Polymorphic Serialization with ScriptableObject crashes Unity 4.2?

Hi,

i tried to confirm if the prefab problem and Polymorphic Serialization using scriptable objects still exists in unity 4.2 as described here:
http://www.codingjargames.com/blog/2012/11/30/advanced-unity-serialization/

To my surprise Unity 4.2 directly crashes if i try to use the code from the example?

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5.  
6. public class Base : ScriptableObject { public int myInt; }
7.  
8. public class Derived : Base { public string myString; }
9.  
10. public class TestClass : MonoBehaviour
11. {
12.     public Base _myBase;
13.  
14.     // This gets called in the Editor when you first create this MonoBehaviour.
15.     public void Reset()
16.     {
17.         _myBase = ScriptableObject.CreateInstance<Derived>();
18.     }
19. }
20.  

If u try to attach TestClass to a gameobject, Unity 4.2 simply crashes. So in terms of Polymorphic Serialization, Unity got even worse?

thx Andy


PS: Coming from UDK it was a little shock, that i cant get a Polymorphic List<Baseclass> correctly serialized and usable in prefabs, since this works without problems in UDK.

 

Did some more testing and also code variations from http://forum.unity3d.com/threads/155352-Serialization-Best-Practices-Megapost now crashes Unity 4.2?

Code (csharp):

1.  
2. using System.Collections;
3. using System.Collections.Generic;
4. using UnityEngine;
5.  
6. [System.Serializable]
7. public class Base : ScriptableObject
8. {
9.     public int myInt;
10.  
11.     public void OnEnable()
12.     {
13.         hideFlags = HideFlags.HideAndDontSave;
14.     }
15. }
16.  
17. [System.Serializable]
18. public class Derived1 : Base
19. {
20.     public string myString;
21. }
22.  
23. [System.Serializable]
24. public class Derived2 : Base
25. {
26.     public float myFloat;
27. }
28.  
29. public class TestClass : MonoBehaviour
30. {
31.     public Base _myBase1;
32.     public Base _myBase2;
33.  
34.     public void Start()
35.     {
36.         if (_myBase1 == null) {
37.             _myBase1 = ScriptableObject.CreateInstance<Derived1>();
38.         }
39.  
40.         if (_myBase2 == null) {
41.             _myBase2 = ScriptableObject.CreateInstance<Derived2>();
42.         }
43.     }
44. }
45.  

 

I just recently discovered this in 4.2. Was surprised how easy it was to cause the editor to crash.

I've submitted a bug report.

Hope they'll clean this up soon (+1 for hot fix)

 

Great. Thank you for that.

Do we have a time frame for 4.3 ?

 

I'll be waiting for the fix anxiously, since it's kind of a showstopper for me By the way, the issue is still present in 4.2.1.

 

I changed your code so that instead of using ScriptableObject.CreateInstance<Derived>(), it simply called the constructor: _myBase = new Derived().

It didn't crash. Instead, it complained that it could not find the type.

So, I moved Base into its own file called Base.cs and Derived into Derived.cs. Unity ceased to crash while using CreateInstance<Derived>().

Using Unity v4.2.0f4

 

This is blocking me currently as well.

Any news on this hotfix or 4.3 release schedule?

 

I believe greg.h if he says this fixes the problem, however my main problem was correct serialization of polymorphic containers, which is not possible in Unity and i did not see any new info/feedback towards this. I just stumbled on the above problem as a result of trying to understand why serialization of polymorphic containers is not working at all.

I would really like if i could just write: "public List<AbstarctBaseClass> MyList; " and in the inspector i get a list of all "derived : BaseClass" objects i can select and add to this list. This was possible out of the box in UDK and was very handy to design modular systems, that are setup via the editor/level designer. The only alternative i could came up with for Unity, was to use the gameObject itself as "container", but this has its limits, is much harder to maintain and setup, compared to a named polymorphic container inside a component.

bye Andy

 

mhh the status on http://feedback.unity3d.com/suggestions/serialization-of-polymorphic-dat did not change since 2012?

Will those changes to "Polymorphic serialisation of non-UnityEngine.Object types" allow to create a polymorphic List/HashSet's that get correctly serialized/deserialized?

As a example we use a modular condition system, but because of this serialization problem, the only way to get this working is to wrap each condition as a Monobehaviour and use the gameobject itself as polymorphic container. This ofc only allows for one condition set per gameobject and only one class can/should use the condition set. What we actually want is to have the ability to store a "Condition Set" aka polymorphic List<BaseCondition> directly inside the using class as field, so we can have as many sets as needed per component/class as opposed to per gameobject.


bye Andy

 

I'd like to share my solution to polymorphic serialization: <VFW> Well, not much can be done about it with Unity's current serialization system. So a custom system with a custom serializer must exist. I used FullSerializer as my backend serializer and managed to serialize pretty much all the types that Unity has trouble dealing with (properties, interfaces, abstract system objects, delegates etc)