Why does my SwiftUI app crash when navigating backwards after placing a `NavigationLink` inside of a `navigationBarItems` in a `NavigationView`?

Question

EDIT: This has been fixed in iOS 13.3!

Minimal reproducible example (Xcode 11.2 beta, this works in Xcode 11.1):

struct Parent: View {         


        

Answer 1

This also has frustrated me for quite some time. Over the past few months, depending on the Xcode version, simulator version and real device type and/or version, it has gone from working to failing to working again, seemingly at random. However, recently it has been failing consistently for me, so yesterday I took a deep dive into it. I am currently using Xcode Version 11.2.1 (11B500).

It looks like the issue revolves around the Nav Bar and the way the buttons were added to it. So instead of using a NavigationLink() for the button itself, I tried using a standard Button() with an action that sets a @State var that activates a hidden NavigationLink. Here is a replacement for Robert's Parent View:

struct Parent: View {
    @State private var showingChildView = false
    var body: some View {
        NavigationView {
            VStack {
                Text("Hello World")
                NavigationLink(destination: Child(),
                               isActive: self.$showingChildView)
                { EmptyView() }
                    .frame(width: 0, height: 0)
                    .disabled(true)
                    .hidden()            
             }
             .navigationBarItems(
                 trailing: Button(action:{ self.showingChildView = true }) { Text("Next") }
             )
        }
    }
}

For me, this works very consistently across all simulators and all real devices.

Here are my helper views:

struct HiddenNavigationLink: View {

    public var destination:  Destination
    public var isActive: Binding

    var body: some View {

        NavigationLink(destination: self.destination, isActive: self.isActive)
        { EmptyView() }
            .frame(width: 0, height: 0)
            .disabled(true)
            .hidden()
    }
}

struct ActivateButton : View where Label : View {

    public var activates: Binding
    public var label: Label

    public init(activates: Binding, @ViewBuilder label: () -> Label) {
        self.activates = activates
        self.label = label()
    }

    var body: some View {
        Button(action: { self.activates.wrappedValue = true }, label: { self.label } )
    }
}

Here is an example of the usage:

struct ContentView: View {
    @State private var showingAddView: Bool = false
    var body: some View {
        NavigationView {
            VStack {
                Text("Hello, World!")
                HiddenNavigationLink(destination: AddView(), isActive: self.$showingAddView)
            }
            .navigationBarItems(trailing:
                HStack {
                    ActivateButton(activates: self.$showingAddView) { Image(uiImage: UIImage(systemName: "plus")!) }
                    EditButton()
            } )
        }
    }
}