threads / discuss / 29566

cloning a tree which has detached branch checked out

Subject: cloning a tree which has detached branch checked out

## tl;dr

10 messages between Feb 7, 2012 and Feb 8, 2012.

replies: 9people: 5as markdown or json

Michael S. Tsirkin· Feb 7, 2012, 07:06 UTC · lore

I have a tree where I checked out a remote, without
creating a local branch, this detaches the HEAD:
# git branch
* (no branch)
  master
#git log|head -1
commit cec64082f689f949a397cb9b39423dc41545fa0e
#git log master..HEAD|head -1
commit cec64082f689f949a397cb9b39423dc41545fa0e

Now if I try to clone it: #git clone -n lab:/home/mst/scm/linux Initialized empty Git repository in /home/mst/scm/linux/.git/ remote: Counting objects: 1693446, done. remote: Compressing objects: 100% (277054/277054), done. Receiving objects: 100% (1693446/1693446), 418.16 MiB | 7.63 MiB/s, done. remote: Total 1693446 (delta 1414353), reused 1681280 (delta 1402358) Resolving deltas: 100% (1414353/1414353), done. error: Trying to write ref HEAD with nonexistant object cec64082f689f949a397cb9b39423dc41545fa0e fatal: Cannot update the ref 'HEAD'.

Looks like a bug, doesn't it?

-- 
MST

Jakub Narebski· Feb 7, 2012, 10:08 UTC · re: Michael S. Tsirkin · lore

Re: cloning a tree which has detached branch checked out

"Michael S. Tsirkin" <mst@redhat.com> writes:

Show 25 quoted lines

> I have a tree where I checked out a remote, without
> creating a local branch, this detaches the HEAD:
> # git branch
> * (no branch)
>   master
> #git log|head -1
> commit cec64082f689f949a397cb9b39423dc41545fa0e
> #git log master..HEAD|head -1
> commit cec64082f689f949a397cb9b39423dc41545fa0e
> 
> 
> Now if I try to clone it:
> #git clone -n lab:/home/mst/scm/linux
> Initialized empty Git repository in /home/mst/scm/linux/.git/
> remote: Counting objects: 1693446, done.
> remote: Compressing objects: 100% (277054/277054), done.
> Receiving objects: 100% (1693446/1693446), 418.16 MiB | 7.63 MiB/s,
> done.
> remote: Total 1693446 (delta 1414353), reused 1681280 (delta 1402358)
> Resolving deltas: 100% (1414353/1414353), done.
> error: Trying to write ref HEAD with nonexistant object
> cec64082f689f949a397cb9b39423dc41545fa0e
> fatal: Cannot update the ref 'HEAD'.
> 
> Looks like a bug, doesn't it?

Which git version? IIRC there was some bugfix recently in that area...

-- 
Jakub Narebski

Michael S. Tsirkin· Feb 7, 2012, 10:41 UTC · re: Jakub Narebski · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 07, 2012 at 02:08:33AM -0800, Jakub Narebski wrote:

Show 30 quoted lines

> "Michael S. Tsirkin" <mst@redhat.com> writes:
> 
> > I have a tree where I checked out a remote, without
> > creating a local branch, this detaches the HEAD:
> > # git branch
> > * (no branch)
> >   master
> > #git log|head -1
> > commit cec64082f689f949a397cb9b39423dc41545fa0e
> > #git log master..HEAD|head -1
> > commit cec64082f689f949a397cb9b39423dc41545fa0e
> > 
> > 
> > Now if I try to clone it:
> > #git clone -n lab:/home/mst/scm/linux
> > Initialized empty Git repository in /home/mst/scm/linux/.git/
> > remote: Counting objects: 1693446, done.
> > remote: Compressing objects: 100% (277054/277054), done.
> > Receiving objects: 100% (1693446/1693446), 418.16 MiB | 7.63 MiB/s,
> > done.
> > remote: Total 1693446 (delta 1414353), reused 1681280 (delta 1402358)
> > Resolving deltas: 100% (1414353/1414353), done.
> > error: Trying to write ref HEAD with nonexistant object
> > cec64082f689f949a397cb9b39423dc41545fa0e
> > fatal: Cannot update the ref 'HEAD'.
> > 
> > Looks like a bug, doesn't it?
> 
> Which git version?  IIRC there was some bugfix recently in that
> area...

