Shallow clone of a specific git revision?

Shallow clone of a specific git revision?

[Michal Suchánek]

Hello,

Looking through clone man page it supports shallow clones of branches
and tags only.

Would it be possible to do shallow clone of a specific revision,
and checkout specific revision on clone?

Thanks

Michal

Re: Shallow clone of a specific git revision?

[Toon Claes]

Michal Suchánek <msuchanek@suse.de> writes:

> Hello,
>
> Looking through clone man page it supports shallow clones of branches
> and tags only.
>
> Would it be possible to do shallow clone of a specific revision,
> and checkout specific revision on clone?

Hi Michal,

I'm working on a patch, and I've submitted a first version [1] a little
while ago to allow users to pass a reference on git-clone(1). Would this
change fit your needs, or what else would you like to support?

--
Toon



[1]: https://lore.kernel.org/git/20240927085438.1010431-1-toon@iotcl.com/

Re: Shallow clone of a specific git revision?

[Michal Suchánek]

On Wed, Nov 13, 2024 at 11:23:47AM +0100, Toon Claes wrote:
> Michal Suchánek <msuchanek@suse.de> writes:
> 
> > Hello,
> >
> > Looking through clone man page it supports shallow clones of branches
> > and tags only.
> >
> > Would it be possible to do shallow clone of a specific revision,
> > and checkout specific revision on clone?
> 
> Hi Michal,
> 
> I'm working on a patch, and I've submitted a first version [1] a little
> while ago to allow users to pass a reference on git-clone(1). Would this
> change fit your needs, or what else would you like to support?

> [1]: https://lore.kernel.org/git/20240927085438.1010431-1-toon@iotcl.com/

Hello,

that slightly expands the available options but it does not make it
possible to clone an arbitrary revision, ie. specified by a SHA

Thanks

Michal

Re: Shallow clone of a specific git revision?

[David Aguilar]

On Wed, Nov 13, 2024 at 11:29:48AM +0100, Michal Suchánek wrote:
> On Wed, Nov 13, 2024 at 11:23:47AM +0100, Toon Claes wrote:
> > Michal Suchánek <msuchanek@suse.de> writes:
> > 
> > > Hello,
> > >
> > > Looking through clone man page it supports shallow clones of branches
> > > and tags only.
> > >
> > > Would it be possible to do shallow clone of a specific revision,
> > > and checkout specific revision on clone?
> > 
> > Hi Michal,
> > 
> > I'm working on a patch, and I've submitted a first version [1] a little
> > while ago to allow users to pass a reference on git-clone(1). Would this
> > change fit your needs, or what else would you like to support?
> 
> > [1]: https://lore.kernel.org/git/20240927085438.1010431-1-toon@iotcl.com/
> 
> Hello,
> 
> that slightly expands the available options but it does not make it
> possible to clone an arbitrary revision, ie. specified by a SHA
> 
> Thanks
> 
> Michal

In case it helps, here's a short recipe demonstrating how to do a
shallow "clone" of a specific commit ID:

    git init the-repo
    cd ./the-repo
    git remote add origin <url>
    git fetch --depth=1 origin <commit-id>
    git checkout <commit-id>

It'd be nice to add this feature to "git clone" for convenience.

This recipe depends on the server's configuration. You must have one of
the following configuration variables set "true" server-side in order
for the server to accept requests for arbitrary commit IDs:

    uploadpack.allowReachableSHA1InWant
        Allow upload-pack to accept a fetch request that asks for an
        object that is reachable from any ref tip. However, note that
        calculating object reachability is computationally expensive.
        Defaults to false. Even if this is false, a client may be able
        to steal objects via the techniques described in the "SECURITY"
        section of the gitnamespaces(7) man page; it’s best to keep
        private data in a separate repository.

    uploadpack.allowAnySHA1InWant
        Allow upload-pack to accept a fetch request that asks for any
        object at all. Defaults to false.

cheers,
-- 
David

Re: Shallow clone of a specific git revision?

