SerializedMonoBehaviour / SerializedScriptableObject nested fields are null

[Ivan Murzak]

1. What happened?

Class fields are always null, even after force initialize it in the constructor. Every field inside the object of the class Subject<Unit> is null. And the class generate NullReferenceException. If don't use SerializedMonoBehaviour everything is fine.

2. How can we reproduce it?

Add UniRx and just execute this code:

using Sirenix.OdinInspector;
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UniRx;
using System;

public class SerializedClass : SerializedMonoBehaviour
{
    public readonly IObservable<Unit> onDie = new Subject<Unit>();
    protected virtual void Awake()
    {
         ((Subject<Unit>)onDie).OnNext(Unit.Default);
    }
}

4. What version of Unity are you using?

2018.1.1 and 2018.1.4

5. What version of Odin are you using? (See "Tools > Odin Inspector > About")

1.0.6.9

6. Do you have Editor Only mode enabled?

No

7. What operating system are you on?

Windows 10 x64

[Tor Esa Vestergaard]

When using Odin's serialization, you need to understand its serialization behaviour. Taking a look at UniRx's Subject class, I can see that it was not made to be serializable, so everything inside it will break when it is serialized/deserialized - yet you have it as a public field, and public fields are serialized by default, since Odin emulates Unity's serialization behaviour. (See this FAQ answer for more details.)

As such, this is not a bug. If you wish Odin to leave your public field alone, you must add [NonSerialized] to it, and then your initialization will not be overriden by the (faulty) serialized value.

[Ivan Murzak]

I didn't know. Thank you!