C# – Best practices for Subversion and Visual Studio projects

Hmm, not sure I agree with Nick re tag being similar to a branch. A tag is just a marker

• Trunk would be the main body of development, originating from the start of the project until the present.

• Branch will be a copy of code derived from a certain point in the trunk that is used for applying major changes to the code while preserving the integrity of the code in the trunk. If the major changes work according to plan, they are usually merged back into the trunk.

• Tag will be a point in time on the trunk or a branch that you wish to preserve. The two main reasons for preservation would be that either this is a major release of the software, whether alpha, beta, RC or RTM, or this is the most stable point of the software before major revisions on the trunk were applied.

In open source projects, major branches that are not accepted into the trunk by the project stakeholders can become the bases for forks -- e.g., totally separate projects that share a common origin with other source code.

The branch and tag subtrees are distinguished from the trunk in the following ways:

Subversion allows sysadmins to create hook scripts which are triggered for execution when certain events occur; for instance, committing a change to the repository. It is very common for a typical Subversion repository implementation to treat any path containing "/tag/" to be write-protected after creation; the net result is that tags, once created, are immutable (at least to "ordinary" users). This is done via the hook scripts, which enforce the immutability by preventing further changes if tag is a parent node of the changed object.

Subversion also has added features, since version 1.5, relating to "branch merge tracking" so that changes committed to a branch can be merged back into the trunk with support for incremental, "smart" merging.

Encourage frequent commits. Teammates new to version control may feel like they need to keep the code out of the repository until "it works right". Teach everyone to commit early and often to find issues as soon as possible. Instead of holding code 'till it works, propose that your teammates create branches for feature that might break trunk. That leads to...

Establish a branching and tagging practice. In addition to branches for features, encourage your teammates to use branches for large-bug fixes. Tag major bug fixes at the beginning and end of the work. Maintain tags (and possibly branches) for production/qa releases.

Establish a policy for trunk and stick to it. One example might be, "trunk must always build without errors." or "trunk must always pass all unit tests". Any work that can't yet meet the standards of trunk must be done in a branch.