enable uncacheable flag if we update a view with check option
and check option has a subselect, otherwise, the check option
can be evaluated after the subselect was freed as independent
(See full_local in JOIN::join_free())


mysql-test/r/subselect.result:
  test result
mysql-test/t/subselect.test:
  test case
sql/mysql_priv.h:
  added UNCACHEABLE_CHECKOPTION flag
sql/sql_update.cc:
  enable uncacheable flag if we update a view with check option
  and check option has a subselect, otherwise, the check option
  can be evaluated after the subselect was freed as independent
  (See full_local in JOIN::join_free())

the problem is the same as reported in bug#20835,
so the fix is backport of bug#20835 patch.


mysql-test/r/subselect.result:
  test result
mysql-test/t/subselect.test:
  test case

      
When switching to indexed ORDER BY we must be sure to reset the index read
flag if we are switching from a covering index to non-covering.

mysql-test/r/subselect.result:
  Bug#37548: test case
mysql-test/t/subselect.test:
  Bug#37548: test case
sql/sql_select.cc:
  Bug#37548: update the index read flag if the index for indexed ORDER BY is not
      covering.

Calling List<Cached_item>::delete_elements for the same list twice
caused a crash of the server in the function JOIN::cleaunup.
Ensured that delete_elements() in JOIN::cleanup would be called only once.


mysql-test/r/subselect.result:
  Added a test case for bug #38191.
mysql-test/t/subselect.test:
  Added a test case for bug #38191.
sql/sql_select.cc:
  Fixed bug #38191.
  Ensured that delete_elements() in JOIN::cleanup would be called only once.

 - moved the test into a separate file to check for presence of the test variable

mysql-test/r/subselect.result:
  Bug#37627: moved the test to a separate file
mysql-test/r/subselect_debug.result:
  Bug#37627: moved the test to a separate file
mysql-test/t/subselect.test:
  Bug#37627: moved the test to a separate file
mysql-test/t/subselect_debug.test:
  Bug#37627: moved the test to a separate file

When there is an error executing EXISTS predicates they return NULL as their string
or decimal value but don't set the NULL value flag.
Fixed by returning 0 (as a decimal or a string) on error exectuting the subquery.
Note that we can't return NULL as EXISTS is not supposed to return NULL.

mysql-test/r/subselect.result:
  Bug#37627: test case
mysql-test/t/subselect.test:
  Bug#37627: test case
sql/item_subselect.cc:
  Bug#37627: return decimal (or string) 0 isntead of a NULL pointer on
  error calculating an EXISTS predicate.

Bug#37492 timing bug in subselect.test
+ similar weaknesses found during testing
+ replace error numbers by error names

The value of JOIN::tables must be set to 0 when there
is no matching min/max row.

mysql-test/r/subselect.result:
  Added a test case for bug #37004.
mysql-test/t/subselect.test:
  Added a test case for bug #37004.

   with dependent subqueries
An IN subquery is executed on EXPLAIN when it's not correlated.
If the subquery required a temporary table for its execution
not all the internal structures were restored from pointing to
the items of the temporary table to point back to the items of
the subquery.
Fixed by restoring the ref array when a temp tables were used in
executing the IN subquery during EXPLAIN EXTENDED.


mysql-test/r/subselect.result:
  Bug #36011: test case
mysql-test/t/subselect.test:
  Bug #36011: test case
sql/sql_select.cc:
  Bug #36011: restore the ref array after execution 
  when there were temp tables.

  Post-commit minor cleanup of testcase (bug#36139).


mysql-test/r/subselect.result:
  Post-commit minor cleanup of testcase (bug#36139).
mysql-test/t/subselect.test:
  Post-commit minor cleanup of testcase (bug#36139).

- Make convert_zerofill_number_to_string() take into account that the 
  constant it is converting may evaluate to NULL.


mysql-test/r/subselect.result:
  BUG#36139 "float, zerofill, crash with subquery"
  - Testcase
mysql-test/t/subselect.test:
  BUG#36139 "float, zerofill, crash with subquery"
  - Testcase

                    Leopard.

The change_user test failed because results of some statements
depended on platform and server build flags.

subselect_notembedded failure was a result of a bad merge from 5.0.

