so that changes from 5.0 propagate (on merge) into the 5.1 version.

Several string comparisons could never yield true because they had an 'x' guard
added to the variable but not to the constant value. Fix that by guarding both sides.

into  trift2.:/MySQL/M51/push-5.1

into  trift2.:/MySQL/M51/push-5.1

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build

into  pippilotta.erinye.com:/shared/home/df/mysql/build/mysql-5.1-build

into  bk-internal.mysql.com:/data0/bk/mysql-5.1-opt

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

into  olga.mysql.com:/home/igor/mysql-5.1-opt

into  olga.mysql.com:/home/igor/mysql-5.1-opt

a crash when the left operand of the predicate is evaluated to NULL.
It happens when the rows from the inner tables (tables from the subquery)
are accessed by index methods with key values obtained by evaluation of
the left operand of the subquery predicate. When this predicate is
evaluated to NULL an alternative access with full table scan is used
to check whether the result set returned by the subquery is empty or not.
The crash was due to the fact the info about the access methods used for
regular key values was not properly restored after a switch back from the
full scan access method had occurred.
The patch restores this info properly.
The same problem existed for queries with IN subquery predicates if they
were used not at the top level of the queries.

into  moonbone.local:/mnt/gentoo64/work/27878-bug-5.0-opt-mysql

  Corrected test case for the bug#27878.

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my50-27957

into  moonbone.local:/mnt/gentoo64/work/27878-bug-5.0-opt-mysql

database.

If a user has a right to update anything in the current database then the 
access was granted and further checks of access rights for underlying tables
wasn't done correctly. The check is done before a view is opened and thus no
check of access rights for underlying tables can be carried out.
This allows a user to update through a view a table from another database for
which he hasn't enough rights.

Now the mysql_update() and the mysql_test_update() functions are forces
re-checking of access rights after a view is opened.

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my50-27957

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27957/my50-27957

into  mysql.com:/home/hf/work/27957/my51-27957

into  mysql.com:/home/hf/work/27921/my51-27921

Bug occurs in INSERT IGNORE ... SELECT ... ON DUPLICATE KEY UPDATE
statements, when SELECT returns duplicated values and UPDATE clause
tries to assign NULL values to NOT NULL fields.
NOTE: By current design MySQL server treats INSERT IGNORE ... ON
DUPLICATE statements as INSERT ... ON DUPLICATE with update of
duplicated records, but MySQL manual lacks this information.
After this fix such behaviour becomes legalized.

The write_record() function was returning error values even within
INSERT IGNORE, because ignore_errors parameter of
the fill_record_n_invoke_before_triggers() function call was
always set to FALSE. FALSE is replaced by info->ignore.

into  trift2.:/MySQL/M51/push-5.1

into  whalegate.ndb.mysql.com:/home/tomas/mysql-5.1-single-user

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

ref access to a less expensive range access. 
This occurred only with InnoDB tables.