Sorry, forgot to mention that. It's pretty recent: $ git --version git version 1.7.9.111.gf3fb0

> -- 
> Jakub Narebski

Nguyen Thai Ngoc Duy· Feb 7, 2012, 12:57 UTC · re: Michael S. Tsirkin · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 7, 2012 at 5:41 PM, Michael S. Tsirkin <mst@redhat.com> wrote:

Show 14 quoted lines

>> > #git clone -n lab:/home/mst/scm/linux
>> > ....
>> > error: Trying to write ref HEAD with nonexistant object
>> > cec64082f689f949a397cb9b39423dc41545fa0e
>> > fatal: Cannot update the ref 'HEAD'.
>> >
>> > Looks like a bug, doesn't it?
>>
>> Which git version?  IIRC there was some bugfix recently in that
>> area...
>
> Sorry, forgot to mention that. It's pretty recent:
> $ git --version
> git version 1.7.9.111.gf3fb0

The series that Jakub mentioned is probably nd/clone-detached 5ce2b97, which is already included in your tree. Does 1.7.9 work?

I tried but it was ok for me. I think ref processing at local probably goes wrong and does not request commit from HEAD. If the repo is not confidential, you can zip it and send me.

-- 
Duy

Michael S. Tsirkin· Feb 7, 2012, 13:02 UTC · re: Nguyen Thai Ngoc Duy · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 07, 2012 at 07:57:08PM +0700, Nguyen Thai Ngoc Duy wrote:

Show 18 quoted lines

> On Tue, Feb 7, 2012 at 5:41 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> >> > #git clone -n lab:/home/mst/scm/linux
> >> > ....
> >> > error: Trying to write ref HEAD with nonexistant object
> >> > cec64082f689f949a397cb9b39423dc41545fa0e
> >> > fatal: Cannot update the ref 'HEAD'.
> >> >
> >> > Looks like a bug, doesn't it?
> >>
> >> Which git version?  IIRC there was some bugfix recently in that
> >> area...
> >
> > Sorry, forgot to mention that. It's pretty recent:
> > $ git --version
> > git version 1.7.9.111.gf3fb0
> 
> The series that Jakub mentioned is probably nd/clone-detached 5ce2b97,
> which is already included in your tree. Does 1.7.9 work?

I'll try that.

> I tried but it was ok for me. I think ref processing at local probably
> goes wrong and does not request commit from HEAD.  If the repo is not
> confidential, you can zip it and send me.

Can't unfortunately :( Would some verbose logs help?

> -- 
> Duy

Nguyen Thai Ngoc Duy· Feb 7, 2012, 13:07 UTC · re: Michael S. Tsirkin · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 7, 2012 at 8:02 PM, Michael S. Tsirkin <mst@redhat.com> wrote:

Show 6 quoted lines

>> I tried but it was ok for me. I think ref processing at local probably
>> goes wrong and does not request commit from HEAD.  If the repo is not
>> confidential, you can zip it and send me.
>
> Can't unfortunately :(
> Would some verbose logs help?

You can try cloning with GIT_TRACE_PACKET=1. bisect should also help.

-- 
Duy

Jeff King· Feb 7, 2012, 15:32 UTC · re: Nguyen Thai Ngoc Duy · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 07, 2012 at 07:57:08PM +0700, Nguyen Thai Ngoc Duy wrote:

Show 22 quoted lines

> On Tue, Feb 7, 2012 at 5:41 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> >> > #git clone -n lab:/home/mst/scm/linux
> >> > ....
> >> > error: Trying to write ref HEAD with nonexistant object
> >> > cec64082f689f949a397cb9b39423dc41545fa0e
> >> > fatal: Cannot update the ref 'HEAD'.
> >> >
> >> > Looks like a bug, doesn't it?
> >>
> >> Which git version?  IIRC there was some bugfix recently in that
> >> area...
> >
> > Sorry, forgot to mention that. It's pretty recent:
> > $ git --version
> > git version 1.7.9.111.gf3fb0
> 
> The series that Jakub mentioned is probably nd/clone-detached 5ce2b97,
> which is already included in your tree. Does 1.7.9 work?
> 
> I tried but it was ok for me. I think ref processing at local probably
> goes wrong and does not request commit from HEAD.  If the repo is not
> confidential, you can zip it and send me.

