Fix editing language item via PIP GUI if it has been missing in a language

See #2545

diff --git a/wcfsetup/install/files/lib/system/package/plugin/LanguagePackageInstallationPlugin.class.php b/wcfsetup/install/files/lib/system/package/plugin/LanguagePackageInstallationPlugin.class.php
index e7abe21e86bb2a54e2d23de88da3d429633fc5e5..1837bc08c5e56a69ddd2956eaaf3c98bc2f50d7c 100644 (file)
--- a/wcfsetup/install/files/lib/system/package/plugin/LanguagePackageInstallationPlugin.class.php
+++ b/wcfsetup/install/files/lib/system/package/plugin/LanguagePackageInstallationPlugin.class.php
@@ -814,12 +814,13 @@ XML;
                
                // replace old element
                $element = $this->getElementByIdentifier($xml, $identifier);
-               
-               if ($element->parentNode === $newElement->parentNode) {
-                       DOMUtil::replaceElement($element, $newElement, false);
-               }
-               else {
-                       DOMUtil::removeNode($element);
+               if ($element !== null) {
+                       if ($element->parentNode === $newElement->parentNode) {
+                               DOMUtil::replaceElement($element, $newElement, false);
+                       }
+                       else {
+                               DOMUtil::removeNode($element);
+                       }
                }
                
                return $newElement;