So, I have some code that basically boils down to this:

class State {
	var item by mutableStateOf<IClass?>(null)
}

@Composable
fun SomeUi(state: State) {
	Text("Item is ${state.item}")
}

SomeUi()

is rendered to screen, and

state.item

is changed from

null

to some value a little afterwards. But

SomeUi

never picks up on that update and thus the text keeps saying

"Item is null"

. But the way I understand the Compose state system, this should work fine, shouldn't it? I can verify that

state.item

does change its value (by just periodically printing it in a coroutine). What's odd is that if I experimentally change

IClass?

to

String?

it works again. I want to put more effort into debugging it, but first I'd like to verify that I'm not simply misunderstanding something about State and how it's supposed to work.

Where are you calling

SomeUI

from?

Nothing special. Some other composable, and eventually a top-level composable. Boiled down, it's basically like this:

application {
	val state = remember { State() } 
	LaunchedEffect(Unit) { // just an example
		delay(100)
		state.item = getMeSomeItem()
	}
	SomeUi(state)
}

The real code is much more involved, but conceptually it's this. Edit: added the

remember { }

You should remember your state.

val state = remember{ State() }

Sorry, my bad! Yes, it is remembered.

I just tried this and it worked

Yeah, I couldn't reproduce it either. Simple examples work, but I can see that the problem exists in my codebase. That's why I can't give a reproducer for the problem. Hence my question of whether this should work or not. I thought, maybe I overlooked a requirement like a stability guarantee for

state

or

item

, or something else. For example if someone had told me "Yeah your State needs to be @Stable for this to work" I could have stopped debugging the problem. But if the answer is "No, this should always work" then I have to do more in-depth debugging to pin point the reason why it doesn't work in this case.

Yep that definitely should work, as written