Catch only I/O exceptions thrown from ResetConnectionAsync.

Catching all exceptions could mask a programming error introduced in ResetConnectionAsync, with the side-effect of silently disabling connection pooling.

Author: bgrainger

src/MySqlConnector/MySqlClient/ConnectionPool.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Threading;
@@ -50,17 +50,7 @@ public async Task<MySqlSession> GetSessionAsync(MySqlConnection connection, IOBe
 					{
 						if (m_connectionSettings.ConnectionReset)
 						{
-							try
-							{
-								// Depending on the server (Aurora?), this can randomly fail when re-authenticating to the server.
-								// If it does, we can just pretend it didn't happen and continue with creating a new session below.
-								await session.ResetConnectionAsync(m_connectionSettings, ioBehavior, cancellationToken).ConfigureAwait(false);
-								reuseSession = true;
-							}
-							catch (Exception)
-							{
-								reuseSession = false;
-							}
+							reuseSession = await session.TryResetConnectionAsync(m_connectionSettings, ioBehavior, cancellationToken).ConfigureAwait(false);
 						}
 						else
 						{

src/MySqlConnector/Serialization/MySqlSession.cs

@@ -257,7 +257,7 @@ public async Task ConnectAsync(ConnectionSettings cs, IOBehavior ioBehavior, Can
 				m_payloadHandler = new CompressedPayloadHandler(m_payloadHandler.ByteHandler);
 		}
 
-		public async Task ResetConnectionAsync(ConnectionSettings cs, IOBehavior ioBehavior, CancellationToken cancellationToken)
+		private async Task ResetConnectionAsync(ConnectionSettings cs, IOBehavior ioBehavior, CancellationToken cancellationToken)
 		{
 			VerifyState(State.Connected);
 			if (ServerVersion.Version.CompareTo(ServerVersions.SupportsResetConnection) >= 0)
@@ -288,6 +288,26 @@ public async Task ResetConnectionAsync(ConnectionSettings cs, IOBehavior ioBehav
 			}
 		}
 
+		public async Task<bool> TryResetConnectionAsync(ConnectionSettings cs, IOBehavior ioBehavior, CancellationToken cancellationToken)
+		{
+			try
+			{
+				await ResetConnectionAsync(cs, ioBehavior, cancellationToken).ConfigureAwait(false);
+				return true;
+			}
+			catch (EndOfStreamException)
+			{
+			}
+			catch (IOException)
+			{
+			}
+			catch (SocketException)
+			{
+			}
+
+			return false;
+		}
+
 		private async Task SwitchAuthenticationAsync(ConnectionSettings cs, PayloadData payload, IOBehavior ioBehavior, CancellationToken cancellationToken)
 		{
 			// if the server didn't support the hashed password; rehash with the new challenge