Best approach to managing software versions via code branches?

Question

I would like to customize an off-the-shelf software that has a Lite Edition and an Enterprise Edition. The features are almost the same so that my extended customizations can work for both, but I have to recompile for each version because they have different version assemblies.

Can someone help advise me on how maintain this? I am using Visual Studio 2008 and Visual SVN. Should I create 2 completely different solutions, create one solution with duplicate projects, or create branches? Branches seem like the elegant route, but what is the idea? Create a "Lite Version" and "Enterprise Version" from the trunk... with the trunk being the "Lite Version"?

Answer 1

It depends on how much your code differs between the two. In the best case, if it's simply a matter of linking to different assembly versions, use NAnt or similar and simply create a build target for each one.

If life isn't quite that utopian, I'd create three projects on one branch: one class library to contain all common code, and another class library per version that only contains unshared code.

If the shared code has dependencies on those multi-version assemblies, though, you're more or less stuck doing things manually, as far as I can tell. That means maintaining a branch-per-target and doing regular merges between them to keep shared pieces in sync. Using a distributed CMS would ease the pain of merging, and creating a battery of unit tests will help reduce the amount of error these cross-project merges introduce.