This bug is actually two. The first one manifests itself on an EXPLAIN
SELECT query with nested subqueries that employs the filesort algorithm.
The whole SELECT under explain is marked as UNCACHEABLE_EXPLAIN to preserve
some temporary structures for explain. As a side-effect of this values of
nested subqueries weren't cached and subqueries were re-evaluated many
times. Each time buffer for filesort was allocated but wasn't freed because
freeing occurs at the end of topmost SELECT. Thus all available memory was
eaten up step by step and OOM event occur.
The second bug manifests itself on SELECT queries with conditions where
a subquery result is compared with a key field and the subquery itself also
has such condition. When a long chain of such nested subqueries is present
the stack overrun occur. This happens because at some point the range optimizer
temporary puts the PARAM structure on the stack. Its size if about 8K and
the stack is exhausted very fast.

Now the subselect_single_select_engine::exec function allows subquery result
caching when the UNCACHEABLE_EXPLAIN flag is set.
Now the SQL_SELECT::test_quick_select function calls the check_stack_overrun
function for stack checking purposes to prevent server crash.

into  mysql.com:/home/psergey/mysql-5.0-bug31450

- Let Item::save_in_field() call set_field_to_null_with_conversions() 
  for decimal type, like this is done for the other item result types.

into  mysql.com:/home/gluh/MySQL/Merge/5.0-opt

into  mysql.com:/home/gluh/MySQL/Merge/5.0-opt

into  mysql.com:/home/hf/work/30638/my50-30638

into  polly.(none):/home/kaa/src/opt/mysql-5.0-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/B30825-new-5.0-opt

into  polly.(none):/home/kaa/src/opt/mysql-5.0-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/B30825-new-5.0-opt

into  mysql.com:/home/hf/work/30638/my50-30638

into  magare.gmz:/home/kgeorge/mysql/autopush/B30825-new-5.0-opt

into  mysql.com:/home/hf/work/30638/my50-30638

into  mysql.com:/home/gluh/MySQL/Merge/4.1-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/B30825-new-5.0-opt

When doing indexed search the server constructs a key image for 
faster comparison to the stored keys. While doing that it must not
perform (and stop if they fail) the additional date checks that can 
be turned on by the SQL mode because there already may be values in 
the table that don't comply with the error checks.
Fixed by ignoring these SQL mode bits while making the key image.

an error, asserts server

In case of a fatal error during filesort in find_all_keys() the error
was returned without the necessary handler uninitialization.
Fixed by changing the code so that handler uninitialization is performed
before returning the error.

into  mysql.com:/home/hf/work/30638/my50-30638

into  mysql.com:/home/hf/work/30638/my50-30638

into  mysql.com:/scratch/tnurnberg/31588/50-31588

into  polly.(none):/home/kaa/src/opt/mysql-5.0-opt

  
Since, as of MySQL 5.0.15, CHAR() arguments larger than 255 are converted into multiple result bytes, a single CHAR() argument can now take up to 4 bytes. This patch fixes Item_func_char::fix_length_and_dec() to take this into account.
  
This patch also fixes a regression introduced by the patch for bug21513. As now we do not always have the 'name' member of Item set for Item_hex_string and Item_bin_string, an own print() method has been added to Item_hex_string so that it could correctly be printed by Item_func::print_args().

into  anubis.xiphis.org:/usr/home/antony/work/mysql-5.0-engines.merge

into  anubis.xiphis.org:/usr/home/antony/work/mysql-5.0-engines.merge

into  anubis.xiphis.org:/usr/home/antony/work/mysql-4.1-engines.merge

into  lambda.hsd1.co.comcast.net.:/home/malff/TREE/mysql-5.0-rt-merge

into  mysql.com:/scratch/tnurnberg/31588/50-31588

into  magare.gmz:/home/kgeorge/mysql/autopush/B31221-5.0-opt

 No warning was generated when a TIMESTAMP with a non-zero time part
 was converted to a DATE value. This caused index lookup to assume
 that this is a valid conversion and was returning rows that match 
 a comparison between a TIMESTAMP value and a DATE keypart.
 Fixed by generating a warning on such a truncation.

The BIG_TABLES define wasn't enabled on Windows.
#define added

into  sin.intern.azundris.com:/misc/mysql/31588/41-31588

into  sin.intern.azundris.com:/misc/mysql/31588/50-31588

Buffer used when setting variables was not dimensioned to accomodate
trailing '\0'. An overflow by one character was therefore possible.
CS corrects limits to prevent such overflows.

    
Previously, UDF *_init functions were passed constant strings with erroneous lengths. The length came from the containing variable's size, not the length of the value itself.
    
Now the *_init functions get the constant as a null terminated string with the correct length supplied too.

in middle of block)

updated result files