Update GIDSignIn to handle placeholder app check tokens

GoogleSignIn/Sources/GIDSignIn.m

@@ -183,6 +183,8 @@ @implementation GIDSignIn {
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
  // The class used to manage presenting the loading screen for fetching app check tokens.
  GIDTimedLoader *_timedLoader;
+ // Flag indicating developer's intent to use App Check.
+ BOOL _configureAppCheckCalled;
 #endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST
 }
 
@@ -481,6 +483,7 @@ + (GIDSignIn *)sharedInstance {
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
 - (void)configureWithCompletion:(nullable void (^)(NSError * _Nullable))completion {
  @synchronized(self) {
+ _configureAppCheckCalled = YES;
  [_appCheck prepareForAppCheckWithCompletion:^(NSError * _Nullable error) {
  if (completion) {
  completion(error);
@@ -538,6 +541,7 @@ - (instancetype)initWithKeychainStore:(GTMKeychainStore *)keychainStore
  self = [self initWithKeychainStore:keychainStore];
  if (self) {
  _appCheck = appCheck;
+ _configureAppCheckCalled = NO;
  }
  return self;
 }
@@ -632,15 +636,18 @@ - (void)authenticateInteractivelyWithOptions:(GIDSignInInternalOptions *)options
 
 - (void)authorizationRequestWithOptions:(GIDSignInInternalOptions *)options completion:
  (void (^)(OIDAuthorizationRequest *_Nullable request, NSError *_Nullable error))completion {
- BOOL shouldCallCompletion = YES;
+ BOOL shouldCreateAuthRequest = YES;
  NSMutableDictionary<NSString *, NSString *> *additionalParameters =
  [self additionalParametersFromOptions:options];
 #if TARGET_OS_IOS && !TARGET_OS_MACCATALYST
  if (@available(iOS 14.0, *)) {
  // Only use `_appCheck` (created via singleton `+[GIDSignIn sharedInstance]` call) if
- // `-[GIDAppCheck prepareForAppCheckWithCompletion:]` has been called
- if ([_appCheck isPrepared]) {
- shouldCallCompletion = NO;
+ // `GIDAppCheck` has been successfully prepared OR if the developer has attempted to configure.
+ // If former is false and the latter true, then preparation step failed for some reason; we
+ // still want to try to pass along the app check token (it just may take longer since the
+ // pre-warm step failed).
+ if ([_appCheck isPrepared] || _configureAppCheckCalled) {
+ shouldCreateAuthRequest = NO;
  UIViewController *presentingVC = options.presentingViewController;
  if (!_timedLoader) {
  _timedLoader = [[GIDTimedLoader alloc] initWithPresentingViewController:presentingVC];
@@ -652,9 +659,14 @@ - (void)authorizationRequestWithOptions:(GIDSignInInternalOptions *)options comp
  if (token) {
  additionalParameters[kClientAssertionTypeParameter] = kClientAssertionTypeParameterValue;
  additionalParameters[kClientAssertionParameter] = token.token;
- request = [self authorizationRequestWithOptions:options
- additionalParameters:additionalParameters];
  }
+ #if DEBUG
+ if (error) {
+ NSLog(@"[Google Sign-In iOS]: Error retrieving App Check limited use token: %@", error);
+ }
+ #endif
+ request = [self authorizationRequestWithOptions:options
+ additionalParameters:additionalParameters];
  if (self->_timedLoader.animationStatus == GIDTimedLoaderAnimationStatusAnimating) {
  [self->_timedLoader stopTimingWithCompletion:^{
  completion(request, error);
@@ -666,7 +678,7 @@ - (void)authorizationRequestWithOptions:(GIDSignInInternalOptions *)options comp
  }
  }
 #endif // TARGET_OS_IOS && !TARGET_OS_MACCATALYST
- if (shouldCallCompletion) {
+ if (shouldCreateAuthRequest) {
  OIDAuthorizationRequest *request = [self authorizationRequestWithOptions:options
  additionalParameters:additionalParameters];
  completion(request, nil);

Samples/Swift/AppAttestExample/AppAttestExample.xcodeproj/xcshareddata/xcschemes/AppAttestExample.xcscheme

@@ -49,13 +49,6 @@
  ReferencedContainer = "container:AppAttestExample.xcodeproj">
  </BuildableReference>
  </BuildableProductRunnable>
- <EnvironmentVariables>
- <EnvironmentVariable
- key = "FIRAppCheckDebugToken"
- value = "F40DF0E8-9CCC-46DF-AC01-43DE96FCEDD8"
- isEnabled = "YES">
- </EnvironmentVariable>
- </EnvironmentVariables>
  </LaunchAction>
  <ProfileAction
  buildConfiguration = "Release"

Samples/Swift/AppAttestExample/Podfile

@@ -1,10 +1,13 @@
+source 'https://github.com/CocoaPods/Specs.git'
+source 'https://github.com/firebase/SpecsDev.git'
+
 pod 'GoogleSignIn', :path => '../../../', :testspecs => ['unit']
 pod 'GoogleSignInSwiftSupport', :path => '../../../', :testspecs => ['unit']
 project 'AppAttestExample.xcodeproj'
 
 use_frameworks! :linkage => :static
 
 target 'AppAttestExample' do
- pod 'AppCheckCore', :git => 'https://github.com/google/app-check.git', :tag => 'CocoaPods-0.1.0-alpha.1'
+ pod 'AppCheckCore'
  platform :ios, '14.0'
 end