Revert "#167410: _initCalled completed twice (#9694)"

packages/google_sign_in/google_sign_in_web/CHANGELOG.md

@@ -1,4 +1,8 @@
-## 1.1.1
+## 1.1.2
+
+* Reverts "Throws a more actionable error when init is called more than once."
+
+## 1.1.1 (withdrawn)
 
 * Throws a more actionable error when init is called more than once.
 * Updates minimum supported SDK version to Flutter 3.35/Dart 3.9.

packages/google_sign_in/google_sign_in_web/example/integration_test/google_sign_in_web_test.dart

@@ -65,36 +65,8 @@ void main() {
       await plugin.init(
         const InitParameters(clientId: 'some-non-null-client-id'),
       );
-    });
-
-    testWidgets('throws if init is called twice', (_) async {
-      await plugin.init(
-        const InitParameters(clientId: 'some-non-null-client-id'),
-      );
-
-      // Calling init() a second time should throw state error
-      expect(
-        () => plugin.init(
-          const InitParameters(clientId: 'some-non-null-client-id'),
-        ),
-        throwsStateError,
-      );
-    });
-
-    testWidgets('throws if init is called twice synchronously', (_) async {
-      final Future<void> firstInit = plugin.init(
-        const InitParameters(clientId: 'some-non-null-client-id'),
-      );
-
-      // Calling init() a second time synchronously should throw state error
-      expect(
-        () => plugin.init(
-          const InitParameters(clientId: 'some-non-null-client-id'),
-        ),
-        throwsStateError,
-      );
 
-      await firstInit;
+      expect(plugin.initialized, completes);
     });
 
     testWidgets('asserts clientId is not null', (_) async {
@@ -113,6 +85,35 @@ void main() {
         );
       }, throwsAssertionError);
     });
+
+    testWidgets('must be called for most of the API to work', (_) async {
+      expect(() async {
+        await plugin.attemptLightweightAuthentication(
+          const AttemptLightweightAuthenticationParameters(),
+        );
+      }, throwsStateError);
+
+      expect(() async {
+        await plugin.clientAuthorizationTokensForScopes(
+          const ClientAuthorizationTokensForScopesParameters(
+            request: AuthorizationRequestDetails(
+              scopes: <String>[],
+              userId: null,
+              email: null,
+              promptIfUnauthorized: false,
+            ),
+          ),
+        );
+      }, throwsStateError);
+
+      expect(() async {
+        await plugin.signOut(const SignOutParams());
+      }, throwsStateError);
+
+      expect(() async {
+        await plugin.disconnect(const DisconnectParams());
+      }, throwsStateError);
+    });
   });
 
   group('support queries', () {

packages/google_sign_in/google_sign_in_web/lib/google_sign_in_web.dart

@@ -49,7 +49,7 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
     @visibleForTesting GisSdkClient? debugOverrideGisSdkClient,
     @visibleForTesting
     StreamController<AuthenticationEvent>? debugAuthenticationController,
-  }) : _debugOverrideGisSdkClient = debugOverrideGisSdkClient,
+  }) : _gisSdkClient = debugOverrideGisSdkClient,
        _authenticationController =
            debugAuthenticationController ??
            StreamController<AuthenticationEvent>.broadcast() {
@@ -68,31 +68,51 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
 
   // A future that completes when the JS loader is done.
   late Future<void> _jsSdkLoadedFuture;
-
-  /// A completer used to track whether [init] has finished.
-  final Completer<void> _initCalled = Completer<void>();
-
-  /// A boolean flag to track if [init] has been called.
-  ///
-  /// This is used to prevent race conditions when [init] is called multiple
-  /// times without awaiting.
-  bool _isInitCalled = false;
+  // A future that completes when the `init` call is done.
+  Completer<void>? _initCalled;
 
   // A StreamController to communicate status changes from the GisSdkClient.
   final StreamController<AuthenticationEvent> _authenticationController;
 
   // The instance of [GisSdkClient] backing the plugin.
-  // Using late final ensures it can only be set once and throws if accessed before initialization.
-  late final GisSdkClient _gisSdkClient;
+  GisSdkClient? _gisSdkClient;
 
-  // An optional override for the GisSdkClient, used for testing.
-  final GisSdkClient? _debugOverrideGisSdkClient;
+  // A convenience getter to avoid using ! when accessing _gisSdkClient, and
+  // providing a slightly better error message when it is Null.
+  GisSdkClient get _gisClient {
+    assert(
+      _gisSdkClient != null,
+      'GIS Client not initialized. '
+      'GoogleSignInPlugin::init() or GoogleSignInPlugin::initWithParams() '
+      'must be called before any other method in this plugin.',
+    );
+    return _gisSdkClient!;
+  }
+
+  // This method throws if init or initWithParams hasn't been called at some
+  // point in the past. It is used by the [initialized] getter to ensure that
+  // users can't await on a Future that will never resolve.
+  void _assertIsInitCalled() {
+    if (_initCalled == null) {
+      throw StateError(
+        'GoogleSignInPlugin::init() or GoogleSignInPlugin::initWithParams() '
+        'must be called before any other method in this plugin.',
+      );
+    }
+  }
 
