Unity gameobject destroyed and returns "null" but still returns "obj == null" as false

Question

I have a class for lists called UniqueListWithActions<T> with the constructor method

    public UniqueListWithActions(List<T> _list)
    {
        list = _list;
    }

list is declared as

    public List<T> list;

but in the method ClearNulls, the debug returns "null and False".

public void ClearNulls()
{
    for (int i = list.Count - 1; i >= 0; i--)
    {
        Debug.Log(list[i] + " and " + (list[i] == null));
        if (list[i] == null)
        {
            list.RemoveAt(i);
        }
    }
}

I set up the following, put it on an empty gameobject, put two other empty game objects into the list through the inspector, destroyed one so the reference was missing, and then hit escape and it still comes up "null and False".

public class ListTest : MonoBehaviour
{
    public UniqueListWithActions<GameObject> uniqueList = new UniqueListWithActions<GameObject>(new List<GameObject>());
    private void Update()
    {
        if (Input.GetKeyDown(KeyCode.Escape))
        {
            uniqueList.ClearNulls();
        }
    }
}

I don't understand how it can be null enough that "null" is what's returned in the debug but not "null" enough that list[i] != null. It's not called the same frame the object is destroyed since i do it by hand. How can I clear all the null objects in the list if null isn't null?

Basically the same answer as for Why does c# null-conditional operator not work with UnityEngine.Object — derHugo
– derHugo, Commented Nov 26 at 5:42

Mikloo · Accepted Answer · 2025-11-25 22:59:59Z

4

Unity shows destroyed objects as "null" , but they aren’t real C# nulls.
Unity’s (==) operator only works if the compiler knows the type is UnityEngine.Object.
In your class, "T" isn’t constrained, so C# uses a normal comparison that’s why list[i] == null returns false.

answered Nov 25 at 22:59

Mikloo

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Comments

BugFinder · Accepted Answer · 2025-11-25 22:29:13Z

3

try a look at

try https://discussions.unity.com/t/how-to-check-if-a-gameobject-is-being-destroyed/822565/7

where


        if (object.ReferenceEquals(obj, null)) return true;

        if (obj is UnityEngine.Object) return (obj as UnityEngine.Object) == null;

        return false;
    }

is the a common test, although it does describe how unity sets items for destruction so its null and not null .. (Anyone have flash backs to hittchikers guide to the galaxy game for tea and no tea?)

answered Nov 25 at 22:29

BugFinder

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1 Comment

derHugo Nov 26 at 5:47

fyi if you already use is you can directly include the type conversion as in if (obj is UnityEngine.Object unityObject) return unityObject == null;

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