Respect ConnectTimeout when resetting connection. Fixes #1321

When a connection is opened by retrieving it from the pool, the Connect Timeout option should control how long the call to Open waits for a response from the server.

Author: bgrainger

src/MySqlConnector/Core/ConnectionPool.cs

@@ -17,7 +17,7 @@ internal sealed class ConnectionPool : IDisposable
 
 	public SslProtocols SslProtocols { get; set; }
 
-	public async ValueTask<ServerSession> GetSessionAsync(MySqlConnection connection, int startTickCount, Activity? activity, IOBehavior ioBehavior, CancellationToken cancellationToken)
+	public async ValueTask<ServerSession> GetSessionAsync(MySqlConnection connection, int startTickCount, int timeoutMilliseconds, Activity? activity, IOBehavior ioBehavior, CancellationToken cancellationToken)
 	{
 		cancellationToken.ThrowIfCancellationRequested();
 
@@ -65,9 +65,16 @@ public async ValueTask<ServerSession> GetSessionAsync(MySqlConnection connection
 				else
 				{
 					if (ConnectionSettings.ConnectionReset || session.DatabaseOverride is not null)
+					{
+						if (timeoutMilliseconds != 0)
+							session.SetTimeout(Math.Max(1, timeoutMilliseconds - (Environment.TickCount - startTickCount)));
 						reuseSession = await session.TryResetConnectionAsync(ConnectionSettings, connection, ioBehavior, cancellationToken).ConfigureAwait(false);
+						session.SetTimeout(Constants.InfiniteTimeout);
+					}
 					else
+					{
 						reuseSession = true;
+					}
 				}
 
 				if (!reuseSession)

src/MySqlConnector/MySqlConnection.cs

@@ -926,7 +926,7 @@ private async ValueTask<ServerSession> CreateSessionAsync(ConnectionPool? pool,
 			if (pool is not null)
 			{
 				// this returns an open session
-				return await pool.GetSessionAsync(this, startTickCount, activity, actualIOBehavior, connectToken).ConfigureAwait(false);
+				return await pool.GetSessionAsync(this, startTickCount, connectionSettings.ConnectionTimeoutMilliseconds, activity, actualIOBehavior, connectToken).ConfigureAwait(false);
 			}
 			else
 			{

tests/MySqlConnector.Tests/ConnectionTests.cs

@@ -203,6 +203,21 @@ public void ConnectionTimeout()
 		}
 	}
 
+	[Fact]
+	public void ResetConnectionTimeout()
+	{
+		var csb = new MySqlConnectionStringBuilder(m_csb.ConnectionString);
+		csb.ConnectionTimeout = 4;
+		using var connection = new MySqlConnection(csb.ConnectionString);
+		connection.Open();
+		connection.Close();
+		m_server.ResetDelay = TimeSpan.FromSeconds(10);
+		var stopwatch = Stopwatch.StartNew();
+		var ex = Assert.Throws<MySqlException>(() => connection.Open());
+		Assert.InRange(stopwatch.ElapsedMilliseconds, 3900, 4100);
+		Assert.Equal(MySqlErrorCode.UnableToConnectToHost, (MySqlErrorCode) ex.Number);
+	}
+
 	[Fact]
 	public void ReadInfinity()
 	{

tests/MySqlConnector.Tests/FakeMySqlServer.cs

@@ -54,6 +54,7 @@ public void Stop()
 	public bool SuppressAuthPluginNameTerminatingNull { get; set; }
 	public bool SendIncompletePostHandshakeResponse { get; set; }
 	public bool BlockOnConnect { get; set; }
+	public TimeSpan? ResetDelay { get; set; }
 
 	internal void CancelQuery(int connectionId)
 	{

tests/MySqlConnector.Tests/FakeMySqlServerConnection.cs

@@ -64,7 +64,12 @@ public async Task RunAsync(TcpClient client, CancellationToken token)
 						break;
 
 					case CommandKind.Ping:
+						await SendAsync(stream, 1, WriteOk);
+						break;
+
 					case CommandKind.ResetConnection:
+						if (m_server.ResetDelay is { } resetDelay)
+							await Task.Delay(resetDelay);
 						await SendAsync(stream, 1, WriteOk);
 						break;