now dataloader checkis that you get at least a valid string as a file name

lib/ansible/parsing/__init__.py

@@ -137,6 +137,8 @@ class DataLoader():
         Reads the file contents from the given file name, and will decrypt them
         if they are found to be vault-encrypted.
         '''
+        if not file_name or not isinstance(file_name, basestring):
+            raise AnsibleParserError("Invalid filename: '%s'" % str(file_name))
 
         if not self.path_exists(file_name) or not self.is_file(file_name):
             raise AnsibleParserError("the file_name '%s' does not exist, or is not readable" % file_name)