Git question. Is there a way of duplicating a git repository?

Git question. Is there a way of duplicating a git repository?

[Alan Mackenzie]

Hello, Emacs.

Now that we've cut the emacs-25 release branch, I'd like to have a
distinct repository for this.

I could simply download another copy from savannah, but this would
(presumably) be a distinct copy, rather than hard linking the repository
files.  This would cost me disk (and backup) space.

Or I could clone my master repository to make emacs-25.  But this would
make the new repo firmly subordinate to the master repo, rather than
directly with savannah.

So, is there any convenient way of duplicating a repo (using hard links,
and preserving config info)?

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: Git question. Is there a way of duplicating a git repository?

[Achim Gratz]

Alan Mackenzie writes:
> Or I could clone my master repository to make emacs-25.  But this would
> make the new repo firmly subordinate to the master repo, rather than
> directly with savannah.

So what, simply copy over the .git/config file from your "master" repo
after you've done cloning.


Regards,
Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

Samples for the Waldorf Blofeld:
http://Synth.Stromeko.net/Downloads.html#BlofeldSamplesExtra

Re: Git question. Is there a way of duplicating a git repository?

[Dmitry Gutov]

On 11/14/2015 01:20 PM, Alan Mackenzie wrote:

> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

See http://nuclearsquid.com/writings/git-new-workdir/.

However, considering your attitude to learning Git internals, maybe you 
should just use one of the two already two methods that you've already 
mentioned, and live with its drawbacks.

git-new-workdir worked fine for me, though, last I tried.

Re: Git question. Is there a way of duplicating a git repository?

[Alan Mackenzie]

Hello, Dmitry.

On Sat, Nov 14, 2015 at 07:06:20PM +0200, Dmitry Gutov wrote:
> On 11/14/2015 01:20 PM, Alan Mackenzie wrote:

> > So, is there any convenient way of duplicating a repo (using hard links,
> > and preserving config info)?

> See http://nuclearsquid.com/writings/git-new-workdir/.

I had a look at that site, thanks.

> However, considering your attitude to learning Git internals, maybe you 
> should just use one of the two already two methods that you've already 
> mentioned, and live with its drawbacks.

Just to clarify that attitude: I'm most unhappy about the fact that I
need to learn about git internals to be able to get work done; I'd far
prefer just to be a git user.  However, when it is necessary to dive
into the internals, I do it.

> git-new-workdir worked fine for me, though, last I tried.

With the help of suggestions from Ken Brown, I've managed to get the
setup I want.

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: Git question. Is there a way of duplicating a git repository?

[Liang Wang]

On Sat, Nov 14, 2015 at 3:20 AM, Alan Mackenzie <acm@muc.de> wrote:
>
> Hello, Emacs.
>
> Now that we've cut the emacs-25 release branch, I'd like to have a
> distinct repository for this.
>
> I could simply download another copy from savannah, but this would
> (presumably) be a distinct copy, rather than hard linking the repository
> files.  This would cost me disk (and backup) space.
>
> Or I could clone my master repository to make emacs-25.  But this would
> make the new repo firmly subordinate to the master repo, rather than
> directly with savannah.
>
> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

https://github.com/git/git/blob/master/contrib/workdir/git-new-workdir
might help.

>
> --
> Alan Mackenzie (Nuremberg, Germany).
>

Thanks,
Liang.

Re: Git question. Is there a way of duplicating a git repository?

[Ivan Shmakov]

>>>>> Alan Mackenzie <acm@muc.de> writes:

 > Now that we've cut the emacs-25 release branch, I'd like to have a
 > distinct repository for this.

 > I could simply download another copy from savannah, but this would
 > (presumably) be a distinct copy, rather than hard linking the
 > repository files.  This would cost me disk (and backup) space.

 > Or I could clone my master repository to make emacs-25.  But this
 > would make the new repo firmly subordinate to the master repo, rather
 > than directly with savannah.

 > So, is there any convenient way of duplicating a repo (using hard
 > links, and preserving config info)?

	I didn’t test it, but given that said subordination is just a
	matter of a few lines in the respective .git/config, something
	along the lines below is ought to work.

$ git clone -- emacs-1 emacs-2 
$ cp --backup=t -- emacs-1/.git/config emacs-2/.git/config 
$ 

-- 
FSF associate member #7257  http://am-1.org/~ivan/      … 3013 B6A0 230E 334A

Re: Git question. Is there a way of duplicating a git repository?

[David Reitter]

On Nov 14, 2015, at 6:20 AM, Alan Mackenzie <acm@muc.de> wrote:

> Now that we've cut the emacs-25 release branch, I'd like to have a
> distinct repository for this.
> I could simply download another copy from savannah, but this would
> (presumably) be a distinct copy, rather than hard linking the repository
> files.  This would cost me disk (and backup) space.
> 
> Or I could clone my master repository to make emacs-25.  But this would
> make the new repo firmly subordinate to the master repo, rather than
> directly with savannah.

