OpenAsync throws System.IO.EndOfStreamException

[alanprot]

Sometimes i'm receiving EndOfStreamException when calling _con.OpenAsync(cancellationToken) maybe due a timeout.

System.AggregateException: One or more errors occurred. (Attempted to read past the end of the stream.) ---> System.IO.EndOfStreamException: Attempted to read past the end of the stream.
   --- End of inner exception stack trace ---
   at System.Threading.Tasks.Task.ThrowIfExceptional(Boolean includeTaskCanceledExceptions)
   at System.Threading.Tasks.Task`1.GetResultCore(Boolean waitCompletionNotification)
   at MySql.Data.ValueTaskExtensions.<>c__DisplayClass0_0`2.<ContinueWith>b__0(Task`1 task)
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.Serialization.MySqlSession.TryAsyncContinuation(Task`1 task)
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
   at System.Threading.Tasks.Task.Execute()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()
   at System.Runtime.CompilerServices.ConfiguredValueTaskAwaitable`1.ConfiguredValueTaskAwaiter.GetResult()
   at MySql.Data.Serialization.MySqlSession.<TryPingAsync>d__24.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.MySqlClient.ConnectionPool.<GetSessionAsync>d__0.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.MySqlClient.MySqlConnection.<CreateSessionAsync>d__54.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at MySql.Data.MySqlClient.MySqlConnection.<OpenAsync>d__11.MoveNext()

I notice that this exception is handled at:

https://github.com/mysql-net/MySqlConnector/blob/master/src/MySqlConnector/Serialization/MySqlSession.cs#L140

        public async Task<bool> TryPingAsync(IOBehavior ioBehavior, CancellationToken cancellationToken)
        {
            await SendAsync(PingPayload.Create(), ioBehavior, cancellationToken).ConfigureAwait(false);
            try
            {
                var payload = await ReceiveReplyAsync(ioBehavior, cancellationToken).ConfigureAwait(false);
                OkPayload.Create(payload);
                return true;
            }
            catch (EndOfStreamException)
            {
            }
            catch (SocketException)
            {
            }

            return false;
        }

Maybe await SendAsync(PingPayload.Create(), ioBehavior, cancellationToken).ConfigureAwait(false); should be inside try catch to?

[alanprot]

I believe that because of that it was not possible to Dispose and remove some bad connection of my Connection Pool.

https://github.com/mysql-net/MySqlConnector/blob/master/src/MySqlConnector/MySqlClient/ConnectionPool.cs#L29

[caleblloyd]

Looks like the problem is that System.AggregateException is getting thrown, and not caught in TryPingAsync

[alanprot]

Yes...
I missed that!

[bgrainger]

Fixed in 0.6.1.

I wasn't able to reproduce the precise crash (in the original call stack you posted), but I did fix the problem of EndOfStreamException (or any exception) being unnecessarily wrapped inside AggregateException. Fixing this should allow the exception to go through the regular exception-handling code path, which should resolve your issue. If it's not fixed, please reopen this case!

[GomesNayagam]

[bgrainger] Moved to #388.