Combination of Searchable, NavigationLink and navigationBarItems break app

Question

When you compile below code and enter "J" in the search field and then click one of the entries, the app crashes when showing the NavigationLink destination. Clicking on an entry without any active filter works fine.

import SwiftUI
import Combine



public class Person: Identifiable, ObservableObject {
    public var id = UUID()
    var firstName: String = ""
    var lastName: String = ""
}

struct PersonView: View{
    @ObservedObject var person: Person = Person()
    @State public var navigationBarTitle: String = "New item"
    
    var body: some View{
        Group{
            VStack{
                Form{
                    Section(header: Text("Some section")){
                        Text("Detail for \(person.firstName) \(person.lastName)")
                    }
                    
                }
            }
        }//Group
        .navigationBarTitle(self.navigationBarTitle)
        .navigationBarItems(leading: (
            EmptyView()
        ), trailing: (
            Button(action: {
                print("-------SAVE-------")
            }, label: {
                Text("Save")
            }
                  )
        ))
    }
}

struct ContentView: View {
    @State var persons: [Person] = []
    @State var searchText = ""
    
    var searchResults: [Person] {
        if searchText.isEmpty {
            return persons
        } else {
            return persons.filter { $0.firstName
                    .lowercased()
                    .contains(searchText.lowercased())
                ||
                $0.lastName
                    .lowercased()
                    .contains(searchText.lowercased())
            }
        }
    }
    
    var body: some View {
        TabView{
            NavigationView{
                ZStack{
                    List{
                        ForEach(searchResults){person in
                            NavigationLink(destination: PersonView(person: person)) {
                                Text("\(person.firstName) \(person.lastName)")
                            }
                        }//ForEach
                        .listStyle(.plain)
                    }//List
                    .refreshable {
                        print("refresh triggered")
                    }
                    .searchable(text: $searchText)
                }//ZStack
                .toolbar(content: {
                    ToolbarItem{
                        Button {
                            print("button pressed")
                        } label: {
                            Image(systemName: "line.3.horizontal.decrease.circle.fill")
                        }
                    }
                })
                .navigationTitle("Persons")
                
            }//NavigationView
            .onAppear(){
                self.initPersons()
            }
            .tabItem {
                Image(systemName: "rectangle.on.rectangle")
                Text("Persons")
            }
        }
        
        
    }
    
    func initPersons(){
        let person = Person()
        person.firstName = "John"
        person.lastName = "Doe"
        
        let person1 = Person()
        person1.firstName = "Jane"
        person1.lastName = "Doe"
        
        let person2 = Person()
        person2.firstName = "Tim"
        person2.lastName = "Appleseed"
        
        let person3 = Person()
        person3.firstName = "Sally"
        person3.lastName = "Snickers"
        
        self.persons.append(person)
        self.persons.append(person1)
        self.persons.append(person2)
        self.persons.append(person3)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

I have noticed that when I remove the code block

.navigationBarItems(leading: (
            EmptyView()
        ), trailing: (
            Button(action: {
                print("-------SAVE-------")
            }, label: {
                Text("Save")
            }
                  )
        ))

from the PersonView view, it works fine. What am I missing here?

UPDATED CODE BELOW BASED ON LOREM IPSUM's recommendation, still does not solve the issue:

import SwiftUI
import Combine



public class Person: Identifiable, ObservableObject {
    public var id = UUID()
    var firstName: String = ""
    var lastName: String = ""
}

struct PersonView: View{
    @ObservedObject var person: Person = Person()
    @State public var navigationBarTitle: String = "New item"
    
    var body: some View{
        Group{
            VStack{
                Form{
                    Section(header: Text("Some section")){
                        Text("Detail for \(person.firstName) \(person.lastName)")
                    }
                    
