If /dev isn't proper, it can lead to all kinds of odd failures. Therefore, it would be useful to validate /dev and and bail out early if appropriate. Two simple tests come to mind:
1) test that /dev/null is a device
2) test that bash process substitution works (relies on /dev/fd), using a simple test like [[ $(< <(echo foo) ) == foo ]]
"Portage development" is a bit wide. Do you have something more specific in mind?
If we just do this check when emerge starts up, then that should be sufficient. We could call it from inside the profile_check function, or close to where that function is called, inside pym/_emerge/main.py.
Patch posted for review: <http://news.gmane.org/gmane.linux.gentoo.portage.devel/cutoff=5221>.
This is fixed in git:
Released in portage-2.2.18