fix

This fixes an issue with the synchronization of NetworkVariables when changing ownership where it was possible to have the previous owner be equal to the current owner when using a distributed authority network topology and the owner handled changing the ownership.

This includes an additional check for ditry states of any collections base NetworkVariables.

This bug was introduced as a regression bug when resolving the issue that any owner read permission NetworkVariables were fully synchronized with the new owner.

Author: NoelStephensUnity

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

@@ -1185,14 +1185,23 @@ internal void MarkVariablesDirty(bool dirty)
             }
         }
 
-        internal void MarkOwnerReadVariablesDirty()
+        /// <summary>
+        /// For owner read permissions, when changing ownership we need to do a full synchronization
+        /// of all NetworkVariables that are owner read permission based since the owner is the only
+        /// instance that knows what the most current values are.
+        /// </summary>
+        internal void MarkOwnerReadDirtyAndCheckOwnerWriteIsDirty()
         {
             for (int j = 0; j < NetworkVariableFields.Count; j++)
             {
                 if (NetworkVariableFields[j].ReadPerm == NetworkVariableReadPermission.Owner)
                 {
                     NetworkVariableFields[j].SetDirty(true);
                 }
+                if (NetworkVariableFields[j].WritePerm == NetworkVariableWritePermission.Owner)
+                {
+                    NetworkVariableFields[j].OnCheckIsDirtyState();
+                }
             }
         }
 

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

@@ -108,8 +108,13 @@ internal void NetworkBehaviourUpdate(bool forceSend = false)
                 foreach (var dirtyobj in m_DirtyNetworkObjects)
                 {
                     dirtyobj.PostNetworkVariableWrite(forceSend);
-                    // Once done processing, we set the previous owner id to the current owner id
-                    dirtyobj.PreviousOwnerId = dirtyobj.OwnerClientId;
+                    // If we are force sending, then we are changing ownership and making sure that we
+                    // do a full synchronization of NetworkVariables.
+                    if (forceSend)
+                    {
+                        // Once done processing, we set the previous owner id to the current owner id
+                        dirtyobj.PreviousOwnerId = dirtyobj.OwnerClientId;
+                    }
                 }
                 m_DirtyNetworkObjects.Clear();
             }

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

@@ -2567,11 +2567,36 @@ internal void MarkVariablesDirty(bool dirty)
             }
         }
 
-        internal void MarkOwnerReadVariablesDirty()
+        /// <summary>
+        /// Used when changing ownership, this will mark any owner read permission base NetworkVariables as dirty
+        /// and will check if any owner write permission NetworkVariables are dirty (primarily for collections) so
+        /// the new owner will get a full state update prior to changing ownership.
+        /// </summary>
+        /// <remarks>
+        /// We have to pass in the original owner and previous owner to "reset" back to the current state of this
+        /// NetworkObject in order to preserve the same ownership change flow. By the time this is invoked, the
+        /// new and previous owner ids have already been set.
+        /// </remarks>
+        /// <param name="originalOwnerId">the owner prior to beginning the change in ownership change.</param>
+        /// <param name="originalPreviousOwnerId">the previous owner prior to beginning the change in ownership change.</param>
+        internal void SynchronizeOwnerNetworkVariables(ulong originalOwnerId, ulong originalPreviousOwnerId)
         {
+            var currentOwnerId = OwnerClientId;
+            OwnerClientId = originalOwnerId;
+            PreviousOwnerId = originalPreviousOwnerId;
             for (int i = 0; i < ChildNetworkBehaviours.Count; i++)
             {
-                ChildNetworkBehaviours[i].MarkOwnerReadVariablesDirty();
+                ChildNetworkBehaviours[i].MarkOwnerReadDirtyAndCheckOwnerWriteIsDirty();
+            }
+            // Force send a state update for all owner read NetworkVariables
+            // and any currently dirty owner write NetworkVariables.
+            NetworkManager.BehaviourUpdater.NetworkBehaviourUpdate(true);
+            // Now set the new owner identifier back to its original new owner identifier
+            OwnerClientId = currentOwnerId;
+            // The previous owner should now be the originalOwnerId at this point.
+            if (PreviousOwnerId != originalOwnerId)
+            {
+                Debug.LogError($"[NetworkVaraible][Full Synchronization] Expected {nameof(PreviousOwnerId)} ({PreviousOwnerId}) to be the original owner id ({originalOwnerId})!");
             }
         }
 

com.unity.netcode.gameobjects/Runtime/Messaging/Messages/ChangeOwnershipMessage.cs

