Subject: Re: [PATCH 0/2] branch: introduce --current display option

From: Ævar Arnfjörð Bjarmason <[email-masked]>
Date: Wed, 10 Oct 2018 17:03:52 +0200

On Tue, Oct 09 2018, Daniels Umanovskis wrote:

> I often find myself needing the current branch name, for which
> currently there's git rev-parse --abrev-ref HEAD. I would expect `git
> branch` to have an option to output the branch name instead.
>
> This is my first patch to Git, so process-related comments (patch
> formatting, et cetera) are quite welcome.

Thanks for your first patch, and sorry to give you this feedback on it
:)

I'm mildly negative on this because git-rev-parse is plumbing, but
git-branch is porcelain, as listed in "man git", and it helps to be able
to clearly say what's a stable API or not.

But of course I wrote the above paragraph seeing that that's a lie. We
also list git-rev-parse as porcelain, just under "Porcelain / Ancillary
Commands / Interrogators".

Should we just move it to plumbing? I don't know.

In any case, if we're adding such a feature to an existing command it
should be prominently noted in the docs that this option and not others
in git-branch are plumbing-ish, like we do for the (very confusingly
named) --porcelain option to git-status. Users writing scripts need some
reasonable high-level overview of what they can and can't use for
scripting purposes if they expect the output to be stable.

Also, as much as our current scripting interface can be very confusing
(you might not think "get current branch" is under rev-parse), I can't
help but think that adding two different ways to spew out the exact same
thing to two different commands is heading in the wrong
direction. I.e. should we perhaps instead add a new git-ref-info and
start slowly moving/recommending to use that for the various ref (but
not rev) stuff that git-rev-parse is doing, or maybe add a "git
rev-parse --current-branch" and document that it's just a convenience
alias for "git rev-parse --abbrev-ref HEAD"?