jq impurity in flake mode

jq is used in nixos-shell and is not a satisfied dependency when using nixos-shell 1.0 from nixpkgs like nix-shell -p nixos-shell

nixos-shell/bin/nixos-shell

Line 32 in 9a81009

    
           flake_uri="$(nix flake metadata --extra-experimental-features "nix-command flakes"  --json -- "$flake" | jq -r .url)"

I'm not sure how this is best solved. Maybe nixos-shell should be a writeShellApplication with all of its runtimInputs resolved properly? Maybe we should use resholve? I'm unsure.