Swizzles APNs token error app delegate method for faster turnaround. (#226)

Also removes the server request in case the token is missing.

12 files changed, 201 insertions, 23 deletions

diff --git a/Example/Auth/Tests/FIRAuthAPNSTokenManagerTests.m b/Example/Auth/Tests/FIRAuthAPNSTokenManagerTests.m
index 37d95a6..68e8bcf 100644
--- a/Example/Auth/Tests/FIRAuthAPNSTokenManagerTests.m
+++ b/Example/Auth/Tests/FIRAuthAPNSTokenManagerTests.m
@@ -80,6 +80,11 @@ static const NSTimeInterval kExpectationTimeout = 1;
       @brief Another piece of data used for testing.
    */
   NSData *_otherData;
+
+  /** @var _error
+      @brief The fake error used for testing.
+   */
+  NSError *_error;
 }
 
 - (void)setUp {
@@ -118,18 +123,20 @@ static const NSTimeInterval kExpectationTimeout = 1;
   // Add first callback, which is yet to be called.
   OCMExpect([_mockApplication registerForRemoteNotifications]);
   __block BOOL firstCallbackCalled = NO;
-  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token) {
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
     XCTAssertEqualObjects(token.data, _data);
     XCTAssertEqual(token.type, FIRAuthAPNSTokenTypeSandbox);
+    XCTAssertNil(error);
     firstCallbackCalled = YES;
   }];
   XCTAssertFalse(firstCallbackCalled);
 
   // Add second callback, which is yet to be called either.
   __block BOOL secondCallbackCalled = NO;
-  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token) {
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
     XCTAssertEqualObjects(token.data, _data);
     XCTAssertEqual(token.type, FIRAuthAPNSTokenTypeSandbox);
+    XCTAssertNil(error);
     secondCallbackCalled = YES;
   }];
   XCTAssertFalse(secondCallbackCalled);
@@ -149,9 +156,10 @@ static const NSTimeInterval kExpectationTimeout = 1;
 
   // Add third callback, which should be called back immediately.
   __block BOOL thirdCallbackCalled = NO;
-  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token) {
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
     XCTAssertEqualObjects(token.data, _data);
     XCTAssertEqual(token.type, FIRAuthAPNSTokenTypeSandbox);
+    XCTAssertNil(error);
     thirdCallbackCalled = YES;
   }];
   XCTAssertTrue(thirdCallbackCalled);
@@ -176,8 +184,48 @@ static const NSTimeInterval kExpectationTimeout = 1;
   // Add callback to time out.
   OCMExpect([_mockApplication registerForRemoteNotifications]);
   XCTestExpectation *expectation = [self expectationWithDescription:@"callback"];
-  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token) {
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
+    XCTAssertNil(token);
+    XCTAssertNil(error);
+    [expectation fulfill];
+  }];
+
+  // Time out.
+  [self waitForExpectationsWithTimeout:kExpectationTimeout handler:nil];
+  OCMVerifyAll(_mockApplication);
+
+  // Calling cancel afterwards should have no effect.
+  [_manager cancelWithError:_error];
+}
+
+/** @fn testCancel
+    @brief Tests cancelling the pending callbacks.
+ */
+- (void)testCancel {
+  // Set up timeout.
+  XCTAssertGreaterThan(_manager.timeout, 0);
+  _manager.timeout = kRegistrationTimeout;
+
+  // Add callback to cancel.
+  OCMExpect([_mockApplication registerForRemoteNotifications]);
+  __block BOOL callbackCalled = NO;
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
+    XCTAssertNil(token);
+    XCTAssertEqualObjects(error, _error);
+    XCTAssertFalse(callbackCalled);  // verify callback is not called twice
+    callbackCalled = YES;
+  }];
+  XCTAssertFalse(callbackCalled);
+
+  // Call cancel.
+  [_manager cancelWithError:_error];
+  XCTAssertTrue(callbackCalled);
+
+  // Add callback to timeout.
+  XCTestExpectation *expectation = [self expectationWithDescription:@"callback"];
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
     XCTAssertNil(token);
+    XCTAssertNil(error);
     [expectation fulfill];
   }];
 
