4.14 Blueprint Garbage Collector Crash

There seems to be a issue with the garbage collector and blueprints / arrays in Unreal Engine 4.14.

These are the assets I got from my project. I have checked the blueprints and re-saved them and it still happens.

Fatal error: [File:C:\UnrealEngine-4.14\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp] [Line: 547] 
Invalid object in GC: 0x000002753f800000, ReferencingObject: IntProperty /Game/RingMenuConstKit/WB_RingMenu.WB_RingMenu_C:DeselectAllButtons.Temp_int_Array_Index_Variable, ReferencingObjectClass: Class /Script/CoreUObject.IntProperty, Property Name: Next, Offset: 48, TokenIndex: 2

Fatal error: [File:C:\UnrealEngine-4.14\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp] [Line: 547] 
Invalid object in GC: 0x000000003e3a0946, ReferencingObject: IntProperty /Game/UI/Menu/Settings/BP_UMG_GraphicsSettings.BP_UMG_GraphicsSettings_C:Load.CallFunc_Add_IntInt_ReturnValue, ReferencingObjectClass: Class /Script/CoreUObject.IntProperty, Property Name: Next, Offset: 48, TokenIndex: 2

Fatal error: [File:C:\UnrealEngine-4.14\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp] [Line: 547] 
Invalid object in GC: 0x000001e53ea00b24, ReferencingObject: IntProperty /Game/Blueprints/Characters/Dinosaurs/BP_BaseDinosaur.BP_BaseDinosaur_C:SetProgressionTier.Temp_int_Array_Index_Variable, ReferencingObjectClass: Class /Script/CoreUObject.IntProperty, Property Name: Next, Offset: 48, TokenIndex: 2

Fatal error: [File:C:\UnrealEngine-4.14\Engine\Source\Runtime\CoreUObject\Private\UObject\GarbageCollection.cpp] [Line: 547] 
Invalid object in GC: 0x0000025b3f800000, ReferencingObject: TextProperty /Game/Blueprints/GameModes/BP_GameMode_OpenWorld.BP_GameMode_OpenWorld_C:DeleteAccount.CallFunc_Conv_StringToText_ReturnValue, ReferencingObjectClass: Class /Script/CoreUObject.TextProperty, Property Name: Next, Offset: 48, TokenIndex: 2

Notice how all 4 fatal errors are all being triggered by some type of temp_int / array index variable. The crashes are more likely to happen if you change maps back to a main menu map, then load the game map again. Most likely due to the garbage collector running again.

Please note that these crashes don’t happen in 4.13.1

I changed the project settings and enabled single threaded garbage collection and didn’t make any differences.
I am using the 4.14 branch on github and not the preview from the launcher. There are no custom engine changes to the code to break this.

Callstack:

https://dl.dropboxusercontent.com/u/81052782/ShareX/devenv_2016-10-28_22-29-07.png

https://dl.dropboxusercontent.com/u/81052782/ShareX/devenv_2016-10-28_22-29-55.png

Hey Deathlyrage,

With limited reproduction steps, I can only guess that in your WB_RingMenu class, there is either an array being used with “DeselectAllButtons” or a integer variable with the name, “Next” causing the issue.

I have looked internally and cannot find any other crash reports that match your call stack, making it difficult to find any potential fix on my end.

Also, can you post the call stacks as text in the future? Images make it very difficult for us to search any common issues, as we have to type out the entire call stack, which is prone to typos causing more issues finding a matching case that may of already been fixed.

If you have any more information in regards to reproducing this crash, please let me know and I will investigate further.

Thanks.

It seems to be caused by Blueprint Temporary variables and references checked in the garbage collector. In that array the ‘Next’ variable is used by the For Each Blueprint Node.

Non-Temporary Blueprint Variables don’t have this issue by the looks of it.

Notice the ''Temp_int_Array_Index_Variable" Name.

I can upload the crash dump + executable + debug symbols and PM it to you on the forums if you want to take a look at it yourself.

Sure, you can PM on the forums and I’ll take a look.

Thanks

Hey Deathlyrage-

Were you able to get the full crash logs and project executable to help us test the crash locally? If you do have this information, please feel free to attach it here or send me a PM on the forums. I will be marking this post as resolved for tracking purposes, however you can respond with the information requested and we will investigate further.

Cheers