NavigationStackStore missunderstanding

[ivangodfather]

I have a top level RootFeature with a TabBar.
In first tab I have NavigationFeature, that pushes ItemFeature using a regular NavigationStack and

            .navigationDestination(
                store: store.scope(state: \.$destination, action: NavigationFeature.Action.destination),
                state: /NavigationFeature.Destination.State.itemAsNavigation,
                action: NavigationFeature.Destination.Action.itemAsNavigation,
                destination: ItemView.init
            )

In a second tab I have in the middle called StackNavFeature. This feature holds a NavigationStackStore, and I'm able to present the NavigaitonFeature from first tab. The problem is that now when I try to use the link with the above pattern the link gets stuck and freezes.
I'm not even sure if mixing like this is possible, or should I always use NavigationStackStore in both cases?

Here is a sample app showcasing the problem:
https://github.com/ivangodfather/TCANavBug

[mbrandonw]

Hi @ivangodfather, I can't say I know exactly why the app is freezing up, but I would say in general you should not mix the NavigationStackStore style of navigation with the presentationDestination(store:) style. The NavigationExampleView is trying to be used in both situations, and that is causing the problem.

Similar things happen when trying to mix NavigationStack with navigationDestination(isPresented:) in vanilla SwiftUI. It doesn't freeze, but it is possible for SwiftUI to become confused as to which screen is actually being presented since the one shown with navigationDestination is not represented in the stack's binding, and it can leave the UI in an inconsistent state.

Also, I am a little confused with the comment in your code:

// I image the bug is here, when I click the item feature (embeeded inside navigation) it goes the with navigation switch

The NavigationLink(state:) you are using is pointed to the navigation case:

NavigationLink(state: StackNavFeature.Path.State.navigation(.init()))

That is why it is destructuring on the navigation case.

[ivangodfather]

@mbrandonw this comment is because when I tap the item as a link the NavigationStackStore destination also gets called, but not entering the case .item, instead the case .navigation.

From your answer I understand the solution is to use a NavigationStackStore in both cases, but still this feature will live inside 2 differents ones,

        NavigationLink(
          state: StackNavFeature.Path.State.item(
           ....
          )
        ) {
          Text("Go to item")
        }
        NavigationLink(
          state: ???.Path.State.item(
           ....
          )
        ) {
          Text("Go to item")
        }

I'm still a bit confused :(

[mbrandonw]

Yeah, in that case, when you need a child feature to live in two different stacks, you cannot use NavigationLink(state:). This is true of vanilla SwiftUI too when using an array for the binding in NavigationStack.

Instead, you need to send an action from the child feature that the parent domain intercepts, and then the parent reducer will append to the path stack state.

[ivangodfather]

Oh ok! Thanks! I wasn't aware of this

[atsixian]

in general you should not mix the NavigationStackStore style of navigation with the presentationDestination(store:) style

Hi @mbrandonw, I'm wondering if we can put this into the doc. My program freezes today because of mixing these two styles, but I didn't find any warning in the Navigation section. I think it may help others who are not familiar with the vanilla SwiftUI issue like me.