Git

Thus far I've covered most of the issues and hurdles we've addressed while experimenting with Git at Slide in parts 1 and 2 of this series, the one thing I've not covered that is very important to address is how to work in the "hybrid" environment we currently have at Slide, where as one team works with Git and the rest of the company works in Subversion. Our setup involves having a "Git-to-Subverison" proxy repository such that everything to the "left" of that proxy repository is entirely Subversion without exceptions and everything to the "right" of that repository is entirely Git, without exceptions. Part of my original motivation for putting this post at the end of the series was that, when I originally wrote the first post on "Experimenting with Git at Slide" I actually didn't have this part of the process figured out. That is to say, I was bringing code back and forth between Git and Subversion courtesy of git-svn(1) and some gnarly manual processes.

No Habla Branching

The primary issue when bringing changesets from Git to Subversion is based in the major differences between how the two handle branching and changesets to begin with. In theory, projects like Tailor were created to help solve this issue by first translating both the source and destination repositories into an intermediary changeset format in order to cross-apply changes from one end to the other. Unfortunately after I spent a couple days battling with Tailor, I couldn't get it to properly handle some of the revisions in Slide's three year history.

In my last post on Git, Experimenting with Git at Slide, I discussed most of the technical hurdles that stood in our way with evaluating Git for a Subversion tree that has 90k+ revisions and over 2GB of data held within. As I've learned from any project that involves more than just myself, technology is only half the battle, the other half is the human element. One of the most difficult things to "migrate" when switching to something as critical to a developer's workflow as a VCS, is habits, good ones and bad ones.

The Bad Habits

When moving my team over to Git, I was able to identify some habits that I view as "bad" that could either be blamed on how we have used Subversion here at Slide, or the development workflow that Subversion encourages. For the sake of avoiding flamewars, I'll say it's 51% us, 49% the system.

For the past two months I've been experimenting with varying levels of success with Git inside of Slide, Inc.. Currently Slide makes use of Subversion and relies heavily on branches in Subversion for everything from project specific branches to release branches (branches that can live anywhere from under 12 hours to three weeks). There are plenty of other blog posts about the pitfalls of branching in Subversion that I won't go into here, suffice to say, it is...sub-par. Below is a rough diagram of our general current workflow with Subversion (I've had some other developers ask me "why don't you just work in trunk?" to which I usually wax poetic about the chaos of trunk when any project gets over 5 active developers (Slide engineering is somewhere between 30-50 engineers)).

• There's always a catch
• Subversion at Slide
• Toying with Git
• Git at Slide