"update -r REVNO" support

[Robert Widhopf-Fenk]

On Monday, August 6, 2007 at 00:34:07, Matthew D. Fuller wrote:
> On Mon, Aug 06, 2007 at 03:25:45PM +1000 I heard the voice of
> Martin Pool, and lo! it spake thus:
> > > +                b_revno = wt.branch.last_revision_info()[0]
> > > +                wt_revno =
> > >                  wt.branch.revision_id_to_revno(wt.last_revision())
> > > +                missing = b_revno - wt_revno
> > > +                warning("Working tree is at revno %d missing %d
> > >                  revision%s!" %
> > > +                        (wt_revno, missing,
> > > +                         (missing > 1) and "s" or ""))
> > 
> > Giving more information here is good.
> 
> But correct information is better.  The above fails twice if the
> working tree is on a non-mainline revision; first because
> revision_id_to_revno() doesn't give you an answer in that case, and
> second because the subtraction wouldn't give you a useful answer if
> it did ("How the heck am I 7.8.37.931.5 revisions out of date?!")
> 
> It would probably be better just to say "Branch is at revision X,
> working tree at revision Y.Z".

Is there a way to get a "numeric" revno for the working
tree?  I cannot figure out how to do it for this case.

Thanks
Robert