Fix sending to another client from OnConnectedAsync

src/SignalR/server/Core/src/Internal/HubCallerClients.cs

@@ -50,7 +50,7 @@ public ISingleClientProxy Client(string connectionId)
     {
         if (!InvokeAllowed)
         {
-            return new NoInvokeSingleClientProxy(_hubClients.Client(_connectionId));
+            return new NoInvokeSingleClientProxy(_hubClients.Client(connectionId));
         }
         return new SingleClientProxy(_hubClients.Client(connectionId), this);
     }

src/SignalR/server/SignalR/test/HubConnectionHandlerTestUtils/Hubs.cs

@@ -1396,3 +1396,15 @@ public void ManyParams(int a1, string a2, bool a3, float a4, string a5, int a6,
         int a64, [FromService] Service1 service)
     { }
 }
+
+public class OnConnectedSendToClientHub : Hub
+{
+    public override async Task OnConnectedAsync()
+    {
+        string id = Context.GetHttpContext()?.Request.Query["client"] ?? string.Empty;
+        if (!string.IsNullOrEmpty(id))
+        {
+            await Clients.Client(id).SendAsync("Test", 1);
+        }
+    }
+}

src/SignalR/server/SignalR/test/HubConnectionHandlerTests.cs

@@ -4891,6 +4891,39 @@ public void TooManyParametersWithServiceThrows()
             () => serviceProvider.GetService<HubConnectionHandler<TooManyParamsHub>>());
     }
 
+    [Fact]
+    public async Task SendToAnotherClientFromOnConnectedAsync()
+    {
+        var serviceProvider = HubConnectionHandlerTestUtils.CreateServiceProvider(provider =>
+        {
+            provider.AddSignalR(options =>
+            {
+                options.EnableDetailedErrors = true;
+            });
+        });
+        var connectionHandler = serviceProvider.GetService<HubConnectionHandler<OnConnectedSendToClientHub>>();
+
+        using (var client1 = new TestClient())
+        using (var client2 = new TestClient())
+        {
+            var httpContext = new DefaultHttpContext();
+            httpContext.Request.QueryString = new QueryString($"?client={client1.Connection.ConnectionId}");
+            var feature = new TestHttpContextFeature
+            {
+                HttpContext = httpContext
+            };
+            client2.Connection.Features.Set<IHttpContextFeature>(feature);
+
+            var connectionHandlerTask = await client1.ConnectAsync(connectionHandler).DefaultTimeout();
+            _ = await client2.ConnectAsync(connectionHandler).DefaultTimeout();
+
+            var message = Assert.IsType<InvocationMessage>(await client1.ReadAsync().DefaultTimeout());
+            Assert.Single(message.Arguments);
+            Assert.Equal(1L, message.Arguments[0]);
+            Assert.Equal("Test", message.Target);
+        }
+    }
+
     private class CustomHubActivator<THub> : IHubActivator<THub> where THub : Hub
     {
         public int ReleaseCount;