these 2 derivations will be built:
  /nix/store/81fq1r3ywj524dgl18hrbvq63bjbq5jy-iets-0.1.0.drv
  /nix/store/hra2jnpn4ybf6gsf2sa1kgjzhd7fnr4p-iets-diff-e2e.drv