how do I merge completely unrelated repositories ?

how do I merge completely unrelated repositories ?

[Christian MICHON]

Hi,

I'd like to create a new empty repository and merge into it 2
completely unrelated remote repositories.

How would you do it, since merge will not merge if it cannot find a
common ancestor ?

-- 
Christian
--
http://detaolb.sourceforge.net/, a linux distribution for Qemu with Git inside !

Re: how do I merge completely unrelated repositories ?

[Miklos Vajna]

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On Thu, Jun 26, 2008 at 11:39:37AM +0200, Christian MICHON <christian.michon@gmail.com> wrote:
> How would you do it, since merge will not merge if it cannot find a
> common ancestor ?

Did you try so?

If there are no conflicting paths then a simple

git pull /path/to/other/repo.git master

or similar should work.

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Re: how do I merge completely unrelated repositories ?

[Christian MICHON]

On Thu, Jun 26, 2008 at 11:45 AM, Miklos Vajna <vmiklos@frugalware.org> wrote:
> On Thu, Jun 26, 2008 at 11:39:37AM +0200, Christian MICHON <christian.michon@gmail.com> wrote:
>> How would you do it, since merge will not merge if it cannot find a
>> common ancestor ?
>
> Did you try so?

yes I did. it was failing.

>
> If there are no conflicting paths then a simple
>
> git pull /path/to/other/repo.git master

pull = fetch + merge

maybe I was not fetching the objects properly.

>
> or similar should work.
>

your hint works fine. thanks!

I was starting considering rebasing the 2 repos on a common empty
commit (that would have been desperate)...

-- 
Christian
--
http://detaolb.sourceforge.net/, a linux distribution for Qemu with Git inside !

Re: how do I merge completely unrelated repositories ?

[Johannes Schindelin]

Hi,

On Thu, 26 Jun 2008, Miklos Vajna wrote:

> On Thu, Jun 26, 2008 at 11:39:37AM +0200, Christian MICHON <christian.michon@gmail.com> wrote:
> > How would you do it, since merge will not merge if it cannot find a
> > common ancestor ?
> 
> Did you try so?
> 
> If there are no conflicting paths then a simple
> 
> git pull /path/to/other/repo.git master
> 
> or similar should work.

FWIW this is how gitk got into git.git... See 5569bf9b(Do a cross-project 
merge of Paul Mackerras' gitk visualizer).  This also was often referred 
to as the "coolest merge ever".

Ciao,
Dscho

Re: how do I merge completely unrelated repositories ?

[Miklos Vajna]

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On Thu, Jun 26, 2008 at 12:25:54PM +0100, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:
> FWIW this is how gitk got into git.git... See 5569bf9b(Do a cross-project 
> merge of Paul Mackerras' gitk visualizer).  This also was often referred 
> to as the "coolest merge ever".

If we are at it, that's not unique, there are other root commits as
well: 2744b23 - git-tools, 161332a - gitweb, cb07fc2 - git-gui, 16d6b8a
- p4-fast-export. ;-)

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Re: how do I merge completely unrelated repositories ?

[Oliver Kullmann]

Hi,

since a similar question burdens my soul for quite some
time, I would like to take the opportunity to extend
the question a bit:

I have around 10 CVS repositories, each with around 5 modules.
This has developed over time, and now I want to combine them
all into a single Git repository, with a new directory
structure introduced.

One possibility would be to convert these 50 CVS modules 
into git repositories, then for each of these git repositories
introduce the new tree structure (that is, what is relevant
for this part), move all files to their new location (via
"git mv"), and finally pull everything in into the common
repository.

This is all fine, except of the inability to follow the history
nicely (for example, via gitk I will only see the history
from the point on where in those temporary git-repositories
the files have been moved to their new place).

To avoid this break in the history, it would be great if
cvsimport could already move the files to the right place
in the directory hierarchy, that is, if an additional
parameter P could be given, the initial path, and files
will be imported as P/file. Then I could import everything right away into
the final git repository, without problems with clashes.
I can't find something like that in the documentation.

Is there perhaps some other possibility?
It seems easiest to me to do this little bit of surgery
at the time of the import, before git gets into his
troubles with hash-values.

thanks!

