bug#57400: 29.0.50; Support sending patches from VC directly

[Philip Kaludercic <philipk@posteo.net>]

Juri Linkov <juri@linkov.net> writes:

>>>> I have done all of the above and am prepared to push the changes, but
>>>> before I do I was wondering if anyone would have any objections to the
>>>> following changes to vc-git.el:
>>>
>>> Indeed, abbreviated commits are more usable.  But please wait a little
>>> for more comments.
>>
>> Also note that this change would also only affect working-revision and
>> previous-revision.  If necessary or preferred, I could also modify the
>> changes to only affect working-revision.
>
> Nicer names would be better everywhere, including previous-revision.
> But: In my recent mail to RMS I raised questions about 'C-u C-x v ='.
> And when I tried your patch then the default value for "HEAD"
> often is very strange.  For example, try to type 'C-u C-x v ='
> on the file lisp/paren.el.  Here is what it shows:
>
>   Older revision [remotes/origin/scratch/eglot2emacs~488]: 
>
> I wonder where comes "eglot2emacs" from when the current branch is master?

Hmm, it looks like Git tried to find a symbolic reference at any cost,
so it found some branch found a relative commit.  I'll try and find out
if there is a way to avoid this, and only use symbolic references if
there is no positional offset.