Git branching to keep sub-projects up-to-date

Question

I have a problem that's very hard to google, so I decided to ask about it here.

I've created a system (a rails app) that handles user registration for a conference. The system is under active development.

Now, I'm helping to run another conference, and I want to use pretty much the same system, with only minor changes to the codebase. However, I want to maintain some level of parallelism between the two projects, so I can easily push generic improvements to both systems. I also want to be able to change both independently.

My gut feeling is that I should use a branch for each conference's system, and then whenever I have a master change, run git merge master in both projects.

Is there a smoother way to do this? Does git have a built-in method for handling automatic pushes to branches?

Thanks in advance. I apologize if this question isn't as "answerable" as stackoverflow likes.

Answer 1

What you propose (3 branches) would certainly work, but if I were to do it, I'd probably make 3 git repositories rather than 3 branches.

There is no way for git to automatically merge the master branch (your shared library) into the two implementation branches. You would need to do that yourself.

Answer 2

I would use two branches for now, but heavily prioritize fixing the code itself to support the modifications in a single codebase. Otherwise you'll experience more and more pain as the code changes and/or the variants diverge: bigger merges, more space for conflicts, harder refactoring, etc.