                }
            }
        }//Group
        .toolbar {
            ToolbarItem(placement: .primaryAction, content: {
                Button("Save"){
                    print("Saved")
                }
            })
        }
        .navigationTitle(self.navigationBarTitle)
    }
}

struct ContentView: View {
    @State var persons: [Person] = []
    @State var searchText = ""
    
    var searchResults: [Person] {
        if searchText.isEmpty {
            return persons
        } else {
            return persons.filter { $0.firstName
                    .lowercased()
                    .contains(searchText.lowercased())
                ||
                $0.lastName
                    .lowercased()
                    .contains(searchText.lowercased())
            }
        }
    }
    
    var body: some View {
        TabView{
            NavigationView{
                ZStack{
                    List{
                        ForEach(searchResults){person in
                            NavigationLink(destination: PersonView(person: person)) {
                                Text("\(person.firstName) \(person.lastName)")
                            }
                        }//ForEach
                        .listStyle(.plain)
                    }//List
                    .refreshable {
                        print("refresh triggered")
                    }
                    .searchable(text: $searchText)
                }//ZStack
                .toolbar(content: {
                    ToolbarItem{
                        Button {
                            print("button pressed")
                        } label: {
                            Image(systemName: "line.3.horizontal.decrease.circle.fill")
                        }
                    }
                })
                .navigationTitle("Persons")
                
            }//NavigationView
            .onAppear(){
                self.initPersons()
            }
            .tabItem {
                Image(systemName: "rectangle.on.rectangle")
                Text("Persons")
            }
        }
        
        
    }
    
    func initPersons(){
        let person = Person()
        person.firstName = "John"
        person.lastName = "Doe"
        
        let person1 = Person()
        person1.firstName = "Jane"
        person1.lastName = "Doe"
        
        let person2 = Person()
        person2.firstName = "Tim"
        person2.lastName = "Appleseed"
        
        let person3 = Person()
        person3.firstName = "Sally"
        person3.lastName = "Snickers"
        
        self.persons.append(person)
        self.persons.append(person1)
        self.persons.append(person2)
        self.persons.append(person3)
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}

Answer 1

you could try a small re-structure of your code and the following approach, using one class PersonsModel: ObservableObject for the view model, and struct Person, such as:

public class PersonsModel: ObservableObject {  // <-- here
    @Published var persons: [Person] = []
}

struct Person: Identifiable {  // <-- here
    let id = UUID()
    var firstName: String = ""
    var lastName: String = ""
}

struct PersonView: View{
    @State var person: Person   // <-- here
    @State public var navigationBarTitle: String = "New item"
    
    var body: some View{
        Group{
            VStack{
                Form{
                    Section(header: Text("Some section")){
                        Text("Detail for \(person.firstName) \(person.lastName)")
                    }
                    
                }
            }
        }//Group
        .toolbar {
            ToolbarItem(placement: .primaryAction, content: {
                Button("Save"){
                    print("Saved")
                }
            })
        }
        .navigationTitle(navigationBarTitle)
    }
}

struct ContentView: View {
    @StateObject var viewModel = PersonsModel() // <-- here
    @State var searchText = ""
    
    var searchResults: [Person] {
        if searchText.isEmpty {
            return viewModel.persons
        } else {
            return viewModel.persons.filter { $0.firstName
                    .lowercased()
                    .contains(searchText.lowercased())
                ||
                $0.lastName
                    .lowercased()
                    .contains(searchText.lowercased())
            }
        }
    }
    
    var body: some View {
        TabView{
            NavigationView{
                ZStack{
                    List{
                        ForEach(searchResults){ person in
                            NavigationLink(destination: PersonView(person: person)) {
                                Text("\(person.firstName) \(person.lastName)")
                            }
                        }//ForEach
                        .listStyle(.plain)
                    }//List
                    .refreshable {
                        print("refresh triggered")
                    }
                    .searchable(text: $searchText)
                }//ZStack
                .toolbar(content: {
                    ToolbarItem{
                        Button {
                            print("button pressed")
                        } label: {
                            Image(systemName: "line.3.horizontal.decrease.circle.fill")
                        }
                    }
                })
                .navigationTitle("Persons")
                
            }//NavigationView
            .onAppear(){
                initPersons()
            }
            .tabItem {
                Image(systemName: "rectangle.on.rectangle")
                Text("Persons")
            }
        }
    }
    
    func initPersons() {
        let person = Person(firstName: "John", lastName: "Doe")
        let person1 = Person(firstName: "Jane", lastName: "Doe")
        let person2 = Person(firstName: "Tim", lastName: "Appleseed")
        let person3 = Person(firstName: "Sally", lastName: "Snickers")
        
        viewModel.persons.append(person)
        viewModel.persons.append(person1)
        viewModel.persons.append(person2)
        viewModel.persons.append(person3)
    }
}

I think that in your original ContentView using @State var persons: [Person] with class Person: ObservableObject is not a good idea.