throw exception if there is no currentUser. rm duplicate arg labels

Author: russellwheatley

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/AuthServiceError.swift

@@ -13,6 +13,7 @@ public struct AccountMergeConflictContext: LocalizedError {
 }
 
 public enum AuthServiceError: LocalizedError {
+  case noCurrentUser
   case invalidEmailLink(String)
   case notConfiguredProvider(String)
   case clientIdNotFound(String)
@@ -24,6 +25,8 @@ public enum AuthServiceError: LocalizedError {
 
   public var errorDescription: String? {
     switch self {
+    case .noCurrentUser:
+      return "No user is currently signed in."
     case let .invalidEmailLink(description):
       return description
     case let .notConfiguredProvider(description):

FirebaseSwiftUI/FirebaseAuthSwiftUI/Sources/Services/AuthService.swift

@@ -180,7 +180,10 @@ public final class AuthService {
     }
   }
 
-  public func handleAutoUpgradeAnonymousUser(credentials credentials: AuthCredential) async throws {
+  public func handleAutoUpgradeAnonymousUser(credentials: AuthCredential) async throws {
+    if currentUser == nil {
+      throw AuthServiceError.noCurrentUser
+    }
     do {
       try await currentUser?.link(with: credentials)
     } catch let error as NSError {
@@ -196,7 +199,7 @@ public final class AuthService {
     }
   }
 
-  public func signIn(credentials credentials: AuthCredential) async throws {
+  public func signIn(credentials: AuthCredential) async throws {
     authenticationState = .authenticating
     do {
       if shouldHandleAnonymousUpgrade {