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Builder/FormContractor.php

@@ -126,6 +126,10 @@ class FormContractor implements FormContractorInterface
 
         } else if ($type == 'sonata_type_collection') {
 
+            if (!$fieldDescription->getAssociationAdmin()) {
+                throw new \RuntimeException(sprintf('The current field `%s` is not linked to an admin. Please create one for the target entity : `%s`', $fieldDescription->getName(), $fieldDescription->getTargetEntity()));
+            }
+
             $options['type']         = 'sonata_type_admin';
             $options['modifiable']   = true;
             $options['type_options'] = array(