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.

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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