This is a bare minimum example of koinNavGraphViewModel failing to restore the state correctly when the VM uses a SavedStateHandle (or at least it doesn't behave in the way I would expect).

To simulate the case where the activity gets killed by the system you should enable the Don't keep activities option in the Developer settings which makes the behavior reproducible.

Expectations:

There are 2 fragments in the flow, FirstFragment and SecondFragment. Each fragment has its own view model but there's also SharedViewModel for the state that's shared across the two fragment and should be valid for the lifecycle of the flow.

The shared state is passed to the first fragment as an argument, then stored in the SharedViewModle, and displayed on the screen in both fragments.

The expected behavior is that the state is persisted for the lifecycle of the flow (navigation subgraph) and that it will be restored after the application comes back from the background where it was killed by the system.

The behavior is correct in the FirstFragment because there the state gets restored from the navigation arguments but it should be restored in the SecondFragment too.

I also added a log and a toast that are shown when the shared VM is cleared to understand its lifecycle.

Behavior:

1. koinNavGraphViewModel

   • the state is lost on the SecondFragment - ("NO STATE" fallback value is displayed)
   • SharedViewModel is cleared as expected when the flow is closed

2. activityViewModel

   • the state is restored correctly on the SecondFragment
   • SharedViewModel is not cleared when the flow is closed, it's only cleared when the app goes to background

3. activityViewModel with custom producers

   • the state is restored correctly on the SecondFragment
   • SharedViewModel is cleared as expected when the flow is closed

val sharedViewModel by activityViewModel<SharedViewModel>(
     ownerProducer = { findNavController().getViewModelStoreOwner(R.id.modifiedactivityvm_shared_state_flow) },
     extrasProducer = { findNavController().getBackStackEntry(R.id.modifiedactivityvm_shared_state_flow).defaultViewModelCreationExtras }
)

To me the current behavior of koinNavGraphViewModel seems incorrect and I would expect it to behave as the case no. 3.