bpo-45235: Revert an argparse bugfix that caused a regression (GH-29525) (GH-29530)
diff --git a/Lib/argparse.py b/Lib/argparse.py
index f1f6f32..9eed24c 100644
--- a/Lib/argparse.py
+++ b/Lib/argparse.py
@@ -1209,8 +1209,7 @@ def __call__(self, parser, namespace, values, option_string=None):
# namespace for the relevant parts.
subnamespace, arg_strings = parser.parse_known_args(arg_strings, None)
for key, value in vars(subnamespace).items():
- if not hasattr(namespace, key):
- setattr(namespace, key, value)
+ setattr(namespace, key, value)
if arg_strings:
vars(namespace).setdefault(_UNRECOGNIZED_ARGS_ATTR, [])
@@ -1844,6 +1843,11 @@ def parse_known_args(self, args=None, namespace=None):
if action.default is not SUPPRESS:
setattr(namespace, action.dest, action.default)
+ # add any parser defaults that aren't present
+ for dest in self._defaults:
+ if not hasattr(namespace, dest):
+ setattr(namespace, dest, self._defaults[dest])
+
# parse the arguments and exit if there are any errors
if self.exit_on_error:
try:
@@ -1854,11 +1858,6 @@ def parse_known_args(self, args=None, namespace=None):
else:
namespace, args = self._parse_known_args(args, namespace)
- # add any parser defaults that aren't present
- for dest in self._defaults:
- if not hasattr(namespace, dest):
- setattr(namespace, dest, self._defaults[dest])
-
if hasattr(namespace, _UNRECOGNIZED_ARGS_ATTR):
args.extend(getattr(namespace, _UNRECOGNIZED_ARGS_ATTR))
delattr(namespace, _UNRECOGNIZED_ARGS_ATTR)
diff --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py
index 6680feb..ec49b2a 100644
--- a/Lib/test/test_argparse.py
+++ b/Lib/test/test_argparse.py
@@ -3095,12 +3095,6 @@ def test_set_defaults_on_parent_and_subparser(self):
xparser.set_defaults(foo=2)
self.assertEqual(NS(foo=2), parser.parse_args(['X']))
- def test_set_defaults_on_subparser_with_namespace(self):
- parser = argparse.ArgumentParser()
- xparser = parser.add_subparsers().add_parser('X')
- xparser.set_defaults(foo=1)
- self.assertEqual(NS(foo=2), parser.parse_args(['X'], NS(foo=2)))
-
def test_set_defaults_same_as_add_argument(self):
parser = ErrorRaisingArgumentParser()
parser.set_defaults(w='W', x='X', y='Y', z='Z')
diff --git a/Misc/NEWS.d/next/Library/2021-11-11-13-03-17.bpo-45235.8ZbkHa.rst b/Misc/NEWS.d/next/Library/2021-11-11-13-03-17.bpo-45235.8ZbkHa.rst
new file mode 100644
index 0000000..f73589c
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-11-11-13-03-17.bpo-45235.8ZbkHa.rst
@@ -0,0 +1,3 @@
+Reverted an argparse bugfix that caused regression in the handling of
+default arguments for subparsers. This prevented leaf level arguments from
+taking precedence over root level arguments.