bug#20637: incompatible, undocumented change to vc-working-revision

[Dmitry Gutov]

On 04/15/2016 04:11 PM, Michael Albinus wrote:

> I would prefer to apply further patches to the master branch only. Only
> patches absolutely necessary for fixing problems shall go to the
> emacs-25 branch, in order not to threaten the release.

I can do that.

> After applying your patch, vc-tests.el fails for me in vc-test-src02-state

How do you install src? Do you build it from source?

> and vc-test-rcs03-working-revision.

This one (failure in vc-checkout-model5) seems to be a real bug 
uncovered by using vc-file-clearprops. I suppose we should add a FIXME 
there and skip that check for RCS.

> > -  (let ((symbol (intern (downcase (format "vc-%s-unregister" backend)))))
> > -    (if (functionp symbol)
> > -       (funcall symbol file)
> > -      ;; CVS, SVN, SCCS, SRC and Mtn are not supported.
> > -      (signal 'vc-not-supported (list 'unregister backend)))))
> > +  ;; CVS, SVN, SCCS, SRC and Mtn are not supported, and will signal
> > +  ;; `vc-not-supported'.
> > +  (vc-call-backend backend 'unregister file)
> > +  (vc-file-clearprops file))
>
> As said, in the master branch I would prefer to add a vc-unregister
> function. Then we won't need this anymore.

We'll need this code either way. Where the function resides and how it 
is called is less important to me.