@@ -381,11 +381,8 @@ private void HandleOwnershipChange(ref NetworkContext context)
 
             if (originalOwner == networkManager.LocalClientId && !networkManager.DistributedAuthorityMode)
             {
-                // Mark any owner read variables as dirty
-                networkObject.MarkOwnerReadVariablesDirty();
-                // Immediately queue any pending deltas and order the message before the
-                // change in ownership message.
-                networkManager.BehaviourUpdater.NetworkBehaviourUpdate(true);
+                // Fully synchronize NetworkVariables with either read or write ownership permissions. 
+                networkObject.SynchronizeOwnerNetworkVariables(originalOwner, networkObject.PreviousOwnerId);
             }
 
             // Always invoke ownership change notifications

com.unity.netcode.gameobjects/Runtime/NetworkVariable/NetworkVariable.cs

@@ -166,6 +166,13 @@ public bool CheckDirtyState(bool forceCheck = false)
             return isDirty;
         }
 
+        /// <inheritdoc/>
+        internal override void OnCheckIsDirtyState()
+        {
+            CheckDirtyState();
+            base.OnCheckIsDirtyState();
+        }
+
         internal ref T RefValue()
         {
             return ref m_InternalValue;

com.unity.netcode.gameobjects/Runtime/NetworkVariable/NetworkVariableBase.cs

@@ -373,6 +373,15 @@ internal ulong OwnerClientId()
             return m_NetworkBehaviour.NetworkObject.OwnerClientId;
         }
 
+        /// <summary>
+        /// Primarily to check for collections dirty states when doing
+        /// a fully owner read/write NetworkVariable update.
+        /// </summary>
+        internal virtual void OnCheckIsDirtyState()
+        {
+
+        }
+
         /// <summary>
         /// Writes the dirty changes, that is, the changes since the variable was last dirty, to the writer
         /// </summary>

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

@@ -432,6 +432,15 @@ internal void RemoveOwnership(NetworkObject networkObject)
 
         internal void ChangeOwnership(NetworkObject networkObject, ulong clientId, bool isAuthorized, bool isRequestApproval = false)
         {
+            if (clientId == networkObject.OwnerClientId)
+            {
+                if (NetworkManager.LogLevel <= LogLevel.Developer)
+                {
+                    Debug.LogWarning($"[{nameof(NetworkSpawnManager)}][{nameof(ChangeOwnership)}] Attempting to change ownership to Client-{clientId} when the owner is already {networkObject.OwnerClientId}! (Ignoring)");
+                }
+                return;
+            }
+
             // For client-server:
             // If ownership changes faster than the latency between the client-server and there are NetworkVariables being updated during ownership changes,
             // then notify the user they could potentially lose state updates if developer logging is enabled.
@@ -530,6 +539,10 @@ internal void ChangeOwnership(NetworkObject networkObject, ulong clientId, bool
                 return;
             }
 
+            // Save the previous owner to work around a bit of a nasty issue with assuring NetworkVariables are serialized when ownership changes
+            var originalPreviousOwnerId = networkObject.PreviousOwnerId;
+            var originalOwner = networkObject.OwnerClientId;
+
             // Used to distinguish whether a new owner should receive any currently dirty NetworkVariable updates
             networkObject.PreviousOwnerId = networkObject.OwnerClientId;
 
@@ -548,10 +561,7 @@ internal void ChangeOwnership(NetworkObject networkObject, ulong clientId, bool
             if (networkObject.PreviousOwnerId == NetworkManager.LocalClientId)
             {
                 // Mark any owner read variables as dirty
-                networkObject.MarkOwnerReadVariablesDirty();
-                // Immediately queue any pending deltas and order the message before the
-                // change in ownership message.
-                NetworkManager.BehaviourUpdater.NetworkBehaviourUpdate(true);
+                networkObject.SynchronizeOwnerNetworkVariables(originalOwner, originalPreviousOwnerId);
             }
 
             var size = 0;