fix(prefab-safe-set): unncecessary prefab overrides are generated

CHANGELOG-PRERELEASE.md

@@ -19,6 +19,7 @@ The format is based on [Keep a Changelog].
 ### Fixed
 - maxSquish cannot be configured for mergePB`#1231`
 - Error from Optimize Texture if there is Merge Skinned Mesh with material slot animation `#1235`
+- Unncecessary Prefab Overrides are Generated with Prefab Safe Set `#1236`
 
 ### Security
 

CHANGELOG.md

@@ -46,7 +46,7 @@ The format is based on [Keep a Changelog].
 - Reimplement Preview system with NDMF Preview System `#1131` `#1195` `#1218`
   - 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`
+- Improved Prefab Safe Set, which are used in MergePhysBone, MergeSkinnedMesh, FreezeBlendShape and more components `#1212` `#1219` `#1221` `#1236`
   - 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/EditorUtil.PrefabModificationOnScene.cs

@@ -27,7 +27,7 @@ public PrefabModificationOnScene(SerializedProperty property, int nestCount,
 
             protected override void InitCurrentLayer(bool force = false)
             {
-                _usingOnSceneLayer.boolValue = true;
+                if (force) _usingOnSceneLayer.boolValue = true;
                 CurrentRemoves = _onSceneLayer.FindPropertyRelative(Names.Removes);
                 CurrentAdditions = _onSceneLayer.FindPropertyRelative(Names.Additions);
                 _prefabLayersSize.Updated();

Internal/PrefabSafeSet/Editor/PrefabSafeSetRuntimeEditorImpl.cs

@@ -32,6 +32,7 @@ public static void OnValidate<TComponent>(TComponent component, Func<TComponent,
                 {
                     // if the prefab is created, we clear onSceneLayer to avoid unnecessary modifications
                     prefabSafeSet.onSceneLayer = new PrefabLayer<T>();
+                    prefabSafeSet.usingOnSceneLayer = false; // this should avoid creating prefab overrides
                 }
             }
 
@@ -48,6 +49,7 @@ public static void OnValidate<TComponent>(TComponent component, Func<TComponent,
 
             if (!shouldUsePrefabOnSceneLayer && prefabSafeSet.usingOnSceneLayer)
             {
+                // migrate onSceneLayer to latest layer
                 var onSceneLayer = prefabSafeSet.onSceneLayer;
 
                 if (maxLayerCount == 0)
@@ -131,7 +133,7 @@ void DistinctCheckArray(ref T[] source, Func<T, bool> filter)
             if (shouldUsePrefabOnSceneLayer)
             {
                 var currentLayer = self.onSceneLayer;
-                self.usingOnSceneLayer = true;
+                //self.usingOnSceneLayer = true; // this will create prefab overrides, which is not good.
                 DistinctCheckArray(ref currentLayer.additions, PrefabSafeSetRuntimeUtil.IsNotNull);
                 DistinctCheckArray(ref currentLayer.removes,
                     x => x.IsNotNull() && !currentLayer.additions.Contains(x));
@@ -169,6 +171,7 @@ private static void ApplyModificationsToLatestLayer(PrefabSafeSet<T> self, int m
             else
             {
                 // nestCount is not zero: apply to current layer
+                if (shouldUsePrefabOnSceneLayer) self.usingOnSceneLayer = true;
                 var targetLayer = shouldUsePrefabOnSceneLayer ? self.onSceneLayer : self.prefabLayers[maxLayerCount - 1];
                 var additions = new ListSet<T>(targetLayer.additions);
                 var removes = new ListSet<T>(targetLayer.removes);