Cannot convert value of type `AuthResultCallback`? - swift

Question

I know about other similar questions, but they are to do with Auth.auth().signIn and signUp respectively, where there is a completion handler argument present within the function.
I'm trying to include a sign in the anonymous function to my SessionStore class so that my app observes the state of the user, i.e., whether he is signed in (anonymously or otherwise) or signed out, and accordingly display the relevant view.
However, when trying to add anonymous sign up to my SessionStore class, I get the following error:
Cannot convert value of type 'AuthResultCallback' (aka '(Optional<User>, Optional<Error>) -> ()') to expected argument type 'AuthDataResultCallback?' (aka 'Optional<(Optional<AuthDataResult>, Optional<Error>) -> ()>')
My code is as follows:
class SessionStore: ObservableObject {
var didChange = PassthroughSubject<SessionStore, Never>()
#Published var session: User? {didSet {self.didChange.send(self)}}
var handle: AuthStateDidChangeListenerHandle?
func listen() {
handle = Auth.auth().addStateDidChangeListener({ (auth, user) in
if let user = user {
self.session = User(uid: user.uid, email: user.email)
} else {
self.session = nil
}
})
}
func signUp(email: String, password: String, handler: #escaping AuthDataResultCallback) {
Auth.auth().createUser(withEmail: email, password: password, completion: handler)
}
func signIn(email: String, password: String, handler: #escaping AuthDataResultCallback) {
Auth.auth().signIn(withEmail: email, password: password, completion: handler)
}
func signOut() {
do {
try Auth.auth().signOut()
self.session = nil
} catch {
print("Error signing user out")
}
}
func signUpAnonymously(handler: #escaping AuthResultCallback) {
Auth.auth().signInAnonymously(completion: handler) // **ERROR APPEARS HERE**
}
func unbind() {
if let handle = handle {
Auth.auth().removeStateDidChangeListener(handle)
}
}
deinit {
unbind()
}
}
struct User {
var uid: String
var email: String?
init(uid: String, email: String?) {
self.uid = uid
self.email = email
}
}
Can someone tell me how to fix this error?

Answer 1

The code snippet you pasted is from an outdated tutorial. As of Xcode 11 beta 5, you no longer need to use PassthroughSubject to send notifications about property changes. Sarun's blog post has a great and concise section on what has changed, I encourage you to read it.
Please also note that you don't need to define your own User class if you only care about the user's ID and their email address, as these attributes are already defined on Firebase's own User type (by way of implementing the UserInfo protocol).
Here is a snippet that shows how to implement the callback you're interested in (see registerStateListener).
class AuthenticationService: ObservableObject {
#Published var user: User?
private var handle: AuthStateDidChangeListenerHandle?
init() {
registerStateListener()
}
func signIn() {
if Auth.auth().currentUser == nil {
Auth.auth().signInAnonymously()
}
}
func signOut() {
do {
try Auth.auth().signOut()
}
catch {
print("Error when trying to sign out: \(error.localizedDescription)")
}
}
func updateDisplayName(displayName: String, completionHandler: #escaping (Result<User, Error>) -> Void) {
if let user = Auth.auth().currentUser {
let changeRequest = user.createProfileChangeRequest()
changeRequest.displayName = displayName
changeRequest.commitChanges { error in
if let error = error {
completionHandler(.failure(error))
}
else {
if let updatedUser = Auth.auth().currentUser {
print("Successfully updated display name for user [\(user.uid)] to [\(updatedUser.displayName ?? "(empty)")]")
// force update the local user to trigger the publisher
self.user = updatedUser
completionHandler(.success(updatedUser))
}
}
}
}
}
private func registerStateListener() {
if let handle = handle {
Auth.auth().removeStateDidChangeListener(handle)
}
self.handle = Auth.auth().addStateDidChangeListener { (auth, user) in
print("Sign in state has changed.")
self.user = user
if let user = user {
let anonymous = user.isAnonymous ? "anonymously " : ""
print("User signed in \(anonymous)with user ID \(user.uid). Email: \(user.email ?? "(empty)"), display name: [\(user.displayName ?? "(empty)")]")
}
else {
print("User signed out.")
self.signIn()
}
}
}
}
If you're interested in more background, check out my article series about building a to-do app with SwiftUI and Firebase: part 1 (building the UI using SwiftUI), part 2 (storing data in Firestore and using Firebase Anonymous Auth), part 3 (Sign in with Apple)