Log error help.

Development Programming & Scripting Blueprint
1

Hello, I need some help deciphering what some log errors mean. Upgrading a project that is stable at 4.15 to 4.16, it constantly crashes.
The error:

[2017.05.24-23.54.30:292] 0]LogOutputDevice:Error: === Handled ensure: ===
[2017.05.24-23.54.30:292] 0]LogOutputDevice:Error:
[2017.05.24-23.54.30:292] 0]LogOutputDevice:Error: Ensure condition failed: ChildActorTemplate == nullptr [File:D:\Build++UE4+Release-4.16+Compile\Sync\Engine\Source\Runtime\Engine\Private\Components\ChildActorComponent.cpp] [Line: 95]
[2017.05.24-23.54.30:292] 0]LogOutputDevice:Error: Found unexpected ChildActorTemplate LinkerPlaceholderExportObject /Game/FirstPersonBP/Blueprints/ElectricitySystem/Parts/Part_Door.PLACEHOLDER-INST_of_PLACEHOLDER-CLASS__Mod_part_Base_Door_C_5 when ChildActorClass is null
[2017.05.24-23.54.30:292] 0]LogOutputDevice:Error: Stack:
[2017.05.24-23.54.30:292] 0]LogOutputDevice:Error: UE4Editor-Core.dll!0x00000000DFEB32B6
etc

I don’t get what this placeholder-inst is.
So I have this class called Part_Door. It has several child actor components, one of them has the class called “Mod_Part_Base_Door”. And Part_Door is also inside a child actor component of another class, if that helps.
Do I need to provide more information? It’s a pretty complex setup.

2

The only way I am able to get rid of that error is by deleting the “Mod_Part_Base_Door” class and cleaning up the blueprints that referenced it.

But then I get another error:

[2017.05.25-12.26.32:572] 97]LogOutputDevice:Error: === Handled ensure: ===
[2017.05.25-12.26.32:572] 97]LogOutputDevice:Error:
[2017.05.25-12.26.32:572] 97]LogOutputDevice:Error: Ensure condition failed: !bIsFilteredOut [File:D:\Build++UE4+Release-4.16+Compile\Sync\Engine\Source\Editor\BlueprintGraph\Private\BlueprintActionFilter.cpp] [Line: 1689]
[2017.05.25-12.26.32:572] 97]LogOutputDevice:Error: Invalid BlueprintActionDatabase entry (for SKEL_Part_Door_C). Was the database properly updated when this class was compiled?
[2017.05.25-12.26.32:572] 97]LogOutputDevice:Error: Stack:
[2017.05.25-12.26.32:572] 97]LogOutputDevice:Error: UE4Editor-Core.dll!0x00000000E2D832B6
etc.

Now it’s Part_Door, but what the SKEL means I don’t know. I guess I’ll have to try to delete that too?

3

It’s been a while since I saw skel_ but from what I remember it’s an internal SKELeton class - usually an indication that you’ve found a bug in the engine. If only you could repro it in a clean project, right?

4

Well. I deleted the Part_Door class, which created the exact same error but for another class. So assuming that would continue, I deleted a bunch of classes, so now all I am left with is the following errors:

LogFeaturePack:Warning: Inserted 1 feature packs
No idea what pack that is or how to fix that.

LogUObjectGlobals:Warning: Failed to find object ‘Class None.’
No idea where that is happening. How am I supposed to find that?

[2017.05.25-13.14.50:819][990]LogCrashTracker:

[2017.05.25-13.14.50:819][990]LogThreadingWindows:Error: Runnable thread TaskGraphThreadNP 1 crashed.
[2017.05.25-13.14.50:819][990]LogThreadingWindows:Error: Runnable thread TaskGraphThreadNP 0 crashed.
[2017.05.25-13.14.50:819][990]LogThreadingWindows:Error: Runnable thread TaskGraphThreadNP 2 crashed.
[2017.05.25-13.14.50:819][990]LogCrashTracker:

[2017.05.25-13.14.50:819][990]LogWindows:Error: HandleError re-entered.
[2017.05.25-13.14.50:819][990]LogWindows:Error: HandleError re-entered.
[2017.05.25-13.14.50:819][990]LogWindows: FPlatformMisc::RequestExit(1)
[2017.05.25-13.14.50:819][990]LogWindows: FPlatformMisc::RequestExit(1)
[2017.05.25-13.14.50:819][990]LogWindows:Error: === Critical error: ===
[2017.05.25-13.14.50:819][990]LogWindows:Error:
[2017.05.25-13.14.50:819][990]LogWindows:Error: Fatal error!
[2017.05.25-13.14.50:819][990]LogWindows:Error:
[2017.05.25-13.14.50:819][990]LogWindows:Error: Unhandled Exception: EXCEPTION_ACCESS_VIOLATION reading address 0xffffffff
[2017.05.25-13.14.50:819][990]Log file closed, 05/25/17 15:14:50

5

Okay, I see. I do plan to submit this as a bug report but I am trying to narrow it down as much as possible.

6

I’m also having the same problem, many classes are getting these “Found unexpected ChildActorTemplate LinkerPlaceholderExportObject” after switching versions to 4.16

7

So if anyone is curious the errors were because of some child actor components. But as I mentioned, fixing these still caused my project to crash.
I have kind of narrowed it down to one class which, if deleted, fixes it.
On the other hand, deleting 5 other classes also fixes it.

How useful is that information to the bugdepartment? Of course, finding out exactly what is causing a crash, pointing at a specific thing and repro steps is of course the most useful. But making a report, stating “delete this class to fix the problem”, just how useful is that?
Been at this bloody thing for 4 days now.