fix

This resolves issues with in-scene placed NetworkObject parenting where the original parent has changed.
This resolves the issue where loading a scene would not order the serialization of loaded in-scene placed NetworkObjects based on their parent-child hierarchy.

Author: NoelStephensUnity

com.unity.netcode.gameobjects/Runtime/Components/NetworkTransform.cs

@@ -3543,7 +3543,10 @@ private void InternalInitialization(bool isOwnershipChange = false)
             {
                 if (CanCommitToTransform)
                 {
-                    InLocalSpace = transform.parent != null;
+                    if (NetworkObject.HasParentNetworkObject(transform))
+                    {
+                        InLocalSpace = true;
+                    }
                 }
                 // Always apply this if SwitchTransformSpaceWhenParented is set.
                 TickSyncChildren = true;

com.unity.netcode.gameobjects/Runtime/Core/NetworkObject.cs

@@ -308,15 +308,18 @@ internal void OnValidate()
         /// </remarks>
         private void CheckForInScenePlaced()
         {
-            if (PrefabUtility.IsPartOfAnyPrefab(this) && gameObject.scene.IsValid() && gameObject.scene.isLoaded && gameObject.scene.buildIndex >= 0)
+            if (gameObject.scene.IsValid() && gameObject.scene.isLoaded && gameObject.scene.buildIndex >= 0)
             {
-                var prefab = PrefabUtility.GetCorrespondingObjectFromSource(gameObject);
-                var assetPath = AssetDatabase.GetAssetPath(prefab);
-                var sourceAsset = AssetDatabase.LoadAssetAtPath<NetworkObject>(assetPath);
-                if (sourceAsset != null && sourceAsset.GlobalObjectIdHash != 0 && InScenePlacedSourceGlobalObjectIdHash != sourceAsset.GlobalObjectIdHash)
+                if (PrefabUtility.IsPartOfAnyPrefab(this))
                 {
-                    InScenePlacedSourceGlobalObjectIdHash = sourceAsset.GlobalObjectIdHash;
-                    EditorUtility.SetDirty(this);
+                    var prefab = PrefabUtility.GetCorrespondingObjectFromSource(gameObject);
+                    var assetPath = AssetDatabase.GetAssetPath(prefab);
+                    var sourceAsset = AssetDatabase.LoadAssetAtPath<NetworkObject>(assetPath);
+                    if (sourceAsset != null && sourceAsset.GlobalObjectIdHash != 0 && InScenePlacedSourceGlobalObjectIdHash != sourceAsset.GlobalObjectIdHash)
+                    {
+                        InScenePlacedSourceGlobalObjectIdHash = sourceAsset.GlobalObjectIdHash;
+                        EditorUtility.SetDirty(this);
+                    }
                 }
                 IsSceneObject = true;
 
@@ -335,6 +338,24 @@ private void CheckForInScenePlaced()
         }
 #endif // UNITY_EDITOR
 
+        internal bool HasParentNetworkObject(Transform transform)
+        {
+            if (transform.parent != null)
+            {
+                var networkObject = transform.parent.GetComponent<NetworkObject>();
+                if (networkObject != null && networkObject != this)
+                {
+                    return true;
+                }
+
+                if (transform.parent.parent != null)
+                {
+                    return HasParentNetworkObject(transform.parent);
+                }
+            }
+            return false;
+        }
+
         /// <summary>
         /// Gets the NetworkManager that owns this NetworkObject instance
         /// </summary>
@@ -2295,7 +2316,7 @@ private void OnTransformParentChanged()
         // we call CheckOrphanChildren() method and quickly iterate over OrphanChildren set and see if we can reparent/adopt one.
         internal static HashSet<NetworkObject> OrphanChildren = new HashSet<NetworkObject>();
 
