From 30845beee0448bea77a7b8770ea9e6d17ca205d8 Mon Sep 17 00:00:00 2001
From: Robert Hensing <robert@roberthensing.nl>
Date: Fri, 23 May 2025 13:12:56 +0200
Subject: [PATCH] nix.nixPath: Do not use environment.darwinConfig if set to
 null

I've personally set it to `null` to make my `system.primaryUser = null;`
configuration work on a machine with `stateVersion = 4;`.

It may apply in other use cases as well.
---
 modules/nix/default.nix | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/modules/nix/default.nix b/modules/nix/default.nix
index 540fbc5..8f8b6c4 100644
--- a/modules/nix/default.nix
+++ b/modules/nix/default.nix
@@ -443,11 +443,14 @@ in
       nixPath = mkOption {
         type = nixPathType;
         inherit (managedDefault "nix.nixPath" (
-          lib.optionals cfg.channel.enable [
-            # Include default path <darwin-config>.
-            { darwin-config = "${config.environment.darwinConfig}"; }
-            "/nix/var/nix/profiles/per-user/root/channels"
-          ]
+          lib.optionals cfg.channel.enable (
+            lib.optionals (config.environment.darwinConfig != null) [
+              # Include default path <darwin-config>.
+              { darwin-config = "${config.environment.darwinConfig}"; }
+            ] ++ [
+              "/nix/var/nix/profiles/per-user/root/channels"
+            ]
+          )
         )) default;
 
         defaultText = lib.literalExpression ''