Incomplete Dispose of WatsonTCPServer

[sancheolz]

This test fails starting from 6.0 version of WatsonTCP:

var server = new WatsonTcpServer("127.0.0.1", 9000);
server.Events.MessageReceived += (_, _) => { Console.WriteLine("srecv"); };
server.Start();
var client = new WatsonTcpClient("127.0.0.1", 9000);
client.Events.MessageReceived += (_, _) => { Console.WriteLine("crecv"); };
client.Connect();
Task.Run(() => { client.SendAsync("aaa"); });
server.Dispose();

It throws

System.AggregateException : One or more errors occurred. (A task was canceled.)
  ----> System.Threading.Tasks.TaskCanceledException : A task was canceled.
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken)
   at System.Threading.Tasks.Task.Wait()
   at WatsonTcp.WatsonTcpServer.Dispose(Boolean disposing) in WatsonTcpServer.cs:line 621

[ShayanFiroozi]

Hi ,

Task.Run(() => { client.SendAsync("aaa"); });

You are executing the SendAsync in the Fire And Forget Task !

Which means the server.Dispose() will be called Before the completion of SendAsync.

Try this two options :

client.SendAsync("aaa").GetAwaiter.GetResult(); ( without Task.Run) and see what happens.

Or

await client.SendAsync("aaa");

Hope this helps.👍

[sancheolz]

@ShayanFiroozi Hi. The client can be on another machine and send messages independently from the server. This example simulates such a scenario. So waiting doesn't make sense.

[jchristn]

Moving this to discussion. The right approach is to await the client.SendAsync so that it has to complete before the server is disposed.

[sancheolz]

Adding await will fix this test, but it won't fix the real-world scenario where the client is on a different host. I think the issue is that the server is still processing the incoming packet, and at that moment, the server's Dispose is being called. I expect the server's Dispose to not throw an exception, regardless of when it is called - either while the incoming message is being processed or when there are no messages. This is one of the rules for writing Dispose - it should not throw exceptions.