code to reproduce issue:
UUserWidget* Widget = CreateWidget<UUserWidget>(MyPlayerController, WidgetTemplate);
if (Widget)
{
Widget->AddToRoot();
Widget->AddToViewport();
}
If invoke AddToRoot and AddToViewport at the same time, UE4Editor would crash when click Stop button
of Editor at runtime.
crash dump:
Assertion failed: !IsRooted() [File:d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\public\uobject\UObjectBaseUtility.h] [Line: 135]
UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\core\private\misc\outputdevice.cpp:421]
UE4Editor_UnrealEd!<lambda_26419e543909ee92ebfb672b1e9c08dc>::operator()() [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:384]
UE4Editor_CoreUObject!ForEachObjectWithOuter() [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjecthash.cpp:678]
UE4Editor_UnrealEd!UEditorEngine::EndPlayMap() [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\playlevel.cpp:380]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1653]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.13+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:371]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2834]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\launch\private\launch.cpp:156]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\build\++ue4+release-4.13+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll
I think UE4 should prevent users to invoke AddToRoot and AddToViewport at the same time, or give an exact tip to warn users from that usage.