Using FInstancedStruct or EditConditionHides inside FTableRowBase causes DataTable to crash under specific conditions

Development Programming & Scripting
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1

Platform

Windows 11 (25H2) [10.0.26200.8037] (x86_64)

Hardware

  • CPU: Intel(R) Core™ Ultra 7 265 (2.40 GHz)

  • RAM: 64.0 GB

Engine Version

5.7.4-51494982+++UE5+Release-5.7

Project Type

C++

Repro Rate

Always (100%)

Description

Using FInstancedStruct or properties with EditConditionHides inside a USTRUCT that derives from FTableRowBase can cause the DataTable editor to crash when interacting with array elements under specific conditions.

The crash is preceded by the following error message:

“Pure virtual function being called while application is running (GIsRunning == 1)”

Steps to Reproduce – Case 1 (FInstancedStruct)

  1. Define a TArray<USTRUCT> inside a struct derived from FTableRowBase

  2. Inside that USTRUCT, include an FInstancedStruct field

  3. Create a DataTable based on this struct

  4. Add a new row

  5. Add an element to the array property in that row

  6. Click on an empty area to clear the row editor panel below

  7. Click the row again

Result:
The error message appears, followed by an engine crash

Steps to Reproduce – Case 2 (EditConditionHides)

  1. Define a TArray<USTRUCT> inside a struct derived from FTableRowBase

  2. Inside that USTRUCT, use properties with EditConditionHides

  3. Create a DataTable based on this struct

  4. Add a new row

  5. Add an element to the array property in that row

  6. Click on an empty area to clear the row editor panel below

  7. Click the row again

Result:
The error message appears, followed by an engine crash

Call Stack

LoginId:5645487c413debb9e6fe23a5431efea2
EpicAccountId:aa8befdb93eb46ec9c7ce771c956ed65

Fatal error: [File:D:\build\++UE5\Sync\Engine\Source\Runtime\Core\Private\Windows\WindowsPlatformMisc.cpp] [Line: 774] 
Pure virtual function being called




VCRUNTIME140
UnrealEditor_PropertyEditor
UnrealEditor_PropertyEditor
UnrealEditor_SlateCore
UnrealEditor_SlateCore
UnrealEditor_SlateCore
UnrealEditor_SlateCore
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UnrealEditor
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UnrealEditor
UnrealEditor
UnrealEditor
kernel32
ntdll

Reproducible Project

or copy follow code:

#pragma once

#include "CoreMinimal.h"
#include "Engine/DataTable.h"
#include "StructUtils/InstancedStruct.h"
#include "TestTableRow.generated.h"

UENUM(BlueprintType)
enum class EUnitEffectType : uint8
{
	AttributeModifier,
	MechanicEffect,
};

USTRUCT(BlueprintType)
struct INSSTRUCTTEST_API FOTAttributeModifier
{
	GENERATED_BODY()

	FOTAttributeModifier()
	{}
};

USTRUCT(BlueprintType)
struct INSSTRUCTTEST_API FUnitEffectEntry
{
	GENERATED_BODY()

	FUnitEffectEntry()
		: EffectType(EUnitEffectType::AttributeModifier), AttributeModifier(0)
	{
	}

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "UnitEffect")
	EUnitEffectType EffectType;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "UnitEffect",
		meta = (EditCondition = "EffectType == EUnitEffectType::AttributeModifier", EditConditionHides))
	float AttributeModifier;
};

USTRUCT(BlueprintType)
struct INSSTRUCTTEST_API FUnitSpatialRuleEntry
{
	GENERATED_BODY()

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = "UnitSpatialRule")
	FInstancedStruct RuleParams;
};

USTRUCT(BlueprintType)
struct INSSTRUCTTEST_API FTestTableRow : public FTableRowBase
{
    GENERATED_BODY()

	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "UnitDef|Effects")
	TArray<FUnitEffectEntry> Effects;

	UPROPERTY(EditAnywhere, BlueprintReadOnly, Category = "UnitDef|SpatialRules")
	TArray<FUnitSpatialRuleEntry> SpatialRules;
};