changeset:   93122:1a3143752db2
branch:      2.7
parent:      93112:927cca0b9337
user:        R David Murray <rdmurray@bitdance.com>
date:        Fri Oct 17 20:07:08 2014 -0400
files:       Lib/argparse.py Lib/test/test_argparse.py Misc/NEWS
description:
#9351: set_defaults on subparser is no longer ignored if set on parent.

Before, if a default was set on the parent parser, any default for that
variable set via set_defaults on a subparser would be ignored.  Now
the subparser set_defaults is honored.

Patch by Jyrki Pullianinen.


diff -r 927cca0b9337 -r 1a3143752db2 Lib/argparse.py
--- a/Lib/argparse.py	Fri Oct 17 16:20:15 2014 -0500
+++ b/Lib/argparse.py	Fri Oct 17 20:07:08 2014 -0400
@@ -1089,7 +1089,14 @@
         # 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)
diff -r 927cca0b9337 -r 1a3143752db2 Lib/test/test_argparse.py
--- a/Lib/test/test_argparse.py	Fri Oct 17 16:20:15 2014 -0500
+++ b/Lib/test/test_argparse.py	Fri Oct 17 20:07:08 2014 -0400
@@ -2726,6 +2726,13 @@
         parser = ErrorRaisingArgumentParser(parents=[parent])
         self.assertEqual(NS(x='foo'), parser.parse_args([]))
 
+    def test_set_defaults_on_parent_and_subparser(self):
+        parser = argparse.ArgumentParser()
+        xparser = parser.add_subparsers().add_parser('X')
+        parser.set_defaults(foo=1)
+        xparser.set_defaults(foo=2)
+        self.assertEqual(NS(foo=2), parser.parse_args(['X']))
+
     def test_set_defaults_same_as_add_argument(self):
         parser = ErrorRaisingArgumentParser()
         parser.set_defaults(w='W', x='X', y='Y', z='Z')
diff -r 927cca0b9337 -r 1a3143752db2 Misc/NEWS
--- a/Misc/NEWS	Fri Oct 17 16:20:15 2014 -0500
+++ b/Misc/NEWS	Fri Oct 17 20:07:08 2014 -0400
@@ -37,6 +37,9 @@
 Library
 -------
 
+- Issue #9351: Defaults set with set_defaults on an argparse subparser
+  are no longer ignored when also set on the parent parser.
+
 - Issue #20421: Add a .version() method to SSL sockets exposing the actual
   protocol version in use.