How to tell if a GameObject is an instance or a prefab?

Questions & Answers
1

In my code I have a reference to a GameObject. Is there any way to tell if this GameObject is an instance of a prefab or the prefab itself? Specifically I want to know whether to call Destroy on the object (if its an instance) or skip it (if its a prefab).

4

There are two equally viable ways to tell if a reference-to-a-GameObject references a Prefab (i.e. given an object reference field in the properties drawer, you drag a Prefab from your assets folder into that field, rather than an object that exists in the scene):

  • someObj.gameObject.scene.name == null
  • scene.rootCount == 0

A result of true, for either test, means that it is a Prefab rather than an instance.

This sort of test can be useful for generic containers or functions that would behave differently depending on whether they are given a live instance versus a Prefab “template”.

It works exactly the same on every platform. It works exactly the same in the editor as it does in fully optimized builds.

3

Edit:
Today I found out about GameObject.hideFlags so it can be used for finding if the gameobject is prefab or not. if hideFlags is HideInHierarchy then it’s a prefab.
Please ignore the rest of this post…

Ladies and gentlemen, I found the answer at last!!! (Play mode only)

    internal static bool IsPrefab(this Transform This)
    {
        var TempObject = new GameObject();
        try
        {
            TempObject.transform.parent = This.parent;

            var OriginalIndex = This.GetSiblingIndex();

            This.SetSiblingIndex(int.MaxValue);
            if (This.GetSiblingIndex() == 0) return true;

            This.SetSiblingIndex(OriginalIndex);
            return false;
        }
        finally
        {
            Object.DestroyImmediate(TempObject);
        }
    }
2

Docs and google are a wonderful thing.

5

I would not recommend to use tags in general because you or someone else may accidentally modify or simply remove it. Instead I would recommend to create “enum PrefabType {FirstClass, SecondClass}” and add public property “public PrefabType prefabType” and set it for every prefab from editor. That way you have 100% guarantee that it will not be deleted accidentally.