How would it be subordinate?
A full clone is just that: a deep copy, with no dependency implied.  You can push and pull entirely independently.  It’s the same as downloading another copy.

Indeed, that’s what I would call “distinct”.

> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

If you are looking for a distinct working directory, but not a distinct repository, “git new-workdir” is what you want.   The actual repository is locally shared, but you can have a second (and third) working directory, which typically will hold another branch.

It’s not what I would call “distinct repository”, but it’s a distinct directory hard-linked against the original repository.

Re: Git question. Is there a way of duplicating a git repository?

[chris.nixon]

[-- Attachment #1: Type: text/plain, Size: 985 bytes --]


Assuming you havn't done anything fancy with your clone and that
you have a recent version of git (at least 2.5) you can use

    git worktree add -b emacs-25 ../emacs-25 origin/emacs-25

From the root of the current clone to create a new worktree at
../emacs-25 that shares the current repository's .git repo.


Chris


Alan Mackenzie writes:

> Hello, Emacs.
>
> Now that we've cut the emacs-25 release branch, I'd like to have a
> distinct repository for this.
>
> I could simply download another copy from savannah, but this would
> (presumably) be a distinct copy, rather than hard linking the repository
> files.  This would cost me disk (and backup) space.
>
> Or I could clone my master repository to make emacs-25.  But this would
> make the new repo firmly subordinate to the master repo, rather than
> directly with savannah.
>
> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?


-- 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 472 bytes --]

Re: Git question. Is there a way of duplicating a git repository?

[John Wiegley]

>>>>> Alan Mackenzie <acm@muc.de> writes:

> So, is there any convenient way of duplicating a repo (using hard links, and
> preserving config info)?

A clone on the same device uses hard-links by default.

A --shared clone uses a symbolic link, so works across devices. However,
changes to the original repository affect it as well.

"git worktree add" lets you create a new working tree directly associated with
a single repository, using neither hardlinks nor symlinks; but has the added
overhead of having to learn the "git worktree" set of commands.

John

Re: Git question. Is there a way of duplicating a git repository?

[Alan Mackenzie]

Hello, John.

On Sat, Nov 14, 2015 at 10:17:33AM -0800, John Wiegley wrote:
> >>>>> Alan Mackenzie <acm@muc.de> writes:

> > So, is there any convenient way of duplicating a repo (using hard links, and
> > preserving config info)?

> A clone on the same device uses hard-links by default.

But what git calls a "clone" is not a duplicate repo.  It is radically
different from the original.  In particular, the new repo's "remote
origin" is set to the original repo; I want it to duplicate what the
original repo had set.

> A --shared clone uses a symbolic link, so works across devices. However,
> changes to the original repository affect it as well.

This isn't what I want.

> "git worktree add" lets you create a new working tree directly associated with
> a single repository, using neither hardlinks nor symlinks; but has the added
> overhead of having to learn the "git worktree" set of commands.

That wasn't what I asked about either.  Maybe it might do, though it is
bound to have drawbacks.

What I want is a command (or a ready recipe) to do for git repositories
what `fork' does for processes (but sharing the maximum possible from
the original repository with hard links).  After writing my opening post
I even tried a `git clone --mirror', but the resulting repository wasn't
a mirror of the original at all.

> John

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: Git question. Is there a way of duplicating a git repository?

[David Kastrup]

Alan Mackenzie <acm@muc.de> writes:

> Hello, John.
>
> On Sat, Nov 14, 2015 at 10:17:33AM -0800, John Wiegley wrote:
>> >>>>> Alan Mackenzie <acm@muc.de> writes:
>
>> > So, is there any convenient way of duplicating a repo (using hard links, and
>> > preserving config info)?
>
>> A clone on the same device uses hard-links by default.
>
> But what git calls a "clone" is not a duplicate repo.  It is radically
> different from the original.  In particular, the new repo's "remote
> origin" is set to the original repo; I want it to duplicate what the
> original repo had set.

git clone --mirror

Curiously, this implies --bare but you can just edit the config file
afterwards and remove the `bare' setting.

-- 
David Kastrup

Re: Git question. Is there a way of duplicating a git repository?

[Stephen Leake]

Alan Mackenzie <acm@muc.de> writes:

> What I want is a command (or a ready recipe) to do for git repositories
> what `fork' does for processes (but sharing the maximum possible from
> the original repository with hard links).  After writing my opening post
> I even tried a `git clone --mirror', but the resulting repository wasn't
> a mirror of the original at all.

I think "git worktree add" is what you are looking for. It requires git
2.5 or later.

-- 
-- Stephe

Re: Git question. Is there a way of duplicating a git repository?

[Andreas Schwab]

Alan Mackenzie <acm@muc.de> writes:

> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

git worktree add

(git 2.5 or later)

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."

