these 2 derivations will be built:
  /nix/store/c1d9lvsihxqx6fvbq1rjhryi82s8cy0l-iets-0.1.0.drv
  /nix/store/8p27kgp9cbzrg4f8cnqvgvvml91sxmbm-iets-diff-e2e.drv