@@ -200,9 +248,10 @@ static const NSTimeInterval kExpectationTimeout = 1;
   [[[_mockApplication expect] ignoringNonObjectArgs] registerForRemoteNotificationTypes:0];
 #pragma clang diagnostic pop
   __block BOOL callbackCalled = NO;
-  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token) {
+  [_manager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token, NSError *_Nullable error) {
     XCTAssertEqualObjects(token.data, _data);
     XCTAssertNotEqual(token.type, FIRAuthAPNSTokenTypeUnknown);
+    XCTAssertNil(error);
     callbackCalled = YES;
   }];
   XCTAssertFalse(callbackCalled);
diff --git a/Example/Auth/Tests/FIRAuthAppDelegateProxyTests.m b/Example/Auth/Tests/FIRAuthAppDelegateProxyTests.m
index d877182..b01ee26 100644
--- a/Example/Auth/Tests/FIRAuthAppDelegateProxyTests.m
+++ b/Example/Auth/Tests/FIRAuthAppDelegateProxyTests.m
@@ -81,6 +81,11 @@ NS_ASSUME_NONNULL_BEGIN
  */
 @property(nonatomic, copy, nullable) NSData *deviceTokenReceived;
 
+/** @var tokenErrorReceived
+    @brief The last token error received, if any.
+ */
+@property(nonatomic, copy, nullable) NSError *tokenErrorReceived;
+
 /** @var notificationReceived
     @brief The last notification received, if any.
  */
@@ -101,6 +106,11 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (void)application:(UIApplication *)application
+    didFailToRegisterForRemoteNotificationsWithError:(nonnull NSError *)error {
+  self.tokenErrorReceived = error;
+}
+
+- (void)application:(UIApplication *)application
     didReceiveRemoteNotification:(NSDictionary *)userInfo
           fetchCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler {
   self.notificationReceived = userInfo;
@@ -153,6 +163,11 @@ NS_ASSUME_NONNULL_BEGIN
    */
   NSData *_deviceToken;
 
+  /** @var _error
+      @brief The fake error for testing.
+   */
+  NSError *_error;
+
   /** @var _notification
       @brief The fake notification for testing.
    */
@@ -173,6 +188,7 @@ NS_ASSUME_NONNULL_BEGIN
   [super setUp];
   _mockApplication = OCMClassMock([UIApplication class]);
   _deviceToken = [@"asdf" dataUsingEncoding:NSUTF8StringEncoding];
+  _error = [NSError errorWithDomain:@"FakeError" code:12345 userInfo:nil];
   _notification = @{ @"zxcv" : @1234 };
   _url = [NSURL URLWithString:@"https://abc.def/ghi"];
   _isIOS9orLater = [[[UIDevice currentDevice] systemVersion] doubleValue] >= 9.0;
@@ -262,6 +278,8 @@ NS_ASSUME_NONNULL_BEGIN
     XCTAssertTrue([delegate respondsToSelector:
                    @selector(application:didRegisterForRemoteNotificationsWithDeviceToken:)]);
     XCTAssertTrue([delegate respondsToSelector:
+                   @selector(application:didFailToRegisterForRemoteNotificationsWithError:)]);
+    XCTAssertTrue([delegate respondsToSelector:
                    @selector(application:didReceiveRemoteNotification:fetchCompletionHandler:)]);
     XCTAssertFalse([delegate respondsToSelector:
                     @selector(application:didReceiveRemoteNotification:)]);
@@ -288,6 +306,12 @@ NS_ASSUME_NONNULL_BEGIN
           didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
       OCMVerifyAll(mockHandler);
 
+      // Verify `application:didFailToRegisterForRemoteNotificationsWithError:` is handled.
+      OCMExpect([mockHandler handleAPNSTokenError:_error]);
+      [delegate application:_mockApplication
+          didFailToRegisterForRemoteNotificationsWithError:_error];
+      OCMVerifyAll(mockHandler);
+
       // Verify `application:didReceiveRemoteNotification:fetchCompletionHandler:` is handled.
       OCMExpect([mockHandler canHandleNotification:_notification]).andReturn(YES);
       __block BOOL fetchCompletionHandlerCalled = NO;
@@ -324,6 +348,8 @@ NS_ASSUME_NONNULL_BEGIN
     [delegate application:_mockApplication
         didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
     [delegate application:_mockApplication
+        didFailToRegisterForRemoteNotificationsWithError:_error];
+    [delegate application:_mockApplication
         didReceiveRemoteNotification:_notification
               fetchCompletionHandler:^(UIBackgroundFetchResult result) {
       XCTFail(@"Should not call completion handler.");
@@ -374,6 +400,8 @@ NS_ASSUME_NONNULL_BEGIN
     // Verify certain methods are swizzled while others are not.
     XCTAssertTrue([delegate respondsToSelector:
                    @selector(application:didRegisterForRemoteNotificationsWithDeviceToken:)]);
+    XCTAssertTrue([delegate respondsToSelector:
+                   @selector(application:didFailToRegisterForRemoteNotificationsWithError:)]);
     XCTAssertFalse([delegate respondsToSelector:
                     @selector(application:didReceiveRemoteNotification:fetchCompletionHandler:)]);
     XCTAssertTrue([delegate respondsToSelector:
@@ -401,6 +429,14 @@ NS_ASSUME_NONNULL_BEGIN
         OCMVerifyAll(mockHandler1);
         OCMVerifyAll(mockHandler2);
 
