Don't AutoEnlist cancellation connection. Fixes #1001

Author: bgrainger

src/MySqlConnector/MySqlConnection.cs

@@ -707,8 +707,11 @@ internal void Cancel(ICancellableCommand command, int commandId, bool isCancel)
 			try
 			{
 				// open a dedicated connection to the server to kill the active query
-				var csb = new MySqlConnectionStringBuilder(m_connectionString);
-				csb.Pooling = false;
+				var csb = new MySqlConnectionStringBuilder(m_connectionString)
+				{
+					AutoEnlist = false,
+					Pooling = false,
+				};
 				if (m_session.IPAddress is not null)
 					csb.Server = m_session.IPAddress.ToString();
 				var cancellationTimeout = GetConnectionSettings().CancellationTimeout;

tests/SideBySide/TransactionScopeTests.cs

@@ -656,6 +656,19 @@ public async Task CommandBehaviorCloseConnection(string connectionString)
 			}
 		}
 
+		[Theory]
+		[MemberData(nameof(ConnectionStrings))]
+		public async Task CancelExecuteNonQueryAsync(string connectionString)
+		{
+			using var connection = new MySqlConnection(AppConfig.ConnectionString + ";" + connectionString);
+			using var transactionScope = new TransactionScope(TransactionScopeAsyncFlowOption.Enabled);
+			await connection.OpenAsync();
+
+			using var command = new MySqlCommand("DO SLEEP(3);", connection);
+			using var tokenSource = new CancellationTokenSource(TimeSpan.FromMilliseconds(100));
+			await command.ExecuteNonQueryAsync(tokenSource.Token);
+		}
+
 		[SkippableFact(Baseline = "Multiple simultaneous connections or connections with different connection strings inside the same transaction are not currently supported.")]
 		public void CommitTwoTransactions()
 		{