I'm working on customizing a couple of open source projects in ways that are very much personalized -- i.e., not appropriate to send the patches back to the maintainers for the public. One of them is stored in CVS, one in SVN. I use SVN for my own work.
The CVS project is fine. I check the tree in to my SVN repository, including the CVS directories. I can commit all my changes, and still do a cvs update to stay up to date with bug fixes/features of the public project.
How should I work on the SVN project? Is there a 'best practice' or known procedure for this kind of scenario?
Take a look at the section in the documentation on vendor branches.