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Tuesday, October 12, 2010

Why we chose Git instead of Subversion

I just got a new job as an ASP.NET developer at a small company that is freshly developing itself into somewhat of a software company. The development team is undergoing a ton of changes over the past 6 months (6 months ago there were two developers, now there is five as well as a new director of technology). As part of our changes we took some time to evaluate the tools we use. We had been using Microsoft's Team Foundation Server for source control and a home-grown system for bug tracking but after our evaluations we settled on Redmine and Git.

The fact that we are using Redmine for ALM and bug tracking isn't particularly surprising to me because it's a feature heavy and mature product that is very natural to use. There are several other feature heavy mature ALM tools that would fit us, but none that are free (I don't consider Trac feature heavy). Git, however, is a bit of a pleasant surprise for me.

For the uninitiated ones, Git is a distributed SCM (source control management) tool. The distributed part  means that it works kind of like Subversion except that everyone has a full clone of the repository. When you want to check your code in you commit first to yourself and then push your changes to the rest of the team. More realistically you would be committing to yourself several times and occasionally pushing your changes to the rest of the team when you verify that your code is stable.

The benefit of this is that you can maintain your own personal branches of the code where you experiment on certain features without having to push them out to everyone else. I see this as psychologically breaking down the barrier to committing code. I often find that I don't commit code for a while because, even though it builds, I'm not sure if some of the pages will run without errors. However, committing to myself means that I can commit whenever I want and not slow any of my teammates down with potential errors.

Git also provides very easy and simple branching. They made it extremely easy to drop everything your doing to fix that top priority bug in production (the "stash" operation lets you save uncommitted changes and move to another part of the code). With this extra change management, Git also forces you to account for all your changes. Before you switch branches you have to either stash, commit or revert your current changes. At first this seems annoying, but on second thought it forces to always have some sort of accounting for why you changed stuff.

We did have some hesitation with changing to Git. Our biggest concern was if one of our partner teams from a different company could keep up with a change in SCM. After some evaluation we realized that Git provided so much flexibility with managing our workflow with this partner that it makes Subversion look like an archaic hack.

Another concern we had was stability. Git itself has been around since 2005 and seems to have pretty strong development community backing it. It has a very strong Linux following and a year ago lacked a good Windows interface. However, TortoiseGit has been developing at a very rapid rate (it's single developer has been releasing more than twice a month and is quickly working toward supporting most of Git's features). Because it is developing so fast we agreed that we could disregard shortcomings in the Windows environment in due to the awesome number and power of the features it brings.

Today I worked on importing our TFS repository into a Git clone. I found a PowerShell script hosted on Github that got me pretty close. The code in the script was a little too brittle so I made the code a little more generic and sent it back to him. It's taking about six hours to migrate the 1200 changesets into Git, so the script probably won't finish running for another couple hours, but I think it's working so far.

I will have to follow up in six months or so with an evaluation of how things have gone.

1 comment:

  1. nice thank you, i will have a look at this Git.