There are two problems with ROUND(X, D) on an exact numeric 
(DECIMAL, NUMERIC type) field of a table:
1) The implementation of the ROUND function would change the number of decimal
places regardless of the value decided upon in fix_length_and_dec. When the
number of decimal places is not constant, this would cause an inconsistent
state where the number of digits was less than the number of decimal places,
which crashes filesort.

Fixed by not allowing the ROUND operation to add any more decimal places than
was decided in fix_length_and_dec.

2) fix_length_and_dec would allow the number of decimals to be greater than
the maximium configured value for constant values of D. This led to the same 
crash as in (1).

Fixed by not allowing the above in fix_length_and_dec.

The fix is a copy of Martin Friebe's suggestion.
added testing for no_appended which will be false if anything,
including the empty string is in result

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

into  gleb.loc:/home/uchum/work/bk/5.0-opt

into  magare.gmz:/home/kgeorge/mysql/autopush/B30715-merged-5.0-opt

into  gleb.loc:/home/uchum/work/bk/5.0-opt

into  mysql.com:/misc/mysql/31662/50-31662

SHOW FIELDS FROM a view with no valid definer was possible (since fix
for Bug#26817), but gave NULL as a field-type. This led to mysqldump-ing
of such views being successful, but loading such a dump with the client
failing. Patch allows SHOW FIELDS to give data-type of field in underlying
table.

doesn't recognize it

This is a 5.0 version of the patch, it will be null-merged to 5.1

Problem:

'log' and 'log_slow_queries' were "fixed" variables, i.e. they showed up
in SHOW VARIABLES, but could not be used in expressions like 
"select @@log". Also, using them in the SET statement produced an 
incorrect "unknown system variable" error.

Solution:

Make 'log' and 'log_slow_queries' read-only dynamic variables to make 
them available for use in expressions, and produce a correct error 
about the variable being read-only when used in the SET statement.

all space column names.

The parser has been modified to check VIEW column names
with the check_column_name function and to report an error
on empty and all space column names (same as for TABLE
column names).

into  magare.gmz:/home/kgeorge/mysql/work/B30715-merged-5.0-opt

  file .\opt_sum.cc, line
The optimizer pre-calculates the MIN/MAX values for queries like
 SELECT MIN(kp_k) WHERE kp_1 = const AND ... AND kp_k-1 = const
when there is a key over kp_1...kp_k
In doing so it was not checking correctly nullability and 
there was a superfluous assert(). 
Fixed by making sure that the field can be null before checking and
taking out the wrong assert().
.
Introduced a correct check for nullability 
The MIN(field) can return NULL when all the row values in the group
are NULL-able or if there were no rows.
Fixed the assertion to reflect the case when there are no rows.

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

in the SELECT INTO OUTFILE clause starts with a special
character (one of n, t, r, b, 0, Z or N) and ENCLOSED BY
is empty, every occurrence of this character within a
field value is duplicated.

Duplication has been avoided.
New warning message has been added: "First character of
the FIELDS TERMINATED string is ambiguous; please use
non-optional and non-empty FIELDS ENCLOSED BY".

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().