these 2 derivations will be built:
  /nix/store/psyff3azffag4y4dn6yf3qx2v7zf2277-iets-0.1.0.drv
  /nix/store/8c73ng1dzlm1yg0x94p99kzws5h69di3-iets-diff-e2e.drv