It's a regression issue.
The reason of the bug appeared to be an error introduced into 5.1 source code.
A piece of code in Create_file_log_event::do_apply_event() did not have test
coverage which made make test and pb unaware.
      
Fixed with inverting the old value of the return value from 
Create_file_log_event::do_apply_event().
The rpl test suite is extended with `rpl_cross_version' the file to hold 
regression cases similar to the current.


mysql-test/suite/rpl/r/rpl_cross_version.result:
  new results file
mysql-test/suite/rpl/t/rpl_cross_version-master.opt:
  options to the server to be able to start replication to itself
mysql-test/suite/rpl/t/rpl_cross_version.test:
  regression test for bug#31240.
sql/log_event.cc:
  Correcting the return value from  Create_file_log_event::do_apply_event()

character_set_database !=character_set_server" is fixed.

This does not bring any contents changes, it is purely
metadata which are affected.

Details:

Even within 5.0, most of these changesets did not cause
file contents changes, because they were backports done
for the "service pack" builds of 5.0.66sp1 and 5.0.72sp1.

The "real" changesets are also already present in 5.1,
so this upmerge doesn't change any contents.

The only "real" changeset in 5.0 was a fix of the shell
scripts used to configure bdb (BerkeleyDB).
As we completele removed bdb from the 5.1 sources already,
the affected files are not present in the 5.1 source tree,
so this changeset also does not cause any contents changes.

this should not happen.

mysql-test/r/cache_innodb.result:
  Update test case result.

This is not the final merge of that release build, but we need early
access to these tool fixes (use of "awk" in the BDB configuration).

with mysql_change_user) to 5.0.

Post-fix test failure: fixed mysqlcheck.test on Windows platforms.


mysql-test/r/mysqlcheck.result:
  fixed mysqlcheck.test on Windows platforms.
mysql-test/t/mysqlcheck.test:
  fixed mysqlcheck.test on Windows platforms.

bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
triggers
and
#41385: Crash when attempting to repair a #mysql50# upgraded table
with triggers.

Problem:
1. trigger code didn't assume a table name may have
a "#mysql50#" prefix, that may lead to a failing ASSERT().
2. "ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME" failed
for databases with "#mysql50#" prefix if any trigger.
3. mysqlcheck --fix-table-name didn't use UTF8 as a default
character set that resulted in (parsing) errors for tables with
non-latin symbols in their names and definitions of triggers.

Fix:
1. properly handle table/database names with "#mysql50#" prefix.
2. handle --default-character-set mysqlcheck option;
if mysqlcheck is launched with --fix-table-name or --fix-db-name
set default character set to UTF8 if no --default-character-set
option given.

Note: if given --fix-table-name or --fix-db-name option,
without --default-character-set mysqlcheck option
default character set is UTF8.


client/mysqlcheck.c:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - check and set default charset if --default-character-set option
      given.
    - set default charset to "utf8" if there's
      --fix-table-name or --fix-db-name and no --default-character-set.
mysql-test/r/mysqlcheck.result:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - test result.
mysql-test/t/mysqlcheck.test:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - test case.
sql/mysql_priv.h:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - check_n_cut_mysql50_prefix() introduced.
sql/sql_table.cc:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - tablename_to_filename() code split into 2 parts
    - check_n_cut_mysql50_prefix() introduced to cut #mysql50# prefixes,
      used in the trigger code as well.
sql/sql_trigger.cc:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - Table_triggers_list::check_n_load() - checking triggers assume
      a table/database name given may have "#mysql50#" prefix in some cases.
    - Table_triggers_list::change_table_name_in_triggers() -
      create .TRG file in new database directory and delete it in old one,
      as they may differ in case of
      "ALTER DATABASE ... UPGRADE DATA DIRECTORY NAME"
    - Table_triggers_list::change_table_name_in_trignames() - remove stale .TRN
      files in #mysql50#dbname directory in case of database upgrade
    - Table_triggers_list::change_table_name() - allow changing trigger's
      database in case of its upgrading
sql/sql_trigger.h:
  Fix for
  bug#33094: Error in upgrading from 5.0 to 5.1 when table contains
  triggers
  and
  #41385: Crash when attempting to repair a #mysql50# upgraded table
  with triggers.
    - new old_db_name parameter added in
      Table_triggers_list::change_table_name_in_trignames() and
      Table_triggers_list::change_table_name_in_triggers()

The next number (AUTO_INCREMENT) field of the table for write
rows events are not initialized, and cause some engines (innodb)
not correctly update the tables's auto_increment value.

This patch fixed this problem by honor next number fields if present.

mysql-test/extra/rpl_tests/rpl_auto_increment.test:
  Add test code for BUG#41986
mysql-test/suite/rpl/r/rpl_auto_increment.result:
  update test result file for BUG#41986
sql/log_event.cc:
  set next_number_field before writing rows, and reset next_number_field after finished writing rows

Use SELECT FROM INFORMATION_SCHEMA instead of SHOW VARIABLES LIKE to restrict
values correctly.

partition_innodb_semi_consistent.test, which was overlooked in the
innodb-5.1-ss3603 snapshot.

The problem is that the query cache stores packets containing
the server status of the time when the cached statement was run.
This might lead to a wrong transaction status in the client side
if a statement is cached during a transaction and is later served
outside a transaction context (and vice-versa).

The solution is to take into account the transaction status when
storing in and serving from the query cache.

mysql-test/r/innodb_cache.result:
  Update test case result.
mysql-test/r/query_cache.result:
  Add test case result for Bug#36326
mysql-test/t/query_cache.test:
  Add test case for Bug#36326
sql/mysql_priv.h:
  Add new flags.
sql/sql_cache.cc:
  Remember the transaction and autocommit status stored in the packet.
tests/mysql_client_test.c:
  Add test case for Bug#36326