From 645ff13a4be67718b624c5b15f316922399cc3dd Mon Sep 17 00:00:00 2001
From: Joachim Fasting <joachifm@fastmail.fm>
Date: Sun, 23 Oct 2016 17:24:17 +0200
Subject: [PATCH] nixos autoUpgrade: fix use of startAt

`startAt = ""` as in `startAt = optionalString false ...` results
in an invalid timer unit (due to "" being promoted to a singleton
list and not filtered out).

Ref: c9941c4b5ef7acc1cb8d734acb383410d99c01ba
---
 nixos/modules/installer/tools/auto-upgrade.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/nixos/modules/installer/tools/auto-upgrade.nix b/nixos/modules/installer/tools/auto-upgrade.nix
index b21b80c666a..dfb43d1a1db 100644
--- a/nixos/modules/installer/tools/auto-upgrade.nix
+++ b/nixos/modules/installer/tools/auto-upgrade.nix
@@ -84,7 +84,7 @@ let cfg = config.system.autoUpgrade; in
         ${config.system.build.nixos-rebuild}/bin/nixos-rebuild switch ${toString cfg.flags}
       '';
 
-      startAt = optionalString cfg.enable cfg.dates;
+      startAt = optional cfg.enable cfg.dates;
     };
 
   };