Fix initialization of authenticator

RELEASE-NOTES.txt

@@ -3,6 +3,7 @@
 
 23.0
 -----
+- [*] Fix initialization of authenticator to avoid crashes during login [https://github.com/woocommerce/woocommerce-ios/pull/15953]
 
 
 22.9

WooCommerce/Classes/Authentication/Epilogue/StorePickerViewController.swift

@@ -369,7 +369,6 @@ private extension StorePickerViewController {
     }
 
     func presentSiteDiscovery() {
-        ServiceLocator.authenticationManager.initialize()
         guard let viewController = WordPressAuthenticator.siteDiscoveryUI() else {
             return
         }

WooCommerce/Classes/ViewRelated/AppCoordinator.swift

@@ -89,7 +89,6 @@ final class AppCoordinator {
                     self.displayLoggedInStateWithoutDefaultStore()
                 case (true, false):
                     self.validateRoleEligibility {
-                        self.configureAuthenticator()
                         self.displayLoggedInUI()
                         self.synchronizeAndShowWhatsNew()
                     }
@@ -200,19 +199,13 @@ private extension AppCoordinator {
             presentLoginOnboarding { [weak self] in
                 guard let self = self else { return }
                 // Only displays the authenticator when dismissing onboarding to allow time for A/B test setup.
-                self.configureAndDisplayAuthenticator()
+                self.displayAuthenticator()
             }
         } else {
-            configureAndDisplayAuthenticator()
+            displayAuthenticator()
         }
     }
 
-    /// Configures the WPAuthenticator and sets the authenticator UI as the window's root view.
-    func configureAndDisplayAuthenticator() {
-        configureAuthenticator()
-        displayAuthenticator()
-    }
-
     /// Configures the WPAuthenticator for usage in both logged-in and logged-out states.
     func configureAuthenticator() {
         authenticationManager.initialize()

WooCommerce/Classes/ViewRelated/JetpackSetup/JetpackSetupCoordinator.swift

@@ -57,10 +57,6 @@ final class JetpackSetupCoordinator {
         self.stores = stores
         self.analytics = analytics
         self.featureFlagService = featureFlagService
-
-        /// the authenticator needs to be initialized with configs
-        /// to be used for requesting authentication link and handle login later.
-        WordPressAuthenticator.initializeWithCustomConfigs(dotcomAuthScheme: dotcomAuthScheme)
     }
 
     func showBenefitModal() {

WooCommerce/WordPressAuthenticator/Authenticator/WordPressAuthenticator.swift

@@ -84,6 +84,12 @@ import WordPressUI
                                   unifiedStyle: WordPressAuthenticatorUnifiedStyle?,
                                   displayImages: WordPressAuthenticatorDisplayImages = .defaultImages,
                                   displayStrings: WordPressAuthenticatorDisplayStrings = .defaultStrings) {
+        guard privateInstance == nil else {
+            if isRunningTests() == false { // avoid crashing in tests
+                assertionFailure("Attempting to initialize WordPressAuthenticator more than once - this would cause the delegate to be reset. Aborting... 🙅⛔️")
+            }
+            return
+        }
         privateInstance = WordPressAuthenticator(configuration: configuration,
                                                  style: style,
                                                  unifiedStyle: unifiedStyle,
@@ -487,3 +493,9 @@ public extension WordPressAuthenticator {
         appleIDCredentialObserver = nil
     }
 }
+
+private extension WordPressAuthenticator {
+    static func isRunningTests() -> Bool {
+        return NSClassFromString("XCTestCase") != nil
+    }
+}

WooCommerce/WordPressAuthenticator/Signin/LoginViewController.swift

@@ -32,7 +32,7 @@ open class LoginViewController: NUXViewController, LoginFacadeDelegate {
 
     var authenticationDelegate: WordPressAuthenticatorDelegate {
         guard let delegate = WordPressAuthenticator.shared.delegate else {
-            fatalError()
+            fatalError("No delegate found for WordPressAuthenticator")
         }
 
         return delegate
@@ -140,7 +140,7 @@ open class LoginViewController: NUXViewController, LoginFacadeDelegate {
 
     func showLoginEpilogue(for credentials: AuthenticatorCredentials) {
         guard let navigationController = navigationController else {
-            fatalError()
+            fatalError("No navigation controller found to show login epilogue")
         }
 
         authenticationDelegate.presentLoginEpilogue(in: navigationController,