NavigationStack: Infinite Loops Investigation

DuplicatePathElements.swift

/// https://mastodon.social/@davedelong/115815506537564728
/// Attempted reproduction for the behavior mentioned in the above toot.

import SwiftUI

struct ContentView: View {
    @State private var path: [Int] = []

    var body: some View {
        NavigationStack(path: $path) {
            VStack(spacing: 20) {
                Text("NavigationStack Bug Demo")
                    .font(.largeTitle)
                    .padding()

                Text("Current path: \(path.description)")
                    .font(.caption)
                    .foregroundColor(.secondary)

                Divider()

                Text("Instructions:")
                    .font(.headline)
                Text("1. Navigate to Screen 1")
                Text("2. Navigate to Screen 2")
                Text("3. Navigate to Screen 1 again (duplicate in path)")
                Text("4. Click the back button on macOS")
                Text("→ This should cause an infinite loop on macOS (but I'm not observing this behavior?")
                    .foregroundColor(.red)
                    .padding(.top)

                Divider()

                ForEach(1..<4) { number in
                    Button("Navigate to Screen \(number)") {
                        path.append(number)
                    }
                    .buttonStyle(.borderedProminent)
                }

                if !path.isEmpty {
                    Button("Pop to Root") {
                        path.removeAll()
                    }
                    .buttonStyle(.bordered)
                }
            }
            .padding()
            .navigationDestination(for: Int.self) { number in
                DetailView(number: number, path: $path)
            }
            .navigationTitle("Root")
        }
    }
}

struct DetailView: View {
    let number: Int
    @Binding var path: [Int]

    var body: some View {
        VStack(spacing: 20) {
            Text("Screen \(number)")
                .font(.largeTitle)

            Text("Current path: \(path.description)")
                .font(.caption)
                .foregroundColor(.secondary)

            Divider()

            Text("Navigate to another screen to create a duplicate in the path:")
                .multilineTextAlignment(.center)
                .padding()

            ForEach(1..<4) { num in
                Button("Navigate to Screen \(num)") {
                    path.append(num)
                }
                .buttonStyle(.borderedProminent)
            }

            Button("Pop to Root") {
                path.removeAll()
            }
            .buttonStyle(.bordered)
            .padding(.top)
        }
        .padding()
        .navigationTitle("Screen \(number)")
    }
}

#Preview {
    ContentView()
}