these 2 derivations will be built:
  /nix/store/s5vhcngic7hzba6zrp9xq5pf3l1ydjv5-pg_regress-15.19.drv
  /nix/store/g6yk8rjja4045077g8ya8fz0g3kblbdh-docker-image-test.drv