Hot reload crashes when using custom WorldSettings class

Development Platform & Builds
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1

Hello,
I have discovered a 100% crash in 4.11 when using a custom world settings class. This doesn’t occur in 4.10.

Steps to repro:

  1. Create a new class that derives from WorldSettings, and call it MyWorldSettings

  2. Add the following to DefaultEngine.ini (replace [PROJECTNAME] with your project name):

    [/Script/Engine.Engine]
    WorldSettingsClassName=/Script/[PROJECTNAME].MyWorldSettings

  3. Build your project and start the editor

  4. Make a small change to your cpp code (like add a newline to the new worldsettings class)

  5. Press the hot “Compile” button in the editor to recompile your cpp code

  6. The editor crashes

Callstack:

>	UE4Editor-Engine.dll!UWorld::Tick(ELevelTick TickType, float DeltaSeconds) Line 1116	C++
 	UE4Editor-UnrealEd.dll!UEditorEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 1149	C++
 	UE4Editor-UnrealEd.dll!UUnrealEdEngine::Tick(float DeltaSeconds, bool bIdleMode) Line 370	C++
 	UE4Editor.exe!FEngineLoop::Tick() Line 2643	C++
 	UE4Editor.exe!GuardedMain(const wchar_t * CmdLine, HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, int nCmdShow) Line 142	C++
 	UE4Editor.exe!WinMain(HINSTANCE__ * hInInstance, HINSTANCE__ * hPrevInstance, char * __formal, int nCmdShow) Line 189	C++
 	[External Code]

This appears to be due to the fact that the first Actor in the editor world’s Actor array is now null, and this is expected to be the worldsettings actor.

2

Note: it appears this crash was previously reported in preview 8:

https://udn.unrealengine.com/questions/277518/411p4-bug-100-repro-sub-classing-aworldsettings-ca.html

3

Hey eyesiah-

As you mentioned, this is a known issue that has been addressed internally and should be available in a future update to the engine.

Cheers

4

Hi ,
This is a real productivity killer for me. Can you point me to the internal fix so that I can look into integrating it into my local engine version?

5

If you are using the engine built from source code, you should be able to get the fix by merging the following commit into your local engine:

https://github.com/EpicGames/UnrealEngine/commit/4c41590c3d19013a848ae5a9ad7f2dcfbf741fb2

6

Thanks .

I notice that 4.11.1 has just been released, but this isn’t listed in the included bug fixes. Can we expect this will be included in a future 4.11 hotfix or will it not be fixed until 4.12?

7

It is unlikely this fix will go into 4.11.2 and will more likely be included in a later update to the engine though it is difficult to say exactly when that will be.

8

Hi , how can we make a request for this fix to be included on 4.11.3 hotfix update? It’s really a productivity killer for my team as we do not have the resources to work with a source built engine (we work remotely and cannot afford a dedicated server for continuous integration and automated builds)

9

Hear hear!

10

Hey Storngrir & eyesiah,

This issue is fixed for the upcoming 4.12 engine version. Currently there is no plan for a 4.11.3 hotfix, however I have indicated this as a possible inclusion if it does become necessary. If you are using a source version of the engine, you can merge the following commit to get the fix now. Be aware there are other fixes as we included in this commit.

https://github.com/EpicGames/UnrealEngine/commit/4c41590c3d19013a848ae5a9ad7f2dcfbf741fb2