Casting from Child Actor Component to Parent Causes Crash on Load

Development Programming & Scripting C++
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1

(Turned this into a bug report after some testing)

In Blueprint, casting from a Child Actor component to its parent actor causes projects to crash on load, even if the cast works just fine.

How to reproduce:

  1. Create a new project (can be based on a template).
  2. Create a new Blueprint Actor class to act as the child.
  3. Create another new Blueprint Actor class to act as the parent.
  4. Attach the child to the parent through a Child Actor component.
  5. Open up the child actor and have it cast to the parent. Doesn’t seem to matter how or when you do it, so long as the cast succeeds. I like to use Get Parent Actor → CastTo.
  6. Compile both blueprints.
  7. Place the parent actor in the level if necessary.
  8. Confirm the cast works.
  9. Save all.
  10. Relaunch the project and watch it crash as it finishes loading.

I had a friend successfully reproduce the issue on his installation of UE4 so I can confirm it’s not just me.

Editor log is attached. Let me know if you want more.

2

How specifically are you casting to the parent? Get Parent Component → CastTo SpaceShipPawn?

3

Get Parent Actor → Cast to SpaceshipPawn, but I’ve also tried Get Parent Component, Get Owner, and combinations of the three. Either they return the wrong class, or crash on load.

4

Hey Apst,

I’ve reproduced the crash, and have entered a bug report which you can track using the link below:

Thanks for your report and for the clear repro steps.

Have a great day

5

Great, thanks! Just a small clarification: the bug doesn’t only happen when using Get Parent Actor. Any input that returns the parent will trigger it, even Get Player Pawn etc.

6

For me the crash only happens if I call a custom event / function from the child.

7

Please reopen the bug, I too have managed to reproduce the crash in 4.14.1 under similair circumstances and can confirm with a great level of certainty that it is infact still there…

8

Yeah I just reopened a bug report… I reproduced this issue and can confirm it remains a problem in at least 4.14.1. Different methods of getting the owner have the same result…

9

Hey Skunkmeister-

This has been fixed for 4.15 and should be included in the 4.15 release.

10

Great to hear that this is fixed.

11

Hey ,
This bug is completely stopping our teams work in some vital areas. Any estimate as to when 4.15 is set to be released? :slight_smile:

12

Hey SkyInAPond,

Currently there is no set release date for 4.15. The other thing you could do is if you are using a source build, merge the fix commit into your engine.

Have a great day

13

I have the same crashing issue, and the 4.15 fix couldn’t come sooner.

14

SkyInAPond, I was able to get around this and keep working by going into my project folder and removing the parent blue print that was causing the crash. I then was able to open the project, modify the child blueprint to no longer have the reference to the parent, then close the project and paste the parent blueprint that I had removed back into the folder I had taken it from. This removes all placed instances of the parent blueprint from levels but I now have a working project without losing any of my work. I will just have to work on other things until this fix is released. Good luck.

15

Alright thanks! OuO

16

Oh alright! Good to know! OuO

17

I have the same issue. I have a child actor BP that I have in my first person BP. If I cast to my First Person BP within the child actor, UE4 will crash on next start up.

I have to go into the windows Content folder and remove the child BP that way just to access my project again. This needs to be fixed asap, please!