go-svn2git is a tiny utility for migrating projects from Subversion to Git while keeping the trunk, branches and tags where they should be. It uses git-svn to clone an svn repository and does some clean-up to make sure branches and tags are imported in a meaningful way, and that the code checked into master ends up being what's currently in your svn trunk rather than whichever svn branch your last commit was in.

This is actually a re-write of svn2git in Go.

Say I have this code in svn:

trunk
  ...
branches
  1.x
  2.x
tags
  1.0.0
  1.0.1
  1.0.2
  1.1.0
  2.0.0

git-svn will go through the commit history to build a new git repo. It will import all branches and tags as remote svn branches, whereas what you really want is git-native local branches and git tag objects. So after importing this project I'll get:

$ git branch
* master
$ git branch -a
* master
  1.x
  2.x
  tags/1.0.0
  tags/1.0.1
  tags/1.0.2
  tags/1.1.0
  tags/2.0.0
  trunk
$ git tag -l
[ empty ]

After go-svn2git is done with your project, you'll get this instead:

$ git branch
* master
  1.x
  2.x
$ git tag -l
  1.0.0
  1.0.1
  1.0.2
  1.1.0
  2.0.0

Finally, it makes sure the HEAD of master is the same as the current trunk of the svn repo.

Make sure you have git, git-svn, and go installed.
go-svn2git is a go wrapper around git's native SVN support through git-svn. It is possible to have git installed without git-svn installed, so please do verify that you can run $ git svn successfully.

There are several ways you can create a git repo from an existing svn repo. The differentiating factor is the svn repo layout. Below is an enumerated listing of the varying supported layouts and the proper way to create a git repo from a svn repo in the specified layout.

1. The svn repo is in the standard layout of (trunk, branches, tags) at the root level of the repo.

    $ go-svn2git http://svn.example.com/path/to/repo
   

2. The svn repo is NOT in standard layout and has only a trunk and tags at the root level of the repo.

    $ go-svn2git http://svn.example.com/path/to/repo -trunk dev -tags rel -no-branches
   

3. The svn repo is NOT in standard layout and has only a trunk at the root level of the repo.

    $ go-svn2git http://svn.example.com/path/to/repo -trunk trunk -no-branches -no-tags
   

4. The svn repo is NOT in standard layout and has no trunk, branches, or tags at the root level of the repo. Instead the root level of the repo is equivalent to the trunk and there are no tags or branches.

    $ go-svn2git http://svn.example.com/path/to/repo -root-is-trunk
   

5. The svn repo is in the standard layout but you want to exclude the massive doc directory and the backup files you once accidently added.

    $ go-svn2git http://svn.example.com/path/to/repo -exclude doc -exclude '.*~$'
   

6. The svn repo actually tracks several projects and you only want to migrate one of them.

    $ go-svn2git http://svn.example.com/path/to/repo/nested_project -no-minimize-url
   

7. The svn repo is password protected.

    $ go-svn2git http://svn.example.com/path/to/repo -username <<user_with_perms>>
   

8. You need to migrate starting at a specific svn revision number.

    $ go-svn2git http://svn.example.com/path/to/repo -revision <<starting_revision_number>>
   

9. You need to migrate starting at a specific svn revision number, ending at a specific revision number.

    $ go-svn2git http://svn.example.com/path/to/repo -revision <<starting_revision_number>>:<<ending_revision_number>>
   

The above will create a git repository in the current directory with the git version of the svn repository. Hence, you need to make a directory that you want your new git repo to exist in, change into it and then run one of the above commands. Note that in the above cases the trunk, branches, tags options are simply folder names relative to the provided repo path. For example if you specified trunk=foo branches=bar and tags=foobar it would be referencing http://svn.example.com/path/to/repo/foo as your trunk, and so on. However, in case 4 it references the root of the repo as trunk.

There is a feature to pull in the latest changes from SVN into your git repository created with go-svn2git. This is a one way sync, but allows you to use go-svn2git as a mirroring tool for your SVN repositories.

The command to call is:

    $ cd <EXISTING_REPO> && go-svn2git -rebase

To convert all your svn authors to git format, create a file somewhere on your system with the list of conversions to make, one per line, for example:

jcoglan = James Coglan <jcoglan@never-you-mind.com>
stnick = Santa Claus <nicholas@lapland.com>

Then pass an +authors+ option to +go-svn2git+ pointing to your file:

$ go-svn2git http://svn.example.com/path/to/repo -authors ~/authors.txt

Alternatively, you can place the authors file into ~/.go-svn2git/authors and svn2git will load it out of there. This allows you to build up one authors file for all your projects and have it loaded for each repository that you migrate.

If you need a jump start on figuring out what users made changes in your svn repositories the following command sequence might help. It grabs all the logs from the svn repository, pulls out all the names from the commits, sorts them, and then reduces the list to only unique names. So, in the end it outputs a list of usernames of the people that made commits to the svn repository which name on its own line. This would allow you to easily redirect the output of this command sequence to ~/.config/go-svn2git/authors and have a very good starting point for your mapping.

$ svn log | grep -E "r[0-9]+ \| .+ \|" | awk '{print $3}' | sort | uniq