1 files changed, 8 insertions, 1 deletions
diff --git a/Lib/argparse.py b/Lib/argparse.py
index 83878b15274..4d26b0701bb 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1122,7 +1122,14 @@ class _SubParsersAction(Action):
         # parse all the remaining options into the namespace
         # store any unrecognized options on the object, so that the top
         # level parser can decide what to do with them
-        namespace, arg_strings = parser.parse_known_args(arg_strings, namespace)
+
+        # In case this subparser defines new defaults, we parse them
+        # in a new namespace object and then update the original
+        # namespace for the relevant parts.
+        subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)
+        for key, value in vars(subnamespace).items():
+            setattr(namespace, key, value)
+
         if arg_strings:
             vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])
             getattr(namespace, _UNRECOGNIZED_ARGS_ATTR).extend(arg_strings)