From c70ffe0dddd2540e428e0c3d67339fc7ce3b6793 Mon Sep 17 00:00:00 2001
From: Archit Gupta <archit@accelbread.com>
Date: Sat, 6 Apr 2024 17:47:55 -0700
Subject: [PATCH] Check HM useGlobalPkgs before propagating

The NixOS home-manager module only uses nixpkgs settings if
useGlobalPkgs is false. If it is true, there is no need to propagate
config (and propagating nixpkgs.config would cause an assertion).
---
 builtinModules/propagationModule.nix | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/builtinModules/propagationModule.nix b/builtinModules/propagationModule.nix
index e5c4c43..6f49a4c 100644
--- a/builtinModules/propagationModule.nix
+++ b/builtinModules/propagationModule.nix
@@ -7,24 +7,27 @@
 
 { lib, config, flakelight, moduleArgs, inputs, outputs, ... }:
 let
-  inherit (lib) mapAttrs mkOption optionalAttrs;
+  inherit (lib) mapAttrs mkOption optional optionalAttrs;
   inherit (flakelight) selectAttr;
   inherit (flakelight.types) module;
+  flakeConfig = config;
 in
 {
   options.propagationModule = mkOption { type = module; internal = true; };
 
   config.propagationModule =
-    { lib, pkgs, options, ... }:
+    { lib, pkgs, options, config, ... }:
     let inherit (pkgs.stdenv.hostPlatform) system; in {
       config = (optionalAttrs (options ? nixpkgs.overlays) {
         # Apply flakelight overlays to NixOS/home-manager configurations
         nixpkgs.overlays = lib.mkOrder 10
-          (config.withOverlays ++ [ config.packageOverlay ]);
+          (flakeConfig.withOverlays ++ [ flakeConfig.packageOverlay ]);
       })
       // (optionalAttrs (options ? home-manager.sharedModules) {
         # Propagate module to home-manager when using its nixos module
-        home-manager.sharedModules = [ config.propagationModule ];
+        home-manager.sharedModules =
+          optional (! config.home-manager.useGlobalPkgs)
+            [ flakeConfig.propagationModule ];
       })
       // {
         # Give access to flakelight module args under `flake` arg.