From 92a9c0756c7fd7edb71aca664d4ea7a3ebae2df4 Mon Sep 17 00:00:00 2001
From: Harald Hoyer <harald@hoyer.xyz>
Date: Sun, 28 Sep 2025 08:09:41 +0200
Subject: [PATCH] feat(nixos): improve nix configuration and tmp handling

- Reformatted function parameters to enhance readability.
- Added `build-dir = "/var/tmp"` to nix settings for better build management.
- Removed redundant `TMPDIR` environment variable for nix-daemon in systemd services.
---
 modules/nixos/nix/default.nix           | 47 +++++++++++++------------
 modules/nixos/services/base/default.nix | 10 +++---
 2 files changed, 30 insertions(+), 27 deletions(-)

diff --git a/modules/nixos/nix/default.nix b/modules/nixos/nix/default.nix
index f5b0c60..61232ea 100644
--- a/modules/nixos/nix/default.nix
+++ b/modules/nixos/nix/default.nix
@@ -59,35 +59,38 @@ in
         users = [
           "root"
           config.metacfg.user.name
-        ] ++ optional config.services.hydra.enable "hydra";
+        ]
+        ++ optional config.services.hydra.enable "hydra";
         extra-substituters = cfg.extra-substituters;
       in
       {
         package = cfg.package;
 
-        settings =
-          {
-            experimental-features = "nix-command flakes";
-            http-connections = 50;
-            warn-dirty = false;
-            log-lines = 50;
-            sandbox = true;
-            auto-optimise-store = true;
-            trusted-users = users;
-            allowed-users = users;
+        settings = {
+          experimental-features = "nix-command flakes";
+          build-dir = "/var/tmp";
+          http-connections = 50;
+          warn-dirty = false;
+          log-lines = 50;
+          sandbox = true;
+          auto-optimise-store = true;
+          trusted-users = users;
+          allowed-users = users;
 
-            substituters = [
-              cfg.default-substituter.url
-            ] ++ (mapAttrsToList (name: value: name) extra-substituters);
-            trusted-public-keys = [
-              cfg.default-substituter.key
-            ] ++ (mapAttrsToList (name: value: value.key) extra-substituters);
+          substituters = [
+            cfg.default-substituter.url
+          ]
+          ++ (mapAttrsToList (name: value: name) extra-substituters);
+          trusted-public-keys = [
+            cfg.default-substituter.key
+          ]
+          ++ (mapAttrsToList (name: value: value.key) extra-substituters);
 
-          }
-          // (lib.optionalAttrs config.metacfg.tools.direnv.enable {
-            keep-outputs = true;
-            keep-derivations = true;
-          });
+        }
+        // (lib.optionalAttrs config.metacfg.tools.direnv.enable {
+          keep-outputs = true;
+          keep-derivations = true;
+        });
 
         gc = {
           automatic = true;
diff --git a/modules/nixos/services/base/default.nix b/modules/nixos/services/base/default.nix
index 259f2c6..ab277df 100644
--- a/modules/nixos/services/base/default.nix
+++ b/modules/nixos/services/base/default.nix
@@ -1,7 +1,8 @@
-{ config
-, lib
-, pkgs
-, ...
+{
+  config,
+  lib,
+  pkgs,
+  ...
 }:
 with lib;
 with lib.metacfg;
@@ -188,7 +189,6 @@ in
     virtualisation.libvirtd.enable = lib.mkDefault true;
 
     boot.tmp.useTmpfs = true;
-    systemd.services.nix-daemon.environment.TMPDIR = "/var/tmp";
 
     services.fstrim.enable = true;
   };