The issue found with bug 25411 is due to the function skip_rear_comments()
which damages the source code while implementing a work around.
The root cause of the problem is in the lexical analyser, which does not
process special comments properly.
For special comments like :
[1] aaa /*!50000 bbb */ ccc
since 5.0 is a version older that the current code, the parser is in lining
the content of the special comment, so that the query to process is
[2] aaa bbb ccc
However, the text of the query captured when processing a stored procedure,
stored function or trigger (or event in 5.1), can be after rebuilding it:
[3] aaa bbb */ ccc
which is wrong.

To fix bug 25411 properly, the lexical analyser needs to return [2] when
in lining special comments.
In order to implement this, some preliminary cleanup is required in the code,
which is implemented by this patch.

Before this change, the structure named LEX (or st_lex) contains attributes
that belong to lexical analysis, as well as attributes that represents the
abstract syntax tree (AST) of a statement.
Creating a new LEX structure for each statements (which makes sense for the
AST part) also re-initialized the lexical analysis phase each time, which
is conceptually wrong.

With this patch, the previous st_lex structure has been split in two:
- st_lex represents the Abstract Syntax Tree for a statement. The name "lex"
has not been changed to avoid a bigger impact in the code base.
- class lex_input_stream represents the internal state of the lexical
  analyser, which by definition should *not* be reinitialized when parsing
  multiple statements from the same input stream.

This change is a pre-requisite for bug 25411, since the implementation of
lex_input_stream will later improve to deal properly with special comments,
and this processing can not be done with the current implementation of
sp_head::reset_lex and sp_head::restore_lex, which interfere with the lexer.

This change set alone does not fix bug 25411.

into  quadxeon.mysql.com:/benchmarks/ext3/TOSAVE/tsmith/bk/maint/mrg04/50

into  recycle.(none):/src/bug23491_ii/my50-bug23491_ii

into  bodhi.local:/opt/local/work/mysql-5.0-runtime

into  pilot.blaudden:/home/msvensson/mysql/mysql-5.0-maint

into  pilot.blaudden:/home/msvensson/mysql/mysql-5.0-maint

into  pilot.blaudden:/home/msvensson/mysql/mysql-4.1-maint

into  pilot.blaudden:/home/msvensson/mysql/mysql-5.0-maint

Remove the setting of --local-load parameter for mysqlbinlog and leave that to the testcases
to decide what params to use.

into  bk-internal.mysql.com:/data0/bk/mysql-5.0-opt

into  mysql.com:/nfsdisk1/lars/MERGE/mysql-5.0-merge

into  mysql.com:/nfsdisk1/lars/MERGE/mysql-5.0-merge

 - Add --local-load option to avoidthat the load data file requested
   by mysqlbinlog end up in local var/tmp dir and not in system global
   tmpdir

into  mysql.com:/nfsdisk1/lars/MERGE/mysql-5.0-merge

into  bk-internal.mysql.com:/data0/bk/mysql-4.1-opt

conditions.
When allocating memory for KEY_FIELD/SARGABLE_PARAM structures the
function update_ref_and_keys did not take into account the fact that
a single row equality could be replaced by several simple equalities.
Fixed by adjusting the counter cond_count accordingly for each subquery
when performing substitution of a row equality for simple equalities. 
 

into  bk-internal.mysql.com:/data0/bk/mysql-5.0-opt

into  mysql.com:/nfsdisk1/lars/MERGE/mysql-5.0-merge

Pushbuild fixes: 
 - Make MAX_SEL_ARGS smaller (even 16K records_in_range() calls is 
   more than it makes sense to do in typical cases)
 - Don't call sel_arg->test_use_count() if we've already allocated 
   more than MAX_SEL_ARGs elements. The test will succeed but will take
   too much time for the test suite (and not provide much value).

into  mysql.com:/home/kent/bk/tmp/mysql-4.1-build

NO_AUTO_VALUE_ON_ZERO mode.

In the NO_AUTO_VALUE_ON_ZERO mode the table->auto_increment_field_not_null
variable is used to indicate that a non-NULL value was specified by the user
for an auto_increment column. When an INSERT .. ON DUPLICATE updates the
auto_increment field this variable is set to true and stays unchanged for the
next insert operation. This makes the next inserted row sometimes wrongly have
0 as the value of the auto_increment field.

Now the fill_record() function resets the table->auto_increment_field_not_null
variable before filling the record.
The table->auto_increment_field_not_null variable is also reset by the
open_table() function for a case if we missed some auto_increment_field_not_null
handling bug.
Now the table->auto_increment_field_not_null is reset at the end of the
mysql_load() function.

Reset the table->auto_increment_field_not_null variable after each
write_row() call in the copy_data_between_tables() function.

- Read the pid from pidfile in order to be able to kill the real process
instead of the pseudo process. Most platforms will have the same real_pid
as pid
- Kill using the real pid

into  chilla.local:/home/mydev/mysql-5.0-axmrg

into  mysql.com:/home/bar/mysql-5.0.b22638

into  chilla.local:/home/mydev/mysql-5.0-axmrg

into  mysql.com:/home/svoj/devel/mysql/BUG25521/mysql-5.0-engines

into  magare.gmz:/home/kgeorge/mysql/autopush/B26815-5.0-opt

into  recycle.(none):/src/bug23491/my50-bug23491

into  magare.gmz:/home/kgeorge/mysql/autopush/B26815-5.0-opt

 When creating a temporary table the concise column type
 of a string expression is decided based on its length:
 - if its length is under 512 it is stored as either 
   varchar or char.
 - otherwise it is stored as a BLOB.
 
 There is a flag (convert_blob_length) to create_tmp_field 
 that, when >0 allows to force creation of a varchar if the
 max blob length is under convert_blob_length.
 However it must be verified that convert_blob_length 
 (settable through a SQL option in some cases) is 
 under the maximum that can be stored in a varchar column.
 While performing that check for expressions in 
 create_tmp_field_from_item the max length of the blob was
 used instead. This causes blob columns to be created in the
 heap temp table used by GROUP_CONCAT (where blobs must not
 be created in the temp table because of the constant 
 convert_blob_length that is passed to create_tmp_field() ).
 And since these blob columns are not expected in that place
 we get wrong results.
 Fixed by checking that the value of the flag variable is 
 in the limits that fit into VARCHAR instead of the max length
 of the blob column.

into  pilot.blaudden:/home/msvensson/mysql/mysql-5.0-maint

into  pilot.blaudden:/home/msvensson/mysql/mysql-4.1-maint