+        // Verify `application:didFailToRegisterForRemoteNotificationsWithError:` is handled.
+        OCMExpect([mockHandler1 handleAPNSTokenError:_error]);
+        OCMExpect([mockHandler2 handleAPNSTokenError:_error]);
+        [delegate application:_mockApplication
+            didFailToRegisterForRemoteNotificationsWithError:_error];
+        OCMVerifyAll(mockHandler1);
+        OCMVerifyAll(mockHandler2);
+
         // Verify `application:didReceiveRemoteNotification:fetchCompletionHandler:` is handled.
         OCMExpect([mockHandler1 canHandleNotification:_notification]).andReturn(YES);
         // handler2 shouldn't been invoked because it is already handled by handler1.
@@ -431,6 +467,12 @@ NS_ASSUME_NONNULL_BEGIN
           didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
       OCMVerifyAll(mockHandler1);
 
+      // Verify `application:didFailToRegisterForRemoteNotificationsWithError:` is handled.
+      OCMExpect([mockHandler1 handleAPNSTokenError:_error]);
+      [delegate application:_mockApplication
+          didFailToRegisterForRemoteNotificationsWithError:_error];
+      OCMVerifyAll(mockHandler1);
+
       // Verify `application:didReceiveRemoteNotification:fetchCompletionHandler:` is NOT handled.
       OCMExpect([mockHandler1 canHandleNotification:_notification]).andReturn(NO);
       [delegate application:_mockApplication didReceiveRemoteNotification:_notification];
@@ -457,6 +499,8 @@ NS_ASSUME_NONNULL_BEGIN
     // Verify the delegate still works after all handlers are released.
     [delegate application:_mockApplication
         didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
+    [delegate application:_mockApplication
+        didFailToRegisterForRemoteNotificationsWithError:_error];
     [delegate application:_mockApplication didReceiveRemoteNotification:_notification];
     XCTAssertEqualObjects(delegate.notificationReceived, _notification);
     delegate.notificationReceived = nil;
@@ -505,6 +549,8 @@ NS_ASSUME_NONNULL_BEGIN
     XCTAssertTrue([delegate respondsToSelector:
                    @selector(application:didRegisterForRemoteNotificationsWithDeviceToken:)]);
     XCTAssertTrue([delegate respondsToSelector:
+                   @selector(application:didFailToRegisterForRemoteNotificationsWithError:)]);
+    XCTAssertTrue([delegate respondsToSelector:
                    @selector(application:didReceiveRemoteNotification:fetchCompletionHandler:)]);
     XCTAssertFalse([delegate respondsToSelector:
                     @selector(application:didReceiveRemoteNotification:)]);
@@ -532,6 +578,14 @@ NS_ASSUME_NONNULL_BEGIN
       XCTAssertEqualObjects(delegate.deviceTokenReceived, _deviceToken);
       delegate.deviceTokenReceived = nil;
 
