these 2 derivations will be built:
  /nix/store/l5j2kik16b9ff60qdh3w0bydf3dqlr7n-iets-0.1.0.drv
  /nix/store/4sl8x2nidrlqf87fhnv6lmlbxbw7pcl1-iets-diff-e2e.drv