   /// A future that resolves when the plugin is fully initialized.
   ///
   /// This ensures that the SDK has been loaded, and that the `init` method
   /// has finished running.
-  Future<void> get _initialized => _initCalled.future;
+  @visibleForTesting
+  Future<void> get initialized {
+    _assertIsInitCalled();
+    return Future.wait<void>(<Future<void>>[
+      _jsSdkLoadedFuture,
+      _initCalled!.future,
+    ]);
+  }
 
   /// Stores the client ID if it was set in a meta-tag of the page.
   @visibleForTesting
@@ -105,14 +125,6 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
 
   @override
   Future<void> init(InitParameters params) async {
-    // Throw if init() is called more than once
-    if (_isInitCalled) {
-      throw StateError(
-        'init() has already been called. Calling init() more than once results in undefined behavior.',
-      );
-    }
-    _isInitCalled = true;
-
     final String? appClientId = params.clientId ?? autoDetectedClientId;
     assert(
       appClientId != null,
@@ -126,27 +138,27 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
       'serverClientId is not supported on Web.',
     );
 
+    _initCalled = Completer<void>();
+
     await _jsSdkLoadedFuture;
 
-    _gisSdkClient =
-        _debugOverrideGisSdkClient ??
-        GisSdkClient(
-          clientId: appClientId!,
-          nonce: params.nonce,
-          hostedDomain: params.hostedDomain,
-          authenticationController: _authenticationController,
-          loggingEnabled: kDebugMode,
-        );
-
-    _initCalled.complete();
+    _gisSdkClient ??= GisSdkClient(
+      clientId: appClientId!,
+      nonce: params.nonce,
+      hostedDomain: params.hostedDomain,
+      authenticationController: _authenticationController,
+      loggingEnabled: kDebugMode,
+    );
+
+    _initCalled!.complete(); // Signal that `init` is fully done.
   }
 
   @override
   Future<AuthenticationResults?>? attemptLightweightAuthentication(
     AttemptLightweightAuthenticationParameters params,
   ) {
-    _initialized.then((void value) {
-      _gisSdkClient.requestOneTap();
+    initialized.then((void value) {
+      _gisClient.requestOneTap();
     });
     // One tap does not necessarily return immediately, and may never return,
     // so clients should not await it. Return null to signal that.
@@ -171,26 +183,26 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
 
   @override
   Future<void> signOut(SignOutParams params) async {
-    await _initialized;
+    await initialized;
 
-    await _gisSdkClient.signOut();
+    await _gisClient.signOut();
   }
 
   @override
   Future<void> disconnect(DisconnectParams params) async {
-    await _initialized;
+    await initialized;
 
-    await _gisSdkClient.disconnect();
+    await _gisClient.disconnect();
   }
 
   @override
   Future<ClientAuthorizationTokenData?> clientAuthorizationTokensForScopes(
     ClientAuthorizationTokensForScopesParameters params,
   ) async {
-    await _initialized;
+    await initialized;
     _validateScopes(params.request.scopes);
 
-    final String? token = await _gisSdkClient.requestScopes(
+    final String? token = await _gisClient.requestScopes(
       params.request.scopes,
       promptIfUnauthorized: params.request.promptIfUnauthorized,
       userHint: params.request.userId,
@@ -204,7 +216,7 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
   Future<ServerAuthorizationTokenData?> serverAuthorizationTokensForScopes(
     ServerAuthorizationTokensForScopesParameters params,
   ) async {
-    await _initialized;
+    await initialized;
     _validateScopes(params.request.scopes);
 
     // There is no way to know whether the flow will prompt in advance, so
@@ -213,9 +225,7 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
       return null;
     }
 
-    final String? code = await _gisSdkClient.requestServerAuthCode(
-      params.request,
-    );
+    final String? code = await _gisClient.requestServerAuthCode(params.request);
     return code == null
         ? null
         : ServerAuthorizationTokenData(serverAuthCode: code);
@@ -237,8 +247,8 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
   Future<void> clearAuthorizationToken(
     ClearAuthorizationTokenParams params,
   ) async {
-    await _initialized;
-    return _gisSdkClient.clearAuthorizationToken(params.accessToken);
+    await initialized;
+    return _gisClient.clearAuthorizationToken(params.accessToken);
   }
 
   @override
@@ -268,13 +278,13 @@ class GoogleSignInPlugin extends GoogleSignInPlatform {
         configuration ?? GSIButtonConfiguration();
     return FutureBuilder<void>(
       key: Key(config.hashCode.toString()),
-      future: _initialized,
+      future: initialized,
       builder: (BuildContext context, AsyncSnapshot<void> snapshot) {
         if (snapshot.hasData) {
           return FlexHtmlElementView(
             viewType: 'gsi_login_button',
             onElementCreated: (Object element) {
-              _gisSdkClient.renderButton(element, config);
+              _gisClient.renderButton(element, config);
             },
           );
         }

packages/google_sign_in/google_sign_in_web/pubspec.yaml

@@ -3,7 +3,7 @@ description: Flutter plugin for Google Sign-In, a secure authentication system
   for signing in with a Google account on Android, iOS and Web.
 repository: https://github.com/flutter/packages/tree/main/packages/google_sign_in/google_sign_in_web
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+google_sign_in%22
-version: 1.1.1
+version: 1.1.2
 
 environment:
   sdk: ^3.9.0