Xcode 16.4以降、NavigationStack の挙動がおかしい

ContentView.swift

//
//  ContentView.swift
//  SampleNavigationStackOnAppear
//
//  Created by wada.kenji on 2025/07/02.
//

import os
import SwiftUI

public enum Logger {
    public static let standard: os.Logger = .init(
        subsystem: Bundle.main.bundleIdentifier!,
        category: "Standard"
    )
}

enum Route: Hashable {
    case screenA
    case screenB
    case screenC
    case screenD
}

class Router: ObservableObject {
    @Published
    private(set) var path = NavigationPath()

    func setPath(path: NavigationPath) {
        self.path = path
    }

    func present(route: Route) {
        path.append(route)
    }

    func pop() {
        path.removeLast()
    }

    func popToRoot() {
        path.removeLast(path.count)
    }
}

struct ContentView: View {
    @StateObject
    private var router = Router()

    var body: some View {
        NavigationStack(path: .init(
            get: { router.path },
            set: { router.setPath(path: $0) }
        )) {
            DummyScreen(screenName: "ScreenA") {
                router.present(route: .screenB)
            }
            .navigationDestination(for: Route.self) { route in
                switch route {
                case .screenA:
                    DummyScreen(screenName: "ScreenA") {
                        router.present(route: .screenB)
                    }
                case .screenB:
                    DummyScreen(screenName: "ScreenB") {
                        router.present(route: .screenC)
                    }
                case .screenC:
                    DummyScreen(screenName: "ScreenC") {
                        router.present(route: .screenD)
                    }
                case .screenD:
                    DummyScreen(screenName: "ScreenD", action: nil)
                }
            }
        }
        .environmentObject(router)
    }
}

struct DummyScreen: View {
    @EnvironmentObject var router: Router

    let screenName: String
    let action: (() -> Void)?

    var body: some View {
        VStack {
            Text(screenName)
                .font(.title)
            if let action {
                Button("Go to next screen", action: action)
            }
        }
        .navigationTitle(Text(screenName))
        .onAppear {
            Logger.standard.debug("\(screenName) の onAppear")
        }
    }
}

@main
struct SampleNavigationStackOnAppearApp: App {
    var body: some Scene {
        WindowGroup {
            ContentView()
        }
    }
}