Source control when working on open source projects

How do people who aren't committers on open source projects keep their changes on source control before they are ready to submit a patch?

Specifically, say I'm working on an apache project like Hadoop. I would like to be able to maintain the original subversion bindings (for things like checking project history, looking at a specific revision, etc), but I would also like to keep my own changes versioned (for my own sanity).

I guess I could use 2 different projec开发者_JAVA技巧ts, each with its own subversion bindings, but I was wondering if the former scenario, only one project, was possible. I would also like to hear about other alternatives.

Thanks.

if the project is running svn try running git in the same installation, that way you can have your own local changes/commmits in the same directory