Unreal Engine Issues and Bug Tracker (UE-109407)

Description

When DuplicateWorldForPIE is called and serializes the references in another AlwaysLoaded sublevel, the properties of a ChildActorComponent are confusingly inaccurate.

Steps to Reproduce

Create new Persistent Level (File -> New Level)
Add new Blueprint class derived from Actor (I named it "ChildActor")
Add a Child Actor Component to the actor from step 5 with Child Actor Class = TargetPoint (any class will work)
Set Replicates = true for the actor from step 5 and Replicates = true (category Child Actor Component -> Child Actor Template -> Replication) for the Child Actor from step 6
Add ChildActor to the level
Start PIE with Net Mode = "Play As Client" and Run Under One Process = false
Run the console command "obj list"

Callstack

UE4Editor-Engine-Win64-Debug.dll!UChildActorComponent::Serialize(FArchive & Ar) Line 130 C++
 UE4Editor-Engine-Win64-Debug.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 3102 C++
 UE4Editor-Core-Win64-Debug.dll!FBinaryArchiveFormatter::Serialize(UObject * & Value) Line 267 C++
 UE4Editor-Core-Win64-Debug.dll!FStructuredArchiveSlot::operator<<(UObject * & Value) Line 508 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FObjectProperty::SerializeItem(FStructuredArchiveSlot Slot, void * Value, const void * Defaults) Line 98 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FProperty::SerializeBinProperty(FStructuredArchiveSlot Slot, void * Data, int ArrayIdx) Line 308 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UStruct::SerializeBin(FStructuredArchiveSlot Slot, void * Data) Line 1093 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::SerializeScriptProperties(FStructuredArchiveSlot Slot) Line 1474 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FStructuredArchiveRecord Record) Line 1377 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FArchive & Ar) Line 1262 C++
 UE4Editor-Engine-Win64-Debug.dll!AActor::Serialize(FArchive & Ar) Line 716 C++
 UE4Editor-Engine-Win64-Debug.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 3102 C++
 UE4Editor-Engine-Win64-Debug.exe.patch_0!operator<<(FArchive & Ar, TArray<AActor *,TSizedDefaultAllocator<32>> & A) Line 1186 C++
 UE4Editor-Engine-Win64-Debug.exe.patch_0!ULevel::Serialize(FArchive & Ar) Line 459 C++
 UE4Editor-Engine-Win64-Debug.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 3102 C++
 UE4Editor-Core-Win64-Debug.dll!FBinaryArchiveFormatter::Serialize(UObject * & Value) Line 267 C++
 UE4Editor-Core-Win64-Debug.dll!FStructuredArchiveSlot::operator<<(UObject * & Value) Line 508 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FObjectProperty::SerializeItem(FStructuredArchiveSlot Slot, void * Value, const void * Defaults) Line 98 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FProperty::SerializeBinProperty(FStructuredArchiveSlot Slot, void * Data, int ArrayIdx) Line 308 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UStruct::SerializeBin(FStructuredArchiveSlot Slot, void * Data) Line 1093 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::SerializeScriptProperties(FStructuredArchiveSlot Slot) Line 1474 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FStructuredArchiveRecord Record) Line 1377 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FArchive & Ar) Line 1262 C++
 UE4Editor-Engine-Win64-Debug.dll!UWorld::Serialize(FArchive & Ar) Line 403 C++
 UE4Editor-Engine-Win64-Debug.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 3102 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FArchiveUObject::SerializeSoftObjectPtr(FArchive & Ar, FSoftObjectPtr & Value) Line 79 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FArchiveUObject::operator<<(FSoftObjectPtr & Value) Line 28 C++
 UE4Editor-Core-Win64-Debug.dll!FBinaryArchiveFormatter::Serialize(FSoftObjectPtr & Value) Line 282 C++
