Heh.  Yeah, I use patch because I don't just work with mercurial/python, and I find the patch command simpler to use for applying patches in general, since I never want an autocommit.   (The exception would be if I'm applying a patch that involves extended diff stuff that patch doesn't recognize.)  It makes sense that the devguide talks about import, though, since the patches here always ought to be things generated by hg and thus handleable by import.  I'm not sure why this one would have failed for you.