[Bug Report - PythonScriptPlugin] Assertion failed: !GeneratedWrappedTypes.Contains(TypeRegistryName) [....../PyWrapperTypeRegistry.cpp] [Line: 711]

Development Programming & Scripting
1

UE4.27.2 c++ only project fails to launch, assert on experimental python plugin which is not used in the project.

What could this be? Verified the engine already.

The line that asserts (711):

check(!GeneratedWrappedTypes.Contains(TypeRegistryName));

TypeRegistryName appears to be asserting 3 times on 3 different class names present in project source code, before the process halts.

UE4Editor_Core!AssertFailedImplV() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Misc\AssertionMacros.cpp:104]
UE4Editor_Core!FDebug::CheckVerifyFailedImpl() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Misc\AssertionMacros.cpp:461]
UE4Editor_PythonScriptPlugin!FPyWrapperTypeRegistry::GenerateWrappedClassType() [D:\Build++UE4\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PyWrapperTypeRegistry.cpp:711]
UE4Editor_PythonScriptPlugin!FPyWrapperTypeRegistry::GenerateWrappedTypesForModule() [D:\Build++UE4\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PyWrapperTypeRegistry.cpp:488]
UE4Editor_PythonScriptPlugin!FPythonScriptPlugin::OnModulesChanged() [D:\Build++UE4\Sync\Engine\Plugins\Experimental\PythonScriptPlugin\Source\PythonScriptPlugin\Private\PythonScriptPlugin.cpp:1344]
UE4Editor_PythonScriptPlugin!TBaseRawMethodDelegateInstance<0,FPythonScriptPlugin,void __cdecl(FName,enum EModuleChangeReason),FDefaultDelegateUserPolicy>::ExecuteIfSafe() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateInstancesImpl.h:469]
UE4Editor_Core!TMulticastDelegate<void __cdecl(FName,enum EModuleChangeReason),FDefaultDelegateUserPolicy>::Broadcast() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Public\Delegates\DelegateSignatureImpl.inl:955]
UE4Editor_Core!FModuleManager::LoadModuleWithFailureReason() [D:\Build++UE4\Sync\Engine\Source\Runtime\Core\Private\Modules\ModuleManager.cpp:547]
UE4Editor_Projects!FModuleDescriptor::LoadModulesForPhase() [D:\Build++UE4\Sync\Engine\Source\Runtime\Projects\Private\ModuleDescriptor.cpp:643]
UE4Editor_Projects!FProjectManager::LoadModulesForProject() [D:\Build++UE4\Sync\Engine\Source\Runtime\Projects\Private\ProjectManager.cpp:62]
UE4Editor!FEngineLoop::LoadStartupModules() [D:\Build++UE4\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:3880]
UE4Editor!FEngineLoop::PreInitPostStartupScreen() [D:\Build++UE4\Sync\Engine\Source\Runtime\Launch\Private\LaunchEngineLoop.cpp:3263]
UE4Editor!GuardedMain() [D:\Build++UE4\Sync\Engine\Source\Runtime\Launch\Private\Launch.cpp:132]
UE4Editor!GuardedMainWrapper() [D:\Build++UE4\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:137]
UE4Editor!LaunchWindowsStartup() [D:\Build++UE4\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:273]
UE4Editor!WinMain() [D:\Build++UE4\Sync\Engine\Source\Runtime\Launch\Private\Windows\LaunchWindows.cpp:320]
UE4Editor!__scrt_common_main_seh() [d:\agent_work\5\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32

2

By pure luck I found out that the project launches after commenting CoreRedirects in my DefaultEngine.ini .

A line like this appears to cause the issue.

+ClassRedirects=(OldName=“PlayerScreenHUDWidget”,NewName=“/Script/CorePlugin.PlayerScreenHUDCoreWidget”)

This redirect would be required when redirecting a blueprint class to a c++ class, or a c++ class to another package.

8 Likes
3

Thanks for this! Deleting my .ini files cures the problem.
Although I would need to rebind my exposed C++ function in BP but better than can’t open the project ahaha

4

Thanks a lot commented redirectors and found the problematic one fixed it and now all works

5

thanks a lot, still helping in 2025