From b0b0c3d94345050a7f86d1ebc6c56eea4389d030 Mon Sep 17 00:00:00 2001
From: Igor <egor@sgf.lt>
Date: Tue, 27 Feb 2024 21:48:27 +0000
Subject: [PATCH] targets/generic-linux: use xdg path for defexpr

Fixes warnings about the non-existent `~/.nix-defexpr` folder when
using `use-xdg-base-directories = true`.

Example:

    warning: Nix search path entry '/home/user/.nix-defexpr/channels' does not exist, ignoring
    Starting Home Manager activation
    Activating checkFilesChanged
    Activating checkLinkTargets
    Activating writeBoundary
    Activating installPackages
    replacing old 'home-manager-path'
    installing 'home-manager-path'
    Activating dconfSettings
    Activating linkDesktopApplications
    Activating linkGeneration
    Cleaning up orphan links from /home/user
    No change so reusing latest profile generation 13
    Creating home file links in /home/user
    Activating onFilesChange
    Activating reloadSystemd
    warning: Nix search path entry '/home/user/.nix-defexpr/channels' does not exist, ignoring
---
 modules/targets/generic-linux.nix | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/modules/targets/generic-linux.nix b/modules/targets/generic-linux.nix
index b5a07d5fa..9dce9f5c8 100644
--- a/modules/targets/generic-linux.nix
+++ b/modules/targets/generic-linux.nix
@@ -99,7 +99,11 @@ in {
         "/usr/share/terminfo" # package default, all distros
       ];
     in {
-      NIX_PATH = "$HOME/.nix-defexpr/channels\${NIX_PATH:+:}$NIX_PATH";
+      NIX_PATH = if config.nix.enable
+      && (config.nix.settings.use-xdg-base-directories or false) then
+        "${config.xdg.stateHome}/nix/defexpr/channels\${NIX_PATH:+:}$NIX_PATH"
+      else
+        "$HOME/.nix-defexpr/channels\${NIX_PATH:+:}$NIX_PATH";
       TERMINFO_DIRS =
         "${profileDirectory}/share/terminfo:$TERMINFO_DIRS\${TERMINFO_DIRS:+:}${distroTerminfoDirs}";
     };