`passAsFile` paths aren't available for `nix develop`

[aameen-tulip]

Describe the bug

Derivations that use passAsFile don't have access to those paths in nix-command nix develop mode.

Steps To Reproduce

$ mkdir -p /tmp/whoops;
$ cd /tmp/whoops;
$ git init;
$ cat <<'EOF' > flake.nix
{  
  outputs = { nixpkgs, ... }: let
    fes = fn: builtins.foldl' ( a: s: a // { ${s} = fn s; } ) {} [
      "aarch64-darwin" "aarch64-linux" "x86_64-darwin" "x86_64-linux"
    ];
  in {
    packages = fes ( system: {
      default = nixpkgs.legacyPackages.${system}.stdenv.mkDerivation {
        name = "whoops";
        data = builtins.concatStringsSep "" ( builtins.genList toString 1024 );
        passAsFile = ["data"];
        buildCommand = ''
          line="$( <"$dataPath"; )";
          echo "$line" > "$out";
        '';
      };
    } );
  };
}
EOF
$ git add ./flake.nix;
$ nix flake lock;
$ git add ./flake.lock;
$ nix build && cat ./result;  # Works
$ rm ./result;
$ nix develop;
$ genericBuild;
bash: /private/tmp/nix-build-whoops-env.drv-0/.attr-1dy8mlivplr3m6ln28k025l0w4ax5kfv4miq9z4qgb1r1xwv0vis: No such file or directory

Expected behavior

Temporary files should be created during devShell initialization.

nix-env --version output

nix-env (Nix) 2.10.3

Additional context

The trivial example above uses buildCommand with stdenv.mkDerivation, but the same issue occurs with (unpack|build|install|...)Phase definition, and even with a direct derivation { ... }.
Defining the installable as devShells = ... in the flake has the same behavior as well.

[lilyinstarlight]

It looks like nix-shell has custom code to handle this (currently here but originally committed in 08355643a). It doesn't seem to check if structured attrs are in use prior to setting env vars either, unlike local-derivation-goal.cc, so I'm not sure if that's a bug or not in nix-shell

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/how-to-replace-nix-develop-with-nix-shell-for-a-flake-based-output/31333/1

[dguibert]

I've identified this issue as well.

Adding __structuredAttrs = true and replacing line="$( <"$dataPath"; )"; by line="$data" provides a workaround.

But despite within a nix-shell, the variable data is not listed by the env command

$ env | grep dataPath