use test && PYTHON_REQ_USE="ipv6" This violates PMS even twice. Firstly, for using 'use' in global scope. Secondly, for making dependencies vary depending on USE. For more explanation, see the tracker.
Fixed in app-admin/ganeti-2.15.1-r1
This needs to be fixed in all ebuilds. Unless you don't mind Portage spamming everyone with a lot of rejected ebuilds.
https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=95bea832acf85cc697689d9afad274c96e164635