-        internal bool ApplyNetworkParenting(bool removeParent = false, bool ignoreNotSpawned = false, bool orphanedChildPass = false)
+        internal bool ApplyNetworkParenting(bool removeParent = false, bool ignoreNotSpawned = false, bool orphanedChildPass = false, bool silentParenting = false)
         {
             if (!AutoObjectParentSync)
             {
@@ -2368,7 +2389,10 @@ internal bool ApplyNetworkParenting(bool removeParent = false, bool ignoreNotSpa
                 // to WorldPositionStays which can cause scaling issues if the parent's
                 // scale is not the default (Vetctor3.one) value.
                 transform.SetParent(null, m_CachedWorldPositionStays);
-                InvokeBehaviourOnNetworkObjectParentChanged(null);
+                if (!silentParenting)
+                {
+                    InvokeBehaviourOnNetworkObjectParentChanged(null);
+                }
                 return true;
             }
 
@@ -2393,7 +2417,10 @@ internal bool ApplyNetworkParenting(bool removeParent = false, bool ignoreNotSpa
             }
             SetCachedParent(parentObject.transform);
             transform.SetParent(parentObject.transform, m_CachedWorldPositionStays);
-            InvokeBehaviourOnNetworkObjectParentChanged(parentObject);
+            if (!silentParenting)
+            {
+                InvokeBehaviourOnNetworkObjectParentChanged(parentObject);
+            }
             return true;
         }
 
@@ -3083,12 +3110,6 @@ internal SceneObject GetMessageSceneObject(ulong targetClientId = NetworkManager
                 var syncRotationPositionLocalSpaceRelative = obj.HasParent && !m_CachedWorldPositionStays;
                 var syncScaleLocalSpaceRelative = obj.HasParent && !m_CachedWorldPositionStays;
 
-                // Always synchronize in-scene placed object's scale using local space
-                if (obj.IsSceneObject)
-                {
-                    syncScaleLocalSpaceRelative = obj.HasParent;
-                }
-
                 // If auto object synchronization is turned off
                 if (!AutoObjectParentSync)
                 {
@@ -3165,6 +3186,16 @@ internal static NetworkObject AddSceneObject(in SceneObject sceneObject, FastBuf
             // Synchronize NetworkBehaviours
             var bufferSerializer = new BufferSerializer<BufferSerializerReader>(new BufferSerializerReader(reader));
             networkObject.SynchronizeNetworkBehaviours(ref bufferSerializer, networkManager.LocalClientId);
+            Debug.Log($"Spawning {networkObject.name}");
+
+            // If we are an in-scene placed NetworkObject and we originally had a parent but when synchronized we are
+            // being told we do not have a parent, then we want to clear the latest parent so it is not automatically
+            // "re-parented" to the original parent. This can happen if not unloading the scene and the parenting of
+            // the in-scene placed Networkobject changes several times over different sessions.
+            if (sceneObject.IsSceneObject && !sceneObject.HasParent && networkObject.m_LatestParent.HasValue)
+            {
+                networkObject.m_LatestParent = null;
+            }
 
             // Spawn the NetworkObject
             networkManager.SpawnManager.SpawnNetworkObjectLocally(networkObject, sceneObject, sceneObject.DestroyWithScene);

com.unity.netcode.gameobjects/Runtime/SceneManagement/SceneEventData.cs

@@ -329,7 +329,14 @@ internal void AddSpawnedNetworkObjects()
                     m_NetworkObjectsSync.Add(sobj);
                 }
             }
+            SortObjectsToSync();
+        }
 
+        /// <summary>
+        /// Used to order the object serialization for both synchronization and scene loading
+        /// </summary>
+        private void SortObjectsToSync()
+        {
             // Sort by INetworkPrefabInstanceHandler implementation before the
             // NetworkObjects spawned by the implementation
             m_NetworkObjectsSync.Sort(SortNetworkObjects);
@@ -671,20 +678,31 @@ internal void SerializeScenePlacedObjects(FastBufferWriter writer)
             // If distributed authority mode and sending to the service, then ignore observers
             var distributedAuthoritySendingToService = distributedAuthority && TargetClientId == NetworkManager.ServerClientId;
 
