Fix phpstan-issues

Author: tvdijen

phpstan-dev.neon

@@ -1,4 +1,4 @@
 parameters:
-  level: 8
+  level: 9
   paths:
     - tests

phpstan.neon

@@ -1,4 +1,4 @@
 parameters:
-  level: 7
+  level: 6
   paths:
     - src

src/Auth/Source/CAS.php

@@ -20,6 +20,7 @@
 use function array_merge_recursive;
 use function preg_split;
 use function strcmp;
+use function strval;
 use function var_export;
 
 /**
@@ -159,18 +160,18 @@ private function casServiceValidate(string $ticket, string $service): array
         if ($message instanceof AuthenticationFailure) {
             throw new Exception(sprintf(
                 "Error when validating CAS service ticket: %s (%s)",
-                $message->getContent(),
-                $message->getCode(),
+                strval($message->getContent()),
+                strval($message->getCode()),
             ));
         } elseif ($message instanceof AuthenticationSuccess) {
             $user = $message->getUser()->getContent();
-            $xPath = XPath::getXPath();
+            $xPath = XPath::getXPath($message->toXML());
 
             $attributes = [];
             if ($casattributes = $this->casConfig['attributes']) {
                 // Some have attributes in the xml - attributes is a list of XPath expressions to get them
                 foreach ($casattributes as $name => $query) {
-                    $attrs = $xPath->xpQuery($query, $xPath);
+                    $attrs = $xPath->query($message->toXML(), $query, $xPath);
                     foreach ($attrs as $attrvalue) {
                         $attributes[$name][] = $attrvalue->textContent;
                     }