- In some cases, flow control optimization implemented in sp::optimize
    removes hreturn instructions, causing SQL exception handlers to:
      * never return
      * execute wrong logic
  - This patch overrides default short cut optimization on hreturn instructions
    to avoid this problem.

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-25411_d

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  blade09.mysql.com:/tmp/mmj/mysql-5.0-runtime

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

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-rt-merge

into  gshchepa.loc:/home/uchum/work/bk-trees/mysql-5.0-opt-27704

into  gshchepa.loc:/home/uchum/work/bk-trees/mysql-5.0-opt-27704

Support for NULL components was incomplete for row comparison,
fixed.  Added support for abort_on_null at compare_row() like
in 5.x

into  magare.gmz:/home/kgeorge/mysql/autopush/B27786-5.0-opt

This bug was intruduced by the fix for bug#17212 (in 4.1). It is not 
ok to call test_if_skip_sort_order since this function will 
alter the execution plan. By contract it is not ok to call 
test_if_skip_sort_order in this context.

This bug appears only in the case when the optimizer has chosen 
an index for accessing a particular table but finds a covering 
index that enables it to skip ORDER BY. This happens in 
test_if_skip_sort_order.

into  romeo.(none):/home/bk/merge-mysql-5.0

into  romeo.(none):/home/bkroot/mysql-5.0-rpl

When merging views into the enclosing statement
the ORDER BY clause of the view is merged to the
parent's ORDER BY clause.
However when the VIEW is merged into an UNION
branch the ORDER BY should be ignored. 
Use of ORDER BY for individual SELECT statements
implies nothing about the order in which the rows
appear in the final result because UNION by default
produces unordered set of rows.
Fixed by ignoring the ORDER BY clause from the merge
view when expanded in an UNION branch.

into  magare.gmz:/home/kgeorge/mysql/autopush/B27530-5.0-opt

They can drop table after table names list creation and before table opening.
We open non existing table and get ER_NO_SUCH_TABLE error.
In this case we do not store the record into I_S table and clear error.

conditions when executing an equijoin query with WHERE condition
containing a subquery predicate of the form join_attr NOT IN (SELECT ...).

To resolve a problem of the correct evaluation of the expression
  attr NOT IN (SELECT ...)
an array of guards is created to make it possible to filter out some 
predicates of the EXISTS subquery into which the original subquery 
predicate is transformed, in the cases when a takes the NULL value. 
If attr is defined as a field that cannot be NULL than such an array 
is not needed and is not created. 
However if the field a occurred also an an equijoin predicate t2.a=t1.b
and table t1 is accessed before table t2 then it may happen that the 
the EXISTS subquery is pushed down to the condition evaluated just after
table t1 has been accessed. In this case any occurrence of t2.a is 
substituted for t1.b. When t1.b takes the value of NULL an attempt is 
made to turn on the corresponding guard. This action caused a crash as 
no guard array had been created.

Now the code of Item_in_subselect::set_cond_guard_var checks that the guard
array has been created before setting a guard variable on. Otherwise the
method does nothing. It cannot results in returning a row that could be
rejected as the condition t2.a=t1.b will be checked later anyway.        

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

into  weblab.(none):/home/marcsql/TREE/mysql-5.0-rt-merge

  Fix warning after fix for bug#27321.

  After merge fix.

into  moonbone.local:/mnt/gentoo64/work/27321-bug-5.0-opt-mysql

The Item_outer_ref class based on the Item_direct_ref class was always used
to represent an outer field. But if the outer select is a grouping one and the 
outer field isn't under an aggregate function which is aggregated in that
outer select an Item_ref object should be used to represent such a field.
If the outer select in which the outer field is resolved isn't grouping then
the Item_field class should be used to represent such a field.
This logic also should be used for an outer field resolved through its alias
name.

Now the Item_field::fix_outer_field() uses Item_outer_field objects to
represent aliased and non-aliased outer fields for grouping outer selects
only.
Now the fix_inner_refs() function chooses which class to use to access outer
field - the Item_ref or the Item_direct_ref. An object of the chosen class
substitutes the original field in the Item_outer_ref object.
The direct_ref and the found_in_select_list fields were added to the
Item_outer_ref class.

into  vajra.(none):/opt/local/work/mysql-5.0-runtime

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  mysql.com:/d2/hf/mrg/mysql-5.0-opt

into  mysql.com:/d2/hf/mrg/mysql-4.1-opt

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-opt

into  a88-113-38-195.elisa-laajakaista.fi:/home/my/new/mysql-5.0-marvel

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-opt

into  a88-113-38-195.elisa-laajakaista.fi:/home/my/new/mysql-5.0-marvel

into  a88-113-38-195.elisa-laajakaista.fi:/home/my/new/mysql-4.1-main

into  mysql.com:/home/bar/mysql-5.0.b20095

Problem: single byte do_varstring1() function was called, which didn't
check limit on "number of character", and checked only "number of bytes".
Fix: adding a multi-byte aware function do_varstring1_mb(),
to limit on "number of characters"

- autoincrement column of size medium int not handled in ndb_restore
- added testcase also for other types, tiny, small... etc

into  gshchepa.localdomain:/home/uchum/work/bk-trees/5507-ci

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.0-opt