Feature Branches: Making it Easy

In my previous post I wrote about the benefits of using feature branches for quality assurance. As with all tools features branches don’t come with benefits only. There are unwanted side effects. Fortunately there are ways to minimize or eliminate them.

One such area is creation of the branches. There are various factors to look at. For one your version control system (VCS) should make it easy to create branches. For some systems this is a no-brainer and for other VCS’s some more work may be required. Most of the teams I work with use Subversion or GIT, and branching is not an issue.

When creating a feature branch, the VCS is only one of the tools that is affected. You also need to consider the client side of the equation. For example, how easy is it to switch between branches? How often do you need to switch between branches? What does the support in the VCS client look like? Do you need integration of your VCS client into the integrated development environment (IDE) your team is using? By choosing an appropriate VCS introducing feature branches becomes much easier.

Apart from the VCS other systems your development team is using may be affected as well when branches are created, whether they are feature branches or others. For example you may be using a continuous integration (CI) system such as TeamCity, Jenkins or CruiseControl.NET. Once the new branch has been created you want to make sure it is picked up by the CI system as well and automatically built. Therefore each time you create a branch you typically want to set up a new branch as well.

You may have other systems that may need to reflect that a new branch has been created. For example a bug tracking system may offer the branch name as the affected version when entering a bug. Or you may use a tool to plan and track progress for a particular feature. Again this would then be set up accordingly when a new branch is created.

As these activities will have to be done each time a feature branch is created, it is an obvious candidate for automation in particular if your team works on dozens or hundreds of features each year. With appropriate APIs of affected systems automation is not an overly complex task. Instead it is just a matter of putting the time in.

In closing I’d like to give you a specific example from one of the teams I am working with. Creating feature branches is completely automated in this case and the time required is only as long as it takes to type in the name of the features branch. The remainder is automated. This includes the creation of the feature branch in the VCS, setting up the new build configuration in the CI, creating the feature as a project in the project tracking system, adding a configuration to the test bed controller and setting up automated merging. Taken together it typically takes about 10 seconds and is saving hundreds of hours of development time per year.

In one of the next posts I’ll describe techniques that help making the merge of feature branches into the main development branch easier.