a temporary table has grown out of heap memory reserved for it and 
the remaining disk space is not big enough to store the table as
a MyISAM table.

The crash happens because the function create_myisam_from_heap
does not handle safely the mem_root structure associated 
with the converted table in the case when an error has occurred.


sql/sql_select.cc:
  Fixed bug #28449: a crash may happen at some rare conditions when
  a temporary table has grown out of heap memory reserved for it and 
  the remaining disk space is not big enough to store the table as
  a MyISAM table.
  
  The crash happens because the function create_myisam_from_heap
  does not handle safely the mem_root structure associated 
  with the converted table in the case when an error has occurred.
  
  As it's hard to create a sitiation that would throw an error 
  a special code has been added that raises an error for a newly 
  created test called error_simulation.
mysql-test/r/error_simulation.result:
  New BitKeeper file ``mysql-test/r/error_simulation.result''
  
  Added a test case for bug #28449.
mysql-test/t/error_simulation-master.opt:
  New BitKeeper file ``mysql-test/t/error_simulation-master.opt''
mysql-test/t/error_simulation.test:
  New BitKeeper file ``mysql-test/t/error_simulation.test''
  
  Added a test case for bug #28449.