How to pull remote branch with specified commit id?

How to pull remote branch with specified commit id?

[Emily Ren]

Git experts,

I want to pull remote branch with specified commit id, how to do it?

Below command can get remote branch
$git pull remote refs/heads/$branch_name

Below command doesn't work
$git pull remote objects/$commit_id

Thanks,
Emily

Re: How to pull remote branch with specified commit id?

[Andreas Ericsson]

Emily Ren wrote:
> Git experts,
> 
> I want to pull remote branch with specified commit id, how to do it?
> 
> Below command can get remote branch
> $git pull remote refs/heads/$branch_name
> 
> Below command doesn't work
> $git pull remote objects/$commit_id
> 

You need to fetch it first, and then merge the commit you want. The
tools operating the fetching protocol only use refs, so if you want
to fetch (or pull) a specific version that has neither a tag nor a
branch head pointing to it, you'll have to write a new tool for that.

The end-result of the following command will be, barring side-effects
in the remote-tracking branches, identical to what you're trying to
do though:
git fetch remote && git merge $commit_id

-- 
Andreas Ericsson                   andreas.ericsson@op5.se
OP5 AB                             www.op5.se
Tel: +46 8-230225                  Fax: +46 8-230231

Re: How to pull remote branch with specified commit id?

[Johannes Sixt]

Emily Ren schrieb:
> Git experts,
> 
> I want to pull remote branch with specified commit id, how to do it?
> 
> Below command can get remote branch
> $git pull remote refs/heads/$branch_name
> 
> Below command doesn't work
> $git pull remote objects/$commit_id

You can't, and that is so by design.

Consider this: You accidentally push a branch with confidential data to a
public repository. You notice it early, and quickly delete the branch
using 'git push the-repo :refs/heads/that-branch'. At this time the
objects with the confidential data are still lingering in the public
repository. But with the current behavior noone can access them even if
the SHA1 happens to be known.

-- Hannes

Re: How to pull remote branch with specified commit id?

[Emily Ren]

Andreas,

I tried your method, it works. Thank you very much !

Emily

On Tue, Jan 13, 2009 at 5:16 PM, Andreas Ericsson <ae@op5.se> wrote:
> Emily Ren wrote:
>>
>> Git experts,
>>
>> I want to pull remote branch with specified commit id, how to do it?
>>
>> Below command can get remote branch
>> $git pull remote refs/heads/$branch_name
>>
>> Below command doesn't work
>> $git pull remote objects/$commit_id
>>
>
> You need to fetch it first, and then merge the commit you want. The
> tools operating the fetching protocol only use refs, so if you want
> to fetch (or pull) a specific version that has neither a tag nor a
> branch head pointing to it, you'll have to write a new tool for that.
>
> The end-result of the following command will be, barring side-effects
> in the remote-tracking branches, identical to what you're trying to
> do though:
> git fetch remote && git merge $commit_id
>
> --
> Andreas Ericsson                   andreas.ericsson@op5.se
> OP5 AB                             www.op5.se
> Tel: +46 8-230225                  Fax: +46 8-230231
>

Re: How to pull remote branch with specified commit id?

[Brad King]

Johannes Sixt wrote:
> Consider this: You accidentally push a branch with confidential data to a
> public repository. You notice it early, and quickly delete the branch
> using 'git push the-repo :refs/heads/that-branch'. At this time the
> objects with the confidential data are still lingering in the public
> repository. But with the current behavior noone can access them even if
> the SHA1 happens to be known.

Might a repack (perhaps an automatic one) put the object in a pack
(perhaps in a delta chain) that can be fetched through another ref?

-Brad

Re: How to pull remote branch with specified commit id?

[thestar]

> Johannes Sixt wrote:
>> Consider this: You accidentally push a branch with confidential data to a
>> public repository. You notice it early, and quickly delete the branch
>> using 'git push the-repo :refs/heads/that-branch'. At this time the
>> objects with the confidential data are still lingering in the public
>> repository. But with the current behavior noone can access them even if
>> the SHA1 happens to be known.

Doesn't this line of reasoning only apply to the ssh and git transports?
  (ie, the file and rsync transport would retrieve it regardless)

Re: How to pull remote branch with specified commit id?

[Johannes Sixt]

Brad King schrieb:
> Johannes Sixt wrote:
>> Consider this: You accidentally push a branch with confidential data to a
>> public repository. You notice it early, and quickly delete the branch
>> using 'git push the-repo :refs/heads/that-branch'. At this time the
>> objects with the confidential data are still lingering in the public
>> repository. But with the current behavior noone can access them even if
>> the SHA1 happens to be known.
> 
> Might a repack (perhaps an automatic one) put the object in a pack
> (perhaps in a delta chain) that can be fetched through another ref?

No, assuming that-branch was the only ref that contained the objects.

Even if the repack happens before the branch is deleted, the objects that
were *only* in that-branch will not be sent out.

-- Hannes

Re: How to pull remote branch with specified commit id?

[Johannes Sixt]

thestar@fussycoder.id.au schrieb:
>> Johannes Sixt wrote:
>>> Consider this: You accidentally push a branch with confidential data
>>> to a
>>> public repository. You notice it early, and quickly delete the branch
>>> using 'git push the-repo :refs/heads/that-branch'. At this time the
>>> objects with the confidential data are still lingering in the public
>>> repository. But with the current behavior noone can access them even if
>>> the SHA1 happens to be known.
> 
> Doesn't this line of reasoning only apply to the ssh and git transports?
>  (ie, the file and rsync transport would retrieve it regardless)

You are right. Http and rsync would happily ship the object.

-- Hannes