My job involves working on other peoples scientific codes, and recently I've been experimenting with using GIT as a VCS. Its very handy for making a quick repository while you change one or two files, nice and lightweight.

What distinguishes science codes from other software projects, both open-source and proprietary, is the comparative lack of formal releases. Often the developers are the users, making changes for their own use. They make a model, write a paper, done. They'll take their old code and edit it to add features, but don't plan on "releasing" it in any formal way. So, often you get a tarball from a fellow researcher with the name 'astro.tar.gz', and beyond the paper describing the science, you'll be lucky to find a changelog. Online repositories, test suites, etc. are a rarity.

So I've been wondering how to improve on this, in terms of refactoring, etc. and how GIT and other Distributed VCS's can best be used in science. Some ideas:

• Keep a separate cleanup branch. When working on a code to add new functionality, keep a branch for simple bugfixes to the original code. Git makes it easy to merge branches, so develop features on a per-feature branch, and keep fixes to a dedicated 'cleanup' branch that the original developer could pull from.
• Tag or label the changes in the Git Changelog. Current labels (the word tag is overloaded) I've been using are:
  • BUGFIX: for fixes.
  • RF: for refactorings
  • DOC: for when adding comments to code I didn't understand.
  • NEW: new functionality
  This makes it easy for someone to see if they want to pull these patches into their version of the code.

Has anyone else seen similar techniques or tags in use, particularly for science ?