fix: Removed unnecessary GC Allocation

com.unity.netcode.gameobjects/CHANGELOG.md

@@ -17,6 +17,7 @@ Additional documentation and release notes are available at [Multiplayer Documen
 - Fixed an issue where `UnityTransport` would not accept single words as valid hostnames (notably "localhost"). (#3591)
 - Fixed issue where viewing a `NetworkBehaviour` with one or more `NetworkVariable` fields could throw an exception if running a distributed authority network topology with a local (DAHost) host and viewed on the host when the host is not the authority of the associated `NetworkObject`. (#3578)
 - Fixed issue when using a distributed authority network topology and  viewing a `NetworkBehaviour` with one or more `NetworkVariable` fields in the inspector view would not show editable fields. (#3578)
+- Fixed issue with unnecessary internal GC Allocations when using the `IReadOnlyList`  `NetworkManager.ConnectedClientsIds` within a `foreach` statement by either replacing with a `for` loop or directly referencing the `NetworkConnectionManager.ConnectedClientIds`. (#3527)
 
 ### Changed
 

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

@@ -996,7 +996,7 @@ internal void CheckForAnimatorChanges()
                 {
                     // Just notify all remote clients and not the local server
                     m_ClientSendList.Clear();
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         if (clientId == NetworkManager.LocalClientId || !NetworkObject.Observers.Contains(clientId))
                         {
@@ -1315,7 +1315,7 @@ private unsafe void SendParametersUpdateServerRpc(ParametersUpdateMessage parame
                 if (NetworkManager.ConnectedClientsIds.Count > (IsHost ? 2 : 1))
                 {
                     m_ClientSendList.Clear();
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         if (clientId == serverRpcParams.Receive.SenderClientId || clientId == NetworkManager.ServerClientId || !NetworkObject.Observers.Contains(clientId))
                         {
@@ -1378,7 +1378,7 @@ private void SendAnimStateServerRpc(AnimationMessage animationMessage, ServerRpc
                 if (NetworkManager.ConnectedClientsIds.Count > (IsHost ? 2 : 1))
                 {
                     m_ClientSendList.Clear();
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         if (clientId == serverRpcParams.Receive.SenderClientId || clientId == NetworkManager.ServerClientId || !NetworkObject.Observers.Contains(clientId))
                         {
@@ -1452,7 +1452,7 @@ internal void SendAnimTriggerServerRpc(AnimationTriggerMessage animationTriggerM
             InternalSetTrigger(animationTriggerMessage.Hash, animationTriggerMessage.IsTriggerSet);
 
             m_ClientSendList.Clear();
-            foreach (var clientId in NetworkManager.ConnectedClientsIds)
+            foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
             {
                 if (clientId == NetworkManager.ServerClientId || !NetworkObject.Observers.Contains(clientId))
                 {

com.unity.netcode.gameobjects/Runtime/Connection/NetworkConnectionManager.cs

@@ -149,12 +149,12 @@ internal void InvokeOnClientConnectedCallback(ulong clientId)
             }
 
             // Invoking connection event on non-authority local client. Need to calculate PeerIds.
-            var peerClientIds = new NativeArray<ulong>(Math.Max(NetworkManager.ConnectedClientsIds.Count - 1, 0), Allocator.Temp);
+            var peerClientIds = new NativeArray<ulong>(Math.Max(ConnectedClientIds.Count - 1, 0), Allocator.Temp);
             // `using var peerClientIds` or `using(peerClientIds)` renders it immutable...
             using var sentinel = peerClientIds;
 
             var idx = 0;
-            foreach (var peerId in NetworkManager.ConnectedClientsIds)
+            foreach (var peerId in ConnectedClientIds)
             {
                 if (peerId == NetworkManager.LocalClientId)
                 {

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

@@ -1616,7 +1616,7 @@ public void NetworkHide(ulong clientId)
                         // Send destroy call
                         size = NetworkManager.ConnectionManager.SendMessage(ref message, NetworkDelivery.ReliableSequenced, clientId);
                         // Broadcast the destroy to all clients so they can update their observers list
-                        foreach (var client in NetworkManager.ConnectedClientsIds)
+                        foreach (var client in NetworkManager.ConnectionManager.ConnectedClientIds)
                         {
                             if (client == clientId || client == NetworkManager.LocalClientId)
                             {
@@ -2363,7 +2363,7 @@ private void OnTransformParentChanged()
                 }
                 else
                 {
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         if (clientId == NetworkManager.ServerClientId)
                         {
@@ -2382,7 +2382,7 @@ private void OnTransformParentChanged()
                     var maxCount = NetworkManager.ConnectedClientsIds.Count;
                     ulong* clientIds = stackalloc ulong[maxCount];
                     int idx = 0;
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         if (clientId == NetworkManager.ServerClientId)
                         {