This particular bug should have been fixed before that, even, with my c1921c1 (clone: always fetch remote HEAD, 2011-06-07). And it is tested explicitly in t5707, so your series does not regress at least a simple case. So I think your guess about a subtle error in the local ref processing is a reasonable one.

-Peff

Junio C Hamano· Feb 7, 2012, 17:11 UTC · re: Jeff King · lore

Re: cloning a tree which has detached branch checked out

Jeff King <peff@peff.net> writes:

Show 15 quoted lines

> On Tue, Feb 07, 2012 at 07:57:08PM +0700, Nguyen Thai Ngoc Duy wrote:
>
>> On Tue, Feb 7, 2012 at 5:41 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
>> >> > #git clone -n lab:/home/mst/scm/linux
>> >> > ....
>> >> > error: Trying to write ref HEAD with nonexistant object
>> >> > cec64082f689f949a397cb9b39423dc41545fa0e
>> >> > fatal: Cannot update the ref 'HEAD'.
>> >> >
>> >> > Looks like a bug, doesn't it?
>> >> ...
>
> This particular bug should have been fixed before that, even, with my
> c1921c1 (clone: always fetch remote HEAD, 2011-06-07). And it is tested
> explicitly in t5707,...

That was my thought when I first saw it. The failure case was that HEAD was pointing at something no ref reaches, and clone was only grabbing the tips of branches, which failed to transfer the history leading to HEAD.

> ... So I think your guess about a subtle error in the local ref
> processing is a reasonable one.

What is funny is "error: Trying to write ref HEAD with nonexistant object". "git grep -e nonexistant f3fb0" does not register any hit.

Could it be that mysterious "lab:" protocol handler that is misbehaving?

Jeff King· Feb 7, 2012, 17:16 UTC · re: Junio C Hamano · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 07, 2012 at 09:11:00AM -0800, Junio C Hamano wrote:

Show 6 quoted lines

> > This particular bug should have been fixed before that, even, with my
> > c1921c1 (clone: always fetch remote HEAD, 2011-06-07). And it is tested
> > explicitly in t5707,...
> [...]
> What is funny is "error: Trying to write ref HEAD with nonexistant object".
> "git grep -e nonexistant f3fb0" does not register any hit.

That misspelling of "nonexistent" was fixed by 7be8b3b (Fix typo: existant->existent, 2011-06-16), around the same time as my clone patch. Which really makes me wonder if the OP is accidentally running an old version of git during the tests.

> >> On Tue, Feb 7, 2012 at 5:41 PM, Michael S. Tsirkin <mst@redhat.com> wrote:
> >> >> > #git clone -n lab:/home/mst/scm/linux
> [...]
> Could it be that mysterious "lab:" protocol handler that is misbehaving?

I think you are misreading. It would be "lab::" in that case, no? The command above should do ssh transport to the machine "lab".

-Peff

Michael S. Tsirkin· Feb 8, 2012, 10:17 UTC · re: Jeff King · lore

Re: cloning a tree which has detached branch checked out

On Tue, Feb 07, 2012 at 12:16:04PM -0500, Jeff King wrote:

Show 13 quoted lines

> On Tue, Feb 07, 2012 at 09:11:00AM -0800, Junio C Hamano wrote:
> 
> > > This particular bug should have been fixed before that, even, with my
> > > c1921c1 (clone: always fetch remote HEAD, 2011-06-07). And it is tested
> > > explicitly in t5707,...
> > [...]
> > What is funny is "error: Trying to write ref HEAD with nonexistant object".
> > "git grep -e nonexistant f3fb0" does not register any hit.
> 
> That misspelling of "nonexistent" was fixed by 7be8b3b (Fix typo:
> existant->existent, 2011-06-16), around the same time as my clone patch.
> Which really makes me wonder if the OP is accidentally running an old
> version of git during the tests.

Double checked and you are right: the box actually runs git 1.7.1. Rechecked with 1.7.9.GIT and it behaves correctly.

My mistake, sorry about the noise.

-- 
MST