+      // Verify `application:didFailToRegisterForRemoteNotificationsWithError:` is handled.
+      OCMExpect([mockHandler handleAPNSTokenError:_error]);
+      [delegate application:_mockApplication
+          didFailToRegisterForRemoteNotificationsWithError:_error];
+      OCMVerifyAll(mockHandler);
+      XCTAssertEqualObjects(delegate.tokenErrorReceived, _error);
+      delegate.tokenErrorReceived = nil;
+
       // Verify `application:didReceiveRemoteNotification:fetchCompletionHandler:` is handled.
       OCMExpect([mockHandler canHandleNotification:_notification]).andReturn(YES);
       __block BOOL fetchCompletionHandlerCalled = NO;
@@ -565,6 +619,10 @@ NS_ASSUME_NONNULL_BEGIN
           didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
       XCTAssertEqualObjects(unaffectedDelegate.deviceTokenReceived, _deviceToken);
       unaffectedDelegate.deviceTokenReceived = nil;
+      [unaffectedDelegate application:_mockApplication
+          didFailToRegisterForRemoteNotificationsWithError:_error];
+      XCTAssertEqualObjects(unaffectedDelegate.tokenErrorReceived, _error);
+      unaffectedDelegate.tokenErrorReceived = nil;
       fetchCompletionHandlerCalled = NO;
       [unaffectedDelegate application:_mockApplication
           didReceiveRemoteNotification:_notification
@@ -590,6 +648,10 @@ NS_ASSUME_NONNULL_BEGIN
         didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
     XCTAssertEqualObjects(delegate.deviceTokenReceived, _deviceToken);
     delegate.deviceTokenReceived = nil;
+    [delegate application:_mockApplication
+        didFailToRegisterForRemoteNotificationsWithError:_error];
+    XCTAssertEqualObjects(delegate.tokenErrorReceived, _error);
+    delegate.tokenErrorReceived = nil;
     __block BOOL fetchCompletionHandlerCalled = NO;
     [delegate application:_mockApplication
         didReceiveRemoteNotification:_notification
@@ -615,7 +677,11 @@ NS_ASSUME_NONNULL_BEGIN
       didRegisterForRemoteNotificationsWithDeviceToken:_deviceToken];
   XCTAssertEqualObjects(delegate.deviceTokenReceived, _deviceToken);
   delegate.deviceTokenReceived = nil;
-    __block BOOL fetchCompletionHandlerCalled = NO;
+  [delegate application:_mockApplication
+      didFailToRegisterForRemoteNotificationsWithError:_error];
+  XCTAssertEqualObjects(delegate.tokenErrorReceived, _error);
+  delegate.tokenErrorReceived = nil;
+  __block BOOL fetchCompletionHandlerCalled = NO;
   [delegate application:_mockApplication
       didReceiveRemoteNotification:_notification
             fetchCompletionHandler:^(UIBackgroundFetchResult result) {
diff --git a/Example/Auth/Tests/FIRPhoneAuthProviderTests.m b/Example/Auth/Tests/FIRPhoneAuthProviderTests.m
index 5d67ac8..9a0a219 100644
--- a/Example/Auth/Tests/FIRPhoneAuthProviderTests.m
+++ b/Example/Auth/Tests/FIRPhoneAuthProviderTests.m
@@ -274,7 +274,7 @@ static const NSTimeInterval kExpectationTimeout = 1;
       .andCallBlock1(^(FIRAuthNotificationForwardingCallback callback) { callback(YES); });
   OCMExpect([_mockAppCredentialManager credential]).andReturn(nil);
   OCMExpect([_mockAPNSTokenManager getTokenWithCallback:OCMOCK_ANY])
-      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(nil); });
+      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(nil, nil); });
   // Expect verify client request to the backend wth empty token.
   OCMExpect([_mockBackend verifyClient:[OCMArg any] callback:[OCMArg any]])
       .andCallBlock2(^(FIRVerifyClientRequest *request,
@@ -314,7 +314,7 @@ static const NSTimeInterval kExpectationTimeout = 1;
   FIRAuthAPNSToken *token = [[FIRAuthAPNSToken alloc] initWithData:data
                                                               type:FIRAuthAPNSTokenTypeProd];
   OCMExpect([_mockAPNSTokenManager getTokenWithCallback:OCMOCK_ANY])
-      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(token); });
+      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(token, nil); });
   // Expect verify client request to the backend.
   OCMExpect([_mockBackend verifyClient:[OCMArg any] callback:[OCMArg any]])
       .andCallBlock2(^(FIRVerifyClientRequest *request,
@@ -417,7 +417,7 @@ static const NSTimeInterval kExpectationTimeout = 1;
   });
 
