MySQL Bugs: #5481: ExecuteReader with transactions

Bug #5481	ExecuteReader with transactions
Submitted:	8 Sep 2004 19:42	Modified:	28 Sep 2004 10:09
Reporter:	José Gabriel Paolantonio Cabrera	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	beta 1.0.0	OS:	Windows (Windows XP)
Assigned to:	Reggie Burnett	CPU Architecture:	Any

Description:
I get a null reference exception on line 622 at MySqlClient\command.cs when calling executereader with a transaction, the query is short and has no parameters:
SELECT compra, venta FROM moneda WHERE tipo = 'P'
the line of code that throws the exception is:
else if (c == parameters.ParameterMarker && delim == Char.MinValue && ! escaped)
and the exception refers to the parameters object.
When I disable transactions, it works fine. Also worked fine on ByteFX 0.76.

How to repeat:
Call execute reader with a transaction

Suggested fix:
n/a

I am unable to reproduce this.  Can you post a small code snippet that shows the problem along with your table schema?

Database: MySQL 4.1.4 with INNODB
.NET Framework 1.1 SP1
Connector beta 1.0.0

I isolated (is that correct english?) the code that generates the exception:

using System;
using System.Data;
using MySql.Data.MySqlClient;

namespace ConsoleApplication1
{
	class Class1
	{
		[STAThread]
		static void Main(string[] args)
		{
			IDbTransaction objtransaccion = null;
			IDbConnection cnx = null;
			IDataReader ObjReader = null;
			string opcion = null;
			try
			{
				Console.WriteLine( "1: With transaction\n2: No transaction" );
				opcion = Console.ReadLine();
				cnx = new MySqlConnection( "Connect Timeout=15;Host=josegabriel;Port=3306;Protocol=socket;Logging=false;Allow Batch=true;Initial Catalog=negnet;Persist Security Info=false;User Id=root;Round Zero Datetime=false; Old Syntax=false;" );
				cnx.Open();
				if( opcion == "1" )
				{
					objtransaccion = cnx.BeginTransaction( System.Data.IsolationLevel.Serializable );
					ObjReader = new MySqlCommand( "SELECT compra, venta FROM moneda WHERE tipo = 'P'", (MySqlConnection)cnx, (MySqlTransaction)objtransaccion ).ExecuteReader();
				}
				else
				{	
					ObjReader = new MySqlCommand( "SELECT compra, venta FROM moneda WHERE tipo = 'P'", (MySqlConnection)cnx ).ExecuteReader();
				}
				ObjReader.Close();
				if( opcion == "1" )
					objtransaccion.Commit();
				Console.WriteLine( "NO ERROR" );
				Console.Read();
			}
			catch( Exception ex )
			{
				if( opcion == "1" )
					objtransaccion.Rollback();
				Console.Write( ex.Message + " | " + ex.StackTrace );
				Console.Read();
			}
			finally
			{
				cnx.Close();
			}
		}
	}
}

The table referenced is:

CREATE TABLE moneda (
  id INT UNSIGNED NOT NULL AUTO_INCREMENT,
  descripcion VARCHAR( 50 ) NOT NULL,
  abreviacion VARCHAR( 10 ) NOT NULL,
  compra INT UNSIGNED default NULL,
  venta INT UNSIGNED default NULL,
  tipo CHAR( 1 ) NOT NULL,
  PRIMARY KEY ( id )
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Please tell me if you need more information and thanks for answer

Simpler code:

MySqlConnection cnx = new MySqlConnection( "Connect Timeout=15;Host=josegabriel;Port=3306;Protocol=socket;Logging=false;Allow Batch=true;Initial Catalog=negnet;Persist Security Info=false;User Id=root;Round Zero Datetime=false; Old Syntax=false;" );
cnx.Open();
MySqlTransaction transaccion = cnx.BeginTransaction();
MySqlCommand comando = new MySqlCommand( "SELECT id FROM moneda", cnx, transaccion );
MySqlDataReader reader = comando.ExecuteReader();
reader.Close();
transaccion.Commit();
cnx.Close();

Thank you for your bug report. This issue has been committed to our
source repository of that product and will be incorporated into the
next release.

If necessary, you can access the source repository and build the latest
available version, including the bugfix, yourself. More information 
about accessing the source trees is available at
    http://www.mysql.com/doc/en/Installing_source_tree.html

Additional info:

I have fixed the problematic code as a result of a different bug.  So, this one is fixed.