fix: #4058 [Command] on host now populates NetworkConnectionToClient automatically (#4063)

Author: miwarnec

Assets/Mirror/Editor/Weaver/Processors/CommandProcessor.cs

@@ -85,7 +85,22 @@ public static MethodDefinition ProcessCommandCall(WeaverTypes weaverTypes, Write
 
             // Load all the remaining arguments (Ldarg_1, Ldarg_2, ...)
             for (int i = 0; i < md.Parameters.Count; i++)
-                worker.Emit(OpCodes.Ldarg, i + 1); // Ldarg_0 is for 'this.'
+            {
+                // special case: NetworkConnection parameter in command needs to be
+                // filled by the sender's connection on server/host.
+                ParameterDefinition param = md.Parameters[i];
+                if (NetworkBehaviourProcessor.IsSenderConnection(param, RemoteCallType.Command))
+                {
+                    // load 'this.'
+                    worker.Emit(OpCodes.Ldarg_0);
+                    // call get_connectionToClient
+                    worker.Emit(OpCodes.Call, weaverTypes.NetworkBehaviourConnectionToClientReference);
+                }
+                else
+                {
+                    worker.Emit(OpCodes.Ldarg, i + 1); // Ldarg_0 is for 'this.'
+                }
+            }
 
             // Call the original function directly (UserCode_CmdTest__Int32)
             worker.Emit(OpCodes.Call, cmd);

Assets/Mirror/Editor/Weaver/WeaverTypes.cs

@@ -13,6 +13,7 @@ public class WeaverTypes
         public MethodReference NetworkBehaviourIsClientReference;
         public MethodReference NetworkBehaviourIsServerReference;
         public FieldReference NetworkBehaviourDirtyBitsReference;
+        public MethodReference NetworkBehaviourConnectionToClientReference;
         public MethodReference GetWriterReference;
         public MethodReference ReturnWriterReference;
 
@@ -97,6 +98,8 @@ public WeaverTypes(AssemblyDefinition assembly, Logger Log, ref bool WeavingFail
 
             NetworkBehaviourDirtyBitsReference = Resolvers.ResolveField(NetworkBehaviourType, assembly, Log, "syncVarDirtyBits", ref WeavingFailed);
 
+            NetworkBehaviourConnectionToClientReference = Resolvers.ResolveMethod(NetworkBehaviourType, assembly, Log, "get_connectionToClient", ref WeavingFailed);
+
             generatedSyncVarSetter = Resolvers.ResolveMethod(NetworkBehaviourType, assembly, Log, "GeneratedSyncVarSetter", ref WeavingFailed);
             generatedSyncVarSetter_GameObject = Resolvers.ResolveMethod(NetworkBehaviourType, assembly, Log, "GeneratedSyncVarSetter_GameObject", ref WeavingFailed);
             generatedSyncVarSetter_NetworkIdentity = Resolvers.ResolveMethod(NetworkBehaviourType, assembly, Log, "GeneratedSyncVarSetter_NetworkIdentity", ref WeavingFailed);

Assets/Mirror/Tests/Editor/NetworkServer/NetworkServerTest.cs

@@ -35,6 +35,20 @@ public class CommandTestNetworkBehaviour : NetworkBehaviour
         public void TestCommand() => ++called;
     }
 
+    public class CommandWithConnectionToClientNetworkBehaviour : NetworkBehaviour
+    {
+        // counter to make sure that it's called exactly once
+        public int called;
+        public NetworkConnectionToClient conn;
+
+        [Command]
+        public void TestCommand(NetworkConnectionToClient conn = null)
+        {
+            this.conn = conn;
+            ++called;
+        }
+    }
+
     public class RpcTestNetworkBehaviour : NetworkBehaviour
     {
         // counter to make sure that it's called exactly once
@@ -837,6 +851,30 @@ public void SendCommand_RequiresAuthority()
             Assert.That(serverComponent.called, Is.EqualTo(0));
         }
 
+        // [Command] with NetworkConnectionToClient parameter on host should be automatically set to .connectionToClient.
+        // this is what happens in server-only mode too.
+        [Test]
+        public void SendCommand_ConnectionToClient_HostMode()
+        {
+            // listen & connect
+            NetworkServer.Listen(1);
+            ConnectHostClientBlockingAuthenticatedAndReady();
+
+            // add an identity with two networkbehaviour components
+            // spawned, otherwise command handler won't find it in .spawned.
+            // WITH OWNER = WITH AUTHORITY
+            CreateNetworkedAndSpawn(out GameObject _, out NetworkIdentity _, out CommandWithConnectionToClientNetworkBehaviour comp, NetworkServer.localConnection);
+
+            // call the command, which has a 'NetworkConnectionToClient = null' default parameter
+            comp.TestCommand();
+            ProcessMessages();
+
+            // on server it should be != null
+            Assert.That(comp.conn, !Is.Null);
+            Assert.That(comp.conn, Is.EqualTo(comp.connectionToClient));
+            Assert.That(comp.called, Is.EqualTo(1));
+        }
+
         [Test]
         public void SendToAll()
         {