   OCMExpect([_mockAPNSTokenManager getTokenWithCallback:OCMOCK_ANY])
-      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(token); });
+      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(token, nil); });
   // Expect verify client request to the backend.
   OCMExpect([_mockBackend verifyClient:[OCMArg any] callback:[OCMArg any]])
       .andCallBlock2(^(FIRVerifyClientRequest *request,
@@ -509,7 +509,7 @@ static const NSTimeInterval kExpectationTimeout = 1;
   });
 
   OCMExpect([_mockAPNSTokenManager getTokenWithCallback:OCMOCK_ANY])
-      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(token); });
+      .andCallBlock1(^(FIRAuthAPNSTokenCallback callback) { callback(token, nil); });
   // Expect verify client request to the backend.
   OCMExpect([_mockBackend verifyClient:[OCMArg any] callback:[OCMArg any]])
       .andCallBlock2(^(FIRVerifyClientRequest *request,
diff --git a/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m b/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m
index 7c29f13..4a0e7e7 100644
--- a/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m
+++ b/Firebase/Auth/Source/AuthProviders/Phone/FIRPhoneAuthProvider.m
@@ -169,7 +169,12 @@ typedef void (^FIRVerifyClientCallback)(FIRAuthAppCredential *_Nullable appCrede
     completion(_auth.appCredentialManager.credential, nil);
     return;
   }
-  [_auth.tokenManager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token) {
+  [_auth.tokenManager getTokenWithCallback:^(FIRAuthAPNSToken *_Nullable token,
+                                             NSError *_Nullable error) {
+    if (!token) {
+      completion(nil, [FIRAuthErrorUtils missingAppTokenErrorWithUnderlyingError:error]);
+      return;
+    }
     FIRVerifyClientRequest *request =
         [[FIRVerifyClientRequest alloc] initWithAppToken:token.string
                                                isSandbox:token.type == FIRAuthAPNSTokenTypeSandbox
diff --git a/Firebase/Auth/Source/FIRAuth.m b/Firebase/Auth/Source/FIRAuth.m
index 0a8af0e..d2915a3 100644
--- a/Firebase/Auth/Source/FIRAuth.m
+++ b/Firebase/Auth/Source/FIRAuth.m
@@ -971,6 +971,12 @@ static NSMutableDictionary *gKeychainServiceNameForAppName;
   });
 }
 
+- (void)handleAPNSTokenError:(NSError *)error {
+  dispatch_sync(FIRAuthGlobalWorkQueue(), ^{
+    [_tokenManager cancelWithError:error];
+  });
+}
+
 - (BOOL)canHandleNotification:(NSDictionary *)userInfo {
   __block BOOL result = NO;
   dispatch_sync(FIRAuthGlobalWorkQueue(), ^{
diff --git a/Firebase/Auth/Source/FIRAuthAPNSTokenManager.h b/Firebase/Auth/Source/FIRAuthAPNSTokenManager.h
index a2d6f4c..566780f 100644
--- a/Firebase/Auth/Source/FIRAuthAPNSTokenManager.h
+++ b/Firebase/Auth/Source/FIRAuthAPNSTokenManager.h
@@ -24,8 +24,11 @@ NS_ASSUME_NONNULL_BEGIN
 /** @typedef FIRAuthAPNSTokenCallback
     @brief The type of block to receive an APNs token.
     @param token The APNs token if one is available.
+    @param error The error happened if any.
+    @remarks Both `token` and `error` being `nil` means the request timed-out.
  */
-typedef void (^FIRAuthAPNSTokenCallback)(FIRAuthAPNSToken *_Nullable token);
+typedef void (^FIRAuthAPNSTokenCallback)(FIRAuthAPNSToken *_Nullable token,
+                                         NSError *_Nullable error);
 
 /** @class FIRAuthAPNSTokenManager
     @brief A class to manage APNs token in memory.
@@ -64,6 +67,12 @@ typedef void (^FIRAuthAPNSTokenCallback)(FIRAuthAPNSToken *_Nullable token);
  */
 - (void)getTokenWithCallback:(FIRAuthAPNSTokenCallback)callback;
 
+/** @fn cancelWithError:
+    @brief Cancels any pending `getTokenWithCallback:` request.
+    @param error The error to return.
+ */
+- (void)cancelWithError:(NSError *)error;
+
 @end
 
