[Auth] Fix delete action in sample app (#13554)

FirebaseAuth/Sources/Swift/User/User.swift

@@ -404,7 +404,7 @@ extension User: NSSecureCoding {}
   }
 
   /// Renews the user's authentication tokens by validating a fresh set of credentials supplied
-  ///    by the user  and returns additional identity provider data.
+  /// by the user  and returns additional identity provider data.
   ///
   /// If the user associated with the supplied credential is different from the current user,
   /// or if the validation of the supplied credentials fails; an error is returned and the current

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/Models/AuthMenu.swift

@@ -353,7 +353,7 @@ class AuthMenuData: DataSourceProvidable {
      customAuthDomainSection, appSection, oobSection, multifactorSection]
 
   static var authLinkSections: [Section] {
-    let allItems = AuthMenuData.sections.flatMap { $0.items }
+    let allItems = [providerSection, emailPasswordSection, otherSection].flatMap { $0.items }
     let header = "Manage linking between providers"
     let footer =
       "Select an unchecked row to link the currently signed in user to that auth provider. To unlink the user from a linked provider, select its corresponding row marked with a checkmark."

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/AccountLinkingViewController.swift

@@ -508,7 +508,7 @@ extension AccountLinkingViewController: ASAuthorizationControllerDelegate,
       return
     }
 
-    let credential = OAuthProvider.credential(withProviderID: "apple.com",
+    let credential = OAuthProvider.credential(providerID: .apple,
                                               idToken: idTokenString,
                                               rawNonce: nonce)
     // Once we have created the above `credential`, we can link accounts to it.

FirebaseAuth/Tests/SampleSwift/AuthenticationExample/ViewControllers/UserViewController.swift

@@ -226,31 +226,46 @@ class UserViewController: UIViewController, DataSourceProviderDelegate {
 
   // MARK: - Sign in with Apple Token Revocation Flow
 
-  // For Sign in with Apple
-  private var currentNonce: String?
+  /// Used for Sign in with Apple token revocation flow.
+  private var continuation: CheckedContinuation<ASAuthorizationAppleIDCredential, Error>?
 
-  // [START token_revocation_deleteuser]
   private func deleteCurrentUser() {
-    do {
-      let nonce = try CryptoUtils.randomNonceString()
-      currentNonce = nonce
-      let appleIDProvider = ASAuthorizationAppleIDProvider()
-      let request = appleIDProvider.createRequest()
-      request.requestedScopes = [.fullName, .email]
-      request.nonce = CryptoUtils.sha256(nonce)
-
-      let authorizationController = ASAuthorizationController(authorizationRequests: [request])
-      authorizationController.delegate = self
-      authorizationController.presentationContextProvider = self
-      authorizationController.performRequests()
-    } catch {
-      // In the unlikely case that nonce generation fails, show error view.
-      displayError(error)
+    Task {
+      guard let user else { return }
+      do {
+        let needsTokenRevocation = user.providerData
+          .contains { $0.providerID == AuthProviderID.apple.rawValue }
+        if needsTokenRevocation {
+          let appleIDCredential = try await signInWithApple()
+
+          guard let appleIDToken = appleIDCredential.identityToken else {
+            print("Unable to fetch identify token.")
+            return
+          }
+          guard let idTokenString = String(data: appleIDToken, encoding: .utf8) else {
+            print("Unable to serialise token string from data: \(appleIDToken.debugDescription)")
+            return
+          }
+
+          let nonce = try CryptoUtils.randomNonceString()
+          let credential = OAuthProvider.credential(providerID: .apple,
+                                                    idToken: idTokenString,
+                                                    rawNonce: nonce)
+
+          try await user.reauthenticate(with: credential)
+          if
+            let authorizationCode = appleIDCredential.authorizationCode,
+            let authCodeString = String(data: authorizationCode, encoding: .utf8) {
+            try await Auth.auth().revokeToken(withAuthorizationCode: authCodeString)
+          }
+        }
+        try await user.delete()
+      } catch {
+        displayError(error)
+      }
     }
   }
 
-  // [END token_revocation_deleteuser]
-
   // MARK: - Private Helpers
 
   private func getVerificationCode() async throws -> String {
@@ -343,48 +358,31 @@ extension UserViewController: ASAuthorizationControllerDelegate,
   ASAuthorizationControllerPresentationContextProviding {
   // MARK: ASAuthorizationControllerDelegate
 
-  // [START token_revocation]
-  func authorizationController(controller: ASAuthorizationController,
-                               didCompleteWithAuthorization authorization: ASAuthorization) {
-    guard let appleIDCredential = authorization.credential as? ASAuthorizationAppleIDCredential
-    else {
-      print("Unable to retrieve AppleIDCredential")
-      return
-    }
-
-    guard let _ = currentNonce else {
-      fatalError("Invalid state: A login callback was received, but no login request was sent.")
-    }
-
-    guard let appleAuthCode = appleIDCredential.authorizationCode else {
-      print("Unable to fetch authorization code")
-      return
-    }
+  func signInWithApple() async throws -> ASAuthorizationAppleIDCredential {
+    return try await withCheckedThrowingContinuation { continuation in
+      self.continuation = continuation
+      let appleIDProvider = ASAuthorizationAppleIDProvider()
+      let request = appleIDProvider.createRequest()
+      request.requestedScopes = [.fullName, .email]
 
-    guard let authCodeString = String(data: appleAuthCode, encoding: .utf8) else {
-      print("Unable to serialize auth code string from data: \(appleAuthCode.debugDescription)")
-      return
+      let authorizationController = ASAuthorizationController(authorizationRequests: [request])
+      authorizationController.delegate = self
+      authorizationController.performRequests()
     }
+  }
 
-    Task {
-      do {
-        try await AppManager.shared.auth().revokeToken(withAuthorizationCode: authCodeString)
-        try await user?.delete()
-        self.updateUI()
-      } catch {
-        self.displayError(error)
-      }
+  func authorizationController(controller: ASAuthorizationController,
+                               didCompleteWithAuthorization authorization: ASAuthorization) {
+    if case let appleIDCredential as ASAuthorizationAppleIDCredential = authorization.credential {
+      continuation?.resume(returning: appleIDCredential)
+    } else {
+      fatalError("Unexpected authorization credential type.")
     }
   }
 
-  // [END token_revocation]
-
   func authorizationController(controller: ASAuthorizationController,
-                               didCompleteWithError error: any Error) {
-    // Ensure that you have:
-    //  - enabled `Sign in with Apple` on the Firebase console
-    //  - added the `Sign in with Apple` capability for this project
-    print("Sign in with Apple failed: \(error)")
+                               didCompleteWithError error: Error) {
+    continuation?.resume(throwing: error)
   }
 
   // MARK: ASAuthorizationControllerPresentationContextProviding