fix: NetworkVariable change prior to ownership change using distributed authority topology fails to sync NetworkVariable (#4107)

* fix

This resolves the issue where in a distributed authority session changing a NetworkVariable prior to changing ownership in the same call-stack would result in the NetworkVariable not being synchronized.

* fix - update

Removing the additional authority check as it is not needed.
Fixing a very edge case scenario that shouldn't happen but in the event it does when finding objects by type within a specific scene, if the scene is invalid then use an empty array for the found objects.

Author: NoelStephensUnity

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

@@ -69,8 +69,8 @@ private struct ObjectsInSceneEnumerator<T> : IEnumerable<T>, IEnumerator<T> wher
             internal ObjectsInSceneEnumerator(Scene scene, bool includeInactive)
             {
                 m_IncludeInactive = includeInactive;
-
-                m_RootObjects = scene.GetRootGameObjects();
+                // If the scene is invalid, use an empty array.
+                m_RootObjects = scene.IsValid() ? scene.GetRootGameObjects() : new UnityEngine.GameObject[0];
                 m_RootIndex = 0;
                 m_CurrentChildObjects = null;
                 m_CurrentChildIndex = 0;

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

@@ -2971,17 +2971,31 @@ internal void SynchronizeOwnerNetworkVariables(ulong originalOwnerId, ulong orig
                 childBehaviour.MarkOwnerReadDirtyAndCheckOwnerWriteIsDirty();
             }
 
+            // If the spawn authority of a distributed authority network topology has invoked a change in ownership,
+            // then we want to invoke the NetworkBehaviourUpdate prior to changing the owner back.
+            if (NetworkManager.DistributedAuthorityMode)
+            {
+                // Force send a state update for all owner read NetworkVariables  and any currently dirty
+                // owner write NetworkVariables.
+                NetworkManagerOwner.BehaviourUpdater.NetworkBehaviourUpdate(true);
+            }
+
             // Now set the new owner and previous owner identifiers back to their original new values
-            // before we run the NetworkBehaviourUpdate. For owner read only permissions this order of
-            // operations is **particularly important** as we need to first (above) mark things as dirty
-            // from the context of the original owner and then second (below) we need to send the messages
-            // which requires the new owner to be set for owner read permission NetworkVariables.
+            // after we run the NetworkBehaviourUpdate.
             OwnerClientId = currentOwnerId;
             PreviousOwnerId = originalOwnerId;
 
-            // Force send a state update for all owner read NetworkVariables  and any currently dirty
-            // owner write NetworkVariables.
-            NetworkManagerOwner.BehaviourUpdater.NetworkBehaviourUpdate(true);
+            // For owner read only permissions this order of operations is **particularly important** as
+            // we need to first (above) mark things as dirty from the context of the original owner and
+            // then second (below) we need to send the messages which requires the new owner to be set.
+            // Note: Owner read only NetworkVariables do not make sense in a distributed authority topology
+            // since the only instance that can write is the owner.
+            if (!NetworkManager.DistributedAuthorityMode)
+            {
+                // Force send a state update for all owner read NetworkVariables and any currently dirty
+                // owner write NetworkVariables.
+                NetworkManagerOwner.BehaviourUpdater.NetworkBehaviourUpdate(true);
+            }
         }
 
         // NGO currently guarantees that the client will receive spawn data for all objects in one network tick.