Re: vc.el and diff-switches containing "-r"

[Andre Spiegel <spiegel@gnu.org>]

Michael Ernst <mernst@alum.mit.edu> writes:

> vc.el unconditionally uses `diff-switches' (though it also concatenates
> `vc-diff-switches').  However, some switches that are sensible in
> `diff-switches' are not sensible as arguments to (say) "cvs diff".  This
> patch corrects the problem.  (Another solution would be for
> `vc-diff-switches' to override `diff-switches', if set, rather than for
> both to be used.)

Thanks for the report.  I do favour the latter approach, where
vc-diff-switches overrides diff-switches if set.  Likewise, I think
vc-cvs-diff-switches should override the other two if set, rather
than be concatenated.

I don't like the idea of treating "-r" specially as in your patch --
the same problem would be bound to come up with other options and
other backends as well.

I will change the behaviour as outlined above as soon as I find time
to rework the backend-specific variable handling, as I am planning
anyway.  It will be before the next Emacs release.  Until then, I hope
you can do with your local modification.