Wikimedia Bugzilla is closed!

In Database.php, the fetchObject, fetchRow, and numRows functions all call
mysql_errno() without a parameter.  The functions should instead call
$this->lastErrno(), like the following:

if ( $this->lastErrno() ) { ... }

The reason is that mysql_errno() without a parameter will return the most recent
mysql error, not necessarily belonging to the mysql connection used by the
Database class.  If there are multiple mysql connection resources in one
instance of MediaWiki, possibly through an extension, and one of these triggers
an error, then MediaWiki will crash on the next database query.