minor #1389 Move method so it's only called when necessary (Tobion)

This PR was merged into the 1.15-dev branch.

Discussion
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Move method so it's only called when necessary

Small performance improvement for getAttribute

Commits
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a28e0f1 Move method so it's only called when necessary

lib/Twig/Template.php

@@ -402,8 +402,6 @@ abstract class Twig_Template implements Twig_TemplateInterface
             throw new Twig_Error_Runtime(sprintf('Impossible to invoke a method ("%s") on a %s variable ("%s")', $item, gettype($object), $object), -1, $this->getTemplateName());
         }
 
-        $class = get_class($object);
-
         // object property
         if (Twig_Template::METHOD_CALL !== $type) {
             if (isset($object->$item) || array_key_exists((string) $item, $object)) {
@@ -419,6 +417,8 @@ abstract class Twig_Template implements Twig_TemplateInterface
             }
         }
 
+        $class = get_class($object);
+
         // object method
         if (!isset(self::$cache[$class]['methods'])) {
             self::$cache[$class]['methods'] = array_change_key_case(array_flip(get_class_methods($object)));