cannot clone --single-commit instead of --single-branch

cannot clone --single-commit instead of --single-branch

[Alexander Mills]

Looking for help with this problem:

https://stackoverflow.com/questions/57316783/git-clone-single-branch-does-not-work-for-sha-commit-ids

Essentially looking for:

git clone --single-commit

since

git clone --single-branch=<sha>

doesn't seem to work?
any help appreciated.

-alex


-- 
Alexander D. Mills
New cell phone # (415)730-1805
alexander.d.mills@gmail.com

www.linkedin.com/pub/alexander-mills/b/7a5/418/

Re: cannot clone --single-commit instead of --single-branch

[Bryan Turner]

On Thu, Aug 1, 2019 at 1:52 PM Alexander Mills
<alexander.d.mills@gmail.com> wrote:
>
> Looking for help with this problem:
>
> https://stackoverflow.com/questions/57316783/git-clone-single-branch-does-not-work-for-sha-commit-ids
>
> Essentially looking for:
>
> git clone --single-commit

There's no such option, which will be why it doesn't work. I suspect
the closest feature is a shallow clone, performed using git clone
--depth=1. That's still not going to allow passing an arbitrary SHA-1,
though; it'll only support a branch name, the same as --single-branch,
which --depth implies (unless --no-single-branch is specified, at
which point it fetches the depth for all branches).

Promisor remotes and other in-flight changes might help provide some
of what you're looking for, but I'm not aware of any already-available
solution. Perhaps something like VFS for Git, if whatever hosting
solution you're using supports it.

Hope this helps!
Bryan

Re: cannot clone --single-commit instead of --single-branch

[Jonathan Nieder]

Hi,

Bryan Turner wrote:

> Promisor remotes and other in-flight changes might help provide some
> of what you're looking for, but I'm not aware of any already-available
> solution.

You can do

	git clone --no-checkout --filter=blob:none $url repo
	cd repo
	git checkout $commit

That gives you commits and trees from other commits, but the only blobs
it downloads are from the named commit.

Using the existing tree filtering features to limit the trees fetched
and/or writing a patch for commit filtering are left as exercises to
the reader.

Thanks and hope that helps,
Jonathan

Re: cannot clone --single-commit instead of --single-branch

[Jonathan Nieder]

(cc: Duy, who might enjoy this walk through history)
Hi,

Alexander Mills wrote:

> git clone --single-branch=<sha>
>
> doesn't seem to work?

I've occasionally wanted something like this (actually, I've wanted to
pass a refname like "refs/meta/config").  builtin/clone.c contains

	static struct ref *find_remote_branch(const struct ref *refs, const char *branch)
	{
		struct ref *ref;
		struct strbuf head = STRBUF_INIT;
		strbuf_addstr(&head, "refs/heads/");
		strbuf_addstr(&head, branch);
		ref = find_ref_by_name(refs, head.buf);
		strbuf_release(&head);

		if (ref)
			return ref;

So far, what one would expect.

		strbuf_addstr(&head, "refs/tags/");
		strbuf_addstr(&head, branch);
		ref = find_ref_by_name(refs, head.buf);
		strbuf_release(&head);

Wait a second: a tag isn't a branch, so why do we accept it as a
value for --branch?  So this is stretching definitions a little
already.

"git log -L:find_remote_branch:builtin/clone.c" tells me this is from
v1.7.10-rc0~125^2~3 (clone: allow --branch to take a tag, 2012-01-16):

	Because a tag ref cannot be put to HEAD, HEAD will become detached.
	This is consistent with "git checkout <tag>".

I think ideally we could first check for a sha1 and then try the full
set of patterns from ref_rev_parse_rules.  What do you think?  Would
you be interested in taking a stab at it?

Thanks,
Jonathan

Re: cannot clone --single-commit instead of --single-branch

[Mike Hommey]

On Thu, Aug 01, 2019 at 07:43:22PM -0700, Jonathan Nieder wrote:
> Hi,
> 
> Bryan Turner wrote:
> 
> > Promisor remotes and other in-flight changes might help provide some
> > of what you're looking for, but I'm not aware of any already-available
> > solution.
> 
> You can do
> 
> 	git clone --no-checkout --filter=blob:none $url repo

TIL. Why doesn't --filter appear in the git-clone manual page?

Mike