threads / discuss / 62482

Shallow clone of a specific git revision?

Subject: Shallow clone of a specific git revision?

## tl;dr

6 messages between Nov 12, 2024 and Nov 15, 2024.

replies: 5people: 4as markdown or json

Michal Suchánek· Nov 12, 2024, 12:24 UTC · lore
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
Toon Claes· Nov 13, 2024, 10:23 UTC · re: Michal Suchánek · lore

Re: Shallow clone of a specific git revision?

Michal Suchánek <msuchanek@suse.de> writes:
Show 7 quoted lines
> 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/
Michal Suchánek· Nov 13, 2024, 10:29 UTC · re: Toon Claes · lore

Re: Shallow clone of a specific git revision?

On Wed, Nov 13, 2024 at 11:23:47AM +0100, Toon Claes wrote:
Show 15 quoted lines
> 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
David Aguilar· Nov 15, 2024, 05:00 UTC · re: Michal Suchánek · lore

Re: Shallow clone of a specific git revision?

On Wed, Nov 13, 2024 at 11:29:48AM +0100, Michal Suchánek wrote:
Show 27 quoted lines
> 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
Jeff King· Nov 15, 2024, 09:37 UTC · re: David Aguilar · lore

Re: Shallow clone of a specific git revision?

On Thu, Nov 14, 2024 at 09:00:43PM -0800, David Aguilar wrote:
Show 10 quoted lines
> 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:
Show 16 quoted lines
> 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
Michal Suchánek· Nov 15, 2024, 10:43 UTC · re: David Aguilar · lore

Re: Shallow clone of a specific git revision?

Hello,
On Thu, Nov 14, 2024 at 09:00:43PM -0800, David Aguilar wrote:
Show 30 quoted lines
> 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.
Show 9 quoted lines
> 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.

Show 16 quoted lines
> 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

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