Using mercurial (hg) for local development

Decentralized Version Control (DVCS) is one of the most useful tools if you are working with multiple people on a project. I used to use version control (such as subversion and git) to not only keep track of code for my research, but also while drafting papers. At work, we use subversion (svn) to maintain our large codebase, but having local versioning is very helpful while developing features. For local version control, I have been using mercurial (hg), which by the way is quite easy to use, and personally I think feels like a mix of svn and git.

When you check out a copy of a codebase from your project's svn trunk, for example, and you decide you want to add a new feature, branching is the way to go and the quick learning curve of mercurial will help get you started.

When you initially add all your files to mercurial, it becomes the "default" branch. For every feature you are going to develop, you can create a new branch and tag it with a name (say "feature1"). You can switch to the "default" branch when there is new code pushed into the central svn repository and you need to do an "svn up"; you can add remove any new files for mercurial and then simply merge it back with your "feature 1" mercurial branch (of course resolving any conflicts). Once "feature1" is complete after all the code reviews and everything that gets needed done, just switch to the "default" mercurial branch, make sure it is updated, and merge your "feature1" branch with it. You can push in your added feature via svn to trunk, and close off the mercurial "feature1" branch.

The basic idea is simply to use named feature branches to work on your new features, and use the default branch to perform updates, propagating to your working branches, and when you are ready to check in your newly developed feature to codebase.

Using mercurial locally on top of a checked out svn repository has been working quite well for me. So I wanted to quickly share, without actually showing you the nitty gritty details, how you might go about using a similar versioning workflow. Maybe in a later post I will sketch out the details with the mercurial commands.