Profiles imports are brittle, causing failure if imported twice

[ymarkus]

Expected Behavior

If I set users.users.<name>.shell in the users/<name>/default.nix file, there should be no conflicts anywhere (happens for any user).

Current Behavior

Building the system configuration errors out with following:
for users.users.<name>.shell = pkgs.zsh:

The unique option `users.users.<name>.shell' is defined multiple times, in:
 - <unknown-file>
 - <unknown-file>.

Possible Solution

Maybe I have to set it somewhere else? Can't find anything in the documentation...

[nrdxp]

I can't reproduce this error in either core or community from a fresh checkout. What revision are you on? The only place I set the default shell for users is: https://github.com/divnix/devos/blob/community/profiles/develop/zsh/default.nix#L9

This doesn't conflict with users.users.<name>.shell though, as I tested it explicitly, and this is only set if your using the community branch and develop or zsh profile. You might want to grep around and see if you accidentally set it twice somewhere, or perhaps this was an issue with an older revision but is now resolved. Worst case scenario, you can always force the setting with mkForce.

I'll leave this open for a bit to help you find a solution.

[ymarkus]

OK, I've found the error. It seems like if you import a profile twice, it does weird things. Here's what happened:

1. users.<name> get imported in core:

core = [ users.nixos users.root  ];

2. core gets imported in graphics:

graphics = core ++ [ graphical ];

3. graphics get imported in pc & gaming:

pc = graphics ++ [ develop networking.samba printing systems.pc virt zfs ];
gaming = graphics ++ [ graphical.games ];

4. pc & gaming get imported in NixOS.nix:

imports = [...] ++ suites.pc ++ suites.gaming;

So everything in the profiles core & graphical got imported twice. That's why mkForce also didn't work.

Maybe a hint in the manual would be fitting if this is the case?

[nrdxp]

Good catch, we don't want this biting us in the future. Perhaps the profiles attribute set in suites should just contain paths to the profile, instead of importing it outright. The default import logic prevents this sort of error when importing the same path twice, so we might want to just leverage that.

[ymarkus]

I just found out it can also happen when importing a profile inside suites and then importing it inside another profile like this:

{
  suites = with profiles; rec {
    [...]
    pc = graphics ++ [ develop networking.samba printing systems.pc virt zfs ];

    laptop = pc ++ [ systems.pc.laptop ];
  };
}

and laptop/default.nix:

{
  imports = [
    ../. # this imports pc
  ];
}

[ymarkus]

Thanks, seems to work now!