Unreal Engine Issues and Bug Tracker (UE-41708)

Description

Defining a ChildActorComponent in code, then setting the component to a blueprint derived from another code class causes the editor to crash when opening the parent blueprint if any changes are made to the child class.

Steps to Reproduce

Open UE4 Editor
Add two classes based on Actor (Parent & Child)

Add the following to Parent.h

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Test)
	class UChildActorComponent* MyChildComp;

Add the following to Parent.cpp

# 	MyChildComp = CreateDefaultSubobject<UChildActorComponent>(TEXT("ChildActorComponent"));
	MyChildComp->SetupAttachment(SceneComp);

Compile
Add two blueprints (ParentBP and ChildBP)
Open ParentBP and set MyChildComp to ChildBP
Save and close the project

Add the following to Child.h

UPROPERTY(VisibleDefaultsOnly, BlueprintReadOnly, Category = Collision)
UCapsuleComponent* CollisionComponent;

Add the following to Child.cpp

CollisionComponent = CreateDefaultSubobject<UCapsuleComponent>(TEXT("CollisionComponent"));

Compile and reopen project
Open ParentBP

Result:
Editor crashes when attempting to open ParentBP

Expected:
ParentBP opens and can be edited.

Callstack

MachineId:7156C35640F86204E61B8383F45DEE17
EpicAccountId:e8c7fa630b6440f69a25a2c64d6c482c

Assertion failed: SubobjectOuter [File:D:\Build\++UE4+Release-4.14+Compile\Sync\Engine\Source\Runtime\CoreUObject\Private\UObject\CoreNative.cpp] [Line: 164] 
No corresponding destination object found for 'ChildBP_C /Game/ChildBP.Default__ChildBP_C' while attempting to instance component 'StaticMeshComponent /Game/ChildBP.Default__ChildBP_C:CollisionComponent'


UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:332]
UE4Editor_CoreUObject!FObjectInstancingGraph::GetInstancedSubobject() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\corenative.cpp:164]
UE4Editor_CoreUObject!FObjectInstancingGraph::InstancePropertyValue() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\corenative.cpp:263]
UE4Editor_CoreUObject!UObjectPropertyBase::InstanceSubobjects() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\propertybaseobject.cpp:34]
UE4Editor_CoreUObject!UStruct::InstanceSubobjectTemplates() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:1456]
UE4Editor_CoreUObject!FObjectInitializer::InstanceSubobjects() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2942]
UE4Editor_CoreUObject!FObjectInitializer::PostConstructInit() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2826]
UE4Editor_CoreUObject!FObjectInitializer::~FObjectInitializer() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:2684]
UE4Editor_CoreUObject!StaticConstructObject_Internal() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\private\uobject\uobjectglobals.cpp:3212]
UE4Editor_Engine!NewObject<AActor>() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\coreuobject\public\uobject\uobjectglobals.h:1227]
UE4Editor_Engine!UWorld::SpawnActor() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\levelactor.cpp:405]
UE4Editor_Engine!UWorld::SpawnActor() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\levelactor.cpp:271]
UE4Editor_Engine!UChildActorComponent::CreateChildActor() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\components\childactorcomponent.cpp:484]
UE4Editor_Engine!UActorComponent::ExecuteRegisterEvents() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\components\actorcomponent.cpp:1179]
UE4Editor_Engine!UActorComponent::RegisterComponentWithWorld() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\components\actorcomponent.cpp:912]
UE4Editor_Engine!AActor::IncrementalRegisterComponents() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\actor.cpp:4041]
UE4Editor_Engine!AActor::RegisterAllComponents() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\actor.cpp:3940]
UE4Editor_Engine!AActor::PostSpawnInitialize() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\actor.cpp:2728]
UE4Editor_Engine!UWorld::SpawnActor() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\levelactor.cpp:438]
UE4Editor_Engine!UWorld::SpawnActor() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\engine\private\levelactor.cpp:271]
UE4Editor_Kismet!FBlueprintEditor::UpdatePreviewActor() [d:\build\++ue4+release-4.14+compile\sync\engine\source\editor\kismet\private\blueprinteditor.cpp:8062]
UE4Editor_Kismet!FBlueprintEditor::Tick() [d:\build\++ue4+release-4.14+compile\sync\engine\source\editor\kismet\private\blueprinteditor.cpp:7028]
UE4Editor_UnrealEd!FTickableEditorObject::TickObjects() [d:\build\++ue4+release-4.14+compile\sync\engine\source\editor\unrealed\public\tickableeditorobject.h:17]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4+release-4.14+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1195]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.14+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:371]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2859]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\launch\private\launch.cpp:152]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.14+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\build\++ue4+release-4.14+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

Community References

ChildActorComponent: ChildActorTemplate causes crash when native child actor class changed

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Fixed

Component	UE - Gameplay - Components
Affects Versions	4.14.3, 4.15
Target Fix	4.16

Fix Commit	3305031
Main Commit	3358685

Created	Feb 7, 2017
Resolved	Feb 15, 2017
Updated	Apr 27, 2018

UE-41708

Crash when opening Blueprint after editing ChildActorComponent base class

Crash when opening Blueprint after editing ChildActorComponent base class

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