question: Home-manager and Flake usage

[paddygoat]

Is there an existing issue for this?

• I have searched the existing issues

Issue description

I'm not sure if this is the right place to ask this question as it's also a flake issue, but seems like running home-manager switch -f ./home.nix does not put my home.nix file into the store with my other DIY config scripts.
After running nixos-rebuild build --flake .# in my DIY config directory, all my files are in /nix/store/ EXCEPT home.nix and I get this error:

[paddygoat@nixos:~/Paddy_Nix_Backup]$ home-manager switch -f ./home.nix
/nix/store/wvxc8aaaxmvpprcp8c3sk12320rsx407-home-manager-generation
Starting home manager activation
Activating checkFilesChanged
Activating checkLinkTargets
Activating writeBoundary
Activating installPackages
replacing old 'home-manager-path'
installing 'home-manager-path'
Activating linkGeneration
Cleaning up orphan links from /home/paddygoat
No change so reusing latest profile generation 2
Creating home file links in /home/paddygoat
Activating onFilesChange
Activating reloadSystemd

There are 154 unread and relevant news items.
Read them by running the command 'home-manager news'.

[paddygoat@nixos:~/Paddy_Nix_Backup]$ nixos-rebuild build --flake .#
warning: Git tree '/home/paddygoat/Paddy_Nix_Backup' is dirty
building the system configuration...
warning: Git tree '/home/paddygoat/Paddy_Nix_Backup' is dirty
error: getting status of '/nix/store/rsfrp307b6a26jsw6s3badmjgjvl2n5z-source/home.nix': No such file or directory
(use '--show-trace' to show detailed location information)

[paddygoat@nixos:~/Paddy_Nix_Backup]$

Please advise ..... Thank you very much !!

Maintainer CC

No response

System information

[paddygoat@nixos:~/Paddy_Nix_Backup]$  nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 5.10.76, NixOS, 21.05.3896.b0274abf850 (Okapi)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.4pre20211006_53e4794`
 - channels(paddy): `"home-manager-21.05"`
 - channels(paddygoat): `"home-manager-21.05"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

[paddygoat]

home.nix:

{ config, pkgs, ... }:

{
  # Let Home Manager install and manage itself:
  programs.home-manager.enable = true;
  
  # Home Manager needs a bit of information about you and the paths it should manage:
  home.username = "paddygoat";
  home.homeDirectory = "/home/paddygoat";
  
  # This value determines the Home Manager release that your configuration is compatible with.
  # This helps avoid breakage when a new Home Manager release introduces backwards incompatible changes.
  #
  # You can update Home Manager without changing this value.
  # See the Home Manager release notes for a list of state version changes in each release.
  home.stateVersion = "21.05";
  
  # home.packages = [ pkgs.plasma5Packages.kdenlive ];
  
  # home.packages = with pkgs; [
  #  git
  #  git-crypt
  #  gnupg
  # ];
  
  home.packages = with pkgs; [
    plasma5Packages.kdenlive
    git
    git-crypt
    gnupg
    audacity
    gimp
    nano
    qtractor
    jack2
    lmms
  ];
    
}

[MatthewCroughan]

When you're using flakes, nothing really matters except the nixos-rebuild switch command, and home-manager switch doesn't exist. The home-manager switch command is intended more for using home-manager outside of NixOS.

Everything ends up as a big .nix expression in the end, as these files are either imported or are not imported. The way you choose to separate them is yours.

So is home.nix being imported by the Nix expression that you're executing when you run nixos-rebuild build --flake .# ?

Do you have something that looks like this?:

{ config, lib, ... }:
{
  imports = [ ./hardware-configuration.nix ./home.nix ];
}

If you are not importing home.nix in any nix expression, it will not be evaluated for any reason.

[MatthewCroughan]

The reason you have the home-manager command at all is your NixOS channel, if you intend to use Flakes you are not supposed to have any channels. You should remove the home-manager channel:
nix-channel --remove home-manager

[paddygoat]

Thanks @MatthewCroughan. I eventually sussed out that capitalisation in my username was causing an issue - bit of a newbie mistake. Then re-vamped another Flake.nix script which worked with a little bit of fine tuning:

{
  description = "My system config based on flake";

  inputs = {
    nixpkgs.url = "nixpkgs/nixos-21.05";
    home-manager.url = "github:nix-community/home-manager/release-21.05";
    home-manager.inputs.nixpkgs.follows = "nixpkgs";
  };

  outputs = { nixpkgs, home-manager, ... }:
  let
    system = "x86_64-linux";

    pkgs = import nixpkgs {
      inherit system;
      config = { allowUnfree = true; };
    };
    
    lib = nixpkgs.lib;

  in {
    homeManagerConfigurations = {
      paddygoat = home-manager.lib.homeManagerConfiguration {
        inherit system pkgs;
        username = "paddygoat";
        homeDirectory = "/home/paddygoat";
        configuration = {
          imports = [
          ./home.nix
          ];
        };      
      };
    };
  
  
    nixosConfigurations = {
      nixos = lib.nixosSystem {
        inherit system;
        
        modules = [
          ./system/configuration.nix
        ];
      };
    };
  };
} 

[dominikh]

I'm slightly confused by the "Everything ends up as a big .nix expression in the end" argument. Doesn't this preclude individual users from managing their homes independently of the system administrator? That is, I want to manage my home with home-manager without the sysadmin having to include my file, or having to rebuild the OS any time I change my config.

