From a27dc9d3ab31634d40905926203484e5d0f3336c Mon Sep 17 00:00:00 2001
From: Silvan Mosberger <infinisil@icloud.com>
Date: Wed, 1 May 2019 00:06:11 +0200
Subject: [PATCH] nixos/znc: Fix config generator for certain null values

The type of ZNC's config option specifies that a configuration like

  config.User.paul = null;

should be valid, which is useful for clearing/disabling property sets
like Users and Networks. However until now the config generator
implementation didn't actually cover null values, meaning you'd get an
error like

  error: value is null while a set was expected, at /foo.nix:29:10

This fixes the implementation to correcly allow clearing of property
sets.
---
 nixos/modules/services/networking/znc/default.nix | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/services/networking/znc/default.nix b/nixos/modules/services/networking/znc/default.nix
index 1ad8855b86db..46bff6954cdd 100644
--- a/nixos/modules/services/networking/znc/default.nix
+++ b/nixos/modules/services/networking/znc/default.nix
@@ -47,11 +47,11 @@ let
           #     Baz=baz
           #     Qux=qux
           #   </Foo>
-          set = concatMap (subname: [
+          set = concatMap (subname: optionals (value.${subname} != null) ([
               "<${name} ${subname}>"
             ] ++ map (line: "\t${line}") (toLines value.${subname}) ++ [
               "</${name}>"
-            ]) (filter (v: v != null) (attrNames value));
+            ])) (filter (v: v != null) (attrNames value));
 
         }.${builtins.typeOf value};