 NS_ASSUME_NONNULL_END
diff --git a/Firebase/Auth/Source/FIRAuthAPNSTokenManager.m b/Firebase/Auth/Source/FIRAuthAPNSTokenManager.m
index 300b7e3..a4e4389 100644
--- a/Firebase/Auth/Source/FIRAuthAPNSTokenManager.m
+++ b/Firebase/Auth/Source/FIRAuthAPNSTokenManager.m
@@ -58,7 +58,7 @@ static const NSTimeInterval kLegacyRegistrationTimeout = 30;
 
 - (void)getTokenWithCallback:(FIRAuthAPNSTokenCallback)callback {
   if (_token) {
-    callback(_token);
+    callback(_token, nil);
     return;
   }
   if (_pendingCallbacks) {
@@ -77,9 +77,13 @@ static const NSTimeInterval kLegacyRegistrationTimeout = 30;
 #pragma clang diagnostic pop
     }
   });
+  NSArray<FIRAuthAPNSTokenCallback> *applicableCallbacks = _pendingCallbacks;
   dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(_timeout * NSEC_PER_SEC)),
                                FIRAuthGlobalWorkQueue(), ^{
-    [self callBack];
+    // Only cancel if the pending callbacks remain the same, i.e., not triggered yet.
+    if (applicableCallbacks == _pendingCallbacks) {
+      [self callBackWithToken:nil error:nil];
+    }
   });
 }
 
@@ -97,22 +101,28 @@ static const NSTimeInterval kLegacyRegistrationTimeout = 30;
     token = [[FIRAuthAPNSToken alloc] initWithData:token.data type:detectedTokenType];
   }
   _token = token;
-  [self callBack];
+  [self callBackWithToken:token error:nil];
+}
+
+- (void)cancelWithError:(NSError *)error {
+  [self callBackWithToken:nil error:error];
 }
 
 #pragma mark - Internal methods
 
 /** @fn callBack
-    @brief Calls back all pending callbacks with the current APNs token, if one is available.
+    @brief Calls back all pending callbacks with APNs token or error.
+    @param token The APNs token if one is available.
+    @param error The error occurred, if any.
  */
-- (void)callBack {
+- (void)callBackWithToken:(nullable FIRAuthAPNSToken *)token error:(nullable NSError *)error {
   if (!_pendingCallbacks) {
     return;
   }
   NSArray<FIRAuthAPNSTokenCallback> *allCallbacks = _pendingCallbacks;
   _pendingCallbacks = nil;
   for (FIRAuthAPNSTokenCallback callback in allCallbacks) {
-    callback(_token);
+    callback(token, error);
   }
 };
 
diff --git a/Firebase/Auth/Source/FIRAuthAppDelegateProxy.h b/Firebase/Auth/Source/FIRAuthAppDelegateProxy.h
index d974e2c..ccae93a 100644
--- a/Firebase/Auth/Source/FIRAuthAppDelegateProxy.h
+++ b/Firebase/Auth/Source/FIRAuthAppDelegateProxy.h
@@ -30,6 +30,12 @@ NS_ASSUME_NONNULL_BEGIN
  */
 - (void)setAPNSToken:(NSData *)token;
 
+/** @fn handleAPNSTokenError:
+    @brief Handles APNs device token error.
+    @param error The APNs device token error.
+ */
+- (void)handleAPNSTokenError:(NSError *)error;
+
 /** @fn canHandleNotification:
     @brief Checks whether the notification can be handled by the receiver, and handles it if so.
     @param notification The notification in question, which will be consumed if returns @c YES.
diff --git a/Firebase/Auth/Source/FIRAuthAppDelegateProxy.m b/Firebase/Auth/Source/FIRAuthAppDelegateProxy.m
index 15151f3..8899407 100644
--- a/Firebase/Auth/Source/FIRAuthAppDelegateProxy.m
+++ b/Firebase/Auth/Source/FIRAuthAppDelegateProxy.m
@@ -82,6 +82,15 @@ static id noop(id object, SEL cmd, ...) {
                                                application:application
           didRegisterForRemoteNotificationsWithDeviceToken:deviceToken];
     }];
+    SEL failToRegisterRemoteNotificationSelector =
+        @selector(application:didFailToRegisterForRemoteNotificationsWithError:);
+    [self replaceSelector:failToRegisterRemoteNotificationSelector
+                withBlock:^(id object, UIApplication* application, NSError *error) {
+      [weakSelf object:object
+                                                  selector:failToRegisterRemoteNotificationSelector
+                                               application:application
+          didFailToRegisterForRemoteNotificationsWithError:error];
+    }];
     SEL receiveNotificationSelector = @selector(application:didReceiveRemoteNotification:);
     SEL receiveNotificationWithHandlerSelector =
         @selector(application:didReceiveRemoteNotification:fetchCompletionHandler:);
@@ -200,6 +209,22 @@ static id noop(id object, SEL cmd, ...) {
 }
 