[MatthewCroughan]

I'm slightly confused by the "Everything ends up as a big .nix expression in the end" argument. Doesn't this preclude individual users from managing their homes independently of the system administrator? That is, I want to manage my home with home-manager without the sysadmin having to include my file, or having to rebuild the OS any time I change my config.

I just mean to say that if home.nix doesn't contain imports = [ ./something.nix ];, then something.nix will not end up being used for any reason. The code will not be automatically used or included for any reason relating to the home-manager command, or any nix command. The expression (the .nix file) is in control of the code the gets used, nothing else.

[wmertens]

So if you want to use flakes, you can't use home-manager to maintain your personal profile?

I'd like to use flakes and use my home-manager configuration on non-nixos systems too.

[cmm]

I actually miserably failed when trying to use nixos-rebuild with home-manager (it does not find the needed output, which seems kind of logical since it looks under nixosConfigurations. and that's probably not where the homeConfigurations. hierarchy is, right? Right?), but home-manager switch --flake ... is working great for me. Wonder what I'm missing here!

EDIT, ah, I think I get it: my home config is separate from system config (for (theoretical at the moment) portability to non-NixOS), so it does make sense that nixos-rebuild does not pick it up. But the home-manager command exists because my NixOS config takes care to furnish my (otherwise bare) user with the home-manager package, no channels needed.

So I guess the question is rather why does the README sound like the home-manager command is not advisable for flakes, when it seems to work totally OK?

[wmertens]

Aha good to know, I'll just give it a try then.

[berbiche]

So I guess the question is rather why does the README sound like the home-manager command is not advisable for flakes, when it seems to work totally OK?

Indeed, this is a mistake in the README. home-manager switch --flake should be used for a standalone installation, while nixos-rebuild switch --flake should be used when Home Manager is integrated with the NixOS configuration with the NixOS module.

failed when trying to use nixos-rebuild with home-manager (it does not find the needed output, which seems kind of logical since it looks under nixosConfigurations. and that's probably not where the homeConfigurations.

The command home-manager switch --flake uses the homeConfigurations output whereas Nix uses nixosConfigurations.

[wmertens]

Slightly hijacking the thread: I have ~/.config/nixpkgs/config.nix to set some nixpkgs things, which worked fine before, but with the flake.nix that is proposed in the Readme it doesn't read that. How can I provide a nixpkgs with this config to home-manager?

EDIT: found the answer here https://nixos.wiki/wiki/Flakes#Enable_unfree_software_in_home-manager

[autra]

The command home-manager switch --flake uses the homeConfigurations output whereas Nix uses nixosConfigurations.

That's the piece of info I needed, thanks! It's in the manpage of home-configuration but this should also be documented https://nix-community.github.io/home-manager/, wdyt?

[kinthaiofficial]

Home-manager with flakes is the recommended modern setup. Here's a minimal but complete template:

# flake.nix
{
  description = "Home Manager configuration";

  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    home-manager = {
      url = "github:nix-community/home-manager";
      inputs.nixpkgs.follows = "nixpkgs";  # Ensure same nixpkgs version
    };
  };

  outputs = { nixpkgs, home-manager, ... }:
  let
    system = "x86_64-linux";  # or "aarch64-darwin" for Apple Silicon
    pkgs = nixpkgs.legacyPackages.${system};
  in {
    homeConfigurations."yourusername" = home-manager.lib.homeManagerConfiguration {
      inherit pkgs;
      modules = [ ./home.nix ];
    };
  };
}

# home.nix
{ config, pkgs, ... }:
{
  home.username = "yourusername";
  home.homeDirectory = "/home/yourusername";
  home.stateVersion = "24.05";  # Keep this fixed, only update intentionally
  
  home.packages = with pkgs; [
    ripgrep
    fd
    bat
    eza
    fzf
  ];
  
  programs.git = {
    enable = true;
    userName = "Your Name";
    userEmail = "you@example.com";
  };
  
  programs.zsh = {
    enable = true;
    enableAutosuggestions = true;
    oh-my-zsh = {
      enable = true;
      plugins = [ "git" "docker" ];
    };
  };
  
  programs.home-manager.enable = true;
}

Then:

# First time
nix run home-manager/master -- init --switch

# Or if you have the flake:
home-manager switch --flake .#yourusername

The inputs.nixpkgs.follows = "nixpkgs" is important — it ensures home-manager uses your top-level nixpkgs version rather than pinning its own, which prevents version conflicts.