Problem: The functions my_like_range_xxx() returned
badly formed maximum strings for Asian character sets,
which made problems for storage engines.

Fix: 
- Removed a number my_like_range_xxx() implementations,
  which were in fact dumplicate code pieces.
- Using generic my_like_range_mb() instead.
- Setting max_sort_char member properly for Asian character sets
- Adding unittest/strings/strings-t.c, 
  to test that my_like_range_xxx() return well-formed 
  min and max strings.

Notes:

- No additional tests in mysql/t/ available.
  Old tests cover the affected code well enough.

Bug#49542 - Do as the comment suggests and downgrade directory errors from find_file() to a warning unless they happen during a SHOW command.

SHOW DATABASES LIKE ... was not converting to lowercase on comparison as the
documentation is suggesting. 
Fixed it to behave similarly to SHOW TABLES LIKE ... and updated the failing
on MacOSX lowercase_table2 test case.

to write into a closed socket

sql/protocol.cc:
  Protocol::flush modified: set thd->main_da.can_overwrite_status= TRUE
  before call to net_flush() in order to prevent crash on assert in case
  of socket write failure, reset it to FALSE when net_flush() returned;
  Protocol::send_fields modified: return from method with error if call to
  my_net_write(), proto.write() or write_eof_packet() failed.
sql/sql_cache.cc:
  Query_cache::send_result_to_client modified: call to
  thd->main_da.disable_status() only if write to socket
  was successful.
sql/sql_cursor.cc:
  Materialized_cursor::fetch modified: leave method if call to
  result->send_data() failed.
sql/sql_prepare.cc:
  send_prep_stmt() modified: call to thd->main_da.disable_status()
  only if thd->protocol_text.send_fields() completed successfully.

           due to GCC preprocessor change
      
Addendum for trunk: add -DMYSQL_ABI_CHECK to the cmake ABI check.

           due to GCC preprocessor change

Addendum for trunk: do not include system header when checking
the ABI.

Fix warnings flagged by the new warning option -Wunused-but-set-variable
that was added to GCC 4.6 and that is enabled by -Wunused and -Wall. The
option causes a warning whenever a local variable is assigned to but is
later unused. It also warns about meaningless pointer dereferences.

client/mysql.cc:
  Meaningless pointer dereferences.
client/mysql_upgrade.c:
  Check whether reading from the file succeeded.
extra/comp_err.c:
  Unused.
extra/yassl/src/yassl_imp.cpp:
  Skip instead of reading data that is discarded.
include/my_pthread.h:
  Variable is only used in debug builds.
include/mysys_err.h:
  Add new error messages.
mysys/errors.c:
  Add new error message for permission related functions.
mysys/mf_iocache.c:
  Variable is only checked under THREAD.
mysys/my_copy.c:
  Raise a error if chmod or chown fails.
mysys/my_redel.c:
  Raise a error if chmod or chown fails.
regex/engine.c:
  Use a equivalent variable for the assert.
server-tools/instance-manager/instance_options.cc:
  Unused.
sql/field.cc:
  Unused.
sql/item.cc:
  Unused.
sql/log.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
  
  Adjust doxygen comment to the right function.
  
  Pass message lenght to log function.
sql/mysqld.cc:
  Do not ignore the return value of freopen: only set buffer if
  reopening succeeds.
sql/partition_info.cc:
  Unused.
sql/slave.cc:
  No need to set pointer to the address of '\0'.
sql/spatial.cc:
  Unused. Left for historical purposes.
sql/sql_acl.cc:
  Unused.
sql/sql_base.cc:
  Pointers are always set to the same variables.
sql/sql_parse.cc:
  End statement if reading fails.
  
  Store the buffer after it has actually been updated.
sql/sql_repl.cc:
  No need to set pointer to the address of '\0'.
sql/sql_show.cc:
  Put variable under the same ifdef block.
sql/udf_example.c:
  Set null pointer flag appropriately.
storage/csv/ha_tina.cc:
  Meaningless dereferences.
storage/example/ha_example.cc:
  Return the error since it's available.
storage/myisam/mi_locking.c:
  Remove unused and dead code.

           due to GCC preprocessor change
      
The problem is that newer GCC versions treats missing headers
as fatal errors. The solution is to use a guard macro to prevent
the inclusion of system headers when checking the ABI with the
C Preprocessor.

Reference: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=15638
           http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44836

Makefile.am:
  Define guard macro.
configure.in:
  Remove workaround.
include/mysql.h:
  Guard the header inclusion.
include/mysql.h.pp:
  Header is not included anymore.

           table with active trx

Essentially, the problem is that InnoDB does a implicit commit
when a cursor (table handler) is unlocked/closed, creating
a dissonance between the transaction state within the server
layer and the storage engine layer. Theoretically, a statement
transaction can encompass several table instances in a similar
manner to a multiple statement transaction, hence it does not
make sense to limit a statement transaction to the lifetime of
the table instances (cursors) used within it.

