[firebase_auth]: Windows Build Error C2665 std::variant

[saketh84]

Is there an existing issue for this?

• I have searched the existing issues.

Which plugins are affected?

Other

Which platforms are affected?

Windows

Description

"When trying to build a Flutter project using firebase_auth for the Windows platform (flutter build windows or flutter run -d windows), the build fails with a C++ compilation error: error C2665: 'std::variant<...>::variant': no overloaded function could convert all the argument types within the firebase_auth_plugin.vcxproj."

Reproducing the issue

"1. Create a new Flutter project (flutter create myapp). 2. Add firebase_core and firebase_auth to pubspec.yaml. 3. Run flutter pub get. 4. Configure Firebase using flutterfire configure for the Windows platform. 5. Attempt to build for Windows using flutter build windows."

Firebase Core version

2.27.1

Flutter Version

=3.22.0 <3.25.0

Relevant Log Output

CMake Deprecation Warning at C:/Users/SakethRam/AndroidStudioProjects/build/windows/x64/extracted/firebase_cpp_sdk_windows/CMakeLists.txt:17 (cmake_minimum_required):  
  Compatibility with CMake < 3.10 will be removed from a future version of
  CMake.

  Update the VERSION argument <min> value.  Or, use the <min>...<max> syntax
  to tell CMake that the project requires at least <min> but has been updated
  to work with policies introduced by <max> or earlier.


C:\Users\SakethRam\AndroidStudioProjects\windows\flutter\ephemeral\cpp_client_wrapper\include\flutter\encodable_value.h(199,60): error C2665: 'std::variant<std::monosta
te,bool,int32_t,int64_t,double,std::string,std::vector<uint8_t,std::allocator<uint8_t>>,std::vector<int32_t,std::allocator<int>>,std::vector<int64_t,std::allocator<int6
4_t>>,std::vector<double,std::allocator<double>>,flutter::EncodableList,flutter::EncodableMap,flutter::CustomEncodableValue,std::vector<float,std::allocator<float>>>::v
ariant': no overloaded function could convert all the argument types [C:\Users\SakethRam\AndroidStudioProjects\build\windows\x64\plugins\firebase_auth\firebase_auth_plugin.vcxproj]
Building Windows application...                                   385.4s
Build process failed.

Flutter dependencies

flutter:
sdk: flutter
firebase_core: ^2.27.1 # Or your current version
firebase_auth: ^4.17.9

Firebase and state management packages

cloud_firestore: ^4.15.9
provider: ^6.1.2
intl: ^0.19.0

Default icon pack

cupertino_icons: ^1.0.2

Additional context and comments

No response

[MichaelVerdon]

I am unable to reproduce this using the example app we have which leads me to believe this is an implementation issue on your end. The error you are getting is related to using flutter::EncodableValue with a type that isn’t one of the allowed variants, so the std::variant constructor can’t pick an overload. Could you send an example of your code or see what data types you are using?