 - (void)object:(id)object
+                                            selector:(SEL)selector
+                                         application:(UIApplication *)application
+    didFailToRegisterForRemoteNotificationsWithError:(NSError *)error {
+  if (object == _appDelegate) {
+    for (id<FIRAuthAppDelegateHandler> handler in [self handlers]) {
+      [handler handleAPNSTokenError:error];
+    }
+  }
+  IMP originalImplementation = [self originalImplementationForSelector:selector];
+  if (originalImplementation && originalImplementation != &noop) {
+    typedef void (*Implmentation)(id, SEL, UIApplication *, NSError *);
+    ((Implmentation)originalImplementation)(object, selector, application, error);
+  }
+}
+
+- (void)object:(id)object
                         selector:(SEL)selector
                      application:(UIApplication *)application
     didReceiveRemoteNotification:(NSDictionary *)notification
diff --git a/Firebase/Auth/Source/FIRAuthErrorUtils.h b/Firebase/Auth/Source/FIRAuthErrorUtils.h
index 4fdfe9b..1537553 100644
--- a/Firebase/Auth/Source/FIRAuthErrorUtils.h
+++ b/Firebase/Auth/Source/FIRAuthErrorUtils.h
@@ -425,11 +425,12 @@ NS_ASSUME_NONNULL_BEGIN
  */
 + (NSError *)quotaExceededErrorWithMessage:(nullable NSString *)message;
 
-/** @fn missingAppTokenError
+/** @fn missingAppTokenErrorWithUnderlyingError
     @brief Constructs an @c NSError with the @c FIRAuthErrorCodeMissingAppToken code.
+    @param underlyingError The underlying error, if any.
     @return The NSError instance associated with the given FIRAuthError.
  */
-+ (NSError *)missingAppTokenError;
++ (NSError *)missingAppTokenErrorWithUnderlyingError:(nullable NSError *)underlyingError;
 
 /** @fn notificationNotForwardedError
     @brief Constructs an @c NSError with the @c FIRAuthErrorCodeNotificationNotForwarded code.
diff --git a/Firebase/Auth/Source/FIRAuthErrorUtils.m b/Firebase/Auth/Source/FIRAuthErrorUtils.m
index ad9ad55..d5b1c9b 100644
--- a/Firebase/Auth/Source/FIRAuthErrorUtils.m
+++ b/Firebase/Auth/Source/FIRAuthErrorUtils.m
@@ -877,8 +877,9 @@ static NSString *const FIRAuthErrorCodeString(FIRAuthErrorCode code) {
   return [self errorWithCode:FIRAuthInternalErrorCodeQuotaExceeded message:message];
 }
 
-+ (NSError *)missingAppTokenError {
-  return [self errorWithCode:FIRAuthInternalErrorCodeMissingAppToken];
++ (NSError *)missingAppTokenErrorWithUnderlyingError:(nullable NSError *)underlyingError {
+  return [self errorWithCode:FIRAuthInternalErrorCodeMissingAppToken
+             underlyingError:underlyingError];
 }
 
 + (NSError *)notificationNotForwardedError {
diff --git a/Firebase/Auth/Source/RPCs/FIRAuthBackend.m b/Firebase/Auth/Source/RPCs/FIRAuthBackend.m
index 0387a1a..afe05bd 100644
--- a/Firebase/Auth/Source/RPCs/FIRAuthBackend.m
+++ b/Firebase/Auth/Source/RPCs/FIRAuthBackend.m
@@ -1023,7 +1023,7 @@ static id<FIRAuthBackendImplementation> gBackendImplementation;
   }
 
   if ([shortErrorMessage isEqualToString:kMissingAppTokenErrorMessage]) {
-    return [FIRAuthErrorUtils missingAppTokenError];
+    return [FIRAuthErrorUtils missingAppTokenErrorWithUnderlyingError:nil];
   }
 
   if ([shortErrorMessage isEqualToString:kMissingAppCredentialErrorMessage]) {