From 199ea6f965b958c7538a48cb0d1472cb2c7582f9 Mon Sep 17 00:00:00 2001
From: raviks789 <33730024+raviks789@users.noreply.github.com>
Date: Thu, 28 Apr 2022 14:52:06 +0200
Subject: [PATCH] Prevent use of empty filters in FilterChain::toQueryString()

Due to instantiation of filters using Filter::matchAll() in ObjectList::getFilter(), we get an empty FilterAnd instance when
$this->filter is null. This prepends unnecessary separator '&' to the query string during conversion of filter to querystring.
This breaks the state badge links for host and service lists.
---
 library/Icinga/Data/Filter/FilterChain.php | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/library/Icinga/Data/Filter/FilterChain.php b/library/Icinga/Data/Filter/FilterChain.php
index 1c5cdf956..0f1e07198 100644
--- a/library/Icinga/Data/Filter/FilterChain.php
+++ b/library/Icinga/Data/Filter/FilterChain.php
@@ -171,7 +171,9 @@ abstract class FilterChain extends Filter
             return '';
         }
         foreach ($this->filters() as $filter) {
-            $parts[] = $filter->toQueryString();
+            if (! $filter->isEmpty()) {
+                $parts[] = $filter->toQueryString();
+            }
         }
 
         // TODO: getLevel??