diff -up ./src/JMS/Serializer/XmlDeserializationVisitor.php.php8 ./src/JMS/Serializer/XmlDeserializationVisitor.php
--- ./src/JMS/Serializer/XmlDeserializationVisitor.php.php8	2021-03-31 13:54:50.261719313 +0200
+++ ./src/JMS/Serializer/XmlDeserializationVisitor.php	2021-03-31 13:54:57.315695261 +0200
@@ -48,7 +48,7 @@ class XmlDeserializationVisitor extends
         $previous = libxml_use_internal_errors(true);
         libxml_clear_errors();
 
-        $previousEntityLoaderState = libxml_disable_entity_loader($this->disableExternalEntities);
+        $previousEntityLoaderState = @libxml_disable_entity_loader($this->disableExternalEntities);
 
         if (false !== stripos($data, '<!doctype')) {
             $internalSubset = $this->getDomDocumentTypeEntitySubset($data);
@@ -63,7 +63,7 @@ class XmlDeserializationVisitor extends
         $doc = simplexml_load_string($data);
 
         libxml_use_internal_errors($previous);
-        libxml_disable_entity_loader($previousEntityLoaderState);
+        @libxml_disable_entity_loader($previousEntityLoaderState);
 
         if (false === $doc) {
             throw new XmlErrorException(libxml_get_last_error());
@@ -176,7 +176,7 @@ class XmlDeserializationVisitor extends
             $nodes = $data->xpath($entryName);
         }
 
-        if (!\count($nodes)) {
+        if (!($nodes && \count($nodes))) {
             if (null === $this->result) {
                 return $this->result = array();
             }