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

[Philip Kaludercic]

Juri Linkov <juri@linkov.net> writes:

>>>> I can also imagine that the initial input outside of a log buffer ought
>>>> to just be the last commit.
>>>
>>> Depends on whether this is one of the most popular workflows.
>>
>> Seems popular to me, you make a change and want to submit it. The issue
>> I have noticed is that vc doesn't allow for an easy way to detect the
>> latest revision.  The best I can do is the last revision for the file
>> associated with the current buffer.
>
> The last revision currently is supported only by git and hg backends
> in vc-git-log-edit-toggle-amend and vc-hg-log-edit-toggle-amend.
>
>> 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.