Detailed revision comments:

r6051 | sunny | 2009-10-12 07:05:00 +0300 (Mon, 12 Oct 2009) | 6 lines
branches/5.1: Ignore negative values supplied by the user when calculating the
next value to store in dict_table_t. Setting autoincrement columns top negative
values is undefined behavior and this change should bring the behavior of
InnoDB closer to what users expect. Added several tests to check.
rb://162