lukebaker.org

I've been using Subversion for a project I recently started at work. The project is a web application in PHP. Having enjoyed using Ruby on Rails on a different project, I wanted to setup a simple framework that borrows some ideas from Rails, like MVC, a test infrastructure, and a general directory layout that makes sense. I want this framework to be reusable for other projects, but I also want to be able to make changes to the framework from within the individual projects that use it and then port those changes over to my vanilla framework. Here's where Subversion comes into action.

FWIW, the process I use here is pretty much the same process you'd use for branches. Pretend I have the framework at /php_framework in Subversion. To start a new project using the framework, I issue the following command:

svn copy svn+ssh://svn_server/php_framework \
snv+ssh://svn_server/new_project -m "Creating new_project"

Then I can check out a copy of /new_project and work on it as I please. If I end up making a change to things that belong in the framework, I'll want to port those changes back into the framework. For simplicity, in most cases I'll want all the changes that affect the framework to be in a changeset of their own. This way a particular revision will contain only changes to the framework and not any changes to the application itself. If I go this route, I can port the changes with the following commands:

svn checkout svn+ssh://svn_server/php_framework
svn merge -r 135:136 svn+ssh://svn_server/new_project \
php_framework/
svn commit php_framework/ -m 'ported r136 from new_project'

The first command gets a working copy of the framework. The merge command takes the diff between revision 135 and 136 of /new_project and applies it to the php_framework directory. Then we commit the changes to the framework.

If this revision has some changes to files that don't belong in the framework, we can specify the file(s) that changed that we want ported to the framework in the merge statement like the following:

svn merge -r 135:136 \
svn+ssh://svn_server/new_project/blah/somefile.php \
php_framework/blah/somefile.php

I was pleased with how simple this process turned out to be. For more information, the Subversion book is online.