Maintaining Multiple Versions of App

I’m working on a major Rails project who’s code base continues to grow. The client wants to have two different versions of the software, with some features in common between the two, and some features diverging. I’m trying to figure out the best strategy for easily maintaining the features the two have in common, while allowing for differences as well.


  • Subversion “branches”, doing diffs and merging to maintain commonality between both. (Seems like a nightmare.)

  • One codebase, w/ configuration settings and if/else statements depending on which version is running. (Also seems like a nightmare.) For example, the following type statements littered throughout the code:

    if version == “A”

    do version “A” logic

    elsif version == “B”

    do version “B” logic


  • Rails plugins and modules. Seems like the best way, but I’m not sure the best way to structure it. Differences will be mostly minor, but at all levels (views, controllers, models emails)

Any feedback or shared experiences would be great.


SVN branches is one way…

another way is to use SVN Externals to manage the common code between many apps.

Another option is to move common models, etc into plugins which can be shared.

Another option is Engines: