clear MapperStub ArgSingletons on clear_mappers() too...

diff --git a/lib/sqlalchemy/orm/__init__.py b/lib/sqlalchemy/orm/__init__.py
index 12cc1316eeff8f585d672e5075c28d005ef954d5..553bd57baf51e96f341461198a8e5c49d7139bde 100644 (file)
--- a/lib/sqlalchemy/orm/__init__.py
+++ b/lib/sqlalchemy/orm/__init__.py
@@ -547,6 +547,8 @@ def clear_mappers():
             mapper.dispose()
         mapper_registry.clear()
         mapperlib.ClassKey.dispose(mapperlib.ClassKey)
+        from sqlalchemy.orm import dependency
+        dependency.MapperStub.dispose(dependency.MapperStub)
     finally:
         mapperlib._COMPILE_MUTEX.release()