Mark session as failed after exception.

This prevents the session from being returned to the pool with potentially-unread data on the network socket.

Author: bgrainger

src/MySqlConnector/MySqlClient/MySqlDataReader.cs

@@ -71,7 +71,14 @@ private void ActivateResultSet(ResultSet resultSet)
 		{
 			if (resultSet.ReadResultSetHeaderException != null)
 			{
-				throw resultSet.ReadResultSetHeaderException is MySqlException mySqlException ?
+				var mySqlException = resultSet.ReadResultSetHeaderException as MySqlException;
+
+				// for any exception not created from an ErrorPayload, mark the session as failed (because we can't guarantee that all data
+				// has been read from the connection and that the socket is still usable)
+				if (mySqlException?.SqlState == null)
+					Command.Connection.Session.SetFailed();
+
+				throw mySqlException != null ?
 					new MySqlException(mySqlException.Number, mySqlException.SqlState, mySqlException.Message, mySqlException) :
 					resultSet.ReadResultSetHeaderException;
 			}

src/MySqlConnector/Serialization/MySqlSession.cs

@@ -142,8 +142,10 @@ public void FinishQuerying()
 
 			lock (m_lock)
 			{
-				VerifyState(State.Querying, State.ClearingPendingCancellation);
-				m_state = State.Connected;
+				if (m_state == State.Querying || m_state == State.ClearingPendingCancellation)
+					m_state = State.Connected;
+				else
+					VerifyState(State.Failed);
 				m_activeCommandId = 0;
 			}
 		}
@@ -788,7 +790,7 @@ private PayloadData TryAsyncContinuation(Task<ArraySegment<byte>> task)
 			return payload;
 		}
 
-		private void SetFailed()
+		internal void SetFailed()
 		{
 			lock (m_lock)
 				m_state = State.Failed;