Fixed the corresponding test cases.


mysql-test/r/change_user.result:
  Fixed the test case.
mysql-test/r/subselect.result:
  Fixed the test case.
mysql-test/r/subselect_notembedded.result:
  Fixed the test case.
mysql-test/t/change_user.test:
  Fixed the test case.
mysql-test/t/subselect.test:
  Fixed the test case.
mysql-test/t/subselect_notembedded.test:
  Fixed the test case.

The test case for the bug#31048 checks that there is no crash on stack
overrun. But due to different stack sizes on different platforms it failed
on some of them.

The new test case check that a query with at least 4 level subquery nesting
works without the stack overrun nesting and other levels of nesting doesn't
cause a crash.


mysql-test/t/subselect.test:
  Corrected test case for the bug#31048.
mysql-test/r/subselect.result:
  Corrected test case for the bug#31048.

of cleanups in the test case for bug33794.

The problem occurred when one had a subquery that had an equality X=Y where 
Y referred to a named select list expression from the parent select. MySQL 
crashed when trying to use the X=Y equality for ref-based access. 

Fixed by allowing non-Item_field items in the described case.


mysql-test/r/subselect.result:
  BUG#33794 "MySQL crashes executing specific query"
  - Testcase
mysql-test/t/subselect.test:
  BUG#33794 "MySQL crashes executing specific query"
  - Testcase
sql/sql_select.cc:
  BUG#33794 "MySQL crashes executing specific query"
  get_store_key() assumed that if it got a reference
    t.key=Item_outer_ref(Item_direct_ref(x)) 
  then x was an Item_field object, which is not the case when one refers to a
  named select list expression out ot subquery.

server crash.

The filesort implementation has an optimization for subquery execution which
consists of reusing previously allocated buffers. In particular the call to
the read_buffpek_from_file function might be skipped when a big enough buffer
for buffer descriptors (buffpeks) is already allocated. Beside allocating
memory for buffpeks this function fills allocated buffer with data read from
disk. Skipping it might led to using an arbitrary memory as fields' data and
finally to a crash.

Now the read_buffpek_from_file function is always called. It allocates
new buffer only when necessary, but always fill it with correct data.


sql/filesort.cc:
  Bug#33675: Usage of an uninitialized memory by filesort in a subquery caused
  server crash.Now the read_buffpek_from_file function is always called. It allocates
  new buffer only when necessary, but always fill it with correct data.
mysql-test/r/subselect.result:
  Added a test case for the bug#33675: Usage of an uninitialized memory by
  filesort in a subquery caused server crash.
mysql-test/t/subselect.test:
  Added a test case for the bug#33675: Usage of an uninitialized memory by
  filesort in a subquery caused server crash.

  Test case for the bug#31048 is moved to the subselect_notembedded tests as the embedded server isn't affected by this bug.


mysql-test/r/subselect.result:
  Test case for the bug#31048 is moved to the subselect_notembedded tests as the embedded server isn't affected by this bug.
mysql-test/r/subselect_notembedded.result:
  Test case for the bug#31048 is moved to the subselect_notembedded tests as the embedded server isn't affected by this bug.
mysql-test/t/subselect.test:
  Test case for the bug#31048 is moved to the subselect_notembedded tests as the embedded server isn't affected by this bug.
mysql-test/t/subselect_notembedded.test:
  Test case for the bug#31048 is moved to the subselect_notembedded tests as the embedded server isn't affected by this bug.

  crashes MySQL 5.122
There was a difference in how UNIONs are handled
on top level and when in sub-query.
Because the rules for sub-queries were syntactically
allowing cases that are not currently supported by
the server we had crashes (this bug) or wrong results
(bug 32051).
Fixed by making the syntax rules for UNIONs match the 
ones at top level.

These rules however do not support nesting UNIONs, e.g.
(SELECT a FROM t1 UNION ALL SELECT b FROM t2) 
 UNION
(SELECT c FROM t3 UNION ALL SELECT d FROM t4)
Supports for statements with nested UNIONs will be
added in a future version.


mysql-test/r/subselect.result:
  Bug #32036: test case
mysql-test/t/subselect.test:
  Bug #32036: test case
sql/sql_yacc.yy:
  Bug #32036: Make the syntax rules for UNIONs in subqueries the same
  as for top level UNIONs.

