fix: Avoid duplicate RPC invocation on host (#2834)

Host acts as both client and server.
Both the client target and the server target points to same instance
This results in two invocations on the host which is not expected
Checking that the server is host and skipping the RpcTarget invocation we avoid this situation

Author: miniwolf

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

@@ -49,6 +49,10 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
                     {
                         continue;
                     }
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
                     m_GroupSendTarget.Add(clientId);
                 }
             }

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

@@ -40,6 +40,10 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
                     {
                         continue;
                     }
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
                     if (clientId == behaviour.NetworkManager.LocalClientId)
                     {
                         m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);
@@ -57,6 +61,10 @@ internal override void Send(NetworkBehaviour behaviour, ref RpcMessage message,
                     {
                         continue;
                     }
+                    if (clientId == NetworkManager.ServerClientId)
+                    {
+                        continue;
+                    }
                     if (clientId == behaviour.NetworkManager.LocalClientId)
                     {
                         m_LocalSendRpcTarget.Send(behaviour, ref message, delivery, rpcParams);

com.unity.netcode.gameobjects/Tests/Runtime/UniversalRpcTests.cs

@@ -24,6 +24,7 @@ public class UniversalRpcNetworkBehaviour : NetworkBehaviour
         public string Received = string.Empty;
         public Tuple<int, bool, float, string> ReceivedParams = null;
         public ulong ReceivedFrom = ulong.MaxValue;
+        public int ReceivedCount;
 
         public void OnRpcReceived()
         {
@@ -32,6 +33,7 @@ public void OnRpcReceived()
 
             var currentMethod = sf.GetMethod();
             Received = currentMethod.Name;
+            ReceivedCount++;
         }
         public void OnRpcReceivedWithParams(int a, bool b, float f, string s)
         {
@@ -40,6 +42,7 @@ public void OnRpcReceivedWithParams(int a, bool b, float f, string s)
 
             var currentMethod = sf.GetMethod();
             Received = currentMethod.Name;
+            ReceivedCount++;
             ReceivedParams = new Tuple<int, bool, float, string>(a, b, f, s);
         }
 
@@ -496,6 +499,7 @@ protected void Clear()
             foreach (var obj in Object.FindObjectsByType<UniversalRpcNetworkBehaviour>(FindObjectsSortMode.None))
             {
                 obj.Received = string.Empty;
+                obj.ReceivedCount = 0;
                 obj.ReceivedParams = null;
                 obj.ReceivedFrom = ulong.MaxValue;
             }
@@ -528,10 +532,11 @@ protected UniversalRpcNetworkBehaviour GetPlayerObject(ulong ownerClientId, ulon
             return m_PlayerNetworkObjects[onClient][ownerClientId].GetComponent<UniversalRpcNetworkBehaviour>();
         }
 
-        protected void VerifyLocalReceived(ulong objectOwner, ulong sender, string name, bool verifyReceivedFrom)
+        protected void VerifyLocalReceived(ulong objectOwner, ulong sender, string name, bool verifyReceivedFrom, int expectedReceived = 1)
         {
             var obj = GetPlayerObject(objectOwner, sender);
             Assert.AreEqual(name, obj.Received);
+            Assert.That(obj.ReceivedCount, Is.EqualTo(expectedReceived));
             Assert.IsNull(obj.ReceivedParams);
             if (verifyReceivedFrom)
             {
@@ -543,6 +548,7 @@ protected void VerifyLocalReceivedWithParams(ulong objectOwner, ulong sender, st
         {
             var obj = GetPlayerObject(objectOwner, sender);
             Assert.AreEqual(name, obj.Received);
+            Assert.That(obj.ReceivedCount, Is.EqualTo(1));
             Assert.IsNotNull(obj.ReceivedParams);
             Assert.AreEqual(i, obj.ReceivedParams.Item1);
             Assert.AreEqual(b, obj.ReceivedParams.Item2);
@@ -556,17 +562,18 @@ protected void VerifyNotReceived(ulong objectOwner, ulong[] receivedBy)
             {
                 UniversalRpcNetworkBehaviour playerObject = GetPlayerObject(objectOwner, client);
                 Assert.AreEqual(string.Empty, playerObject.Received);
+                Assert.That(playerObject.ReceivedCount, Is.EqualTo(0));
                 Assert.IsNull(playerObject.ReceivedParams);
             }
         }
 
