Bug#681419: tech-ctte help needed: main dependencies on non-free/contrib
Niels Thykier writes ("Re: tech-ctte help needed: main dependencies on non-free/contrib"):
> I suspect installability checking of all packages should find them if
> they are there. One run with non-free+contrib and one without - the
> "newly" uninstallable between the two runs should be set you are looking
> for. It does not catch issues like "foo-nonfree | foo", but they would
> be caught by your other query.
Unless all the package managers always prefer to avoid installing from
non-free unless there is no other way to satisfy the user's request,
this is not a sufficient test.
In practice I think if we had installability bugs of the form you
suggest, in testing, people would notice. Since those packages would
not be installable in testing at all.