  Fix for the bug#31048 for 64bit platforms.
subselect.test, subselect.result:
  Corrected text case for the bug#31048.


mysql-test/t/subselect.test:
  Corrected text case for the bug#31048.
mysql-test/r/subselect.result:
  Corrected text case for the bug#31048.
sql/opt_range.cc:
  Fix for the bug#31048 for 64bit platforms.

Index lookup does not always guarantee that we can
simply remove the relevant conditions from the WHERE
clause. Reasons can be e.g. conversion errors, 
partial indexes etc. 
The optimizer was removing these parts of the WHERE 
condition without any further checking.
This leads to "false positives" when using indexes.
Fixed by checking the index reference conditions
(using WHERE) when using indexes with sub-queries.


mysql-test/r/subselect.result:
  Bug #30788: 
   - using where
   - test case
mysql-test/r/subselect3.result:
  Bug #30788: using where
mysql-test/t/subselect.test:
  Bug #30788: test case
sql/item.h:
  Bug #30788: 
   - Declare eq() method of Item_cache descendants : this is used in
   test_if_ref()
   - preserve the field that is being cached for type comparisions
sql/sql_select.cc:
  Bug #30788: Don't remove the WHERE when using index lookup 
  with subqueries.

 only on some occasions

Referencing an element from the SELECT list in a WHERE 
clause is not permitted. The namespace of the WHERE
clause is the table columns only. This was not enforced
correctly when resolving outer references in sub-queries.

Fixed by not allowing references to aliases in a 
sub-query in WHERE.


mysql-test/include/ps_query.inc:
  Bug #32400: fixed old test queries
mysql-test/r/ps_2myisam.result:
  Bug #32400: fixed old test queries
mysql-test/r/ps_3innodb.result:
  Bug #32400: fixed old test queries
mysql-test/r/ps_4heap.result:
  Bug #32400: fixed old test queries
mysql-test/r/ps_5merge.result:
  Bug #32400: fixed old test queries
mysql-test/r/ps_6bdb.result:
  Bug #32400: fixed old test queries
mysql-test/r/ps_7ndb.result:
  Bug #32400: fixed old test queries
mysql-test/r/subselect.result:
  Bug #32400: test case
mysql-test/t/subselect.test:
  Bug #32400: test case
sql/item.cc:
  Bug #32400: don't allow references to aliases in WHERE
tests/mysql_client_test.c:
  Bug #32400: fixed old test queries

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.


mysql-test/t/subselect.test:
  Added a test case for the bug#31048: Many nested subqueries may cause server crash.
mysql-test/r/subselect.result:
  Added a test case for the bug#31048: Many nested subqueries may cause server crash.
sql/opt_range.cc:
  Bug#31048: Many nested subqueries may cause server crash.
  Now the SQL_SELECT::test_quick_select function calls the check_stack_overrun
  function for stack checking purposes to preven server crash.
sql/item_subselect.cc:
  Bug31048: Many nested subqueries may cause server crash.
  Now the subselect_single_select_engine::exec function allows subquery result
  caching when the UNCACHEABLE_EXPLAIN flag is set.

After adding an index the <VARBINARY> IN (SELECT <BINARY> ...)
clause returned a wrong result: the VARBINARY value was illegally padded
with zero bytes to the length of the BINARY column for the index search.
(<VARBINARY>, ...) IN (SELECT <BINARY>, ... ) clauses are affected too.


sql/item.cc:
  Fixed bug #28076.
  The Item_cache_str::save_in_field method has been overloaded
  to check cached values for an illegal padding before the saving
  into a field.
sql/item.h:
  Fixed bug #28076.
  The Item_cache_str::is_varbinary flag has been added and the
  Item_cache_str::save_in_field method has been overloaded to prevent
  cached values from an illegal padding when saving in fields.
  The signature of the Item_cache::get_cache method has been
  changed to accept pointers to Item instead of Item_result
  values.
sql/item_cmpfunc.cc:
  Fixed bug #28076.
  The Item_in_optimizer::fix_left method has been modified to
  to call Item_cache::get_cache in a new manner.
sql/item_subselect.cc:
  Fixed bug #28076.
  The subselect_indexsubquery_engine::exec method has been
  modified to take into account field conversion errors
  (copy&paste from subselect_uniquesubquery_engine::exec).
sql/sp_rcontext.cc:
  Fixed bug #28076.
  The sp_rcontext::create_case_expr_holder method has been
  modified to call Item_cache::get_cache in a new manner.
sql/sp_rcontext.h:
  Fixed bug #28076.
  The sp_rcontext::create_case_expr_holder method signature
  has been modified to pass Item pointers to the
  Item_cache::get_cache method.
sql/sql_class.cc:
  Fixed bug #28076.
  The select_max_min_finder_subselect::send_data method has been
  modified to call Item_cache::get_cache in a new manner.
mysql-test/t/subselect.test:
  Added test case for bug #28076.
mysql-test/r/subselect.result:
  Added test case for bug #28076.

