AGORA GAMES

When I joined Agora, one of the first things I did was talk up git and how it’ll cure cancer, AIDS, and solve world peace. All at once. What that means for me is I’ve basically been tasked with the job of migrating anything that’s not git to git.

For some things these kinds of migration are first class citizens. Conveniently SVN, our old VCS is one of those. One of my new migrations was, less conveniently, Bazaar. Now we have nothing against Bazaar at Agora but we agreed we would rather only have one VCS in house.

After looking around and trying some fancy tools that didn’t work (read: tailor), I stumbled on a really quick solution that seems like it does everything necessary. Both Git and Bazaar (via plugins) support the fast-import/export format. I’m not sure about the mystic ways of how this format works but I do know it made my Bazaar repository a Git repository, and that makes me pleased.

Getting the bzr plugin

The first step would be to get the fast-import plugin for Bazaar from the launchpad mirror.

mkdir -p ~/.bzr/plugins
cd ~/.bzr/plugins
bzr clone lp:bzr-fastimport fastimport

You can make sure it installed properly using a bzr fast-export --help and ensure that it doesn’t complain.

Copy the repository

Now that we have all the tools, time to copy it over

mkdir ~/project.git
cd ~/project.git
git init
bzr fast-export --plain ~/path/to/bzr/branch | git fast-import
git checkout master  # only needed for a non-bare repository, like I made above

Wait a little while (or a long while if you’re testing the above code on a netbook for some reason like me). And that should be it.

I’m not sure how well this works with multiple Bazaar branches. There may be some crazy --flags on each side to make it work but running the code I put above on a full repo makes fast-export complain that I’m not pointing it to a valid branch. Please give us your comments if you know how to do this :).

It’s amazing how a few months can change your mindset around the version control system you use. Ever since I joined Agora Games in May 2008, we have used Subversion (SVN). Subversion is a fine version control system. We have one new project using Subversion and we will probably have a few legacy projects that will always use Subversion. However, last year, one of our project teams made the switch to Git and ever since then, new projects have been using Git. Looking at CruiseControl, here’s the breakdown of Subversion and Git projects:

Subversion: 4

Git: 7

Here is what I found personally about my Git transition experience.

• * If you look at the simple examples or cursory blog post introductions of using Git as a version control system, you’re probably not going to switch. I didn’t find those examples or Git blog posts enlightening at all. I just thought to myself, “Great, Git can track changes to files just like Subversion, so why should I switch?”.
• * Git is something I can use independent of a service like GitHub locally to implement version control on projects that might never make it off of my machine.
• * Git can be taken to the extreme where every “change” can be separated from the main branch of development and then merged at a later point. At Agora, we’ve taken a more balanced approach where major features go into a new branch and then are reviewed and merged back into the main branch, after which the new branch can be safely removed (e.g. replacing an authentication system).
• * Although tools like SmartGit exist, I needed to get comfortable by using Git from the command-line.
• * There are a lot of Git commands and capabilities I haven’t used yet, and that’s OK.
• * I love the idea of the Git stash, where you can scurry away local changes and revert to a clean working directory, but then recover those changes later.

Git is just something you need to try. I’m no expert in Git (yet). Git’s barrier to entry feels very minimal when compared to other version control systems.

P.S. I realize this blog post falls under the “cursory blog post introductions of using Git as a version control system” category. Whatever.

:)