Oliver


On Thu, Jun 26, 2008 at 12:25:54PM +0100, Johannes Schindelin wrote:
> Hi,
> 
> On Thu, 26 Jun 2008, Miklos Vajna wrote:
> 
> > On Thu, Jun 26, 2008 at 11:39:37AM +0200, Christian MICHON <christian.michon@gmail.com> wrote:
> > > How would you do it, since merge will not merge if it cannot find a
> > > common ancestor ?
> > 
> > Did you try so?
> > 
> > If there are no conflicting paths then a simple
> > 
> > git pull /path/to/other/repo.git master
> > 
> > or similar should work.
> 
> FWIW this is how gitk got into git.git... See 5569bf9b(Do a cross-project 
> merge of Paul Mackerras' gitk visualizer).  This also was often referred 
> to as the "coolest merge ever".
> 

Re: how do I merge completely unrelated repositories ?

[Asheesh Laroia]

On Thu, 26 Jun 2008, Oliver Kullmann wrote:

> I have around 10 CVS repositories, each with around 5 modules. This has 
> developed over time, and now I want to combine them all into a single 
> Git repository, with a new directory structure introduced.

I had a similar desire with git-svn; instead, what I do is a 
git-filter-branch that renames all the files in the repository.

man git-filter-branch gives you one way to do that; I basically 
re-invented that due to not scrolling all the way to the bottom, and run 
it every night on the git-svn repo since I want my everything-renamed repo 
to be kept as an up-to-date mirror of the svn repo.

That's my idea for you.

-- Asheesh.

-- 
Fast, cheap, good: pick two.

RE: how do I merge completely unrelated repositories ?

[Kelly F. Hickel]

> -----Original Message-----
> From: git-owner@vger.kernel.org [mailto:git-owner@vger.kernel.org] On
> Behalf Of Oliver Kullmann
> Sent: Thursday, June 26, 2008 11:20 AM
> To: git@vger.kernel.org
> Subject: Re: how do I merge completely unrelated repositories ?
> 
> Hi,
> 
> since a similar question burdens my soul for quite some
> time, I would like to take the opportunity to extend
> the question a bit:
> 
> I have around 10 CVS repositories, each with around 5 modules.
> This has developed over time, and now I want to combine them
> all into a single Git repository, with a new directory
> structure introduced.
> 
> One possibility would be to convert these 50 CVS modules
> into git repositories, then for each of these git repositories
> introduce the new tree structure (that is, what is relevant
> for this part), move all files to their new location (via
> "git mv"), and finally pull everything in into the common
> repository.
> 
> This is all fine, except of the inability to follow the history
> nicely (for example, via gitk I will only see the history
> from the point on where in those temporary git-repositories
> the files have been moved to their new place).
> 
> To avoid this break in the history, it would be great if
> cvsimport could already move the files to the right place
> in the directory hierarchy, that is, if an additional
> parameter P could be given, the initial path, and files
> will be imported as P/file. Then I could import everything right away
> into
> the final git repository, without problems with clashes.
> I can't find something like that in the documentation.
> 
> Is there perhaps some other possibility?
> It seems easiest to me to do this little bit of surgery
> at the time of the import, before git gets into his
> troubles with hash-values.
> 
> thanks!
> 
> Oliver
> 
> 
Oliver,
  I wrote a little (314 line) perl script to blend multiple cvsps output
streams together before handing them to git-cvsimport, it seems to work
fine.  It should (but I haven't tested it) even still allow the
incremental approach.

Not sure if I should just attach it here (it's not that big, but still),
but if you need/want a copy of "cvsps_blender.pl", just send me an email
and I'll send it out....

-Kelly

Re: how do I merge completely unrelated repositories ?

[Jakub Narebski]

Christian MICHON wrote:

> I'd like to create a new empty repository and merge into it 2
> completely unrelated remote repositories.
> 
> How would you do it, since merge will not merge if it cannot find a
> common ancestor ?

The problem probably is _empty_ repository (what do you want to merge),
not lack of common ancestors.  git.git repository has joined unrelated
projects (git-mail-tools, gitweb, gitk, git-gui) and it has several
roots, and even a few separate branches.

-- 
Jakub Narebski
Warsaw, Poland
ShadeHawk on #git