treewide: add environment module from hjem PR

This commit adds the module I made for hjem (https://github.com/feel-co/hjem/pull/16). Needs to be removed after it gets merged.

flake.lock

@@ -269,16 +269,15 @@
         ]
       },
       "locked": {
-        "lastModified": 1738780311,
-        "narHash": "sha256-78uYeNb6yGvd2PClTNbtY25AdLyND1Sv6oMN1reN2ww=",
-        "owner": "nezia1",
+        "lastModified": 1737619027,
+        "narHash": "sha256-jEzZs9dHdmVP5X9HCC/7jrv08aWFfqZV5cZ+cZWYGA4=",
+        "owner": "feel-co",
         "repo": "hjem",
-        "rev": "f8b3fb8f46aba8768001cca1936ca3d40d7e12ab",
+        "rev": "48cfa21987672a31a358b7e4d582fc174556e633",
         "type": "github"
       },
       "original": {
-        "owner": "nezia1",
-        "ref": "implement-environment-variables",
+        "owner": "feel-co",
         "repo": "hjem",
         "type": "github"
       }

flake.nix

@@ -113,7 +113,7 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
     hjem = {
-      url = "github:nezia1/hjem/implement-environment-variables"; # TODO: change to github:feel-co/hjem if env var PR gets in
+      url = "github:feel-co/hjem";
       inputs.nixpkgs.follows = "nixpkgs";
     };
     nix-gaming = {

hosts/default.nix

@@ -5,10 +5,7 @@
       specialArgs = {inherit inputs lib';};
       modules =
         (args.modules or [])
-        ++ [
-          ../modules
-          inputs.hjem.nixosModules.default
-        ];
+        ++ [../modules];
     };
 in {
   vamos = mkSystem {

modules/core/users.nix

@@ -1,13 +1,17 @@
 {
+  inputs,
   lib,
   config,
   ...
 }: let
-  inherit (lib) mkIf;
+  inherit (lib.modules) mkIf;
+  inherit (lib.lists) singleton;
+  inherit (lib.filesystem) listFilesRecursive;
   inherit (config.local.systemVars) username;
   inherit (config.local.homeVars) fullName;
   inherit (config.local.profiles) desktop;
 in {
+  imports = [inputs.hjem.nixosModules.default];
   users.users.${username} = {
     isNormalUser = true;
     description = fullName;
@@ -26,9 +30,11 @@ in {
       enable = true;
       directory = "/home/${username}";
       user = "${username}";
-      environment = {
-        forceOverride = true;
+      environment.forceOverride = true;
     };
+
+    extraModules = singleton {
+      imports = listFilesRecursive ../../shared/modules/hjem;
     };
   };
 }

shared/modules/hjem/environment.nix

@@ -0,0 +1,74 @@
+{
+  config,
+  lib,
+  ...
+}: let
+  inherit (lib.options) mkOption;
+  inherit (lib.types) attrsOf listOf oneOf bool int path str;
+  inherit (lib.attrsets) attrNames mapAttrsToList;
+  inherit (lib.strings) concatStringsSep;
+  inherit (lib.lists) elem filter isList;
+
+  envFile = "99-user-env.conf";
+  cfg = config.environment;
+
+  toEnv = env:
+    if isList env
+    then concatStringsSep ":" (map toString env)
+    else toString env;
+
+  toConf = attrs:
+    concatStringsSep "\n"
+    (mapAttrsToList (name: value: "${name}=\"${toEnv value}\"") attrs);
+in {
+  options.environment = {
+    sessionVariables = mkOption {
+      type = attrsOf (oneOf [(listOf (oneOf [int str path])) int str path]);
+      default = {};
+      example = {
+        EDITOR = "nvim";
+        VISUAL = "nvim";
+      };
+      description = ''
+        A set of environment variables used in the user environment.
+        These variables will be set as systemd user environment
+        variables, using `environment.d`. The value of each
+        variable can be either a string or a list of strings. The
+        latter is concatenated, interspersed with colon
+        characters.
+      '';
+    };
+    forceOverride = mkOption {
+      type = bool;
+      default = false;
+      example = true;
+      description = ''
+        Whether to override environment variables that might exist.
+        This is useful for variables such as {env}`EDITOR`, which are set by
+        default on NixOS.
+      '';
+    };
+  };
+
+  config = {
+    files.".config/environment.d/${envFile}".text = toConf cfg.sessionVariables;
+
+    warnings = let
+      overlappingVars = filter (x: elem x (attrNames config.environment.sessionVariables)) (attrNames cfg.sessionVariables);
+    in
+      if
+        !cfg.forceOverride
+        && overlappingVars != []
+      then
+        map (name: ''
+          The session variable '${name}' is defined in both
+          `hjem.users.<name>.environment.sessionVariables` and
+          `config.environment.variables`. This may lead to conflicts.
+
+          If you want the one defined in hjem to take precedence, make sure you
+          set `forceOverride` to `true`.
+        '')
+        overlappingVars
+      else [];
+  };
+}