Question Do scriptable objects initialise their fields automatically?

I can't seem to find the answer to this.

In the following code, the condition in the if statement never evaluates true.

Code (CSharp):

1. public class WaveConfig : ScriptableObject
2. {
3.     [SerializeField] private GameObject pathPrefab;
4.    
5.     private List<Transform> waypoints = null;
6.    
7.     public List<Transform> Waypoints
8.     {
9.         get
10.         {
11.             if (waypoints  == null)
12.             {
13.                 waypoints = new List<Transform>();
14.                 foreach (Transform waypoint in pathPrefab.transform)
15.                 {
16.                     waypoints.Add(waypoint);
17.                 }
18.             }
19.  
20.             return waypoints;
21.         }
22.     }
23. }

Yet the same condition but with MonoBehaviour works:

Code (CSharp):

1. public class ExperimentScript : MonoBehaviour
2. {
3.     private List<GameObject> gameObjects;
4.  
5.     public List<GameObject> GameObjects
6.     {
7.         get
8.         {
9.             if (gameObjects == null)
10.             {
11.                 Debug.Log("gameObjects is unassigned");
12.  
13.                 gameObjects = new List<GameObject>();
14.             }
15.             return gameObjects;
16.         }
17.     }
18. }

I have solved the ScriptableObject code by testing with Count:

Code (CSharp):

1. if (waypoints.Count == 0)

It seems that the scriptable object initialises the List for me? Is that correct?

 

yes its correct, it will be an empty list object, not null, just empty

 

I was pretty sure that it is not like that, but you have made me doubt so I have checked and no, it is not like that.
Unity only initialized by itself serialized fields (public fields and those marked with [SerializeField] attribute). At my pc code run exactly as I was specting...

 

K this is weird. I made a new project, did everything you did in the video and it still doesn't work. Could it be something to do with Unity version? I'm using 2020.3.5f1.

 

Scriptable Objects are veeeeery sneaky. If you have a private field (such as

private bool Initialized;

), it will NOT be reset to false... its value will be persisted until your app quits or until you exit the editor.

Mark it as

[NonSerialized]

to prevent this.

 

Most important thing to understand is that ScriptableObject that you drag in editor to you components persist during application run (it is created once).
It does not get reloaded after you load new scene and all modifications to it stays until application ends.

 

I'm sorry, I'm not sure I understand. I added

[System.NonSerialized]

in front of the waypoints list, deleted any existing instances of the scriptable object, restarted Unity Editor, Unity Hub and Visual Studio, and after restart the waypoints List is still being initialized (not null).