[google_sign_in] Don't crash a misconfigured iOS app (#9486)

In flutter/plugins#1180 the plugin was deliberately made to crash when misconfigured. The reasoning was that the app shouldn't be released this way, which is true, but crashing the entire app means that a developer has to use Xcode to debug the app to understand what's happening, which is a very poor user experience.

The PR indicated that the error would be printed from the Dart side after that PR, but that's not actually what happens; method channel returns are asynchronous, whereas crashing the app on the native side with an unhandled exception happens immediately, so even though the native side does call the completion, the async process of that completion being received on the Dart side as a `PlatformException` was never happening, and the crash was silent outside the context of a native debugger.

This removes the throw, so that it can be received as a Dart exception, which is much easier for most developers to debug.

## Pre-Review Checklist

[^1]: Regular contributors who have demonstrated familiarity with the repository guidelines only need to comment if the PR is not auto-exempted by repo tooling.

Author: stuartmorgan-g

packages/google_sign_in/google_sign_in_ios/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 6.0.1
+
+* Returns configuration errors as `PlatformException`s in Dart instead of
+  crashing the app.
+
 ## 6.0.0
 
 * **BREAKING CHANGE**: Switches to implementing version 3.0 of the platform

packages/google_sign_in/google_sign_in_ios/darwin/Tests/GoogleSignInTests.m

@@ -371,26 +371,26 @@ - (void)testSignInError {
   [self waitForExpectationsWithTimeout:5.0 handler:nil];
 }
 
-- (void)testSignInException {
+- (void)testSignInExceptionReturnsError {
   OCMExpect([self configureMock:self.mockSignIn
                 forSignInWithHint:OCMOCK_ANY
                  additionalScopes:OCMOCK_ANY
                        completion:OCMOCK_ANY])
       .andThrow([NSException exceptionWithName:@"MockName" reason:@"MockReason" userInfo:nil]);
 
-  __block FlutterError *error;
-  XCTAssertThrows([self.plugin
-      signInWithScopeHint:@[]
-                    nonce:nil
-               completion:^(FSISignInResult *result, FlutterError *signInError) {
-                 // Unexpected errors, such as runtime exceptions, are returned as FlutterError.
-                 XCTAssertNil(result);
-                 error = signInError;
-               }]);
-
-  XCTAssertEqualObjects(error.code, @"google_sign_in");
-  XCTAssertEqualObjects(error.message, @"MockReason");
-  XCTAssertEqualObjects(error.details, @"MockName");
+  XCTestExpectation *expectation = [self expectationWithDescription:@"completion called"];
+  [self.plugin signInWithScopeHint:@[]
+                             nonce:nil
+                        completion:^(FSISignInResult *result, FlutterError *error) {
+                          // Unexpected errors, such as runtime exceptions, are returned as
+                          // FlutterError.
+                          XCTAssertNil(result);
+                          XCTAssertEqualObjects(error.code, @"google_sign_in");
+                          XCTAssertEqualObjects(error.message, @"MockReason");
+                          XCTAssertEqualObjects(error.details, @"MockName");
+                          [expectation fulfill];
+                        }];
+  [self waitForExpectationsWithTimeout:5.0 handler:nil];
 }
 
 #pragma mark - refreshedAuthorizationTokens

packages/google_sign_in/google_sign_in_ios/darwin/google_sign_in_ios/Sources/google_sign_in_ios/FLTGoogleSignInPlugin.m

@@ -196,7 +196,6 @@ - (void)signInWithScopeHint:(NSArray<NSString *> *)scopeHint
               }];
   } @catch (NSException *e) {
     completion(nil, [FlutterError errorWithCode:@"google_sign_in" message:e.reason details:e.name]);
-    [e raise];
   }
 }
 

packages/google_sign_in/google_sign_in_ios/pubspec.yaml

@@ -2,7 +2,7 @@ name: google_sign_in_ios
 description: iOS implementation of the google_sign_in plugin.
 repository: https://github.com/flutter/packages/tree/main/packages/google_sign_in/google_sign_in_ios
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+google_sign_in%22
-version: 6.0.0
+version: 6.0.1
 
 environment:
   sdk: ^3.6.0