Re: [PATCH v2] clone: Allow combining --bare and --origin

From: Junio C Hamano <gitster@pobox.com>
Date: Aug 3, 2021, 21:28 UTC
Message-ID: <xmqqv94mtdyj.fsf@gitster.g>
In-Reply-To: <20210802174944.53745-1-oystwa@gmail.com>

Øystein Walle <oystwa@gmail.com> writes:

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> The constraint on passing both these options simultaneously has been
> present since long before clone was ported to C. At the time no
> configuration referencing the remote repository was written at all in
> bare clones.
>
> Since df61c88979 (clone: also configure url for bare clones, 2010-03-29)
> the remote repository is mentioned in the configuration file also for
> bare repos, so it makes sense to allow the user to rename it if they
> wish.

Sounds sensible.

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> Ævar, I was a bit melodramatic when I wrote "especially useful". I have
> toned the commit message down a bit :-) In truth, I don't personally
> have a use-case for this (I did reach out to the person who asked about
> it in #git but did't get a reply) and have no problems with seeing this
> patch ultimately rejected. It's just a result of me seeing it asked
> about and getting an itch from it. But in my humble opinion this is now
> an "artificial" constraint (for lack of a better term) and should be
> removed on the grounds that there is no reason for it to be there in the
> first place.

Yup, that is exactly my thought when I responded to your v1.

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> +test_expect_success '--bare works with -o/--origin' '
> +	git clone --bare --origin=somewhere parent clone-bare &&
> +	url="$(git -C clone-bare config --local remote.somewhere.url)" &&
> +	test -n "$url" &&
> +	test_must_fail git -C clone-bare config --local remote.origin.url
>  '

It is somewhat unfortunate that we do not say what the name of the "origin" is anywhere in the resulting configuration file. The only way to tell that "--origin somewhere" was used is to notice that there is only one remote and its name is "somewhere". Instead of "usually the thing is called 'origin', so let's make sure it does not exist", we may want to say "there is only one remote and it is called somewhere because that is how we named it", i.e.

	git -C clone-bare config --name-only \
		--get-regexp "remote\..*\.url" >actual &&
	echo remote.somewhere.url >expect &&
	test_cmp actual expect

But stepping back a bit, I think this shows another reason why use of '--origin' with '--bare' as-is may not be so pleasant to use.

In a repository _with_ working tree, this lack of "what is 'origin' called in this repository?" is not a problem because you'd get these after cloning:

    [remote "somewhere"]
	url = ...
	fetch = ...
    [branch "master"]
	remote = "somewhere"
	merge = refs/heads/master

You can say "git fetch" or "git pull" without the remote name and we will know which remote to interact with, because our branch knows which remote to fetch from.

In a bare repository, however, you only get this:

    [remote "somewhere"]
	url = ...

I do not think "git fetch" in such a repository knows that it needs to fetch from 'somewhere', even whe it is the only remote repository available to us.

We may need a bit _more_ work (e.g. leave an optional configuration remote.originName = "somewhere" when "--bare --origin somewhere" is used, and teach "git fetch" to pay attention to it, instead of assuming 'origin') before "--bare --origin somewhere" becomes truly usable. And I suspect that "git fetch" is not the only one that needs such "fix".