From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Git List <git@vger.kernel.org>,
Johannes Schindelin <Johannes.Schindelin@gmx.de>
Subject: Re: Is origin/HEAD only being created on clone a bug? #leftoverbits
Date: Thu, 31 May 2018 09:42:03 +0200 [thread overview]
Message-ID: <87bmcw9sqc.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <xmqqo9gyey13.fsf@gitster-ct.c.googlers.com>
On Wed, May 30 2018, Junio C Hamano wrote:
> Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:
>
>> If you make an initial commit and push to a remote repo "origin", you
>> don't get a remote origin/HEAD reference, and a "fetch" won't create it
>> either.
>> ...
>> Some code spelunking reveals remote_head_points_at, guess_remote_head()
>> etc. in builtin/clone.c. I.e. this is special-cased as part of the
>> "clone".
>
> Correct. Originally, there was *no* way in the protocol to carry
> the information, so the code always had to guess. The point of
> setting origin/HEAD was mostly so that you can say "log origin.."
> and rely on it getting dwimmed down to "refs/remotes/%s/HEAD..",
> and it wasn't a common practice to interact with multiple remotes
> with remote tracking branches (integrator interacting with dozens
> of remotes, responding to pull requests using explicit URL but
> without configured remotes was not uncommon), so it was sufficient
> for "git clone" to create it, and "git remote add" did not exist
> back then anyway.
>
> There are two aspects in my answer to your question.
>
> - If we create additional remote (that is, other than the one we
> get when we create a repository via "clone", so if your "origin"
> is from "git init there && cd there && git remote add origin", it
> does count in this category), should we get a remote-tracking
> symref $name/HEAD so that we can say "log $name.."?
>
> We absolutely should. We (eh, rather, those who added "remote
> add"; this was not my itch and I am using "royal we" in this
> sentence) just did not bother to and I think it is a bug that you
> cannot say "log $name.." Of course, it is just a "git symbolic-ref"
> away to make it possible locally, so it is understandable if
> "remote add" did not bother to.
>
> - When we fetch from a remote that has refs/remotes/$name/HEAD, and
> if the protocol notices that their HEAD today is pointing to a
> branch different from what our side has, should we repoint ours
> to match?
>
> I am leaning against doing this, but mostly out of superstition.
> Namely, I feel uneasy about the fact that the meaning of "log
> ..origin" changes across a fetch in this sequence:
>
> log ..origin && fetch origin && log ..origin
>
> Without repointing origin/HEAD, two occurrences of "log ..origin"
> both means "how much ahead the primary branch we have been
> interested in from this remote is, relative to our effort?".
> Even though we fully expect that two "log ..origin" would report
> different results (after all, that is the whole point of doing
> another one after "fetch" in such a sequence like this example),
> our question is about the same "primary branch we have been
> interested in". But once fetch starts messing with where
> origin/HEAD points at, that would no longer be the case, which is
> why I am against doing something magical like that.
We already have to deal with this special case of origin/HEAD being
re-pointed in a repository that we "clone", so we would just do whatever
happens to a repository that's cloned.
I.e. the "clone" sets the origin/HEAD up as a one-off, and then keeps
updating it on the basis of updating existing refs. We'd similarly set
it up as a one-off if we ever "fetch" and notice that the ref doesn't
exist yet, and then we'd update it in the same way we update it now.
So this seems like a non-issue to me as far as me coming up with some
patch to one-off write the origin/HEAD on the first "fetch", or am I
missing something?
next prev parent reply other threads:[~2018-05-31 7:42 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-29 18:30 Is origin/HEAD only being created on clone a bug? #leftoverbits Ævar Arnfjörð Bjarmason
2018-05-29 19:17 ` Brandon Williams
2018-05-30 1:24 ` Junio C Hamano
2018-05-30 2:46 ` Junio C Hamano
2018-06-01 6:51 ` Jeff King
2018-05-31 7:42 ` Ævar Arnfjörð Bjarmason [this message]
2018-06-01 1:32 ` Junio C Hamano
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