4.12.1 crash compiling character blueprints

Development Programming & Scripting
1

As soon as we installed 4.12.1, my coding partner and I are crashing 100% of the time trying to compile our blueprints involving our character hierarchy (a simple basecharacter, NPC character, and PC character hierarchy).

Some other blueprints compile without crashing. I’ll work towards a minimal reproduction case if this is not a widely reported crash (I’ve seen one other mention in the 4.12 thread that sounds the same so far).

Here is the stack trace:

Access violation - code c0000005 (first/second chance not available)

UE4Editor_UnrealEd!FBlueprintEditorUtils::RefreshExternalBlueprintDependencyNodes() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\blueprinteditorutils.cpp:572]
UE4Editor_KismetCompiler!FKismetCompilerContext::Compile() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\kismetcompiler\private\kismetcompiler.cpp:3627]
UE4Editor_KismetCompiler!FKismet2CompilerModule::CompileBlueprintInner() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\kismetcompiler\private\kismetcompilermodule.cpp:100]
UE4Editor_KismetCompiler!FKismet2CompilerModule::CompileBlueprint() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\kismetcompiler\private\kismetcompilermodule.cpp:203]
UE4Editor_UnrealEd!FKismetEditorUtilities::CompileBlueprint() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\unrealed\private\kismet2\kismet2.cpp:756]
UE4Editor_Kismet!FBlueprintEditor::Compile() [d:\build++ue4+release-4.12+compile\sync\engine\source\editor\kismet\private\blueprinteditor.cpp:3184]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,TTypeWrapper __cdecl(void)>::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_Kismet!TBaseSPMethodDelegateInstance<0,FBlueprintEditor,0,void __cdecl(void)>::ExecuteIfSafe() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:427]
UE4Editor_Slate!FUICommandList::ExecuteAction() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\commands\uicommandlist.cpp:87]
UE4Editor_Slate!SToolBarButtonBlock::OnClicked() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\multibox\stoolbarbuttonblock.cpp:300]
UE4Editor_Slate!TMemberFunctionCaller::operator()<>() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstanceinterface_variadics.h:161]
UE4Editor_Slate!TTupleImpl >::ApplyAfter_ExplicitReturnType >() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\tuple.h:128]
UE4Editor_Slate!TBaseSPMethodDelegateInstance<0,SToolBarButtonBlock,0,FReply __cdecl(void)>::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:321]
UE4Editor_Slate!TBaseDelegate::Execute() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\public\delegates\delegatesignatureimpl_variadics.inl:521]
UE4Editor_Slate!SButton::OnMouseButtonUp() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\widgets\input\sbutton.cpp:275]
UE4Editor_Slate!::operator()() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4598]
UE4Editor_Slate!FEventRouter::Route >() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:215]
UE4Editor_Slate!FSlateApplication::RoutePointerUpEvent() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:4587]
UE4Editor_Slate!FSlateApplication::ProcessMouseButtonUpEvent() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5041]
UE4Editor_Slate!FSlateApplication::OnMouseUp() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:5021]
UE4Editor_Core!FWindowsApplication::ProcessDeferredMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1507]
UE4Editor_Core!FWindowsApplication::DeferMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:1847]
UE4Editor_Core!FWindowsApplication::ProcessMessage() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:742]
UE4Editor_Core!FWindowsApplication::AppWndProc() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsapplication.cpp:664]
user32
user32
UE4Editor_Core!FWindowsPlatformMisc::PumpMessages() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\core\private\windows\windowsplatformmisc.cpp:903]
UE4Editor!FEngineLoop::Tick() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:2728]
UE4Editor!GuardedMain() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\launch.cpp:148]
UE4Editor!GuardedMainWrapper() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\build++ue4+release-4.12+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll

2

I’m having similar issue, blueprint crashing right after 4.12.1 - I’ve just reproduced it on very simple blueprint setup and I’ll post it soon to help fixing it. I’ll let know about it here, soon (withing an hour i guess)

3

Nice find. Our involved blueprints do have arrays of references to other blueprint classes as well, in case that ends up being related from your minimal case.

4

You rock the party that rocks the body. Thanks.

Is there an easy way to track the status of a bug report by the UE-XXXXX number? It’s not obvious from the links we have.

5

I’m having the same issue here. Debugging it a bit:

The crash happens in file BlueprintEditorUtils.cpp function RefreshExternalBlueprintDependencyNodes (line 572).

UClass* OwnerClass = Struct->GetOwnerClass(); returns null, often with different structs; some are user Blueprint structs, some are user C++ USTRUCTS, others are engine USTRUCTS (such as Vector).

After transitioning from 4.10.1 to 4.12.1

6

OK, I did it, here I posted my repro demo project and repro steps:

Maybe it will help fixing this.

7

Hello,

I have reproduced this crash and entered a bug report, UE-31740. Thank you for your report.

Have a great day

8

Is there a known workaround? Because not being able to compile some blueprints really hurts.
Or perhaps a way to downgrade to 4.12.0? I can’t find a way to download that anymore, and would rather not go back to 4.11.

9

Hi folks.

@DaGaffer - no current way to track bug reports, but we are working on a way to that we hope to roll out in the near future.

@BStbck - We have already fixed this issue internally. If you are a source code developer using GitHub, you can grab and integrate the fix here: https://github.com/EpicGames/UnrealEngine/commit/38457aec8e69e7423b6f606dc9ac22a8e63e2635 (you need to be signed into your GitHub account). If you use the binary release from the launcher instead, then we will be releasing a new hotfix for this issue very soon this week.

Cheers

10

Great, thanks for the help!

11

Getting this also :\ Pretty big bug to wait to roll out

12

I was about to go cry in a corner hehe, had a rough day and then Blueprints were crashing, thanks for the fix

13

I’m out of commission till this is fixed :frowning:

14

Have the same problem. Glad you guys are on it. I was worried it was just me. Gives me an excuse to work on level design and put programming aside for a few days.

15

We are also having the same problem with character and some other blueprints. Please publish the fix, we don’t want to use master branch yet.

16

I spent two hours in trying to find workaround, but… All straight references causes crash…

17

Same for me Acrossfy and same for me and I also tried to find a way back to 4.12.0 BStbck!

18

Your tears are also shared with mine ahahaha

19

As am I, struggling to find anything useful that doesn’t involve said class :stuck_out_tongue:

20

same here, blueprint heirarchy crashing all the time :frowning: boo