Pushing an existing Git repository to SVN

I needed this as well, and with the help of Bombe's answer + some fiddling around, I got it working. Here's the recipe:

Import Git -> Subversion

1. cd /path/to/git/localrepo
2. svn mkdir --parents protocol:///path/to/repo/PROJECT/trunk -m "Importing git repo"
3. git svn init protocol:///path/to/repo/PROJECT -s
4. git svn fetch
5. git rebase origin/trunk
5.1.  git status
5.2.  git add (conflicted-files)
5.3.  git rebase --continue
5.4.  (repeat 5.1.)
6. git svn dcommit

After #3 you'll get a cryptic message like this:

Using higher level of URL: protocol:///path/to/repo/PROJECT => protocol:///path/to/repo

Just ignore that.

When you run #5, you might get conflicts. Resolve these by adding files with state "unmerged" and resuming rebase. Eventually, you'll be done; then sync back to the SVN repository, using dcommit. That's all.

Keeping repositories in sync

You can now synchronise from SVN to Git, using the following commands:

git svn fetch
git rebase trunk

And to synchronise from Git to SVN, use:

git svn dcommit

Final note

You might want to try this out on a local copy, before applying to a live repository. You can make a copy of your Git repository to a temporary place; simply use cp -r, as all data is in the repository itself. You can then set up a file-based testing repository, using:

svnadmin create /home/name/tmp/test-repo

And check a working copy out, using:

svn co file:///home/name/tmp/test-repo svn-working-copy

That'll allow you to play around with things before making any lasting changes.

Addendum: If you mess up git svn init

If you accidentally run git svn init with the wrong URL, and you weren't smart enough to take a backup of your work (don't ask ...), you can't just run the same command again. You can however undo the changes by issuing:

rm -rf .git/svn
edit .git/config

And remove the section [svn-remote "svn"] section.

You can then run git svn init anew.

Here's how we made it work:

Clone your Git repository somewhere on your machine.

Open .git/config and add the following (from Maintaining a read-only SVN mirror of a Git repository):

[svn-remote "svn"]
    url = https://your.svn.repo
    fetch = :refs/remotes/git-svn

Now, from a console window, type these:

git svn fetch svn
git checkout -b svn git-svn
git merge master

Now, if it breaks here for whatever reason, type these three lines:

git checkout --theirs .
git add .
git commit -m "some message"

And finally, you can commit to SVN:

git svn dcommit

Note: I always scrap that folder afterwards.

Using git rebase directly will lose the first commit. Git treats it different and can't rebase it.

There is a procedure that will preserve full history: http://kerneltrap.org/mailarchive/git/2008/10/26/3815034

I will transcribe the solution here, but credits are for Björn.

Initialize git-svn:

git svn init -s --prefix=svn/ https://svn/svn/SANDBOX/warren/test2

The --prefix gives you remote tracking branches like "svn/trunk" which is nice because you don't get ambiguous names if you call your local branch just "trunk" then. And -s is a shortcut for the standard trunk/tags/branches layout.

Fetch the initial stuff from SVN:

git svn fetch

Now look up the hash of your root commit (should show a single commit):

git rev-list --parents master | grep '^.\{40\}$'

Then get the hash of the empty trunk commit:

git rev-parse svn/trunk

Create the graft:

git replace --graft <root-commit-hash> <svn-trunk-commit-hash>

Now, "gitk" should show svn/trunk as the first commit on which your master branch is based.

Make the graft permanent:

git filter-branch -- ^svn/trunk --all

Drop the graft:

git replace -d <root-commit-hash>

gitk should still show svn/trunk in the ancestry of master.

Linearize your history on top of trunk:

git svn rebase

And now "git svn dcommit -n" should tell you that it is going to commit to trunk.

git svn dcommit