Cast result from ExpressionLanguage eval to bool

Author: merk

Provider/Indexable.php

@@ -82,7 +82,7 @@ public function isObjectIndexable($indexName, $typeName, $object)
         }
 
         if ($callback instanceof Expression) {
-            return $this->getExpressionLanguage()->evaluate($callback, array(
+            return (bool) $this->getExpressionLanguage()->evaluate($callback, array(
                 'object' => $object,
                 $this->getExpressionVar($object) => $object,
             ));

Tests/Provider/IndexableTest.php

@@ -73,6 +73,8 @@ public function provideIsIndexableCallbacks()
             array('entity.maybeIndex()', true),
             array('!object.isIndexable() && entity.property == "abc"', true),
             array('entity.property != "abc"', false),
+            array('["array", "values"]', true),
+            array('[]', false)
         );
     }