-        protected void VerifyRemoteReceived(ulong objectOwner, ulong sender, string message, ulong[] receivedBy, bool verifyReceivedFrom, bool waitForMessages = true)
+        protected void VerifyRemoteReceived(ulong objectOwner, ulong sender, string message, ulong[] receivedBy, bool verifyReceivedFrom, bool waitForMessages = true, int expectedReceived = 1)
         {
             foreach (var client in receivedBy)
             {
                 if (client == sender)
                 {
-                    VerifyLocalReceived(objectOwner, sender, message, verifyReceivedFrom);
+                    VerifyLocalReceived(objectOwner, sender, message, verifyReceivedFrom, expectedReceived);
 
                     break;
                 }
@@ -628,6 +635,7 @@ protected void VerifyRemoteReceived(ulong objectOwner, ulong sender, string mess
             {
                 UniversalRpcNetworkBehaviour playerObject = GetPlayerObject(objectOwner, client);
                 Assert.AreEqual(message, playerObject.Received);
+                Assert.That(playerObject.ReceivedCount, Is.EqualTo(expectedReceived));
                 Assert.IsNull(playerObject.ReceivedParams);
                 if (verifyReceivedFrom)
                 {
@@ -701,6 +709,7 @@ protected void VerifyRemoteReceivedWithParams(ulong objectOwner, ulong sender, s
             {
                 UniversalRpcNetworkBehaviour playerObject = GetPlayerObject(objectOwner, client);
                 Assert.AreEqual(message, playerObject.Received);
+                Assert.That(playerObject.ReceivedCount, Is.EqualTo(1));
 
                 Assert.IsNotNull(playerObject.ReceivedParams);
                 Assert.AreEqual(i, playerObject.ReceivedParams.Item1);
@@ -1636,17 +1645,20 @@ public void TestMutualRecursion()
 
             VerifyNotReceived(NetworkManager.ServerClientId, s_ClientIds);
 
-            for (var i = 0; i < 10; ++i)
+            var clientListExpected = 1;
+            var serverListExpected = 2;
+            for (var i = 1; i <= 10; ++i)
             {
                 WaitForMessageReceivedWithTimeTravel<RpcMessage>(clientList);
-                VerifyRemoteReceived(NetworkManager.ServerClientId, NetworkManager.ServerClientId, nameof(UniversalRpcNetworkBehaviour.MutualRecursionClientRpc), clientIdArray, false, false);
+                VerifyRemoteReceived(NetworkManager.ServerClientId, NetworkManager.ServerClientId, nameof(UniversalRpcNetworkBehaviour.MutualRecursionClientRpc), clientIdArray, false, false, clientListExpected);
                 VerifyNotReceived(NetworkManager.ServerClientId, serverIdArray);
+                clientListExpected *= 2;
 
                 Clear();
-
                 WaitForMessageReceivedWithTimeTravel<RpcMessage>(serverList);
-                VerifyRemoteReceived(NetworkManager.ServerClientId, NetworkManager.ServerClientId, nameof(UniversalRpcNetworkBehaviour.MutualRecursionServerRpc), serverIdArray, false, false);
+                VerifyRemoteReceived(NetworkManager.ServerClientId, NetworkManager.ServerClientId, nameof(UniversalRpcNetworkBehaviour.MutualRecursionServerRpc), serverIdArray, false, false, serverListExpected);
                 VerifyNotReceived(NetworkManager.ServerClientId, clientIdArray);
+                serverListExpected *= 2;
 
                 Clear();
             }