diff --git a/addons/product/product.py b/addons/product/product.py
index e1950861528..8a2765a05f3 100644
--- a/addons/product/product.py
+++ b/addons/product/product.py
@@ -832,6 +832,7 @@ class product_template(osv.osv):
             template_ids.add(p.product_tmpl_id.id)
         while (results and len(template_ids) < limit):
             domain = [('product_tmpl_id', 'not in', list(template_ids))]
+            args = args if args is not None else []
             results = product_product.name_search(
                 cr, user, name, args+domain, operator=operator, context=context, limit=limit)
             product_ids = [p[0] for p in results]