bpo-39058: Preserve attribute order in argparse Namespace reprs. (GH-17621)

Author: rhettinger

Lib/argparse.py

@@ -129,7 +129,7 @@ def __repr__(self):
         return '%s(%s)' % (type_name, ', '.join(arg_strings))
 
     def _get_kwargs(self):
-        return sorted(self.__dict__.items())
+        return list(self.__dict__.items())
 
     def _get_args(self):
         return []

Lib/test/test_argparse.py

@@ -4725,7 +4725,7 @@ def test_argument(self):
 
     def test_namespace(self):
         ns = argparse.Namespace(foo=42, bar='spam')
-        string = "Namespace(bar='spam', foo=42)"
+        string = "Namespace(foo=42, bar='spam')"
         self.assertStringEqual(ns, string)
 
     def test_namespace_starkwargs_notidentifier(self):

Misc/NEWS.d/next/Library/2019-12-15-19-17-10.bpo-39058.7ci-vd.rst

@@ -0,0 +1,4 @@
+In the argparse module, the repr for Namespace() and other argument holders
+now displayed in the order attributes were added.  Formerly, it displayed in
+alphabetical order even though argument order is preserved the user visible
+parts of the module.