Re: reviving a git-svn clone

[Deskin Miller <deskinm@gmail.com>]

On Mon, Apr 20, 2009 at 23:51, Sam Vilain <sam@vilain.net> wrote:
> On Mon, 2009-04-20 at 12:43 +0200, martin f krafft wrote:
>> I am now trying to revive the clone, but git-svn remains "unable to
>> determine the upstream SVN information from the working tree
>> history". This baffles me.
>>
>> Here are my steps:
>
>> -8<--8<--8<-
>> alioth:~|master|% git clone /git/collab-maint/hibernate.git hibernate-svnsync
>> Initialized empty Git repository in /srv/alioth.debian.org/chroot/home/users/madduck/hibernate-svnsync/.git/
>>
>> alioth:~|master|% cd hibernate-svnsync
>>
>> alioth:~/hibernate-svnsync|master|% git branch --no-track upstream origin/upstream
>>
>> alioth:~/hibernate-svnsync|master|% cat >> .git/config <<_eof
>> heredoc> [svn-remote "svn"]
>> heredoc>        url = svn+ssh://svn.suspend2.net/svn/hibernate-script
>> heredoc>        fetch = trunk:refs/remotes/upstream/trunk
>> heredoc>        branches = branches/*:refs/remotes/upstream/*
>> heredoc>        tags = tags/*:refs/remotes/upstream/tags/*
>> heredoc> _eof
>
> for git-svn to resume, it needs the refs all in the right place.  If you
> clone a git-svn repository they will be in the wrong place.
>
> eg for this use case something like this to copy the
> refs/remotes/origin/* refs to refs/remotes/upstream/*:
>
>  git for-each-ref --format="%(refname)" refs/remotes/origin/* |
>     perl -le '$x = $_; $x =~ s{origin}{upstream};
>       system "git update-ref $x $_"'

Sam is on the right track.  I got the rev-map to rebuild with the
following steps (sufficient, perhaps not all necessary); enter these
after you hack .git/config with the svn info.

First, we need the backend .git/svn/.metadata file, populated with the
right URL and svn uuid; the uuid follows the URL and revision on log
messages:

$ mkdir .git/svn
$ cat > .git/svn/.metadata << EOF
[svn-remote "svn"]
        reposRoot = svn+ssh://svn.suspend2.net/svn
        uuid = c12ee44c-9ede-0310-94ea-d4716f4f7118
EOF

Now, make the remote-tracking branch upstream/trunk at the right
commit, and check out a local copy; the commit ID is the latest commit
from svn, also known as master^2 (at the time of this writing) if you
do a normal git clone from your provided url:

$ git update-ref refs/remotes/upstream/trunk 1784ac6d
$ git checkout -b upstream upstream/trunk

Now, do git svn info or your other favourite local command to rebuild
the rev-map:

$ git svn info

If you have access to the svn remote, you should be able to avoid
hacking config and .metadata entirely by entering

$ git svn init --stdlayout --prefix=upstream/
svn+ssh://svn.suspend2.net/svn/hibernate-script

This doesn't fetch any commits, but will contact the svn server to
obtain the uuid.  Plus, it's much easier to type.  At any rate, the
commands prior to that rebuilt the rev-map metadata for me; I can't
guarantee the alternative last one, since I can't test it myself.

> It's a bit hard to test without access to the upstream svn!

I concur :)  Hope that straightens things out.

Deskin Miller

P.S. Thanks Dscho for the excellent msysgit package