Unreal Engine Issues and Bug Tracker (UE-58657)

Description

Attempting to duplicate an instance of a Blueprint in a level where the parent code class has overridden PreEditChange() without including a call to Super results in the Editor crashing.

Steps to Reproduce

Create a new Basic Code project.
Add a new Actor code class to the project.

In the new Actor code class, override PreEditChange(), but do not include a Super call.

eg:

// .h
#if WITH_EDITOR
	void PreEditChange(UProperty* PropertyThatWillChange) override;
#endif

// .cpp
#if WITH_EDITOR
void AMyActor::PreEditChange(UProperty* PropertyThatWillChange)
{
	
}
#endif

Create a new Blueprint that derives from the new Actor code class.
Add a Skeletal Mesh Component to the Blueprint.
Set a Skeletal Mesh and Anim Blueprint in the Skeletal Mesh Component.
Place an instance of the Blueprint into the level.
Select the instance of the Blueprint in the World Outliner.
Right-click the instance and select Edit -> Duplicate.

RESULT:
The Editor crashes due to an access violation. The log shows the following error message immediately before the crash: Error: BEGIN OBJECT: No base template named TutorialTPP_AnimBlueprint_C_250 found in parent class SkinnedMeshComponent: Begin Object Name="TutorialTPP_AnimBlueprint_C_250"

EXPECTED:
Either a warning message is displayed stating that the Blueprint cannot be duplicated (and ideally indicates why), a compile error occurs noting that the Super call is missing, or the Blueprint is successfully duplicated.

Callstack

Access violation - code c0000005 (first/second chance not available)

UE4Editor_Core!FParse::LineExtended() [d:\main-builds\stream\engine\source\runtime\core\private\misc\parse.cpp:1059]
UE4Editor_UnrealEd!ImportProperties() [d:\main-builds\stream\engine\source\editor\unrealed\private\editorobject.cpp:258]
UE4Editor_UnrealEd!ImportObjectProperties() [d:\main-builds\stream\engine\source\editor\unrealed\private\editorobject.cpp:707]
UE4Editor_UnrealEd!ImportObjectProperties() [d:\main-builds\stream\engine\source\editor\unrealed\private\editorobject.cpp:815]
UE4Editor_UnrealEd!ULevelFactory::FactoryCreateText() [d:\main-builds\stream\engine\source\editor\unrealed\private\factories\editorfactories.cpp:1125]
UE4Editor_UnrealEd!UUnrealEdEngine::edactPasteSelected() [d:\main-builds\stream\engine\source\editor\unrealed\private\editoractor.cpp:351]
UE4Editor_UnrealEd!DuplicateSelectedActors::FDuplicateJob::DuplicateActorsToLevel() [d:\main-builds\stream\engine\source\editor\unrealed\private\editoractor.cpp:451]
UE4Editor_UnrealEd!UUnrealEdEngine::edactDuplicateSelected() [d:\main-builds\stream\engine\source\editor\unrealed\private\editoractor.cpp:565]
UE4Editor_UnrealEd!UUnrealEdEngine::Exec_Actor() [d:\main-builds\stream\engine\source\editor\unrealed\private\unrealedsrv.cpp:2754]
UE4Editor_UnrealEd!UUnrealEdEngine::Exec() [d:\main-builds\stream\engine\source\editor\unrealed\private\unrealedsrv.cpp:759]
UE4Editor_UnrealEd!UEditorEngine::Exec() [d:\main-builds\stream\engine\source\editor\unrealed\private\editorserver.cpp:5472]
UE4Editor_UnrealEd!UUnrealEdEngine::Exec() [d:\main-builds\stream\engine\source\editor\unrealed\private\unrealedsrv.cpp:696]
UE4Editor_LevelEditor!FLevelEditorActionCallbacks::ExecuteExecCommand() [d:\main-builds\stream\engine\source\editor\leveleditor\private\leveleditoractions.cpp:1674]
UE4Editor_LevelEditor!TBaseStaticDelegateInstance<void __cdecl(void),FString>::ExecuteIfSafe() [d:\main-builds\stream\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:788]
UE4Editor_Slate!FUICommandList::ExecuteAction() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:97]
UE4Editor_Slate!SMenuEntryBlock::OnClicked() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:1028]
UE4Editor_Slate!SMenuEntryBlock::OnMenuItemButtonClicked() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:988]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SMenuEntryBlock,0,FReply __cdecl(void)>::Execute() [d:\main-builds\stream\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:269]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\main-builds\stream\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:282]
UE4Editor_Slate!SMenuEntryButton::OnMouseButtonUp() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\multibox\smenuentryblock.cpp:385]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_1002768c627006711ef2f351a87ec0e7> >() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:268]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5434]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5932]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\main-builds\stream\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5912]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [d:\main-builds\stream\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1726]
UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [d:\main-builds\stream\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2172]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [d:\main-builds\stream\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:889]
UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [d:\main-builds\stream\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:726]
user32
user32
UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [d:\main-builds\stream\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:129]
UE4Editor!FEngineLoop::Tick() [d:\main-builds\stream\engine\source\runtime\launch\private\launchengineloop.cpp:3286]
UE4Editor!GuardedMain() [d:\main-builds\stream\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\main-builds\stream\engine\source\runtime\launch\private\windows\launchwindows.cpp:144]
UE4Editor!WinMain() [d:\main-builds\stream\engine\source\runtime\launch\private\windows\launchwindows.cpp:223]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:283]
kernel32
ntdll

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Won't Fix

Component	UE - Gameplay - Blueprint
Affects Versions	4.18.3, 4.19.1, 4.20

Created	May 4, 2018
Resolved	Aug 18, 2021
Updated	Aug 18, 2021

View Jira Issue

UE-58657

Editor crashes when duplicating a Blueprint instance whose parent class overrides PreEditChange() without including a call to Super

Editor crashes when duplicating a Blueprint instance whose parent class overrides PreEditChange() without including a call to Super

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