Comment sign of -- at line begin in test files lead to warnings
from mysqltest.
  
Changed -- to #.


mysql-test/t/subselect.test:
  Bug#32108 - subselect.test produces warnings files
  Changed -- to # at comment begin to avoid warnings files.

Item_in_subselect's only externally callable method is val_bool().
However the nullability in the wrapper class (Item_in_optimizer) is 
established by calling the "forbidden" method val_int().

Fixed to use the correct method (val_bool() ) to establish nullability 
of Item_in_subselect in Item_in_optimizer.


mysql-test/r/subselect.result:
  Bug #31884: test case
mysql-test/t/subselect.test:
  Bug #31884: test case
sql/item_subselect.h:
  Bug #31884: Use the correct method to establish nullability

Fixed typos and comment styles in tests.


mysql-test/r/rpl_partition.result:
  Post-merge fixes.
  Removed warnings after fixing --disable_warnings command.
mysql-test/t/ctype_uca.test:
  Post-merge fixes.
  Fixed comment style.
mysql-test/t/rpl_partition.test:
  Post-merge fixes.
  Fixed typo in --disable_warnings and --enable_warnings.
mysql-test/t/subselect.test:
  Post-merge fixes.
  Fixed comment style.

query / no aggregate of subquery
 The optimizer counts the aggregate functions that 
 appear as top level expressions (in all_fields) in 
 the current subquery. Later it makes a list of these
 that it uses to actually execute the aggregates in
 end_send_group().
 That count is used in several places as a flag whether
 there are aggregates functions.
 While collecting the above info it must not consider
 aggregates that are not aggregated in the current 
 context. It must treat them as normal expressions 
 instead. Not doing that leads to incorrect data about
 the query, e.g. running a query that actually has no
 aggregate functions as if it has some (and hence is
 expected to return only one row).
 Fixed by ignoring the aggregates that are not aggregated
 in the current context. 
 One other smaller omission discovered and fixed in the 
 process : the place of aggregation was not calculated for
 user defined functions. Fixed by calling 
 Item_sum::init_sum_func_check() and 
 Item_sum::check_sum_func() as it's done for the rest of 
 the aggregate functions.


mysql-test/r/subselect.result:
  Bug #27333: test case
mysql-test/t/subselect.test:
  Bug #27333: test case
sql/item_subselect.cc:
  Bug#27333: need select_lex to filter out
   aggregates that are not aggregated in
   the current select.
sql/item_sum.cc:
  Bug#27333: need select_lex to filter out
   aggregates that are not aggregated in
   the current select.
sql/item_sum.h:
  Bug#27333: calculate the place of 
   aggregation for user defined functions.
sql/sql_select.cc:
  Bug#27333: When counting the aggregated functions
   and collecting a list of them we must not consider
   the aggregates that are not aggregated in the local
   context as "local" : i.e. we must treat them as 
   normal functions and not add them to the aggregate
   functions list.
sql/sql_select.h:
  Bug#27333: need select_lex to filter out
   aggregates that are not aggregated in
   the current select.

ORDER BY and LIMIT 1. 
The bug was introduced by the patch for bug 21727. The patch
erroneously skipped initialization of the array of headers
for sorted records for non-first evaluations of the subquery.

To fix the problem a new parameter has been added to the
function make_char_array that performs the initialization.
Now this function is called for any invocation of the 
filesort procedure. Yet it allocates the buffer for sorted
records only if this parameter is NULL.


mysql-test/r/subselect.result:
  Added a test case for bug #28811.
mysql-test/t/subselect.test:
  Added a test case for bug #28811.

forbid the use of subselect in PURGE LOGS BEFORE command


mysql-test/r/subselect.result:
  test result
mysql-test/t/subselect.test:
  test case
sql/sql_yacc.yy:
  forbid the use of subselect in PURGE LOGS BEFORE command

using a derived table over a grouping subselect.

