these 2 derivations will be built:
  /nix/store/pdndzx3i9lh5y4a1mlfz7r83ljmafnyz-iets-0.1.0.drv
  /nix/store/hcccxk8jba45cqr6y6n5z6l1zfv8w48h-iets-diff-e2e.drv