these 3 derivations will be built:
  /nix/store/bp887zs5n9f70s6shbg3ch89sk8lsrfw-source.drv
  /nix/store/v8rz0viw8sx6aqv4xvsn2yhxs8whva6x-herdr-eternal-deps-0.1.0.drv
  /nix/store/9sq3yi70yzfm64jv2kjq82v9z0fa99i8-herdr-eternal-test-0.1.0.drv