From 4212177a2d5884e46ffc5a649baab75516a3509e Mon Sep 17 00:00:00 2001
From: Vitaliy Filippov <vitalif@yourcmc.ru>
Date: Mon, 1 Oct 2018 16:53:17 +0300
Subject: [PATCH] Fix "xxx does not contains yyy AND (...)" not matching NULL
 values

---
 Bugzilla/Search.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Bugzilla/Search.pm b/Bugzilla/Search.pm
index d1eec4bad..482260cb5 100644
--- a/Bugzilla/Search.pm
+++ b/Bugzilla/Search.pm
@@ -3446,7 +3446,7 @@ sub negate_expression
     if (ref $q eq 'HASH')
     {
         $q->{neg} = !$q->{neg};
-        $q->{allow_null} = ($q->{allow_null} || 0) == 1 ? 0 : $q->{allow_null};
+        $q->{allow_null} = ($q->{allow_null} || 0) == 1 ? 0 : 1;
         $q->{description}->[1] = NEGATE_ALL_OPERATORS->{$q->{description}->[1]} || $q->{description}->[1];
     }
     elsif (!ref $q)