[4.6.1 to 4.7.2] UMG Blueprint Corruption

Development Programming & Scripting UI
, , , , ,
1

Hello, I currently have a major bug with a UMG blueprint.

  • It works fine in 4.6.1
  • It breaks when it gets converted to 4.7.2
  • ‘PreviewActor’ is null in the engine code when it crashes
  • Multiple UMG Blueprints cause this crash, but not all
  • Trying to open a crashing UMG Blueprint in-editor will also crash the editor

I have a .zip (~70mb) file containing the UMG that will cause this crash available upon request.

Thanks

33734-umg_46_to_47_crash.png
33734-umg_46_to_47_crash.png1811×940 137 KB

2

Hello kevin_g,

I have a couple of questions for you before I ask for you project.

Quick questions:

  1. Can you reproduce this in a clean project?
  2. If so, could you provide a detailed list of steps to reproduce this issue on our end?
3

Hey Rudy,

there are 2 methods I can do for repro, one costs much more time than the other. The .zip file only contains relevant files for the UMG files that crashes.

Option 1 (quick):

  1. Startup a clean project in 4.6.1
  2. Add the files from the .zip into the project
  3. Open the offending UMG blueprint and keep note that it works fine
  4. Create a new clean project in 4.7.2
  5. Migrate the UMG files from 4.6.1 to the 4.7.2 project
  6. OR Add UMG files with copy/paste into 4.7.2 project
  7. Attempt to open the offending UMG blueprint in 4.7.2 and it should crash

Option 2 (slow):

  1. Open project containing the offending UMG blueprint in 4.6.1
  2. Create a new clean project in 4.7.2
  3. Begin to rebuild the UMG blueprint in 4.7.2
  4. Attempt to open UMG blueprint to check for crash

Option 2 is similar to my mitigation of just rebuilding the UMG.

Some details on what the UMG actually is: it’s menu related, where users can click buttons to switch between menu states to modify options and so on. Because of this, there are many parts to the UMG, and the reason why option 2 would cost a lot of time (time that could be used simply rebuilding the UMG from 4.7.2).

EDIT: I just realized a couple more cases I should be checking to see if this crash is really 100%. I will update when I find out.

4

Yeap, 100% if the UMG moves from 4.6.1 to 4.7.2

5

Hello kevin_g,

I noticed that you said you had included a zip file. However, I do not see one attached to your post. Could you try and upload it again?

6

Hey Rudy,

I uploaded the contents to my GDrive. (5.2mb limit to upload directly here)

https://drive.google.com/file/d/0BxJi1ETdgff2RnNTTlowZkxlUU0/view?usp=sharing (Link will expire on 03/14/2015)

The offending blueprint is named ‘WBP_PauseMenu’.
There are other widget blueprints in the file that will also cause the crash.

Thanks a lot for the help.

7

Hello kevin_g,

After opening the file, I did not see a blueprint named “WBP_PauseMenu” and project given was created in the 4.5.1 version of the engine. Did you by chance upload the wrong project by mistake?

8

Hey Rudy,

That’s strange. I double-checked the directories. The file should be located at [project directory]\Content\UserInterface\WidgetBlueprint

I also realized I left the project name as the default ‘MyProject’ so there is the possibility that you opened up a different project, as well.

9

Hello kevin_g,

You were correct, I had another users project with the same name. I was able to open your project. I noticed that the blueprints had a lot of errors in them already. While your project is helpful in narrowing down this issue. This is not exactly what I mean when I said a clean project. Is it possible to create this issue without relying on any assets from the project with the issue? I will continue to look over your project, however if you could reproduce this in a clean project that would be most helpful.

10

Hey Rudy,

I will try. I’m currently on a very busy schedule, so it may take me a couple days before I have time to get you a cleaner project.

Thanks for your patience and help.

11

Hello kevin_g,

We have not heard back from you in a few days, so we are marking this post as Resolved for tracking purposes. If you are still experiencing the issue you reported, please respond to this message with additional information and we will offer further assistance.

Thank you.