Automating svn<->git gateway

> Hello Folks,
>
> I want to set up a gateway between subversion and git, which would keep the
> master synchonized with subversion trunk, both ways, and allow working with
> any additional branches independent of subversion. For users it should behave
> as any other shared git repository accessed by push and pull. And it needs to
> be automatic.
>
> Did anybody try to set up something like this?
>
> Background:
>
> At $work, we are considering switch from subversion to git. However to avoid
> big disruptions in the work, we need to do it gradually. So the idea is to
> switch to git one by one. The people who already switch need to be able to
> test the final workflow with git, while other people still commit to the
> subversion repository.
>
> This basically rules out everybody just using git-svn, because individual
> conversions are incompatible (or is there some way to make them compatible?),
> so the people couldn't easily share their working branches.
>
> That leaves me with creating one git-svn repository and having everybody
> clone from that. Keeping the repository up-to-date from subversion side seems
> trivial (just 'git svn fetch' to it from subversion's post-commit hook).
>
> The trickier part is exporting changes pushed from the git side to
> subversion. My plan is to write a post-receive hook, that will
> 'git svn dcommit' to svn trunk.
>
> I suppose I will have to get the rewritten commit back from subversion and
> merge it back to the master. I have not yet tested whether when dcommiting
> a merge will properly keep the second parent in the rewritten commit or not.
> I can do extra merge if it does not at the cost of slightly uglier history.
>
> Thanks,
> Jan
>
> --
>                                                 Jan 'Bulb' Hudec <bulb@ucw.cz>
> --
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> Check out the article and third-to-last comment (as of today) at
> http://blog.emmanuelbernard.com/2010/05/git-how-my-life-has-improved-since-last-month-when-i-used-svn/comment-page-1/#comment-2248
> 
> The comment (by Josh) is mine, and details how I've approached this
> problem.  It's worked very well for us, and follows from a workflow
> presented in Jon Loeliger's "Version Control with Git."  I haven't
> messed with any hooks, but I'd imagine that wouldn't be too difficult.
>  Right now, we keep a couple legacy maintenance SVN branches sync'd up
> with their corresponding Git branches.  The one thing that we haven't
> attempted (and don't plan on) is creating a new branch in Git that we
> want to duplicate in SVN.  We're only syncing branches that existed in
> SVN prior to our move to Git.  Any new branches are "Git-only."

> On Mon, Oct 11, 2010 at 3:30 PM, Jan Hudec <bulb@ucw.cz> wrote:
> > Hello Folks,
> >
> > I want to set up a gateway between subversion and git, which would keep the
> > master synchonized with subversion trunk, both ways, and allow working with
> > any additional branches independent of subversion. For users it should behave
> > as any other shared git repository accessed by push and pull. And it needs to
> > be automatic.
> >
> > Did anybody try to set up something like this?

> I want to set up a gateway between subversion and git, which would keep the
> master synchonized with subversion trunk, both ways, and allow working with
> any additional branches independent of subversion. For users it should behave
> as any other shared git repository accessed by push and pull. And it needs to
> be automatic.
> 
> Did anybody try to set up something like this?

> Jan Hudec <bulb@ucw.cz> writes:
> 
> > I want to set up a gateway between subversion and git, which would keep the
> > master synchonized with subversion trunk, both ways, and allow working with
> > any additional branches independent of subversion. For users it should behave
> > as any other shared git repository accessed by push and pull. And it needs to
> > be automatic.
> > 
> > Did anybody try to set up something like this?
> 
> It is a pity that "Native SVN support in git" project at Google Summer of
> Code 2010 (https://git.wiki.kernel.org/index.php/SoC2010Projects) turned
> out to be too much for one summer; though people are working on it.  It
> would be perfect for this situation.

> On Tue, Oct 12, 2010 at 12:54:54 -0700, Jakub Narebski wrote:
> > Jan Hudec <bulb@ucw.cz> writes:
> > 
> > > I want to set up a gateway between subversion and git, which would keep the
> > > master synchonized with subversion trunk, both ways, and allow working with
> > > any additional branches independent of subversion. For users it should behave
> > > as any other shared git repository accessed by push and pull. And it needs to
> > > be automatic.
> > > 
> > > Did anybody try to set up something like this?
> > 
> > It is a pity that "Native SVN support in git" project at Google Summer of
> > Code 2010 (https://git.wiki.kernel.org/index.php/SoC2010Projects) turned
> > out to be too much for one summer; though people are working on it.  It
> > would be perfect for this situation.
> 
> I am not actually sure it would. What I want is that for people who already
> switch to git may immediately stop caring about subversion. From their point
> of view, it shouldn't be there.
> 
> So while I'm sure the native SVN support will solve the quirks and bugs of
> git-svn, it will not do away with need for the gateway repository that will
> somehow synchronize itself with subversion.

> On wtorek 12. października 2010 22:31, Jan Hudec napisał:
> > So while I'm sure the native SVN support will solve the quirks and bugs of
> > git-svn, it will not do away with need for the gateway repository that will
> > somehow synchronize itself with subversion.
> 
> Well, I think that native SVN support would allow to treat subversion
> repository as one of repositories in the network of repositories.  Those
> repositories could be set in that pushing to central git repository pushes
> also to subversion repository, and like central git repository fetches
> from leaf repositories, it would fetch from subversion repository.

> > > So while I'm sure the native SVN support will solve the quirks and bugs of
> > > git-svn, it will not do away with need for the gateway repository that will
> > > somehow synchronize itself with subversion.
> > 
> > Well, I think that native SVN support would allow to treat subversion
> > repository as one of repositories in the network of repositories.  Those
> > repositories could be set in that pushing to central git repository pushes
> > also to subversion repository, and like central git repository fetches
> > from leaf repositories, it would fetch from subversion repository.
> 
> Yes. Except I don't know how to do the "pushing to central git repository
> pushes also to..." part. Subversion or not.
> 
> Though, I guess if it worked well enough to preserve the merge commit (i.e.
> when I push and pull, I see the commit I pushed, not any kind of rewrite),
> pushing in update-hook would be quite many bits simpler.