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

@@ -250,8 +250,9 @@ public void Handle(ref NetworkContext context)
                 }
                 else
                 {
-                    foreach (var clientId in clientList)
+                    for (int i = 0; i < clientList.Count; i++)
                     {
+                        var clientId = clientList[i];
                         if (clientId == networkManager.LocalClientId)
                         {
                             continue;

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

@@ -247,9 +247,9 @@ internal static void CreateObject(ref NetworkManager networkManager, ulong sende
                     var clientList = hasObserverIdList && !networkObject.IsPlayerObject ? observerIds : networkManager.ConnectedClientsIds;
 
                     // Update the observers for this instance
-                    foreach (var clientId in clientList)
+                    for (int i = 0; i < clientList.Count; i++)
                     {
-                        networkObject.Observers.Add(clientId);
+                        networkObject.Observers.Add(clientList[i]);
                     }
 
                     // Mock CMB Service and forward to all clients

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

@@ -191,7 +191,7 @@ private void HandleDAHostForwardMessage(ulong senderId, ref NetworkManager netwo
                 DeferredDespawnTick = DeferredDespawnTick,
             };
             var ownerClientId = networkObject == null ? senderId : networkObject.OwnerClientId;
-            var clientIds = networkObject == null ? networkManager.ConnectedClientsIds.ToList() : networkObject.Observers.ToList();
+            var clientIds = networkObject == null ? networkManager.ConnectionManager.ConnectedClientIds : networkObject.Observers.ToList();
 
             foreach (var clientId in clientIds)
             {

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

@@ -228,7 +228,7 @@ public void Handle(ref NetworkContext context)
                     if (isServerAndDeltaForwarding)
                     {
                         m_ForwardUpdates = new Dictionary<ulong, List<int>>();
-                        foreach (var clientId in networkManager.ConnectedClientsIds)
+                        foreach (var clientId in networkManager.ConnectionManager.ConnectedClientIds)
                         {
                             if (clientId == context.SenderId || clientId == networkManager.LocalClientId || !networkObject.Observers.Contains(clientId))
                             {

com.unity.netcode.gameobjects/Runtime/Messaging/RpcTargets/BaseRpcTarget.cs

@@ -11,6 +11,8 @@ public abstract class BaseRpcTarget : IDisposable
         /// The <see cref="NetworkManager"/> instance which can be used to handle sending and receiving the specific target(s)
         /// </summary>
         protected NetworkManager m_NetworkManager;
+
+        internal NetworkConnectionManager ConnectionManager;
         private bool m_Locked;
 
         internal void Lock()
@@ -26,6 +28,7 @@ internal void Unlock()
         internal BaseRpcTarget(NetworkManager manager)
         {
             m_NetworkManager = manager;
+            ConnectionManager = m_NetworkManager.ConnectionManager;
         }
 
         /// <summary>

com.unity.netcode.gameobjects/Runtime/Messaging/RpcTargets/NotAuthorityRpcTarget.cs

@@ -40,7 +40,7 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
                 }
                 else
                 {
-                    foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in ConnectionManager.ConnectedClientIds)
                     {
                         if (clientId == behaviour.OwnerClientId || !networkObject.Observers.Contains(clientId))
                         {

com.unity.netcode.gameobjects/Runtime/Messaging/RpcTargets/NotMeRpcTarget.cs

@@ -43,7 +43,7 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
             }
             else
             {
-                foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                foreach (var clientId in ConnectionManager.ConnectedClientIds)
                 {
                     if (clientId == behaviour.NetworkManager.LocalClientId)
                     {

com.unity.netcode.gameobjects/Runtime/Messaging/RpcTargets/NotOwnerRpcTarget.cs

@@ -64,7 +64,7 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
             }
             else
             {
-                foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                foreach (var clientId in ConnectionManager.ConnectedClientIds)
                 {
                     if (clientId == behaviour.OwnerClientId)
                     {

com.unity.netcode.gameobjects/Runtime/Messaging/RpcTargets/NotServerRpcTarget.cs

@@ -44,7 +44,7 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
             }
             else
             {
-                foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+                foreach (var clientId in ConnectionManager.ConnectedClientIds)
                 {
                     if (clientId == NetworkManager.ServerClientId)
                     {

