Unreal Engine Issues

UE-179298

Editor crash on level load when bUseActorFolders is true after dragging Actor into another folder in the Outliner

Editor crash on level load when bUseActorFolders is true after dragging Actor into another folder in the Outliner

Description

From licensee:

Hello! Our level streaming setup enables the bUseActorFolders on our levels. When moving the Actor into another folder via the Outline, the editor will crash on the next load

Assertion failed: FoundSet && FoundSet->GetActorFolders().Num() > 1 && FoundSet->GetActorFolders().Contains(Folder) [Link Removed] [Line: 2869] 

 

After debugging it, the property

UPROPERTY(Transient)

TMap<FString, FActorFolderSet> FolderLabelToActorFolders;

 

is not re-initialized with the level ActorFolders when loading the level, the FixupActorFolders function will assert because the list is empty. I fixed it by adding this to the ULevel::FixupActorFolders() function

ForEachActorFolder([this](UActorFolder* ActorFolder)

{

FActorFolderSet& Folders = FolderLabelToActorFolders.FindOrAdd(ActorFolder->GetLabel());

Folders.Add(ActorFolder);

return true;

}, /bSkipDeleted/ true);

Steps to Reproduce
  • Create a level (non-WP) and save it.
  • Enable "Use Actor Folder Objects" in World Settings.
  • Add an actor to the scene and create a folder in the world outliner.
  • Save.
  • Add another actor to the scene and then move it into the folder.
  • Save.
  • Open a different level and then reopen the level that has 
    "Use Actor Folder Objects" enabled.
Callstack
>	UnrealEditor-Engine.dll!ULevel::FixupActorFolders() Line 2894	C++
 	UnrealEditor-Engine.dll!ULevel::OnLevelLoaded() Line 2975	C++
 	UnrealEditor-Engine.dll!UWorld::InitWorld(const FWorldInitializationValues IVS) Line 1951	C++
 	UnrealEditor-UnrealEd.dll!UEditorEngine::Map_Load(const wchar_t * Str, FOutputDevice & Ar) Line 2793	C++
 	UnrealEditor-UnrealEd.dll!UEditorEngine::HandleMapCommand(const wchar_t * Str, FOutputDevice & Ar, UWorld * InWorld) Line 6298	C++
 	UnrealEditor-UnrealEd.dll!UEditorEngine::Exec_Editor(UWorld * InWorld, const wchar_t * Stream, FOutputDevice & Ar) Line 5759	C++
 	UnrealEditor-Core.dll!FExec::Exec(UWorld * InWorld, const wchar_t * Cmd, FOutputDevice & Ar) Line 15	C++
 	UnrealEditor-Engine.dll!UEngine::Exec(UWorld * InWorld, const wchar_t * Cmd, FOutputDevice & Ar) Line 4624	C++
 	UnrealEditor-UnrealEd.dll!UUnrealEdEngine::Exec(UWorld * InWorld, const wchar_t * Stream, FOutputDevice & Ar) Line 662	C++
 	UnrealEditor-UnrealEd.dll!FEditorFileUtils::LoadMap(const FString & InFilename, bool LoadAsTemplate, const bool bShowProgress) Line 2901	C++
 	UnrealEditor-LevelEditor.dll!FLevelEditorActionCallbacks::OpenRecentFile(int RecentFileIndex) Line 319	C++
 	[Inline Frame] UnrealEditor-LevelEditor.dll!Invoke(void(*)(int) &) Line 47	C++
 	[Inline Frame] UnrealEditor-LevelEditor.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int,0>,int>::ApplyAfter(void(*)(int) &) Line 311	C++
 	UnrealEditor-LevelEditor.dll!TBaseStaticDelegateInstance<void __cdecl(void),FDefaultDelegateUserPolicy,int>::ExecuteIfSafe() Line 658	C++
 	UnrealEditor-Slate.dll!FUICommandList::ExecuteAction(const TSharedRef<FUICommandInfo const ,1> InUICommandInfo) Line 117	C++
 	UnrealEditor-Slate.dll!SMenuEntryBlock::OnClicked(bool bCheckBoxClicked) Line 1158	C++
 	UnrealEditor-Slate.dll!SMenuEntryBlock::OnMenuItemButtonClicked() Line 1118	C++
 	[Inline Frame] UnrealEditor-Slate.dll!Invoke(FReply(SMenuEntryBlock::*)()) Line 66	C++
 	[Inline Frame] UnrealEditor-Slate.dll!UE::Core::Private::Tuple::TTupleBase<TIntegerSequence<unsigned int>>::ApplyAfter(FReply(SMenuEntryBlock::*)() &) Line 311	C++
