Opening certain blueprint assets crash 4.2

Development Programming & Scripting Blueprint
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1

After updating a (blueprint only) project to 4.2 certain blueprint assets can not be accessed anymore without a crash. Here are the log and the dump for the crash when I try to open such an asset.
So far the following things seem to be affected: the pawn, its controller, weapons, game mode, game state, HUD and any interfaces they might use. Things not directly related to the pawn remain editable.

Example scenes like Vehicle Game and Content Examples work as expected.

2

Hi ,

Is this limited to a single project or does this happen in other projects as well?

3

I only have one project. I could send it to you in private or build the engine from github to see if it yields a more detailed error description.

4

Hi ,

Could you post a test asset that is causing this crash to occur? We would be happy to have a look at one. Thank you!

5

Hi ,

I see what you were talking about with the specific assets, however creating a new blueprint seems to work correctly. If you can, please open this project in 4.1, copy your blueprints into a text document, then open the project in 4.2 and try creating a new blueprint to see if that will crash the editor as well.

6

A direct node copy-paste from 4.1.1 to 4.2 does end up crashing the editor but that’s hardly a surprise since none of the referenced components, interfaces or other classes exits. I’m somewhat reluctant to start rebuilding everything from scratch so first I’ll make several copies of my original pawn, each with less and less stuff in it to see which, if any, makes it through to 4.2

7

What about migrating the content to a new project? That might resolve the problem.

8

This is probably the same crash as described here. I rolled back to 4.1.1 myself since I didn’t currently need any features in 4.2. I hope we can get a fix for this; since it can ruin the ability to use 4.2 update altogether

9

The problem was that one particular asset got screwed up along the way: it opened fine in 4.1.1 but crashed on compile or rename. Anything referencing that asset crashed 4.2 on open.

Since a copy of that asset worked fine the steps of fixing the project were these:

  1. Made a backup of the project.
  2. Created a copy of the corrupted asset.
  3. Made sure that it didn’t reference any other blueprints which referenced the corrupted one.
  4. Closed the editor and deleted all the .asset files which referenced the corrupted blueprint.
  5. Opened the editor and deleted the corrupted blueprint. It went smoothly now that nothing used it.
  6. Renamed the copy, gave it the name of the original asset.
  7. Stored the now fixed .asset file in a safe place and deleted this messed up project.
  8. Restored the original project, overwrote the corrupted original asset with the fixed one.
  9. The once corrupted asset then compiled fine so the project was ready to be upgraded to 4.2.

I’m not sure if it’s related but I also had to manually remove

#include "ProjectName.generated.inl"

from Source/ProjectName/ProjectName.cpp and delete the Intermediate folder to make 4.2 compile.

Migrating all the assets didn’t fix the problem.