InvalidOperationException thrown while opening a connection

[ddunkin]

System.InvalidOperationException: The operation is not allowed on non-connected sockets.
   at System.Net.Sockets.TcpClient.GetStream()
   at MySqlConnector.Core.ServerSession.<OpenTcpSocketAsync>d__69.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Core.ServerSession.<ConnectAsync>d__56.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySqlConnector.Core.ConnectionPool.<GetSessionAsync>d__6.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1.ConfiguredValueTaskAwaiter.GetResult()
   at MySql.Data.MySqlClient.MySqlConnection.<CreateSessionAsync>d__83.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1.ConfiguredValueTaskAwaiter.GetResult()
   at MySql.Data.MySqlClient.MySqlConnection.<OpenAsync>d__25.MoveNext()

Running MySqlConnector 0.36.1 on .NET Framework 4.7.

This network occasionally has connectivity problems.

[bgrainger]

AFAICT, tcpClient.ConnectAsync (

MySqlConnector/src/MySqlConnector/Core/ServerSession.cs

Line 703 in c175893

await tcpClient.ConnectAsync(ipAddress, cs.Port).ConfigureAwait(false);

) succeeded (no SocketException was thrown) but then tcpClient.Client.Connected was false (so GetStream threw). The most likely explanation seems to be that there's a race with the callback passed to cancellationToken.Register and it closed the socket after ConnectAsync completed successfully.

We should check m_socket.Connected and throw a MySqlException.

[bgrainger]

Fixed in 0.40.0.