From 0ee81bc9b7ae4fbab00a0a4b603c8057538a81f0 Mon Sep 17 00:00:00 2001
From: Robert Lange <robert.lange@uni-leipzig.de>
Date: Fri, 18 Oct 2024 16:42:37 +0200
Subject: [PATCH] refs vufind-org#2999 handle nullable result set id -
 initializing to null and concat to empty string

---
 .../VuFindSearch/src/VuFindSearch/Backend/AbstractBackend.php   | 1 +
 module/VuFindSearch/src/VuFindSearch/Response/RecordTrait.php   | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/module/VuFindSearch/src/VuFindSearch/Backend/AbstractBackend.php b/module/VuFindSearch/src/VuFindSearch/Backend/AbstractBackend.php
index eaa8841fa2b..bee16ac7f84 100644
--- a/module/VuFindSearch/src/VuFindSearch/Backend/AbstractBackend.php
+++ b/module/VuFindSearch/src/VuFindSearch/Backend/AbstractBackend.php
@@ -34,6 +34,7 @@
 use VuFindSearch\Response\RecordCollectionFactoryInterface;
 use VuFindSearch\Response\RecordCollectionInterface;
 
+use function count;
 use function sprintf;
 
 /**
diff --git a/module/VuFindSearch/src/VuFindSearch/Response/RecordTrait.php b/module/VuFindSearch/src/VuFindSearch/Response/RecordTrait.php
index 274fe9fbe93..c4ad4110cb6 100644
--- a/module/VuFindSearch/src/VuFindSearch/Response/RecordTrait.php
+++ b/module/VuFindSearch/src/VuFindSearch/Response/RecordTrait.php
@@ -55,7 +55,7 @@ trait RecordTrait
      *
      * @var string|null
      */
-    protected $resultSetIdentifier;
+    protected $resultSetIdentifier = null;
 
     /**
      * Used for identifying the search backend used to find the record