Re: master 4803fba487 1/2: 'C-x v v' on a diff buffer commits it as a patch (bug#52349)

[Juri Linkov <juri@jurta.org>]

>> Can we please implement this for other VCSes as well?
>
> Personally I hope we discover some popular extension to Mercurial which
> we'll be able to use in the same way as we do Git's index area here. And
> then say job well done and keep the less-popular and outdated backends
> unsupported.
>
> 'man hg' didn't give me enough clues, though.

I am unfamiliar with Mercurial, but looking at
https://www.mercurial-scm.org/wiki/GitConcepts#Git.27s_staging_area
where the table says that index/staging area is not necessary in Mercurial
and suggests to use shelve instead that corresponds to Git's stash,
it would be possible to do the same with Hg as we first tried to do
with Git using stash: put changes to stash/shelve, commit and restore
the previous state.  In older VCSes that have neither index/staging area
nor stash/shelve, working area should be cleared by temporarily moving
changed files somewhere.

Anyway, the main point is that adepts of any existing VCS or any future
VCS can easily adapt their VCSes for this feature by just implementing
the backend call 'checkin-patch'.