Unreal Engine Issues and Bug Tracker (UE-42572)

Description

Getting a crash when trying to access a non-empty TSet or TMap local variable in a blueprint function. This is only occurring with local variables. The issue also does not occur if the TSet or TMap is empty when trying to access it.

This does NOT occur in //UE4/Main CL-3332594

Steps to Reproduce

Create / Open a blank Blueprint Project
Create a new Blueprint based on Actor (name it TestBP)
Open TestBP
Create a function (Foo)
Select Foo in the My Blueprint panel and add a new Local Variable (TestSet)
Change the Variable's type to String and make it a Set
Compile the Blueprint
Select TestSet in the My Blueprint panel and add an element to the TSet
In Foo's graph place a GET reference for TestSet
From the GET reference place an Add node (pass in "Test" for the String value) and connect the execs
Place a call to Foo in TestBP's event graph and connect the in exec to BeginPlay
Compile and place an instance of TestBP in the level
PIE

Result: Editor Crashes.

Callstack

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

UE4Editor_Core!rml::internal::Block::findObjectSize() [d:\depot\ue4\engine\source\thirdparty\inteltbb\inteltbb-4.4u3\src\tbbmalloc\frontend.cpp:2107]
UE4Editor_Core!FMallocTBB::Free() [d:\builds\samuel.proctor_framework\engine\source\runtime\core\private\hal\malloctbb.cpp:112]
UE4Editor_Core!FMemory::Free() [d:\builds\samuel.proctor_framework\engine\source\runtime\core\public\hal\fmemory.inl:52]
UE4Editor_Core!FString::operator=() [d:\builds\samuel.proctor_framework\engine\source\runtime\core\public\containers\unrealstring.h:1700]
UE4Editor_CoreUObject!UObject::execStringConst() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2423]
UE4Editor_CoreUObject!UObject::execSetMap() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2691]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:943]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:845]
UE4Editor_CoreUObject!UObject::execVirtualFunction() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2271]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:943]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:845]
UE4Editor_CoreUObject!UObject::execVirtualFunction() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2271]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:943]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\class.cpp:4486]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\builds\samuel.proctor_framework\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1313]
UE4Editor_Engine!AActor::ProcessEvent() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\actor.cpp:685]
UE4Editor_Engine!AActor::ReceiveBeginPlay()
UE4Editor_Engine!AActor::BeginPlay() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\actor.cpp:3124]
UE4Editor_Engine!AActor::DispatchBeginPlay() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\actor.cpp:3092]
UE4Editor_Engine!AWorldSettings::NotifyBeginPlay() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\worldsettings.cpp:183]
UE4Editor_Engine!AGameStateBase::HandleBeginPlay() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\gamestatebase.cpp:177]
UE4Editor_Engine!UWorld::BeginPlay() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\world.cpp:3430]
UE4Editor_Engine!UGameInstance::StartPlayInEditorGameInstance() [d:\builds\samuel.proctor_framework\engine\source\runtime\engine\private\gameinstance.cpp:338]
UE4Editor_UnrealEd!UEditorEngine::CreatePIEGameInstance() [d:\builds\samuel.proctor_framework\engine\source\editor\unrealed\private\playlevel.cpp:3413]
UE4Editor_UnrealEd!UEditorEngine::PlayInEditor() [d:\builds\samuel.proctor_framework\engine\source\editor\unrealed\private\playlevel.cpp:2508]
UE4Editor_UnrealEd!UEditorEngine::StartQueuedPlayMapRequest() [d:\builds\samuel.proctor_framework\engine\source\editor\unrealed\private\playlevel.cpp:1215]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\builds\samuel.proctor_framework\engine\source\editor\unrealed\private\editorengine.cpp:1521]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\builds\samuel.proctor_framework\engine\source\editor\unrealed\private\unrealedengine.cpp:391]
UE4Editor!FEngineLoop::Tick() [d:\builds\samuel.proctor_framework\engine\source\runtime\launch\private\launchengineloop.cpp:3061]
UE4Editor!GuardedMain() [d:\builds\samuel.proctor_framework\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\builds\samuel.proctor_framework\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\builds\samuel.proctor_framework\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
kernel32
ntdll

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Fixed

Component	UE - Gameplay - Blueprint
Affects Versions	4.16
Target Fix	4.16

Fix Commit	3340369
Main Commit	3358685

Created	Mar 6, 2017
Resolved	Mar 9, 2017
Updated	May 1, 2019

UE-42572

Crash accessing a non-empty TSet or TMap local variable in a blueprint function

Crash accessing a non-empty TSet or TMap local variable in a blueprint function

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