System.Object polymorphism with array and non-array types breaks the inspector

[Nicolás Ezcurra]

Using Unity 2017.4.11f1 and Odin 2.0.5, when a field of type object, has it actual value changed while inspecting it, will break the inspector.

This behaviour occurs when the value types changes from an array type to a non array type, and vice versa.

Here is a simple component where this issue can be checked:

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

using Sirenix.OdinInspector;
using System;

public class SimpleObjectFieldTest : SerializedMonoBehaviour 
{
    [SerializeField]
    public object field;


    [Button]
    public void SetInt()
    {
        field = default(int);
    }

    [Button]
    public void SetTransform()
    {
        field = transform;
    }

    [Button]
    public void SetFloatArray()
    {
        field = new float[0];
    }

    [Button]
    public void SetGameObjectArray()
    {
        field = new GameObject[0];
    }

    [Button]
    public void PrintType()
    {
        Debug.LogFormat("[ObjectFieldTest] Field type: {0}.", (field == null) ? "null" : field.GetType().ToString());
    }
}

I'm also attaching an attempt of solution using an Attribute (ObjectFieldTest, DrawAsTypeAttribute and DrawAsTypeAttributeDrawer).

Thanks for your time!

[Tor Esa Vestergaard]

If you change values that change the "layout" of the data during the GUI loop (such as in a button press), you will get GUI layout errors. The issue can in this case be resolved by delaying the actual value change to a later time when it is "safe" to do:

[Button]
public void SetInt()

{
    EditorApplication.delayCall += () => field = default(int);
}

Let me know if there's any other issues, or if the code above does not fix the problem at hand.

[Nicolás Ezcurra]

I'm already trying to use the delayCall delegate, and is not working. For example, this simple script won't work either when changing some types:

using UnityEngine;

using Sirenix.OdinInspector;

#if UNITY_EDITOR
using UnityEditor;
#endif

public class ObjectFieldTest : SerializedMonoBehaviour
{
#if UNITY_EDITOR
    [SerializeField]
    public object field;

    [Button]
    public void SetInt() => EditorApplication.delayCall += () => field = default(int);

    [Button]
    public void SetTransform() => EditorApplication.delayCall += () => field = transform;

    [Button]
    public void SetFloatArray() => EditorApplication.delayCall += () => field = new float[0];

    [Button]
    public void SetGameObjectArray() => EditorApplication.delayCall += () => field = new GameObject[0];    

    [Button]
    public void Restore() => EditorApplication.delayCall += () => field = default(System.Object);    

    [Button]
    public void PrintType()
    {
        UnityEngine.Debug.LogFormat("[ObjectFieldTest] Field type: {0}.", (field == null) ? "null" : field.GetType().ToString());
    }
#endif
}