[RFC] Separating last-revision from parents

[Henry Ludemann]

> Subject: [RFC] Separating last-revision from parents
> From: Aaron Bentley <aaron.bentley at utoronto.ca>
> 
> In that bug, Henry suggests separating last-revision and pending-merges
> back to the way they used to be.
> 
> I've been thinking about a related issue lately, and I think separation
> is good, but we should have last_revision, and pending_parents.

When you say 'pending_parents', is that only for
bzrlib.workingtree.WorkingTree, or for all bzrlib.tree.Tree classes? If
its for all Tree classes, then 'pending-parents' doesn't make a lot of
sense, as they are no longer pending...

Otherwise, it makes sense... there would be enough information present
to calculate the merged revisions at any given revision (including a
merge to revision 1, so long as last_revision was set to None).