From 8bb6fdc4f9c9bd6f61a62dfd57180d394ced6fc8 Mon Sep 17 00:00:00 2001
From: Jaka Hudoklin <jakahudoklin@gmail.com>
Date: Sun, 7 Dec 2014 21:44:20 +0100
Subject: [PATCH] nixos/systemd: ignore null environment options

---
 nixos/modules/system/boot/systemd.nix | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/nixos/modules/system/boot/systemd.nix b/nixos/modules/system/boot/systemd.nix
index 78fe8c49fb05..05f8c8009bfd 100644
--- a/nixos/modules/system/boot/systemd.nix
+++ b/nixos/modules/system/boot/systemd.nix
@@ -348,7 +348,8 @@ let
           [Service]
           ${let env = cfg.globalEnvironment // def.environment;
             in concatMapStrings (n:
-              let s = "Environment=\"${n}=${env.${n}}\"\n";
+              let s = optionalString (env."${n}" != null)
+                "Environment=\"${n}=${env.${n}}\"\n";
               in if stringLength s >= 2048 then throw "The value of the environment variable ‘${n}’ in systemd service ‘${name}.service’ is too long." else s) (attrNames env)}
           ${if def.reloadIfChanged then ''
             X-ReloadIfChanged=true