 	UnrealEditor-Slate.dll!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,1,FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() Line 275	C++
 	[Inline Frame] UnrealEditor-Slate.dll!TDelegate<FReply __cdecl(void),FDefaultDelegateUserPolicy>::Execute() Line 632	C++
 	UnrealEditor-Slate.dll!SButton::ExecuteOnClick() Line 465	C++
 	UnrealEditor-Slate.dll!SButton::OnMouseButtonUp(const FGeometry & MyGeometry, const FPointerEvent & MouseEvent) Line 390	C++
 	UnrealEditor-Slate.dll!SMenuEntryButton::OnMouseButtonUp(const FGeometry & MyGeometry, const FPointerEvent & MouseEvent) Line 434	C++
 	[Inline Frame] UnrealEditor-Slate.dll!FSlateApplication::RoutePointerUpEvent::__l8::<lambda_2>::operator()(const FArrangedWidget &) Line 5134	C++
 	UnrealEditor-Slate.dll!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,`FSlateApplication::RoutePointerUpEvent'::`8'::<lambda_2>>(FSlateApplication * ThisApplication, FEventRouter::FToLeafmostPolicy RoutingPolicy, FPointerEvent EventCopy, const FSlateApplication::RoutePointerUpEvent::__l8::<lambda_2> & Lambda, ESlateDebuggingInputEvent DebuggingInputEvent) Line 427	C++
 	UnrealEditor-Slate.dll!FSlateApplication::RoutePointerUpEvent(const FWidgetPath & WidgetsUnderPointer, const FPointerEvent & PointerEvent) Line 5120	C++
 	UnrealEditor-Slate.dll!FSlateApplication::ProcessMouseButtonUpEvent(const FPointerEvent & MouseEvent) Line 5689	C++
 	UnrealEditor-Slate.dll!FSlateApplication::OnMouseUp(const EMouseButtons::Type Button, const UE::Math::TVector2<double> CursorPos) Line 5654	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessDeferredMessage(const FDeferredWindowsMessage & DeferredMessage) Line 2219	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::DeferMessage(TSharedPtr<FWindowsWindow,1> & NativeWindow, HWND__ * InHWnd, unsigned int InMessage, unsigned __int64 InWParam, __int64 InLParam, int MouseX, int MouseY, unsigned int RawInputFlags) Line 2726	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::ProcessMessage(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 1895	C++
 	[Inline Frame] UnrealEditor-ApplicationCore.dll!WindowsApplication_WndProc(HWND__ *) Line 919	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsApplication::AppWndProc(HWND__ * hwnd, unsigned int msg, unsigned __int64 wParam, __int64 lParam) Line 925	C++
 	user32.dll!UserCallWinProcCheckWow()	Unknown
 	user32.dll!DispatchMessageWorker()	Unknown
 	[Inline Frame] UnrealEditor-ApplicationCore.dll!WinPumpMessages() Line 113	C++
 	UnrealEditor-ApplicationCore.dll!FWindowsPlatformApplicationMisc::PumpMessages(bool bFromMainLoop) Line 142	C++
 	UnrealEditor.exe!FEngineLoop::Tick() Line 5736	C++
 	[Inline Frame] UnrealEditor.exe!EngineTick() Line 61	C++
 	UnrealEditor.exe!GuardedMain(const wchar_t * CmdLine) Line 188	C++
 	UnrealEditor.exe!LaunchWindowsStartup(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow, const wchar_t * CmdLine) Line 233	C++
 	UnrealEditor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * pCmdLine, int nCmdShow) Line 284	C++
 	[Inline Frame] UnrealEditor.exe!invoke_main() Line 102	C++
 	UnrealEditor.exe!__scrt_common_main_seh() Line 288	C++
 	kernel32.dll!BaseThreadInitThunk()	Unknown
 	ntdll.dll!RtlUserThreadStart()	Unknown

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Fixed
ComponentUE - World Creation - Worldbuilding Tools - OFPA
Affects Versions5.2
Target Fix5.3
Fix Commit24589806
Main Commit24589806
CreatedMar 7, 2023
ResolvedMar 10, 2023
UpdatedApr 29, 2023
View Jira Issue