Description

When assigning an array of actors that implement a specific interface to an array of the specific interface the engine crashes. This doesn't happen if the actor array is put through a for each loop and checked for the interface before being added the interface array per element.

I have attached an example project.

Found in 4.22.3 CL#7053642
Reproduced in 4.23.0 CL#8386587, 4.24.0 Main CL#8707833

Steps to Reproduce

1. Create a new blueprint project.
2. Create a blueprint interface (BPI_Item)
3. Create a blueprint (BP_Item) that implements BPI_Item
4. Create a blueprint (BP_Consumer) that has an array of BPI_Items(ItemInterfaces).
5. Create a blueprint (BP_Inventory) that has an array of BP_Items (Items).
6. In BP_Inventory on BeginPlay spawn a BP_Item and store it in Items. Next spawn a BP_Consumer and set ItemInterfaces to Items.
7. Place a BP_Inventory in the level and play.

Results: The engine crashes.

Expected: The array is copied successfully.

Callstack

LoginId:9a8d08644d702ac44f074090ac311686
EpicAccountId:580fb2844ad145d79dff08f42acea7c6

Unhandled exception

UE4Editor_CoreUObject!UClass::ImplementsInterface() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:3792]
UE4Editor_CoreUObject!UObject::execObjectToInterface() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:3096]
UE4Editor_CoreUObject!UObject::execLet() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2100]
UE4Editor_CoreUObject!ProcessLocalScriptFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:974]
UE4Editor_CoreUObject!ProcessScriptFunction<void (__cdecl*)(UObject *,FFrame &,void *)>() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:809]
UE4Editor_CoreUObject!ProcessLocalFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1033]
UE4Editor_CoreUObject!ProcessLocalScriptFunction() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:974]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1058]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4643]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\build\++ue4\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1464]
UE4Editor_Engine!AActor::ProcessEvent() [d:\build\++ue4\sync\engine\source\runtime\engine\private\actor.cpp:769]
UE4Editor_DetailCustomizations!FObjectDetails::OnExecuteCallInEditorFunction() [d:\build\++ue4\sync\engine\source\editor\detailcustomizations\private\objectdetails.cpp:208]
UE4Editor_DetailCustomizations!TBaseSPMethodDelegateInstance<0,FObjectDetails,0,FReply __cdecl(void),TWeakObjectPtr<UFunction,FWeakObjectPtr> >::Execute() [d:\build\++ue4\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl.h:279]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\build\++ue4\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:293]
UE4Editor_Slate!FEventRouter::Route<FReply,FEventRouter::FToLeafmostPolicy,FPointerEvent,<lambda_6c1f6b862bcfb82ea6dcab28fbcc9463> >() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:271]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5598]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:6203]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\build\++ue4\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:6176]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessDeferredMessage() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1842]
UE4Editor_ApplicationCore!FWindowsApplication::DeferMessage() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:2292]
UE4Editor_ApplicationCore!FWindowsApplication::ProcessMessage() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:1522]
UE4Editor_ApplicationCore!FWindowsApplication::AppWndProc() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsapplication.cpp:772]
user32
user32
UE4Editor_ApplicationCore!FWindowsPlatformApplicationMisc::PumpMessages() [d:\build\++ue4\sync\engine\source\runtime\applicationcore\private\windows\windowsplatformapplicationmisc.cpp:130]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3882]
UE4Editor!GuardedMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\launch.cpp:168]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:145]
UE4Editor!WinMain() [d:\build\++ue4\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:275]
UE4Editor!__scrt_common_main_seh() [d:\agent\_work\3\s\src\vctools\crt\vcstartup\src\startup\exe_common.inl:288]
kernel32
ntdll

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Unresolved
ComponentGameplay
Affects Versions4.234.244.22.3
CreatedSep 17, 2019
UpdatedSep 17, 2019