we don't remove the entire feature in one go to make review easier.
impure derivations are rather unintrusive on their own, at least if
we compare them to dynamic or ca derivations in general, so we will
be done with this soon. as it stands impure derivations cannot work
without ca derivations, and those we *really* want to leave behind.
Change-Id: I4f01d8d758b2c85dcd6c3078304b5ee1b52f65b0
The UnkeyedValidPathInfo test was testing an ancient version but not the
current version. Doesn't make much sense to me.
Change-Id: Ib476a4297d9075f2dcd31a073b3e7b149b2189af
this lets us set per-test-program environment variables rather than only
a single, global default. this was supported in nix originally but
might've gone partially missing in the upstream backports process?
Change-Id: Iad0919841b1b6d11e0b7ebd3920449a62f544e77
eldritch horrors