 UE4Editor-Core-Win64-Debug.dll!FStructuredArchiveSlot::operator<<(FSoftObjectPtr & Value) Line 536 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FSoftObjectProperty::SerializeItem(FStructuredArchiveSlot Slot, void * Value, const void * Defaults) Line 60 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FProperty::SerializeBinProperty(FStructuredArchiveSlot Slot, void * Data, int ArrayIdx) Line 308 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UStruct::SerializeBin(FStructuredArchiveSlot Slot, void * Data) Line 1093 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::SerializeScriptProperties(FStructuredArchiveSlot Slot) Line 1474 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FStructuredArchiveRecord Record) Line 1377 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FArchive & Ar) Line 1262 C++
 UE4Editor-Engine-Win64-Debug.exe.patch_0!ULevelStreaming::Serialize(FArchive & Ar) Line 358 C++
 UE4Editor-Engine-Win64-Debug.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 3102 C++
 UE4Editor-Core-Win64-Debug.dll!FBinaryArchiveFormatter::Serialize(UObject * & Value) Line 267 C++
 UE4Editor-Core-Win64-Debug.dll!FStructuredArchiveSlot::operator<<(UObject * & Value) Line 508 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FObjectProperty::SerializeItem(FStructuredArchiveSlot Slot, void * Value, const void * Defaults) Line 98 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FArrayProperty::SerializeItem(FStructuredArchiveSlot Slot, void * Value, const void * Defaults) Line 299 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!FProperty::SerializeBinProperty(FStructuredArchiveSlot Slot, void * Data, int ArrayIdx) Line 308 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UStruct::SerializeBin(FStructuredArchiveSlot Slot, void * Data) Line 1093 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::SerializeScriptProperties(FStructuredArchiveSlot Slot) Line 1474 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FStructuredArchiveRecord Record) Line 1377 C++
 UE4Editor-CoreUObject-Win64-Debug.dll!UObject::Serialize(FArchive & Ar) Line 1262 C++
 UE4Editor-Engine-Win64-Debug.dll!UWorld::Serialize(FArchive & Ar) Line 403 C++
 UE4Editor-Engine-Win64-Debug.dll!FFixupSmartPointersForPIEArchive::operator<<(UObject * & Object) Line 3102 C++
 UE4Editor-Engine-Win64-Debug.dll!UWorld::DuplicateWorldForPIE(const FString & PackageName, UWorld * OwningWorld) Line 3175 C++
 > UE4Editor-Engine-Win64-Debug.exe.patch_0!ULevelStreaming::RequestLevel(UWorld * PersistentWorld, bool bAllowLevelLoadRequests, ULevelStreaming::EReqLevelBlock BlockPolicy) Line 963 C++
 UE4Editor-Engine-Win64-Debug.exe.patch_0!ULevelStreaming::UpdateStreamingState::__l2::<lambda>() Line 552 C++
 UE4Editor-Engine-Win64-Debug.exe.patch_0!ULevelStreaming::UpdateStreamingState(bool & bOutUpdateAgain, bool & bOutRedetermineTarget) Line 627 C++
 UE4Editor-Engine-Win64-Debug.dll!UWorld::UpdateLevelStreaming() Line 3427 C++
 UE4Editor-Engine-Win64-Debug.dll!UGameViewportClient::Draw(FViewport * InViewport, FCanvas * SceneCanvas) Line 1564 C++
 UE4Editor-Engine-Win64-Debug.dll!FViewport::Draw(bool bShouldPresent) Line 1559 C++
 UE4Editor-UnrealEd-Win64-Debug.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1919 C++
 UE4Editor-UnrealEd-Win64-Debug.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 426 C++
 UE4Editor-Win64-Debug.exe!FEngineLoop::Tick() Line 4836 C++
 UE4Editor-Win64-Debug.exe!EngineTick() Line 63 C++
 UE4Editor-Win64-Debug.exe!GuardedMain(const wchar_t * CmdLine) Line 172 C++
 UE4Editor-Win64-Debug.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 257 C++
 [Inline Frame] UE4Editor-Win64-Debug.exe!invoke_main() Line 102 C++
 UE4Editor-Win64-Debug.exe!__scrt_common_main_seh() Line 288 C++
 kernel32.dll!BaseThreadInitThunk() Unknown
 ntdll.dll!RtlUserThreadStart() Unknown

Have Comments or More Details?

There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-109407 in the post.

1	Login to Vote

Fixed

Component	UE - Networking
Affects Versions	4.26
Target Fix	5.0

Fix Commit	18449332
Main Commit	18449377
Release Commit	18449332

Created	Feb 25, 2021
Resolved	Dec 13, 2021
Updated	Jan 26, 2023

View Jira Issue

UE-109407

ChildActor is being set to null on client via replication

ChildActor is being set to null on client via replication

Have Comments or More Details?