nix repl for home-manager home.nix config

readme.md

https://logs.nix.samueldr.com/home-manager/2020-06-24#3652401;

NIX_PATH=nixpkgs=http://nixos.org/channels/nixos-21.05/nixexprs.tar.xz:home-manager=https://github.com/nix-community/home-manager/archive/release-21.05.tar.gz:nix-on-droid=https://github.com/t184256/nix-on-droid/archive/release-21.05.tar.gz nix repl
nix-repl> hm = import <home-manager/modules> { configuration = ~/.config/nixpkgs/home.nix; pkgs = import <nixpkgs> {}; }
~> hm.config.TAB

Very useful. Thanks for sharing.

Just to explain what is going on here, the $NIX_PATH makes <nixpkgs> and <home-manager> available in the repl. This can also be done with -I as per the nix repl documentation:

If a path in the Nix search path starts with http:// or https://, it is interpreted as the URL of a tarball that will be downloaded and unpacked to a temporary location. The tarball must consist of a single top-level directory. For example, passing

-I nixpkgs=https://github.com/NixOS/nixpkgs/archive/master.tar.gz

to nix repl tells Nix to download and use the current contents of the master branch in the nixpkgs repository.

I'm using nix flakes, so I wanted a way to load the flake (with :lf .) and use its inputs to generate the config within nix repl. In my directory I have flake.nix and home.nix. Not sure if it's idiomatic, but this works:

nix repl
nix-repl> :lf .
nix-repl> system = "x86_64-darwin"
nix-repl> pkgs = inputs.nixpkgs.legacyPackages.${system}
nix-repl> hm = inputs.home-manager.lib.homeManagerConfiguration { inherit pkgs; modules = [ ./home.nix ]; }
nix-repl> hm.config.<TAB>

Thanks, glad you like it.

The flakes way you described I'd go for nowadays as well.