@State's initial value doesn't change on re-render

Problem Statement

I'm having trouble understanding how to reset a @State property to its initial value.

In my app, I have one view that sets an integer "default value". The other view reads it, but doesn't change it:

Code Block 
struct ContentView: View {
    @State var selectedValue = 1
    var body: some View {
        VStack{
            DefaultValueView(defaultValue: $selectedValue)
            ComputeView(defaultValue: selectedValue)
        }
    }
}

The first view is simple: it uses a @Binding to the selected value and updates it based on the user's selection. Here, we let the user choose a default value between 1 and 10:

Code Block 
struct DefaultValueView: View {
    @Binding var defaultValue: Int
    var body: some View {
        VStack {
            Text("Select the default value")
            ForEach(1...10, id: \.self) { i in
                Button("Value: \(i)") {
                    defaultValue = i
                }.background(i == defaultValue ? Color.red : Color.clear)
            }
        }
    }
}

In a second, I want to have the following behavior:

• When the selectedValue changes, it displays the selected value.

• The user can increment or decrement the displayed value. This doesn't change the selectedValue, just what's displayed in this view.

My attempt was this:

Code Block 
struct ComputeView: View {
    @State var additionalValue: Int
    
    init(defaultValue: Int) {
        _additionalValue = State(initialValue: defaultValue)
    }
    
    var body: some View {
        VStack {
            Text("10 plus..")
            Stepper("\(additionalValue)") {
                additionalValue += 1
            } onDecrement: {
                additionalValue -= 1
            }
            Text("= \(10 + additionalValue)")
        }.padding()
    }
}

This achieves the 2nd behavior (I can edit the displayed value with the stepper) but not the 1st. When I change "default value" to something else, it doesn't change in this view. I've got a breakpoint in the init method, so I know it's being re-set to the new initialValue, but it doesn't change.


What am I missing?

Full app to copy/paste:

Code Block 
import SwiftUI
@main
struct DefaultEditableValueApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}
struct ContentView: View {
    @State var selectedValue = 1
    var body: some View {
        VStack{
            DefaultValueView(defaultValue: $selectedValue)
            ComputeView(defaultValue: selectedValue)
        }
    }
}
struct DefaultValueView: View {
    @Binding var defaultValue: Int
    var body: some View {
        VStack {
            Text("Select the default value")
            ForEach(1...10, id: \.self) { i in
                Button("Value: \(i)") {
                    defaultValue = i
                }.background(i == defaultValue ? Color.red : Color.clear)
            }
        }
    }
}
struct ComputeView: View {
    @State var additionalValue: Int
    
    init(defaultValue: Int) {
        _additionalValue = State(initialValue: defaultValue)
    }
    
    var body: some View {
        VStack {
            Text("10 plus..")
            Stepper("\(additionalValue)") {
                additionalValue += 1
            } onDecrement: {
                additionalValue -= 1
            }
            Text("= \(10 + additionalValue)")
        }.padding()
    }
}

Code Block 
import SwiftUI
@main
struct DefaultEditableValueApp: App {
		var body: some Scene {
				WindowGroup {
						ContentView()
				}
		}
}
class SelectedState: ObservableObject {
		@Published var value: Int = 1
}
struct ContentView: View {
		@StateObject var selectedState = SelectedState()
		var body: some View {
				VStack{
						DefaultValueView(defaultValue: $selectedState.value)
						ComputeView(selectedState: selectedState)
				}
		}
}
struct DefaultValueView: View {
		@Binding var defaultValue: Int
		var body: some View {
				VStack {
						Text("Select the default value")
						ForEach(1...10, id: \.self) { i in
								Button("Value: \(i)") {
										defaultValue = i
								}.background(i == defaultValue ? Color.red : Color.clear)
						}
				}
		}
}
struct ComputeView: View {
		@State var additionalValue: Int = 0
		@ObservedObject var selectedState: SelectedState
		
		var body: some View {
				VStack {
						Text("10 plus..")
						Stepper("\(additionalValue)") {
								additionalValue += 1
						} onDecrement: {
								additionalValue -= 1
						}
						Text("= \(10 + additionalValue)")
				}.padding()
				.onReceive(selectedState.$value) {value in
						additionalValue = value
				}
		}
}