
Without the change `resolvedUrl` fails on non-mirror:// packages as: $ nix eval --impure --expr 'with import ./. {}; AMB-plugins.src.resolvedUrl' error: ... error: expected a list but found null: null After ther change the eval works as expected: $ nix eval --impure --expr 'with import ./. {}; AMB-plugins.src.resolvedUrl' "http://kokkinizita.linuxaudio.org/linuxaudio/downloads/AMB-plugins-0.8.1.tar.bz2"