+1 on the proposal for me, though I would think that we could add the new
attribute/method to the interface with a note that it does not have to be
implemented yet. This gets us back to our interface versioning discussion. I
know you just wanted to avoid this by declaring a new interface, but
Primary problem:
We frequently want to know the full closure of group membership. The
groups attribute of zope.security.interfaces.IGroupAwarePrincipal is
a list of groups to which the principal directly belongs. The full
closure--including the groups to which the principal's groups
