Main problem: mysql 5.1 cannot read binlogs from 4.1.
Subproblem 1: There is a mistake in sql_ex_info::init. The read_str()
function updates its first argument to point to the next character to
read. However, it is applied only to a copy of the buffer pointer, so the
real buffer pointer is not updated.
Fix 1: do not take a copy of the buffer pointer. The copy was needed
because sql_ex_info::init does not use the const attribute on some of its
arguments. So we add the const attribute, too.
Subproblem 2: The first BINLOG statement is asserted to be a
FORMAT_DESCRIPTION_LOG_EVENT, but 4.1 binlogs begin with START_EVENT_V3.
Fix 2: allow START_EVENT_V3 too.
Problem: Replication fails when master is mysql-5.1-wl2325-5.0-drop6 and
slave is mysql-5.1-new-rpl. The reason is that, in
mysql-5.1-wl2325-5.0-drop6, the event type id's were different than in
mysql-5.1-new-rpl.
Fix (in mysql-5.1-new-rpl):
(1) detect that the server that generated the events uses the old
format, by checking the server version of the format_description_log_event
This patch recognizes mysql-5.1-wl2325-5.0-drop6p13-alpha,
mysql-5.1-wl2325-5.0-drop6, mysql-5.1-wl2325-5.0, mysql-5.1-wl2325-no-dd.
(2) if the generating server is old, map old event types to new event
types using a permutation array.
I've also added a test case which reads binlogs for four different
versions.
