MySQL Bugs: #39294: Reading negative time value greater than -01:00:00 return positive value

Bug #39294	Reading negative time value greater than -01:00:00 return positive value
Submitted:	7 Sep 2008 12:59	Modified:	15 Sep 2008 15:00
Reporter:	Michal Minárik	Email Updates:
Status:	Closed	Impact on me:	None
Category:	Connector / NET	Severity:	S2 (Serious)
Version:	5.2.3	OS:	Windows (Vista 32-bit)
Assigned to:		CPU Architecture:	Any
Tags:	time negative select

Description:
Reading negative time value greater than -01:00:00 return positive value (absolute value of the original time value).

How to repeat:
-- SQL

DROP TABLE IF EXISTS test;

CREATE TABLE `test` (
`id` int(11) NOT NULL auto_increment,
`time` time NOT NULL default '00:00:00',
PRIMARY KEY  (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;

INSERT INTO `my_db`.`test` (`time`) VALUES ('-00:10:00');

-- C#

MySqlCommand command = new MySqlCommand();
command.Connection = conn;
command.CommandType = CommandType.Text;
command.CommandText = "SELECT time FROM test";
using (MySqlDataReader reader = command.ExecuteReader())
{
  reader.Read();
  TimeSpan time = reader.GetTimeSpan(reader.GetOrdinal("time"));
  // time is 00:10:00
}

Suggested fix:
The definition of MySqlTime.ParseMySql(...) could be:

private void ParseMySql(string s, bool is41)
{
  string[] parts = s.Split(':');
  int hours = Int32.Parse(parts[0]);
  int mins = Int32.Parse(parts[1]);
  int secs = Int32.Parse(parts[2]);

  if (hours < 0 || parts[0].StartsWith("-"))
  {
    mins *= -1;
    secs *= -1;
  }

  int days = hours / 24;
  hours = hours - (days * 24);
  mValue = new TimeSpan(days, hours, mins, secs, 0);
  isNull = false;
}

Hi Michal and thanks for your report.

Truly there is a bug and it can be seen just by looking into code. I suppose fix for Bug#25912 was incomplete.

A patch for this bug has been committed. After review, it may
be pushed to the relevant source trees for release in the next
version. You can access the patch from:

  http://lists.mysql.com/commits/53539

fixed in 5.2.4

Added an entry to the 5.2.4 changelog:

Reading a negative time value greater than -01:00:00 returned the absolute value of the original time value.