Summary is not quite correct, but I don't know how to sum it up better. rox-base/zeroinstall-injector-0.31-r1 got installed with rox-clib-2.1.10 After that I was unable to start local version of rox-session, till I read rox-clib-2.1.10.ebuild and copied that process for ROX-Filer. I think ROX-Filer ebuild should be updated for zeroinstall.
Thanks very much for the report, I can fix this right away. I was waiting for ppc to keyword some thumbs, videothumbnail, and mime-editor (since rox-filer will soon RDEPEND on them), but rox-2.7-r1 that installs the local feed is ready to go any time.
Okay, checked in rox-base/rox-2.7-r1 which installs the 0install native feed, so now rox-session will not freak out if 0install is found. Also made <=rox-base/rox-session-0.30 block rox-base/zeroinstall-injector, so this won't happen to anyone else by mistake. New version rox-base/rox-session-0.30-r1 requires new rox-2.7-r1, so it does not block zeroinstall-injector. TODO: I don't have rox-session installing its own 0install feed yet, since it requires "ROX-Defaults", and I have to figure out how to deal with that, but this shouldn't be required for normal operation of rox-session.