nix devshell for developing runtime stuff

[VuiMuich]

I was wondering, how people are developing stuff in runtime from a nix shell.
My struggle was two-ways:

1. in the default shell, changes to files in local runtime were not reflected in the build at all
2. the whole runtime directory got copied into its own helix-runtime derivation and not symlinked to <project-root>/runtime

For the first issue my workaround was to add a second devShell to flake.nix that declares projectRoot = builtins.toString ./. but that lead to issue two. For this my workaround is to change the devShell to this:

i        runtimeDev = pkgs.mkShell {
          name = "helix-runtime-dev-shell";

          shellHook = ''
            export HELIX_RUNTIME=$(pwd)/runtime
            echo Set \$HELIX_RUNTIME to: $HELIX_RUNTIME
          '';
        };

But this feels quite hacky.
Is there some "official" way I am overlooking? How is others solution to conventiently work on runtime stuff without requiring the nix shell to rebuild on each edit?