How do I fix 'unrecognized selector sent to instance' in swift?

Question

I am working on an app using coreData and a log in. For that, I have a LoginView and LoginViewModel that I use to get the info to the ContentView. I keep getting this error message: "Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[abcText2Speech.UserEntity firstname]: unrecognized selector sent to instance 0x6000017f14c0'"

Here is my code where I think the issue lies :

this is from LoginViewModel:

func signup()-\> (UserEntity, Int){ @StateObject var dataController = DataController.shared buttonState = .loading(title: "Loading", systemImage: "person") DispatchQueue.main.asyncAfter(deadline: .now()+1.5){ if self.isValidEmail() && self.isValidPassword() && self.isValidName(){ self.isLoggedIn = true dataController.addUser(firstname: self.fname, lastname: self.lname, email: self.email, password: self.password) print("signed in") print(dataController.savedEntities[(dataController.savedEntities.count)-1].email ?? "email") print(self.isLoggedIn) self.buttonState = .enabled(title: "Login", systemImage: "checkmark.circle") } else{ self.buttonState = .disabled(title: "Fill out all fields to log in", systemImage: "exclamationmark.circle") } } print("Test") print(dataController.savedEntities[(dataController.savedEntities.count)-1].email ?? "email") return (dataController.savedEntities[(dataController.savedEntities.count)-1], 1) } 

and this all prints with no issue.

this is the relevant part of sign up view

ActionButton(state: $model.buttonState, onTap:{ signup = model.signup() user = signup.0 }, backgroundColor: .primary , foregroundColor: Color(UIColor.systemBackground) ) NavigationLink (destination: LoginView()){ Text("Already have a profile? Click here to Log in") } } } label: { Label("Welcome!", systemImage: "hand.wave") } .padding() .textFieldStyle(.plain) let keyboard = abcTextViewModel() NavigationLink (destination: ContentView(viewModel: keyboard, currentUser: user) , isActive: $model.isLoggedIn){ EmptyView() }` 

and this is the part of Content view that breaks it

Text(currentUser.firstname ?? "name") 

these are the details of UserEntity

and this is the DataController code

import Foundation import CoreData class DataController: ObservableObject{ static let shared = DataController() let container: NSPersistentContainer @Published var savedEntities: [UserEntity] = [] init(){ container = NSPersistentContainer(name: "Model") container.loadPersistentStores { description, error in if let error = error { print("Core Data failed to load: \(error.localizedDescription)") } } fetchUsers() } func fetchUsers() { let request = NSFetchRequest<UserEntity>(entityName: "UserEntity") do { savedEntities = try container.viewContext.fetch(request) } catch let error { print("Error while fetching: \(error)") } } func addUser(firstname: String, lastname: String, email: String, password: String) { let newUser = UserEntity(context: container.viewContext) newUser.firstname = firstname newUser.lastname = lastname newUser.email = email newUser.id = password saveData() } func saveData(){ do { try container.viewContext.save() fetchUsers() } catch let error { print("Error saving: \(error)") } } } 

any help would be greatly appreciated, I have been stuck on this one error for quite a while

This is where the code sends the error (on the struct abcText2SpeechApp line):

import SwiftUI @main struct abcText2SpeechApp: App { var body: some Scene { WindowGroup{ SignUpView() .environment(\.managedObjectContext, DataController.shared.container.viewContext) } } } 

I tried printing the user details in login view model which worked, however that did not carry over to content view.

Answer 1

That error message means you are trying to call a method on an object that has been deallocated. You're using a function, method, or accessor on a variable, but that variable doesn't have a valid object anymore.

If the line is

Text(currentUser.firstname ?? "name") 

Then it means that currentUser does not have a valid object. Maybe it did once, but it doesn't when the crash happens.

Why this happens is not clear from the code you posted. There is no currentUser variable anywhere in the code except on that one line, so it's impossible to say where that variable is defined, where it gets its value, or why the object might be deallocated.