[BUGFIX] Fix adding empty xpath results to metadata array (kitodo#1564)

Co-authored-by: Michael Kubina <[email protected]>
Co-authored-by: Sebastian Meyer <[email protected]>

Author: 3 people

Classes/Common/MetsDocument.php

@@ -850,7 +850,9 @@ private function setMetadataFieldValues(array $resArray, DOMXPath $domXPath, DOM
                     }
                 }
             } elseif (!($values instanceof DOMNodeList)) {
-                $metadata[$resArray['index_name']] = [trim((string) $values)];
+                if (!empty($values)) {
+                    $metadata[$resArray['index_name']] = [trim((string) $values)];
+                }
             }
         }
     }