Re: vc-directory breakage

["Eric S. Raymond" <esr@thyrsus.com>]

Stefan Monnier <monnier@iro.umontreal.ca>:
> I believe you have misunderstood the request, then: "support the multi-VCS
> case" means exactly what Dan asks, which is "make sure only one backend
> is used for a given command, even if the command includes files that are
> under various backends".
> 
> I.e. the issue is not "several subdirs of *vc-dir* which each use
> a different backend", but "all the files under *vc-dir* are under the
> control of several backends at the same time".

I understood the second part.  But your first paragraph leaves me
more confused than I was before.

It is already the case that "only one backend is used for a given
command, even if the command includes files that are under various
backends".  If a fileset is not all owned by the same backend, a
consistency check in vc-deduce-fileset will fail.  And C-u C-x v v 
allows us to change the preferred backend for a set of files.

What I don't see is what any of this has to do with keeping a buffer-local
backend variable per directory, which is what Dan is saying he wants.  By
hypothesis, backend is a per-*file* property.  I don't see how trying to 
cache it per directory can be a good idea.
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>