This crash happens only when materialization of the derived tables 
requires creation of auxiliary temporary table, for example when
a grouping operation is carried out with usage of a temporary table.

The crash happened because EXPLAIN EXTENDED when printing the query
expression made an attempt to use the objects created in the mem_root
of the temporary table which has been already freed by the moment
when printing is called.

This bug appeared after the method Item_field::print() had been 
introduced.    


mysql-test/r/subselect.result:
  Added a test case for bug #28728.
mysql-test/t/subselect.test:
  Added a test case for bug #28728.
sql/sql_select.cc:
  Fixed bug #28728: a crash when executing EXPLAIN EXTENDED for a query
  using a derived table over a grouping subselect.
  The crash happened because EXPLAIN EXTENDED when printing the query
  expression made an attempt to use the objects created in the mem_root
  of the temporary table which has been already freed by the moment
  when printing is accomplished.
  The fix in JOIN::exec() ensures using existing objects when printing 
  subselects for a derived tables by EXPLAIN EXTENDED.

subqueries in WHERE conditions.
This bug was introduced by the patch for bug 27321.


mysql-test/r/subselect.result:
  Added a test case for bug #28337.
mysql-test/t/subselect.test:
  Added a test case for bug #28337.
sql/item.cc:
  Fixed bug #28337: wrong results for grouping queries with correlated
  subqueries in WHERE conditions.
  This bug was introduced by the patch for bug 27321.
  
  Now in the Item_field::fix_outer_field function we create an Item_outer_ref
  object for an outer reference only if it is used in the SELECT list or
  in the HAVING clause of the subquery against which the reference is resolved.

Non-correlated scalar subqueries may get executed
in EXPLAIN at the optimization phase if they are
part of a right hand sargable expression.
If the scalar subquery uses a temp table to 
materialize its results it will replace the 
subquery structure from the parser with a simple
select from the materialization table.
As a result the EXPLAIN will crash as the 
temporary materialization table is not to be shown
in EXPLAIN at all.
Fixed by preserving the original query structure
right after calling optimize() for scalar subqueries
with temp tables executed during EXPLAIN.


mysql-test/r/subselect.result:
  Bug #27807: test case
mysql-test/t/subselect.test:
  Bug #27807: test case
sql/item_subselect.cc:
  Bug #27807: preserve the join structure
sql/sql_select.cc:
  Bug #27807: introduce initialization function for tmp_join
sql/sql_select.h:
  Bug #27807: introduce initialization function for tmp_join

Validity checks for nested set functions
were not taking into account that the enclosed
set function may be on a nest level that is
lower than the nest level of the enclosing set
function.
Fixed by :
 - propagating max_sum_func_level
up the enclosing set functions chain.
 - updating the max_sum_func_level of the 
   enclosing set function when the enclosed set
   function is aggregated above or on the same
   nest level of as the level of the enclosing 
   set function.
 - updating the max_arg_level of the enclosing
   set function on a reference that refers to
   an item above or on the same nest level
   as the level of the enclosing set function.
 - Treating both Item_field and Item_ref as possibly
   referencing items from outer nest levels.


mysql-test/r/subselect.result:
  Bug #27363: test cases
mysql-test/t/subselect.test:
  Bug #27363: test cases
sql/item.cc:
  Bug #27363:
  Treat the reference as an outer reference for the
  enclosing set function even if it's referencing
  an item that is above the nest level of the
  enclosing set function.
  Consider both Item_field and Item_ref.
sql/item_sum.cc:
  Bug #27363: Use the enclosed set function aggregation
  level to mark the enclosing set function even 
  if it's aggregated on a level that is above the 
  nest level of the enclosing set function.
  Pass max_sum_func_level up the accending branch of the
  recursion because it must take into account each
  directly or indirectly nested set function.

  After merge fix.


mysql-test/r/subselect.result:
  After merge fix.
mysql-test/t/subselect.test:
  After merge fix.