com.unity.netcode.gameobjects/Runtime/Messaging/RpcTargets/RpcTarget.cs

@@ -119,10 +119,11 @@ public enum RpcTargetUse
     public class RpcTarget
     {
         private NetworkManager m_NetworkManager;
+        private NetworkConnectionManager m_ConnectionManager;
         internal RpcTarget(NetworkManager manager)
         {
             m_NetworkManager = manager;
-
+            m_ConnectionManager = manager.ConnectionManager;
             Everyone = new EveryoneRpcTarget(manager);
             Owner = new OwnerRpcTarget(manager);
             NotOwner = new NotOwnerRpcTarget(manager);
@@ -312,7 +313,7 @@ public BaseRpcTarget Not(ulong excludedClientId, RpcTargetUse use)
                 }
             }
             target.Clear();
-            foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+            foreach (var clientId in m_ConnectionManager.ConnectedClientIds)
             {
                 if (clientId != excludedClientId)
                 {
@@ -495,7 +496,7 @@ public BaseRpcTarget Not(NativeArray<ulong> excludedClientIds, RpcTargetUse use)
                 asASet.Add(clientId);
             }
 
-            foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+            foreach (var clientId in m_ConnectionManager.ConnectedClientIds)
             {
                 if (!asASet.Contains(clientId))
                 {
@@ -584,13 +585,13 @@ public BaseRpcTarget Not<T>(T excludedClientIds, RpcTargetUse use) where T : IEn
             }
             target.Clear();
 
-            using var asASet = new NativeHashSet<ulong>(m_NetworkManager.ConnectedClientsIds.Count, Allocator.Temp);
+            using var asASet = new NativeHashSet<ulong>(m_ConnectionManager.ConnectedClientIds.Count, Allocator.Temp);
             foreach (var clientId in excludedClientIds)
             {
                 asASet.Add(clientId);
             }
 
-            foreach (var clientId in m_NetworkManager.ConnectedClientsIds)
+            foreach (var clientId in m_ConnectionManager.ConnectedClientIds)
             {
                 if (!asASet.Contains(clientId))
                 {

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

@@ -2593,7 +2593,7 @@ internal void HandleSceneEvent(ulong clientId, FastBufferReader reader)
                                 EventData = sceneEventData,
                             };
                             // Forward synchronization to client then exit early because DAHost is not the current session owner
-                            foreach (var client in NetworkManager.ConnectedClientsIds)
+                            foreach (var client in NetworkManager.ConnectionManager.ConnectedClientIds)
                             {
                                 if (client == NetworkManager.LocalClientId)
                                 {

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

@@ -166,7 +166,7 @@ internal SceneEventProgress(NetworkManager networkManager, SceneEventProgressSta
                 {
                     m_NetworkManager.OnClientDisconnectCallback += OnClientDisconnectCallback;
                     // Track the clients that were connected when we started this event
-                    foreach (var connectedClientId in networkManager.ConnectedClientsIds)
+                    foreach (var connectedClientId in networkManager.ConnectionManager.ConnectedClientIds)
                     {
                         // Ignore the host or session owner
                         if ((!networkManager.DistributedAuthorityMode && NetworkManager.ServerClientId == connectedClientId) || (networkManager.DistributedAuthorityMode && networkManager.CurrentSessionOwner == connectedClientId))

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

@@ -1099,7 +1099,7 @@ internal void SpawnNetworkObjectLocally(NetworkObject networkObject, ulong netwo
                 }
                 else
                 {
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         // If SpawnWithObservers is enabled, then authority does take networkObject.CheckObjectVisibility into consideration
                         if (networkObject.CheckObjectVisibility != null && !networkObject.CheckObjectVisibility.Invoke(clientId))
@@ -1695,7 +1695,9 @@ internal void OnDespawnObject(NetworkObject networkObject, bool destroyGameObjec
                 // Otherwise send to the clients for which the object is visible
                 else
                 {
-                    foreach (var clientId in NetworkManager.ConnectedClientsIds)
+                    // We keep only the client for which the object is visible
+                    // as the other clients have them already despawned
+                    foreach (var clientId in NetworkManager.ConnectionManager.ConnectedClientIds)
                     {
                         if ((distributedAuthority && clientId == networkObject.OwnerClientId) || clientId == NetworkManager.LocalClientId)
                         {

com.unity.netcode.gameobjects/Runtime/Transports/UTP/UnityTransport.cs

@@ -1089,9 +1089,9 @@ private void ExtractNetworkMetrics()
         {
             if (m_NetworkManager.IsServer)
             {
-                var ngoConnectionIds = m_NetworkManager.ConnectedClients.Keys;
-                foreach (var ngoConnectionId in ngoConnectionIds)
+                for (int i=0; i<m_NetworkManager.ConnectedClientsIds.Count; ++i)
                 {
+                    var ngoConnectionId =  m_NetworkManager.ConnectedClientsIds[i];
                     if (ngoConnectionId == 0 && m_NetworkManager.IsHost)
                     {
                         continue;