AssetImporter is referencing an asset from the previous import. This should not happen.

Hello.
The new prefab system is so powers. but it is some issue.

MySo.cs

Code (CSharp):

1.  
2. using UnityEngine;
3. #if UNITY_EDITOR
4. using UnityEditor;
5. #endif
6.  
7. public class MySO : ScriptableObject
8. {
9.  
10.     public GameObject prefab;
11.  
12.  
13. #if UNITY_EDITOR
14.     [MenuItem("Tools/AddSOToPrefab")]
15.     public static void AddSOToPrefab()
16.     {
17.         var prefab = Selection.activeObject as GameObject;
18.         if(prefab)
19.         {
20.             var so = CreateInstance<MySO>();
21.             so.name = "MySo";
22.             so.prefab = prefab;
23.             Debug.Log(prefab, prefab);
24.             var path = AssetDatabase.GetAssetPath(prefab);
25.             AssetDatabase.AddObjectToAsset(so, path);
26.             AssetDatabase.SaveAssets();
27.         }
28.     }
29.  
30. #endif
31. }
32.  

1. Create an Prefab and name is MyPrefab
2. Create MySo and add to MyPrefab
3. Select MySo and Drag MyPrefab to prefab property.
4. save it. So far, so good,

flowing yaml in MyPrefab.prefab

Code (CSharp):

1.  
2. --- !u!114 &114721633881386746
3. MonoBehaviour:
4.   m_ObjectHideFlags: 0
5.   m_CorrespondingSourceObject: {fileID: 0}
6.   m_PrefabInstance: {fileID: 0}
7.   m_PrefabAsset: {fileID: 0}
8.   m_GameObject: {fileID: 0}
9.   m_Enabled: 1
10.   m_EditorHideFlags: 0
11.   m_Script: {fileID: 11500000, guid: 40b994cea1c45b64683d08d6cb75bb44, type: 3}
12.   m_Name: MySo
13.   m_EditorClassIdentifier:
14.   prefab: {fileID: 5928805271164938062}
15.  

5. Open MyPrefab and modity the position.
6. Save it.


prefab property is None for MySO in Inspector panel

flowing error log in console.

Code (CSharp):

1.  
2. AssetImporter is referencing an asset from the previous import. This should not happen.
3. UnityEditor.EditorApplication:Internal_CallGlobalEventHandler()
4.  

flowing yaml in MyPrefab.prefab

Code (CSharp):

1.  
2. --- !u!114 &114721633881386746
3. MonoBehaviour:
4.   m_ObjectHideFlags: 0
5.   m_CorrespondingSourceObject: {fileID: 0}
6.   m_PrefabInstance: {fileID: 0}
7.   m_PrefabAsset: {fileID: 0}
8.   m_GameObject: {fileID: 0}
9.   m_Enabled: 1
10.   m_EditorHideFlags: 0
11.   m_Script: {fileID: 11500000, guid: 40b994cea1c45b64683d08d6cb75bb44, type: 3}
12.   m_Name: MySo
13.   m_EditorClassIdentifier:
14.   prefab: {fileID: 5928805271164938062, guid: cd7bea1403b5b8249b137f72cddbd1ff, type: 3}
15.  

7. modify the position and save it again.

MyPrefab.prefab change following, notice the prefab property.

Code (CSharp):

1.  
2. --- !u!114 &114721633881386746
3. MonoBehaviour:
4.   m_ObjectHideFlags: 0
5.   m_CorrespondingSourceObject: {fileID: 0}
6.   m_PrefabInstance: {fileID: 0}
7.   m_PrefabAsset: {fileID: 0}
8.   m_GameObject: {fileID: 0}
9.   m_Enabled: 1
10.   m_EditorHideFlags: 0
11.   m_Script: {fileID: 11500000, guid: 40b994cea1c45b64683d08d6cb75bb44, type: 3}
12.   m_Name: MySo
13.   m_EditorClassIdentifier:
14.   prefab: {fileID: 0}
15.  

yaml file change flow:

1. drag asset to prefab property, and save.

Code (CSharp):

1. prefab: {fileID: 5928805271164938062}

2. modify the prefab and save.
log error in console panel.

Code (CSharp):

1. prefab: {fileID: 5928805271164938062, guid: cd7bea1403b5b8249b137f72cddbd1ff, type: 3}

3. modity the prefab again and save.

Code (CSharp):

1. prefab: {fileID: 0}

 

It looks like he's reporting a case where a Unity-internal check message similar to an assert failure. "AssetImporter is referencing an asset from the previous import. This should not happen."

 

It seems like adding a ScriptableObject to a prefab through AssetDatabase.AddObjectToAsset, and then assigning that prefab to that SO makes the serializer all kinds of confused.

If you look at the different yaml files, it's jumping between how the prefab is referenced between each time something unrelated (the position value of the prefab) is changed.

 

I'm sorry for my bad English.
I'm report an issue via unity editor.
I push a repository to github https://github.com/litefeel/PrefabRefByInsideSO


What happened?
Prefab cannot be referenced by internal ScriptObject when the prefab any change and save.

How we can reproduce it using the example you attached?
1. Drag MyPrefab to MySo's prefab property
2. Save it.
3. Open MyPrefab and modify anything and save it.
4. MySo's prefab property is Null

 

Hi.

Yes.
The case id is 1090541
Title is (Open) Prefab cannot be referenced by inside ScriptObject

 

Hi.
Is this bug handled? It seems that there are no updates.

 

Thanks.

 

Hi.
This bug have not fiexed in unity2018.3.0b11.

Do you mean 2018.3.0b12?

Thanks.

 

@litefeel - it's not ideal, but the temporary workaround I'm using is to make a variant of the prefab, and set their prefab properties to eachother.

For example:
set MySo's prefab property to MySoVariant
and set MySoVariants's prefab property to MySo

 

Thanks.
I split myso into another file with the same name as prefab.

https://issuetracker.unity3d.com/product/unity/issues/guid/1090541/
Hi. When can you fix it?

 

I was able to fix the issue by moving the prefab to the hierarchy temporarily, setting the reference in the hierarchy and applying the prefab changes. Not 100% sure whether you had the same case so ignore me if this is irrelevant to your case. Still not completely familiar with the new prefab system.

 

Hi, kubajs, could you please elaborate on your answer? How do I get rid of this error?

 

In my case the workaround was I drag & dropped the prefab to project hierarchy, edited the prefab instance in there and then applied the changes to prefab.
When I made the change directly in prefab, it hasn't been persisted so I then tried the described solution based on this thread.