Ammonite "exec" format issue on fish

[fabianhjr]

Describe the bug
The ammonite package is broken if a user sets their shell to fish.

To Reproduce

1. Set the user shell to fish

    users.fabian = {
      isNormalUser = true;
      extraGroups = [ "wheel" ];
      shell = pkgs.fish;
    };

2. Install the ammonite package (nix-env -iA nixos.ammonite
3. Try to run the amm executable.

One will get the following error:

Failed to execute process '/home/fabian/.nix-profile/bin/amm'. Reason:
exec: Exec format error
The file '/home/fabian/.nix-profile/bin/amm' is marked as an executable but could not be run by the operating system.

However,

bash
amm

works.

Expected behavior
Ammonite loads a REPL

Metadata

• system: "x86_64-linux"
• host os: Linux 5.2.11, NixOS, 19.03.173426.541d9cce8af (Koi)
• multi-user?: yes
• sandbox: yes
• version: nix-env (Nix) 2.2.2
• channels(root): "nixos-19.03.173426.541d9cce8af"
• channels(fabian): "nixos-unstable-19.09pre191505.7d5375ebf4c"
• nixpkgs: /nix/var/nix/profiles/per-user/root/channels/nixos

Maintainer information:

# a list of nixos modules affected by the problem
module: ammonite

Maintainer: /cc @NeQuissimus

[symphorien]

amm is a shell script without a shebang. The behavior of exec(3) in this case if to execute /bin/sh amm. Apparently fish does otherwise. Looks like it is a deficiency in fish.

[fabianhjr]

exec depends on the shell being used. (Since it is a built-in of each(?) shell)

https://fishshell.com/docs/current/commands.html#exec exec(1)

https://www.gnu.org/savannah-checkouts/gnu/bash/manual/bash.html#index-exec

[denisgarci]

@fabianhjr I have the same issue. Should we open an issue on the Ammonite repo?

[fabianhjr]

Not really sure, I think it has mostly to do with the nix package rather than upstream.

Maybe add a shebang for /bin/sh or require bash and add a bash shebang or have a fish version (an amm.fish)?

[denisgarci]

I have the same issue with z-lua:

Failed to execute process '/Users/dgarcia/.nix-profile/bin/z'. Reason:
exec: Exec format error
The file '/Users/dgarcia/.nix-profile/bin/z' is marked as an executable but could not be run by the operating system.

Should I open a separate issue? I'm going to try to open an issue on fish to see what they recommend.

[denisgarci]

I found this related issue: fish-shell/fish-shell#4946
Also I installed ammonite by hand and it works.

[bbjubjub2494]

I use fish too and I had the same issue. The ammonite documentation recommends adding the shebang line when installing. I think it's on the Nixpkgs derivation to fix this.