Some Principles For Working With Branches

To work successfully with branches, your development group should adhere to these principles:

• Minimize the number of branches active at any one time. The more branches under development at the same time, the more likely they are to conflict when merged into the trunk. In practical terms, the way to accomplish this is to merge as frequently as you can (whenever a branch is at a stable point) and to move development back onto the trunk as soon as feasible. By minimizing the amount of parallel development going on, everyone is better able to keep track of what's going on on each branch, and the possibility of conflicts on merge is reduced.

  This does not mean minimizing the absolute number of branches in the project, just the number being worked on at any given time.

• Minimize the complexity – that is, the depth – of your branching scheme. There are circumstances in which it's appropriate to have branches from branches, but they are very rare (you may get through your entire programming life without ever encountering one). Just because CVS makes it technically possible to have arbitrary levels of nested branching, and to merge from any branch to any other branch, doesn't mean you actually want to do these things. In most situations, it's best to have all your branches rooted at the trunk and to merge from branch to trunk and back out again.
• Use consistently named tags to mark all branch and merge events. Ideally, the meaning of each tag and its relationship to other branches and tags should be apparent from the tag name. (The point of this will become clearer as we go through the examples.)

With those principles in mind, let's take a look at a typical branch development scenario. We'll have jrandom on the trunk and qsmith on the branch, but note that there could just as well be multiple developers on the trunk and/or on the branch. Regular development along either line can involve any number of people; however, the tagging and merging are best done by one person on each side, as you'll see.