Best approach to managing software versions via code branches?

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, bu开发者_Go百科t what is the idea? Create a "Lite Version" and "Enterprise Version" from the trunk... with the trunk being the "Lite Version"?

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.