Since this particular instance of the problem is only triggerable
on 5.1 and is masked on 5.5 due 2PC being skipped (assertion is in
the prepare phase of a 2PC), the solution (which is less risky) is
to explicitly end the transaction before the cached table is unlock
on rename table.

The patch is to be null merged into trunk.

mysql-test/include/commit.inc:
  Fix counters, the binlog engine does not get involved anymore.
mysql-test/suite/innodb_plugin/r/innodb_bug54453.result:
  Add test case result for Bug#54453
mysql-test/suite/innodb_plugin/t/innodb_bug54453.test:
  Add test case for Bug#54453
sql/sql_table.cc:
  End transaction as otherwise InnoDB will end it behind our backs.

Problem: when SHOW BINLOG EVENTS was issued, it increased the value of
@@session.max_allowed_packet. This allowed a non-root user to increase
the amount of memory used by her thread arbitrarily. Thus, it removes
the bound on the amount of system resources used by a client, so it
presents a security risk (DoS attack).

Fix: it is correct to increase the value of @@session.max_allowed_packet
while executing SHOW BINLOG EVENTS (see BUG 30435). However, the
increase should only be temporary. Thus, the fix is to restore the value
when SHOW BINLOG EVENTS ends.
The value of @@session.max_allowed_packet is also increased in
mysql_binlog_send (i.e., the binlog dump thread). It is not clear if this
can cause any trouble, since normally the client that issues
COM_BINLOG_DUMP will not issue any other commands that would be affected
by the increased value of @@session.max_allowed_packet. However, we
restore the value just in case.


mysql-test/suite/rpl/r/rpl_packet.result:
  update result file
mysql-test/suite/rpl/t/rpl_packet.test:
  Add test that verifies that @@session.max_allowed_packet does not change
  when issuing SHOW BINLOG EVENTS.
  Make previous sub-test clean up.
  Add comments listing the bugs in this test case.
sql/sql_repl.cc:
  Restore the old value of thd->variables.max_allowed_packet at the
  end of mysql_binlog_send and mysql_show_binlog_events.

This bug is a design flaw of the fix for the bug#33546. It assumed that an
item can be used only in one comparison context, but actually it isn't the
case. Item_cache_datetime is used to store result for MIX/MAX aggregate
functions. Because Arg_comparator always compares datetime values as INTs when
possible the Item_cache_datetime most time caches only INT value. But
since all datetime values has STRING result type MIN/MAX functions are asked
for a STRING value when the result is being sent to a client. The
Item_cache_datetime was designed to avoid conversions and get INT/STRING
values from an underlying item, but at the moment the values is asked
underlying item doesn't hold it anymore thus wrong result is returned.
Beside that MIN/MAX aggregate functions was wrongly initializing cached result
and this led to a wrong result.

The Item::has_compatible_context helper function is added. It checks whether
this and given items has the same comparison context or can be compared as
DATETIME values by Arg_comparator. The equality propagation optimization is
adjusted to take into account that items which being compared as DATETIME
can have different comparison contexts.
The Item_cache_datetime now converts cached INT value to a correct STRING
DATETIME value by means of number_to_datetime & my_TIME_to_str functions.
The Arg_comparator::set_cmp_context_for_datetime helper function is added. 
It sets comparison context of items being compared as DATETIMEs to INT if
items will be compared as longlong.
The Item_sum_hybrid::setup function now correctly initializes its result
value.
In order to avoid unnecessary conversions Item_sum_hybrid now states that it
can provide correct longlong value if the item being aggregated can do it
too.

mysql-test/r/group_by.result:
  Added a test case for the bug#49771.
sql/item.cc:
  Bug#49771: Incorrect MIN/MAX for date/time values.
  The equality propagation mechanism is adjusted to take into account that
  items which being compared as DATETIME can have different comparison
  contexts.
  The Item_cache_datetime now converts cached INT value to a correct STRING
  DATETIME/TIME value.
sql/item.h:
  Bug#49771: Incorrect MIN/MAX for date/time values.
  The Item::has_compatible_context helper function is added. It checks whether
  this and given items has the same comparison context or can be compared as
  DATETIME values by Arg_comparator.
  Added Item_cache::clear helper function.
sql/item_cmpfunc.cc:
  Bug#49771: Incorrect MIN/MAX for date/time values.
  The Arg_comparator::set_cmp_func now sets the correct comparison context
  for items being compared as DATETIME values.
sql/item_cmpfunc.h:
  Bug#49771: Incorrect MIN/MAX for date/time values.
  The Arg_comparator::set_cmp_context_for_datetime helper function is added. 
  It sets comparison context of items being compared as DATETIMEs to INT if
  items will be compared as longlong.
sql/item_sum.cc:
  Bug#49771: Incorrect MIN/MAX for date/time values.
  The Item_sum_hybrid::setup function now correctly initializes its result
  value.
sql/item_sum.h:
  Bug#49771: Incorrect MIN/MAX for date/time values.
  In order to avoid unnecessary conversions Item_sum_hybrid now states that it
  can provide correct longlong value if the item being aggregated can do it
  too.