If MySQL tries to do SELECT from an InnoDB table, but has set no table locks at all in ::external_lock(), print a descriptive error message and assert; some subquery bugs were of this type


innobase/row/row0sel.c:
  If MySQL tries to do SELECT from an InnoDB table, but has set no table locks at all in ::external_lock(), print a descriptive error message and assert; some subquery bugs were of this type