Unreal Engine Issues and Bug Tracker (UE-173901)

Description

This is not a Regression. Tested in //UE5/Release-5.0 CL23058290.

Crash occurs when creating a USkeletalMeshComponent inside a UMotionControllerComponent when applied to a Character. Commenting out mccHandMesh = CreateDefaultSubobject<USkeletalMeshComponent>(TEXT("mccHandMesh")); prevents the crash from occurring.

Steps to Reproduce

Create a new C++ Blank project
Select Tools > New C++ Class
Select All Classes then search for and select Motion Controller Component
Name the Class MyControllerComponent
Wait for the wizard to finish and open the IDE then close the Editor

In MyMotionControllerComponent.h after GENERATED_BODY() add:

public:

	UMyMotionControllerComponent();

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "Test")
	class USkeletalMeshComponent* mccHandMesh;

In the MyMotionControllerComponent.cpp add the #include "Components/SkeletalMeshComponent.h"

Then add these lines of codes:

UMyMotionControllerComponent::UMyMotionControllerComponent()
{
    mccHandMesh = CreateDefaultSubobject<USkeletalMeshComponent>(TEXT("mccHandMesh"));
}

Build the project in the IDE
Open the editor then press Ctrl+Alt+F11 then wait for Live Coding to finish
In the C++ Classes folder find the MyMotionControllerComponent right click then select Create Child Blueprint Class saving it in the Content folder
Create a new Blueprint Character
Add the MyMyMotionControllerComponent to the character
Compile the Blueprint

Expected Results:
The component is added and the blueprint compiles or a warning is given regarding the component

Actual Results:
The editor crashes with an Assertion:

Assertion failed: Pair != nullptr [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Map.h] [Line: 656]

Callstack

Assertion failed: Pair != nullptr [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Public\Containers\Map.h] [Line: 656]

UnrealEditor-Engine!FAnimUpdateRateManager::CleanupUpdateRateParametersRef(USkinnedMeshComponent *) [SkinnedMeshComponent.cpp:173]
UnrealEditor-Engine!USkinnedMeshComponent::OnUnregister() [SkinnedMeshComponent.cpp:650]
UnrealEditor-Engine!UActorComponent::ExecuteUnregisterEvents() [ActorComponent.cpp:1707]
UnrealEditor-Engine!UActorComponent::BeginDestroy() [ActorComponent.cpp:726]
UnrealEditor-Engine!UPrimitiveComponent::BeginDestroy() [PrimitiveComponent.cpp:1451]
UnrealEditor-Engine!USkinnedMeshComponent::BeginDestroy() [SkinnedMeshComponent.cpp:3785]
UnrealEditor-CoreUObject!UObject::ConditionalBeginDestroy() [Obj.cpp:1024]
UnrealEditor-CoreUObject!UnhashUnreachableObjects(bool,double) [GarbageCollection.cpp:2616]
UnrealEditor-CoreUObject!CollectGarbageInternal(EObjectFlags,bool) [GarbageCollection.cpp:2422]
UnrealEditor-CoreUObject!CollectGarbage(EObjectFlags,bool) [GarbageCollection.cpp:2671]
UnrealEditor-Kismet!FBlueprintCompilationManagerImpl::CompileSynchronouslyImpl(FBPCompileRequestInternal const &) [BlueprintCompilationManager.cpp:315]
UnrealEditor-Kismet!FBlueprintCompilationManager::CompileSynchronously(FBPCompileRequest const &) [BlueprintCompilationManager.cpp:3294]
UnrealEditor-UnrealEd!7fff8f380000  + b93fae
UnrealEditor-Kismet!FBlueprintEditor::Compile() [BlueprintEditor.cpp:4060]
UnrealEditor-Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,1,void ,FDefaultDelegateUserPolicy>::ExecuteIfSafe() [DelegateInstancesImpl.h:312]
UnrealEditor-Slate!7fffba350000  + e0a01
UnrealEditor-Slate!7fffba350000  + 1f18e7
UnrealEditor-Slate!7fffba350000  + 1c9e24
UnrealEditor-Slate!7fffba350000  + 2705f6
UnrealEditor-Slate!7fffba350000  + 296793
UnrealEditor-Slate!7fffba350000  + 2a3e8
UnrealEditor-Slate!7fffba350000  + ffca
UnrealEditor-Slate!7fffba350000  + 76743
UnrealEditor-Slate!7fffba350000  + 65223
UnrealEditor-Slate!7fffba350000  + 5aecc
UnrealEditor-ApplicationCore!FWindowsApplication::ProcessDeferredMessage(FDeferredWindowsMessage const &) [WindowsApplication.cpp:2219]
UnrealEditor-ApplicationCore!FWindowsApplication::DeferMessage(TSharedPtr<FWindowsWindow,1> &,HWND__ *,unsigned int,unsigned __int64,__int64,int,int,unsigned int) [WindowsApplication.cpp:2726]
UnrealEditor-ApplicationCore!FWindowsApplication::ProcessMessage(HWND__ *,unsigned int,unsigned __int64,__int64) [WindowsApplication.cpp:1895]
UnrealEditor-ApplicationCore!FWindowsApplication::AppWndProc(HWND__ *,unsigned int,unsigned __int64,__int64) [WindowsApplication.cpp:925]
USER32!7ff82aac0000  + e7e8
USER32!7ff82aac0000  + e47e
InkObj!202a3550000  + e7e59
atlthunk!7ff81c560000  + 1028
USER32!7ff82aac0000  + e7e8
USER32!7ff82aac0000  + e229
UnrealEditor-ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages(bool) [WindowsPlatformApplicationMisc.cpp:142]
UnrealEditor!7ff600d30000  + 7332
UnrealEditor!7ff600d30000  + 2287d
UnrealEditor!7ff600d30000  + 2296a
UnrealEditor!7ff600d30000  + 25680
UnrealEditor!7ff600d30000  + 371b4
UnrealEditor!7ff600d30000  + 3a516
KERNEL32!7ff82b900000  + 17614
ntdll!7ff82be10000  + 526a1

Have Comments or More Details?

There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-173901 in the post.

1	Login to Vote

Fixed

Component	UE - Anim - Runtime
Affects Versions	5.1
Target Fix	5.2

Fix Commit	24098100
Main Commit	24100357
Release Commit	24098100

Created	Jan 11, 2023
Resolved	Feb 9, 2023
Updated	Apr 29, 2023

UE-173901

Crash when creating a USkeletalMeshComponent inside a UMotionControllerComponent

Crash when creating a USkeletalMeshComponent inside a UMotionControllerComponent

Have Comments or More Details?