From c27ec0a5b10a9e9af2b25e2145ed6968f44d1366 Mon Sep 17 00:00:00 2001
From: Kiara Grouwstra <kiara@procolix.eu>
Date: Wed, 9 Apr 2025 16:55:24 +0200
Subject: [PATCH] set NIX_PATH, enables use of <nixpkgs>

---
 infra/common/nixos/default.nix | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/infra/common/nixos/default.nix b/infra/common/nixos/default.nix
index b870ab03..c789a04e 100644
--- a/infra/common/nixos/default.nix
+++ b/infra/common/nixos/default.nix
@@ -1,8 +1,8 @@
-{ lib, ... }:
+{ lib, pkgs, ... }:
 
 let
   inherit (lib) mkDefault;
-
+  nixPath = "/run/current-system/nixpkgs";
 in
 {
   imports = [
@@ -16,6 +16,15 @@ in
   system.stateVersion = "24.05"; # do not change
   nixpkgs.hostPlatform = mkDefault "x86_64-linux";
 
+  # use flake's nixpkgs over channels
+  nix.nixPath = [ "nixpkgs=${nixPath}" ];
+  system.extraSystemBuilderCmds = ''
+    ln -sv ${pkgs.path} $out/nixpkgs
+  '';
+  systemd.tmpfiles.rules = [
+    "L+ ${nixPath} - - - - ${pkgs.path}"
+  ];
+
   ## This is just nice to have, but it is also particularly important for the
   ## Forgejo CI runners because the Nix configuration in the actions is directly
   ## taken from here.