Crash when copying blueprint structures

[anonymous_user_e80730da]

This happens only in packaged builds. Game started from an editor works (and its logic also).

Output:

Assertion failed: Src [File:path\Engine\Source\Runtime\CoreUObject\Private\UObject\Class.cpp] [Line: 2288]
Game.exe has triggered a breakpoint.

Script Stack:

BuildingPrices_Functions_C.GetBuildingConfigByTierId
BP_GameMovementCharacter_C.ExecuteUbergraph_BP_GameMovementCharacter
BP_GameMovementCharacter_C.UpdateTooltip
W_BuilderUI_C.ExecuteUbergraph_W_BuilderUI
W_BuilderUI_C.BndEvt__StarterHouse_BTN_K2Node_ComponentBoundEvent_106_OnButtonHoverEvent__DelegateSignature

Source code Class.cpp

void UScriptStruct::CopyScriptStruct(void* InDest, void const* InSrc, int32 ArrayDim) const
{
	uint8 *Dest = (uint8*)InDest;
	check(Dest);
	uint8 const* Src = (uint8 const*)InSrc;
	check(Src);
	…
}

Let’s check last function in script stack: GetBuildingConfigByTierId. This is one of functions in our blueprint function library.

Buggy version:

Iterate through records from data table and find record that have proper TierId and Class, then save Config array (of type ResourceRequirementEntries) to temporary local variable.

Then:

Read from temporary variable and return array of ResourceRequirementEntries.

Structure: BuildingCostEntry:

Data table contains records of this type (above).

Structure: ResourceRequirementEntry:

Each record in data table has an array of entries (below).

Engine crashed in CopyScriptStruct method, apparently it has issues with copying blueprint structures, so let’s try to avoid it.

Working version:

Iterate through records from data table and find record that have TierId and Class, then save corresponding row name in temporary variable.

Then:

Get record again by previously saved row name and return Config array.

This works.