Merge pull request #1348 from anatawa12/fix-nre-prefab

fix: NRE on save prefab from PrefabStage

CHANGELOG-PRERELEASE.md

@@ -16,6 +16,7 @@ The format is based on [Keep a Changelog].
 ### Removed
 
 ### Fixed
+- NRE when saving Prefab with PrefabSafeUniqueCollection `#1348`
 
 ### Security
 

CHANGELOG.md

@@ -82,7 +82,7 @@ The format is based on [Keep a Changelog].
 - Reimplement Preview system with NDMF Preview System `#1131` `#1195` `#1218` `#1270`
   - This will prevent issues relates to Animation Mode bug.
   - This allows you to preview Remove Mesh components without selecting Mesh OR while in Animation Mode.
-- Improved Prefab Safe Set, which are used in MergePhysBone, MergeSkinnedMesh, FreezeBlendShape and more components `#1212` `#1219` `#1221` `#1236` `#1287` `#1294`
+- Improved Prefab Safe Set, which are used in MergePhysBone, MergeSkinnedMesh, FreezeBlendShape and more components `#1212` `#1219` `#1221` `#1236` `#1287` `#1294` `#1348`
   - This should improve compatibility with replacing base prefab, which is added in Unity 2022.
 - Allow multiple component for Remove Mesh components with API `#1216` `#1218`
   - This allows non-destructive tools to add Remove Mesh components even if Remove Mesh component are added before.

Internal/PrefabSafeSet/Editor/UniqueCollection/PrefabSafeUniqueCollectionRuntimeEditorImpl.cs

@@ -32,6 +32,9 @@ public static void OnValidate<TComponent>(TComponent component,
             // - OnValidate will be called for prefab instance when the base prefab is changed
             var PrefabSafeUniqueCollection = getPrefabSafeUniqueCollection(component);
 
+            // The prefab from prefab stage is going to be saved. I don't update on this phase.
+            if (component == null) return;
+
             // detect creating new prefab
             var newCorrespondingObject = PrefabUtility.GetCorrespondingObjectFromSource(component);
             if (newCorrespondingObject != null &&