The problem was that maybe_null of Item_row and its componetes was unsynced after update_used_tables() (and so pushed_cond_guards was not initialized but then requested).

Fix  updates Item_row::maybe_null on update_used_tables().

MDEV-3900 Optimizer difference between MySQL and MariaDB with stored functions in WHERE clause of UPDATE or DELETE statements

Analysis
The reason for the less efficient plan was result of a prior design decision -
to limit the eveluation of constant expressions during optimization to only
non-expensive ones. With this approach all stored procedures were considered
expensive, and were not evaluated during optimization. As a result, SPs didn't
participate in range optimization, which resulted in a plan with table scan
rather than index range scan.

Solution
Instead of considering all SPs expensive, consider expensive only those SPs
that are non-deterministic. If an SP is deterministic, the optimizer will
checj if it is constant, and may eventually evaluate it during optimization.

Don't reset maybe_null in update_used_tables(); This breaks ROLLUP
This fixed failing test in group_by.test

Subquery turned into constant too late to be excluded from grouping list so test for constant added to the create_temp_table().

The bug could lead to a wrong estimate of the number of expected rows
in the output of the EXPLAIN commands for queries with GROUP BY.
This could be observed in the test case for LP bug 934348.

MDEV-4020 : Make sure strmov symbol is exported by client library  on Linux (even if the server and libraries itself use stpcpy instead of it)

It is a workaround that allows myodbc built by certain distributions' (CentOS,Fedora) to peacefully coexist with mariadb client libraries.
The problem is that MyODBC in these distros needs strmov() to be exported by mysql client shared library, or else myodbc fails to load.

MDEV-3942 FROM_DAYS(<timestamp column>) returns different result in MariaDB comparing to MySQL: NULL vs 0000-00-00

fixed a regression, introduced while fixing MDEV-456

from a MERGE view.

The problem was in the lost ability to be null for the table of a left join if it
is a view/derived table.

It hapenned because setup_table_map(), was called earlier then we merged
the view or derived.

Fixed by propagating new maybe_null flag during Item::update_used_tables().

Change in join_outer.test and join_outer_jcl6.test appeared because
IS NULL reported no used tables (i.e. constant) for argument which could not be
NULL and new maybe_null flag was propagated for IS NULL argument (Item_field)
because table the Item_field belonged to changed its maybe_null status.

MDEV-3928: Assertion `example' failed in Item_cache::is_expensive_processor with a 2-level IN subquery

Analysis:
The following call stack shows that it is possible to set Item_cache::value_cached, and the relevant value
without setting Item_cache::example.

#0 Item_cache_temporal::store_packed at item.cc:8395
#1 get_datetime_value at item_cmpfunc.cc:915
#2 resolve_const_item at item.cc:7987
#3 propagate_cond_constants at sql_select.cc:12264
#4 propagate_cond_constants at sql_select.cc:12227
#5 optimize_cond at sql_select.cc:13026
#6 JOIN::optimize at sql_select.cc:1016
#7 st_select_lex::optimize_unflattened_subqueries at sql_lex.cc:3161
#8 JOIN::optimize_unflattened_subqueries at opt_subselect.cc:4880
#9 JOIN::optimize at sql_select.cc:1554

The fix is to set Item_cache_temporal::example even when the value is
set directly by Item_cache_temporal::store_packed. This makes the
Item_cache_temporal object consistent.

taking a change done to main 5.1 by Dmitri Lenev.

This is the original comment:

> committer: Dmitry Lenev <Dmitry.Lenev@oracle.com>
> branch nick: mysql-5.1-15954896
> timestamp: Wed 2012-12-05 19:26:56 +0400
> message:
>   Bug #15954896 "SP, MULTI-TABLE DELETE AND LONG ALIAS".

  Using too long table aliases in stored routines might
  have caused server crashes.

  Code in sp_head::merge_table_list() which is responsible
  for collecting information about tables used in stored
  routine was not aware of the fact that table alias might
  have arbitrary length. I.e. it assumed that table alias
  can't be longer than NAME_LEN bytes and allocated buffer
  for a key identifying table accordingly.

  This patch fixes the issue by ensuring that we use
  dynamically allocated buffer for table key when table
  alias is too long. By default stack based buffer is used
  in which NAME_LEN bytes are reserved for table alias.

The failure is caused by failing stat() call . C Runtime function stat() uses old struct with 32bit st_size member,
and since Visual Studio 2010 , it returns an error on st_size overflow (i.e on files larger than 4GB)

Fix replaces stat() by my_stat(), the later is backed by 64bit-able stat64().

Fixed algorithm of detecting of first real table in view/subquery-in-the-FROM-clase.

Link feedback plugin with yassl libraries, if with-ssl=bundled is used, since mysqld does not export SSL symbols anymore.

Compile yassl and taocrypt using -fvisibility=hidden, when possible.  This prevent symbols from being exported.

If the setting of system variables does not allow to use join buffer
for a join query with GROUP BY <f1,...> / ORDER BY <f1,...> then
filesort is not needed if the first joined table is scanned in
the order compatible with order specified by the list <f1,...>.

Fix some problems in the TC_LOG_MMAP commit processing, which could
lead to assertions in some cases.

Problems are mostly reproducible in MariaDB 10.0 with asynchroneous
commit checkpoints, but most of the problems were present in earlier
versions also.

Adjust unstable test case.

Properly drop all unused keys.
Patch by Igor Babaev.

MDEV-736 LP:1004615 - Unexpected warnings "Encountered illegal value '' when converting to DECIMAL" on a query with aggregate functions and GROUP BY

fix: don't call field->val_decimal() if the field->is_null()
because the buffer at field->ptr might not hold a valid decimal value

sql/item_sum.cc:
  do not call field->val_decimal() if the field->is_null()
storage/maria/ma_blockrec.c:
  cleanup
storage/maria/ma_rrnd.c:
  cleanup
strings/decimal.c:
  typo

followup fixes for MySQL Bug #13889741: HANDLE_FATAL_SIGNAL IN _DB_ENTER_ | HANDLE_FATAL_SIGNAL IN STRNLEN

Take into account that length of strings passed down to this function can be up to FN_REFLEN+1 bytes. including terminating zero.
The overwrite was caused by incomplete fix to MySQL Bug # 44834

If triggers are used for an insert/update/delete statement than the values of
all virtual columns must be computed as any of them may be used by the triggers.