer

the short answer is no not really But can I ask you to elaborate more on why you want to I m curious about how this type of thing manifests in the wild and would like to understand it more

Leland Richardson [G] · Answer

in the future for instance it might be possible for us to infer certain patterns as stable for instance `listOf foo bar `

Leland Richardson [G] · Answer

but right now we can t do that safely for a variety of reasons

Adam Powell · Answer

`ModelList` might be a solution here depending

Adam Powell · Answer

but I assume we don t have a readonly interface type for it yet

Leland Richardson [G] · Answer

no List is read only but not stable but we figured that would be good enough

Leland Richardson [G] · Answer

but i don t think that List lt String gt being stable should be a requirement for correctness

molikto · Answer

I don t really have a valid case for this except for my desire that more calls be cached but in practice there might not be any performance difference or there are cases it is worse performnace

Leland Richardson [G] · Answer

it can go either way but if there s a chance for all parameters to compare true with previous versions then generally it will be a performance win

Leland Richardson [G] · Answer

but my recommendation to you would be to not worry about it until it is an actual problem

Leland Richardson [G] · Answer

for instance if you re passing these strings into some other composable somewhere Strings are stable and then you might get some good skipping happening at those call sites

Leland Richardson [G] · Answer

in the long run we want to gradually make things smarter so that this can happen a higher percentage of the time

Leland Richardson [G] · Answer

but we would like for it to be something that you just don t really need to worry about in most cases

molikto · Answer

Agreed I think most of time it doesn t mater that much because all the heavy lifting happens inside widget API

molikto · Answer

If it really matters one can always use a wrapping Stable class so I guess I am just nitpicking

Leland Richardson [G] · Answer

yeah especially as we improve performance more and more my hope is that we can just recommend to not worry about this in user land You re right that the heavy lifting happens below widget level APIs in most cases That said there will no doubt be cases where this does make or break whether a certain API in user land is sensible and we are definitely trying to think about the right way to tackle this problem

Leland Richardson [G] · Answer

i really don t want to see ` Stable` annotation sprinkled over almost every type in user land though

Leland Richardson [G] · Answer

ideally kotlin at some point can provide some notion of immutability that we can rely on from a more language level ecosystem standpoint

molikto · Answer

thanks

Zach Klippenstein (he/him) [MOD] · Answer

gt ideally kotlin at some point can provide some notion of immutability that we can rely on from a more language level ecosystem standpoint This would be awesome but this seems very unlikely anytime soon It would probably require a better notion of immutability on the JVM or value types or something wouldn t it I haven t been following the progress of Valhalla too closely but I would think it s quite a ways off for android use

Leland Richardson [G] · Answer

correct for some definition of soon lol

Leland Richardson [G] · Answer

there s a lot of different avenues here but basically i want us to be cautious about creating a world where ` Stable` is sprinkled all around the entire ecosystem

Leland Richardson [G] · Answer

at least without thinking carefully about it first