The crash occurs when trying to assign a new value to RootComponent if the Pawn is already placed on the level
Crash does not happen in P4 //UE4/Release-4.25.3 CL 13942748
Other steps to reproduce №1:
1) Create Blank C++ project
2) Create a new Pawn C++ class.
3) Open MyPawn.cpp
4) Add two includes:
#include "UObject/ConstructorHelpers.h" #include "Components/SphereComponent.h"
5) Add two lines under PrimaryActorTick.bCanEverTick = true;
USphereComponent* SphereComponent = CreateDefaultSubobject<USphereComponent>(TEXT("RootComponent"));
RootComponent = SphereComponent;
6) Place the Pawn on the level
7) Compile
Result: Editor crashed with the same Callstack
Other steps to reproduce №2:
1) Create a Blank C++ project With Starter Content
2) Create a new Actor C++ class. Name it MyClass
3) Open MyClass.h.
4) Add following lines under AMyClass();
UPROPERTY(VisibleAnywhere) UStaticMeshComponent* VisualMesh;
5) Open MyClass.cpp
6) Add following lines under PrimaryActorTick.bCanEverTick = true;
VisualMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Test Mesh")); VisualMesh->SetupAttachment(RootComponent); static ConstructorHelpers::FObjectFinder<UStaticMesh> CubeVisualAsset(TEXT("/Game/StarterContent/Shapes/Shape_Cube.Shape_Cube")); if (CubeVisualAsset.Succeeded()) { VisualMesh->SetStaticMesh(CubeVisualAsset.Object); VisualMesh->SetRelativeLocation(FVector(0.0f, 0.0f, 0.0f)); }
7) Compile and place MyClass on the level
8) Change
VisualMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Test Mesh"));
to
VisualMesh = CreateDefaultSubobject<UStaticMeshComponent>(TEXT("Test1 Mesh"));
9) Compile again
Actual: Crash at the end of compiling
1) Create Blank C++ project
2) Create a new Pawn C++ class.
3) Open MyPawn.cpp
4) Add line under PrimaryActorTick.bCanEverTick = true;
RootComponent = CreateDefaultSubobject<USceneComponent>(TEXT("RootComponent"));
6) Place the Pawn on the level
7) Compile
Actual: Crash at the end of compiling
Expected: Compiling successfully. Subobject for RootComponent is created.
UE4Editor_CoreUObject!GetArchetypeFromRequiredInfoImpl() [UObjectArchetype.cpp:131] UE4Editor_CoreUObject!GetArchetypeFromRequiredInfoImpl() [UObjectArchetype.cpp:82] UE4Editor_CoreUObject!UObject::GetArchetype() [UObjectArchetype.cpp:207] UE4Editor_Engine!AActor::PostSpawnInitialize() [Actor.cpp:3112] UE4Editor_Engine!UWorld::SpawnActor() [LevelActor.cpp:567] UE4Editor_Engine!UWorld::SpawnActor() [LevelActor.cpp:304] UE4Editor_UnrealEd!ReplaceActorHelper() [KismetReinstanceUtilities.cpp:1832] UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReplaceInstancesOfClass_Inner() [KismetReinstanceUtilities.cpp:2114] UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReplaceInstancesOfClass() [KismetReinstanceUtilities.cpp:1499] UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReinstanceInner() [KismetReinstanceUtilities.cpp:707] UE4Editor_UnrealEd!FBlueprintCompileReinstancer::ReinstanceObjects() [KismetReinstanceUtilities.cpp:781] UE4Editor_HotReload!FHotReloadModule::ReinstanceClass() [HotReload.cpp:1258] UE4Editor_HotReload!FHotReloadModule::ReinstanceClasses() [HotReload.cpp:1244] UE4Editor_HotReload!TBaseRawMethodDelegateInstance<0,FHotReloadModule,void __cdecl(void) [DelegateInstancesImpl.h:469] UE4Editor_CoreUObject!UClassReplaceHotReloadClasses() [UObjectBase.cpp:842] UE4Editor_CoreUObject!ProcessNewlyLoadedUObjects() [UObjectBase.cpp:1002] UE4Editor_CoreUObject!TBaseStaticDelegateInstance<void __cdecl(FName,bool) [DelegateInstancesImpl.h:731] UE4Editor_Core!TMulticastDelegate<void __cdecl(FName,bool) [DelegateSignatureImpl.inl:955] UE4Editor_Core!FModuleManager::LoadModuleWithFailureReason() [ModuleManager.cpp:508] UE4Editor_Core!FModuleManager::LoadModule() [ModuleManager.cpp:342] UE4Editor_HotReload!FHotReloadModule::DoHotReloadInternal() [HotReload.cpp:799] UE4Editor_HotReload!UE4Function_Private::TFunctionRefCaller<<lambda_d85446a946c3f6776c68ebfeb93e5785>,void __cdecl(TMap<FName,FString,FDefaultSetAllocator,TDefaultMapHashableKeyFuncs<FName,FString,0> > const &,bool,enum ECompilationResult::Type) [Function.h:549] UE4Editor_HotReload!FHotReloadModule::CheckForFinishedModuleDLLCompile() [HotReload.cpp:1853] UE4Editor_HotReload!FHotReloadModule::Tick() [HotReload.cpp:1415] UE4Editor_Core!FTicker::Tick() [Ticker.cpp:95] UE4Editor!FEngineLoop::Tick() [LaunchEngineLoop.cpp:5043] UE4Editor!GuardedMain() [Launch.cpp:169] UE4Editor!GuardedMainWrapper() [LaunchWindows.cpp:137] UE4Editor!WinMain() [LaunchWindows.cpp:268] UE4Editor!__scrt_common_main_seh() [exe_common.inl:288]
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-102707 in the post.
| 4 |
| Component | UE - Foundation - Cpp Tools - Hot Reload |
|---|---|
| Affects Versions | 4.26 |
| Target Fix | 4.26.1 |
| Created | Nov 6, 2020 |
|---|---|
| Resolved | Jan 6, 2021 |
| Updated | Jul 23, 2021 |