Use ambient transaction in bulk loader. Fixes #300

Author: bgrainger

src/MySqlConnector/MySql.Data.MySqlClient/MySqlBulkLoader.cs

@@ -22,7 +22,6 @@ public sealed class MySqlBulkLoader
         public List<string> Columns { get; }
         public MySqlBulkLoaderConflictOption ConflictOption { get; set; }
         public MySqlConnection Connection { get; set; }
-		public MySqlTransaction Transaction { get; set; }
         public char EscapeCharacter { get; set; }
         public List<string> Expressions { get; }
         public char FieldQuotationCharacter { get; set; }
@@ -60,7 +59,6 @@ public MySqlBulkLoader(MySqlConnection connection)
             ConflictOption = MySqlBulkLoaderConflictOption.None;
             Columns = new List<string>();
             Expressions = new List<string>();
-	        Transaction = connection.CurrentTransaction;
         }
 
         private string BuildSqlCommand()
@@ -186,11 +184,11 @@ private async Task<int> LoadAsync(IOBehavior ioBehavior, CancellationToken cance
                 closeConnection = true;
                 Connection.Open();
             }
-            
+
             try
             {
                 var commandString = BuildSqlCommand();
-                var cmd = new MySqlCommand(commandString, Connection, Transaction)
+                var cmd = new MySqlCommand(commandString, Connection, Connection.CurrentTransaction)
                 {
                     CommandTimeout = Timeout,
                 };

tests/SideBySide/BulkLoaderSync.cs

@@ -245,6 +245,42 @@ public void BulkLoadLocalCsvFileInTransactionWithCommit()
 			}
 		}
 
+		[Fact]
+		public void BulkLoadLocalCsvFileBeforeTransactionWithCommit()
+		{
+			try
+			{
+				m_database.Connection.Open();
+				var bulkLoader = new MySqlBulkLoader(m_database.Connection)
+				{
+					FileName = AppConfig.MySqlBulkLoaderLocalCsvFile,
+					TableName = m_testTable,
+					CharacterSet = "UTF8",
+					NumberOfLinesToSkip = 1,
+					FieldTerminator = ",",
+					FieldQuotationCharacter = '"',
+					FieldQuotationOptional = true,
+					Local = true,
+				};
+				bulkLoader.Expressions.Add("five = UNHEX(five)");
+				bulkLoader.Columns.AddRange(new[] { "one", "two", "three", "four", "five" });
+
+				using (var transaction = m_database.Connection.BeginTransaction())
+				{
+					var rowCount = bulkLoader.Load();
+					Assert.Equal(20, rowCount);
+
+					transaction.Commit();
+				}
+
+				Assert.Equal(20, m_database.Connection.ExecuteScalar<int>($@"select count(*) from {m_testTable};"));
+			}
+			finally
+			{
+				m_database.Connection.Close();
+			}
+		}
+
 		[Fact]
 		public void BulkLoadLocalCsvFileInTransactionWithRollback()
 		{
@@ -281,6 +317,42 @@ public void BulkLoadLocalCsvFileInTransactionWithRollback()
 			}
 		}
 
+		[Fact]
+		public void BulkLoadLocalCsvFileBeforeTransactionWithRollback()
+		{
+			try
+			{
+				m_database.Connection.Open();
+				var bulkLoader = new MySqlBulkLoader(m_database.Connection)
+				{
+					FileName = AppConfig.MySqlBulkLoaderLocalCsvFile,
+					TableName = m_testTable,
+					CharacterSet = "UTF8",
+					NumberOfLinesToSkip = 1,
+					FieldTerminator = ",",
+					FieldQuotationCharacter = '"',
+					FieldQuotationOptional = true,
+					Local = true,
+				};
+				bulkLoader.Expressions.Add("five = UNHEX(five)");
+				bulkLoader.Columns.AddRange(new[] { "one", "two", "three", "four", "five" });
+
+				using (var transaction = m_database.Connection.BeginTransaction())
+				{
+					var rowCount = bulkLoader.Load();
+					Assert.Equal(20, rowCount);
+
+					transaction.Rollback();
+				}
+
+				Assert.Equal(0, m_database.Connection.ExecuteScalar<int>($@"select count(*) from {m_testTable};"));
+			}
+			finally
+			{
+				m_database.Connection.Close();
+			}
+		}
+
 		[Fact]
 		public void BulkLoadMissingFileName()
 		{