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.


mysql-test/t/subselect3.test:
  Some test cases were corrected after the fix for the bug#27321.
mysql-test/r/subselect3.result:
  Some test cases were corrected after the fix for the bug#27321.
mysql-test/t/subselect.test:
  Added a test case for the bug#27321: Wrong subquery result in a grouping select.
mysql-test/r/subselect.result:
  Added a test case for the bug#27321: Wrong subquery result in a grouping select.
  Some test cases were corrected after this fix.
sql/sql_union.cc:
  Bug#27321: Wrong subquery result in a grouping select.
  Cleanup of the inner_refs_list.
sql/sql_select.cc:
  Bug#27321: Wrong subquery result in a grouping select.
  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.
  A comment is corrected.
sql/item.cc:
  Bug#27321: Wrong subquery result in a grouping select.
  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.
sql/item.h:
  Bug#27321: Wrong subquery result in a grouping select.
  The direct_ref and the found_in_select_list fields were added to the
  Item_outer_ref class.

If a set function with a outer reference s(outer_ref) cannot be aggregated 
the outer query against which the reference has been resolved then MySQL
interpretes s(outer_ref) in the same way as it would interpret s(const).
Hovever the standard requires throwing an error in this situation.
Added some code to support this requirement in ansi mode.
Corrected another minor bug in Item_sum::check_sum_func.
 


mysql-test/r/subselect.result:
  Added a test case for bug #27348.
mysql-test/t/subselect.test:
  Added a test case for bug #27348.
sql/item_sum.cc:
  Fixed bug #27348.
  If a set function with a outer reference s(outer_ref) cannot be aggregated 
  the outer query against which the reference has been resolved then MySQL
  interprets s(outer_ref) in the same way as it would interpret s(const).
  Hovever the standard requires throwing an error in this situation.
  Added some code to support this requirement in ansi mode.
  Corrected another minor bug in Item_sum::check_sum_func.

context was used as an argument of GROUP_CONCAT.
Ensured correct setting of the depended_from field in references
generated for set functions aggregated in outer selects.
A wrong value of this field resulted in wrong maps returned by 
used_tables() for these references.
Made sure that a temporary table field is added for any set function
aggregated in outer context when creation of a temporary table is 
needed to execute the inner subquery. 


mysql-test/r/subselect.result:
  Added a test case for bug #27229.
mysql-test/t/subselect.test:
  Added a test case for bug #27229.
sql/item.cc:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  Ensured correct setting of the depended_from field in references
  generated for set functions aggregated in outer selects.
sql/item_sum.cc:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  Added the field aggr_sel to the objects of the class Item_sum.
  In any Item_sum object created for a set function this field 
  has to contain a pointer to the select where the set function
  is aggregated.
sql/item_sum.h:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  Added the field aggr_sel to the objects of the class Item_sum.
  In any Item_sum object created for a set function this field 
  has to contain a pointer to the select where the set function
  is aggregated.
  Added a method that says whether a set function is aggregated
  in outer context and, if so, returns the aggregating select.
  Removed the field nest_level_tables_count introduced by the
  patch for bug 24484 as aggr_sel->join->tables contains the
  sane number.
sql/sql_base.cc:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  Added the field aggr_sel to the objects of the class Item_sum.
  Removed changes introduced by the patch for bug 24484 as 
  the field leaf_count of the THD class is not used anymore.
sql/sql_class.h:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  Added the field aggr_sel to the objects of the class Item_sum.
  Removed changes introduce by the patch for bug 24484 as 
  the field leaf_count of the THD class is not used anymore.
sql/sql_insert.cc:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  Added the field aggr_sel to the objects of the class Item_sum.
  Removed changes introduce by the patch for bug 24484 as 
  the field leaf_count of the THD class is not used anymore.
sql/sql_select.cc:
  Fixed bug #27229: crash when a set function aggregated in outer
  context was used as an argument of GROUP_CONCAT.
  When creating a temporary table a field is added in it for any 
  set function aggregated in outer context.

aggregated in outer context returned wrong results.
This happened only if the subquery did not contain any references
to outer fields.
As there were no references to outer fields the subquery erroneously
was taken for non-correlated one.
Now any set function aggregated in outer context makes the subquery
correlated.


mysql-test/r/subselect.result:
  Added a test case for bug #27257.
mysql-test/t/subselect.test:
  Added a test case for bug #27257.