+            // Clear our objects to sync and build a list of the in-scene placed NetworkObjects instantiated and spawned locally
+            m_NetworkObjectsSync.Clear();
             foreach (var keyValuePairByGlobalObjectIdHash in m_NetworkManager.SceneManager.ScenePlacedObjects)
             {
                 foreach (var keyValuePairBySceneHandle in keyValuePairByGlobalObjectIdHash.Value)
                 {
                     if (keyValuePairBySceneHandle.Value.Observers.Contains(TargetClientId) || distributedAuthoritySendingToService)
                     {
-                        // Serialize the NetworkObject
-                        var sceneObject = keyValuePairBySceneHandle.Value.GetMessageSceneObject(TargetClientId, distributedAuthority);
-                        sceneObject.Serialize(writer);
-                        numberOfObjects++;
+                        m_NetworkObjectsSync.Add(keyValuePairBySceneHandle.Value);
                     }
                 }
             }
 
+            // Sort the objects to sync based on parenting hierarchy
+            SortObjectsToSync();
+
+            // Serialize the sorted objects to sync.
+            foreach(var objectToSycn in m_NetworkObjectsSync)
+            {
+                // Serialize the NetworkObject
+                var sceneObject = objectToSycn.GetMessageSceneObject(TargetClientId, distributedAuthority);
+                sceneObject.Serialize(writer);
+                numberOfObjects++;
+            }
+
             // Write the number of despawned in-scene placed NetworkObjects
             writer.WriteValueSafe(m_DespawnedInSceneObjectsSync.Count);
             // Write the scene handle and GlobalObjectIdHash value

com.unity.netcode.gameobjects/Runtime/Spawning/NetworkSpawnManager.cs

@@ -922,19 +922,29 @@ internal NetworkObject CreateLocalNetworkObject(NetworkObject.SceneObject sceneO
                 // SPECIAL CASE FOR IN-SCENE PLACED:  (only when the parent has a NetworkObject)
                 // This is a special case scenario where a late joining client has joined and loaded one or
                 // more scenes that contain nested in-scene placed NetworkObject children yet the server's
-                // synchronization information does not indicate the NetworkObject in question has a parent.
-                // Under this scenario, we want to remove the parent before spawning and setting the transform values.
+                // synchronization information does not indicate the NetworkObject in question has a parent =or=
+                // the parent has changed.
+                // For this we will want to remove the parent before spawning and setting the transform values based
+                // on several possible scenarios.
                 if (sceneObject.IsSceneObject && networkObject.transform.parent != null)
                 {
                     var parentNetworkObject = networkObject.transform.parent.GetComponent<NetworkObject>();
                     // if the in-scene placed NetworkObject has a parent NetworkObject but the synchronization information does not
-                    // include parenting, then we need to force the removal of that parent
+                    // include parenting, then we need to force the removal of that parent (i.e. it is at the root)
                     if (!sceneObject.HasParent && parentNetworkObject)
                     {
                         // remove the parent
                         networkObject.ApplyNetworkParenting(true, true);
                     }
-                    else if (sceneObject.HasParent && !parentNetworkObject)
+                    else // If we are parented and our latest parent known is not the parent =or= we are keeping world space values when parenting.
+                    if (parentNetworkObject && sceneObject.HasParent && sceneObject.LatestParent.HasValue
+                        && (sceneObject.LatestParent.Value != parentNetworkObject.NetworkObjectId || sceneObject.WorldPositionStays))
+                    {
+                        // remove the parent silently so we can re-parent an in-scene placed NetworkObject
+                        networkObject.ApplyNetworkParenting(true, true, silentParenting: true);
+                    }
+                    else // special case to handle being parented under a GameObject with no NetworkObject
+                    if (sceneObject.HasParent && !parentNetworkObject)
                     {
                         nonNetworkObjectParent = true;
                     }