Re: Git question. Is there a way of duplicating a git repository?

[Andy Moreton]

On Sat 14 Nov 2015, Alan Mackenzie wrote:

> Hello, Emacs.
>
> Now that we've cut the emacs-25 release branch, I'd like to have a
> distinct repository for this.
>
> I could simply download another copy from savannah, but this would
> (presumably) be a distinct copy, rather than hard linking the repository
> files.  This would cost me disk (and backup) space.
>
> Or I could clone my master repository to make emacs-25.  But this would
> make the new repo firmly subordinate to the master repo, rather than
> directly with savannah.
>
> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

Something like this should do what you want:

cd master/..
git clone --reference master git://git.sv.gnu.org/emacs --branch emacs-25 emacs-25

I'm sure someone more expert with git will report a better recipe.

    AndyM

Re: Git question. Is there a way of duplicating a git repository?

[Ken Brown]

On 11/14/2015 6:20 AM, Alan Mackenzie wrote:
> Hello, Emacs.
> 
> Now that we've cut the emacs-25 release branch, I'd like to have a
> distinct repository for this.
> 
> I could simply download another copy from savannah, but this would
> (presumably) be a distinct copy, rather than hard linking the repository
> files.  This would cost me disk (and backup) space.
> 
> Or I could clone my master repository to make emacs-25.  But this would
> make the new repo firmly subordinate to the master repo, rather than
> directly with savannah.

You can fix that by issuing the following command in the new repo:

  git remote set-url origin <userid>@git.sv.gnu.org:/srv/git/emacs.git master

After doing that, you'll to do 'git pull' in order to bring in the remote branches, and then you can do 'git checkout emacs-25'.

Ken

Re: Git question. Is there a way of duplicating a git repository?

[Alan Mackenzie]

Hello, Ken.

On Sat, Nov 14, 2015 at 04:02:27PM -0500, Ken Brown wrote:
> On 11/14/2015 6:20 AM, Alan Mackenzie wrote:
> > Hello, Emacs.

> > Now that we've cut the emacs-25 release branch, I'd like to have a
> > distinct repository for this.

> > I could simply download another copy from savannah, but this would
> > (presumably) be a distinct copy, rather than hard linking the repository
> > files.  This would cost me disk (and backup) space.

> > Or I could clone my master repository to make emacs-25.  But this would
> > make the new repo firmly subordinate to the master repo, rather than
> > directly with savannah.

> You can fix that by issuing the following command in the new repo:

>   git remote set-url origin <userid>@git.sv.gnu.org:/srv/git/emacs.git master

> After doing that, you'll to do 'git pull' in order to bring in the remote branches, and then you can do 'git checkout emacs-25'.

First of all, many thanks for actually addressing the question I asked.
;-)

What I did in the end was to clone a new repo with the --mirror argument
(so as to copy all the branches, rather than creating new ones pointing
at the original repo), and manually edited .../.git/config so as to get
working directories.  Then I changed the remote origin url in that file
by hand.

Having done "git checkout", I was then able to "git pull" from savannah,
and switch to branch emacs-25 with another "git checkout".

So, I'm where I want to be!

Thanks again.

> Ken

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: Git question. Is there a way of duplicating a git repository?

[Mike Gerwitz]

[-- Attachment #1: Type: text/plain, Size: 679 bytes --]

On Sat, Nov 14, 2015 at 11:20:27 +0000, Alan Mackenzie wrote:
> So, is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

Each branch has its own tracking branch (upstream).  So you can just
branch off of emacs-25, and either keep that local copy, or set the
upstream to your own remote repository:

  $ git checkout emacs-25
  $ git checkout -b foo
  $ git remote add my-origin path/to/remote/repo
  $ git push --set-upstream my-origin foo

This is as close to a hard-copy as you'll get.


-- 
MIKE Gerwitz
Free Software Hacker | GNU Maintainer
http://mikegerwitz.com
FSF Member #5804 | GPG Key ID: 0x8EE30EAB

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 818 bytes --]

Re: Git question. Is there a way of duplicating a git repository?

[Paul Eggert]

Alan Mackenzie wrote:
> is there any convenient way of duplicating a repo (using hard links,
> and preserving config info)?

Not sure what you mean by "preserving config info", but if your current 
repository is in a directory named 'master', you could do something like this:

git clone master emacs-25
cd emacs-25
git remote add savannah YOURNAME@git.sv.gnu.org:/srv/git/emacs.git
git fetch savannah
git branch --track emacs-25 savannah/emacs-25
git checkout emacs-25

Re: Git question. Is there a way of duplicating a git repository?

[Steinar Bang]

>>>>> Alan Mackenzie <acm@muc.de>:

> Now that we've cut the emacs-25 release branch, I'd like to have a
> distinct repository for this.

cd ..
cp -a emacs emacs-25
cd emacs-25
git pull
git checkout -b emacs-25