[Jeff King]

On Thu, Nov 14, 2024 at 09:00:43PM -0800, David Aguilar wrote:

> In case it helps, here's a short recipe demonstrating how to do a
> shallow "clone" of a specific commit ID:
> 
>     git init the-repo
>     cd ./the-repo
>     git remote add origin <url>
>     git fetch --depth=1 origin <commit-id>
>     git checkout <commit-id>
> 
> It'd be nice to add this feature to "git clone" for convenience.

Agreed on all parts of this, but wanted to mention one thing here:

> This recipe depends on the server's configuration. You must have one of
> the following configuration variables set "true" server-side in order
> for the server to accept requests for arbitrary commit IDs:
> 
>     uploadpack.allowReachableSHA1InWant
>         Allow upload-pack to accept a fetch request that asks for an
>         object that is reachable from any ref tip. However, note that
>         calculating object reachability is computationally expensive.
>         Defaults to false. Even if this is false, a client may be able
>         to steal objects via the techniques described in the "SECURITY"
>         section of the gitnamespaces(7) man page; it’s best to keep
>         private data in a separate repository.
> 
>     uploadpack.allowAnySHA1InWant
>         Allow upload-pack to accept a fetch request that asks for any
>         object at all. Defaults to false.

In the v2 protocol, the reachability checks are gone (as if allowAny was
set). So if the server speaks v2, your instructions should just work.
Most servers should be new enough to support this (and certainly big
forges like GitHub and GitLab do), though note that for git-over-ssh the
server side might need to configure ssh to allow the correct environment
variables. There's discussion in the GIT_PROTOCOL section of git(1).

-Peff

Re: Shallow clone of a specific git revision?

[Michal Suchánek]

Hello,

On Thu, Nov 14, 2024 at 09:00:43PM -0800, David Aguilar wrote:
> On Wed, Nov 13, 2024 at 11:29:48AM +0100, Michal Suchánek wrote:
> > On Wed, Nov 13, 2024 at 11:23:47AM +0100, Toon Claes wrote:
> > > Michal Suchánek <msuchanek@suse.de> writes:
> > > 
> > > > Hello,
> > > >
> > > > Looking through clone man page it supports shallow clones of branches
> > > > and tags only.
> > > >
> > > > Would it be possible to do shallow clone of a specific revision,
> > > > and checkout specific revision on clone?
> > > 
> > > Hi Michal,
> > > 
> > > I'm working on a patch, and I've submitted a first version [1] a little
> > > while ago to allow users to pass a reference on git-clone(1). Would this
> > > change fit your needs, or what else would you like to support?
> > 
> > > [1]: https://lore.kernel.org/git/20240927085438.1010431-1-toon@iotcl.com/
> > 
> > Hello,
> > 
> > that slightly expands the available options but it does not make it
> > possible to clone an arbitrary revision, ie. specified by a SHA
> > 
> > Thanks
> > 
> > Michal
> 
> In case it helps, here's a short recipe demonstrating how to do a

Yes, that's helpful, thanks.

> shallow "clone" of a specific commit ID:
> 
>     git init the-repo
>     cd ./the-repo
>     git remote add origin <url>
>     git fetch --depth=1 origin <commit-id>
>     git checkout <commit-id>
> 
> It'd be nice to add this feature to "git clone" for convenience.

This is how many git reatures start, after all. They are provided as a
script on top of core git functionality.

> This recipe depends on the server's configuration. You must have one of
> the following configuration variables set "true" server-side in order
> for the server to accept requests for arbitrary commit IDs:
> 
>     uploadpack.allowReachableSHA1InWant
>         Allow upload-pack to accept a fetch request that asks for an
>         object that is reachable from any ref tip. However, note that
>         calculating object reachability is computationally expensive.
>         Defaults to false. Even if this is false, a client may be able
>         to steal objects via the techniques described in the "SECURITY"
>         section of the gitnamespaces(7) man page; it’s best to keep
>         private data in a separate repository.
> 
>     uploadpack.allowAnySHA1InWant
>         Allow upload-pack to accept a fetch request that asks for any
>         object at all. Defaults to false.

I would be fetching from a forge most of the time which would use its own
implementation of git server most of the time but it's good to know what
the options are on the canonical implementation at least.

Thanks

Michal