Some of the Composable DSL functions could be optimized

[Nek-12]

I was looking at the sources and realized there could be improvements made to the recompositions of DI functions.

1. LocalDi should be made public to allow clients to provide the DI via a uniform syntax. When the localDi function is used, it is not marked as non-skippable, which leads to an additional nesting level in the tree. Instead, the LocalDi composition local should be made public so that clients can provide the DI more efficiently:

@Composable
internal fun ProvideDestinationLocals(
    component: DestinationComponent,
    content: @Composable () -> Unit
) = CompositionLocalProvider(
    LocalSubscriberLifecycle provides component.subLifecycle,
    LocalDestinationContext provides component,
    // LocalDi provides component.diContext // desired, avoids composition and object creation
) {
    // current - requires a nesting level in the tree
    OnDIContext(content = content, context = remember { diContext(component.context) })
}

2. Some of the functions, such as OnDIContext(context: DIContext<*>, content: @Composable () -> Unit) create the DiContext in-place in the composition. This can lead to unnecessary allocations of contexts on every recomposition and heap pollution. We should avoid creating objects directly in composition and use remember with a lambda-driven DSL where possible.

3. The functions that provide the DI context do not utilize rememberUpdatedState, which means once a lambda is captured inside the remember block, it will not change. If the user of the code has their lambda be recreated on recomposition, this will lead to issues as the With* functions from kodein that take lambdas will not pick up the updated lambda. This can only manifest if the lambdas capture parameters out of composition that can change. See docs for details

4. DI value is not properly recreated when incoming params change. An optimized solution will make use of remember keys to properly re-create the di when the incoming parameters change. This is avoided by #3 and #2 but has to be kept in mind when those are addressed.

Would you like for me to take a stab at this feature in a PR?

[romainbsl]

Improving / Enhancing / Fixing Compose is my next task on Kodein, but it is a side project, so not sure when. If you have some time and the whiling to contribute, be my guest :)

[Nek-12]

Got it, I'll take a stab at it and let you know.