diff --git a/src/php/Metadata/PropertyMetadataFactory.php b/src/php/Metadata/PropertyMetadataFactory.php
index 76fd3ddcda625fdee6bfd7fb5b1f576a4e495515..55d0e2542ac97289c3f118901575397214f3b4a7 100644
--- a/src/php/Metadata/PropertyMetadataFactory.php
+++ b/src/php/Metadata/PropertyMetadataFactory.php
@@ -110,7 +110,7 @@ class PropertyMetadataFactory
             $propertyName,
             '',
             $typeMeta,
-            $propertyMeta->isIdentifier(),
+            $propertyMeta->isIdentifier() ?: false,
             $nullable,
             $propertyMeta->isReadable(),
             $propertyMeta->isWritable(),