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On Sep 12, 2012, at 10:39 AM, R. David Murray wrote:
>diff --git a/Lib/argparse.py b/Lib/argparse.py
>--- a/Lib/argparse.py
>+++ b/Lib/argparse.py
>@@ -1962,7 +1962,8 @@
> # only if it was defined already in the namespace
> if (action.default is not None and
> hasattr(namespace, action.dest) and
>- action.default is getattr(namespace, action.dest)):
>+ action.default is getattr(namespace, action.dest) and
>+ isinstance(action.default, str)):
> setattr(namespace, action.dest,
> self._get_value(action, action.default))
For me, this results in the following failure.
[307/371/1] test_argparse
NS(foo='foo_converted')
Namespace(foo=0)
NS(foo='foo_converted')
Namespace(foo=0)
test test_argparse failed -- Traceback (most recent call last):
 File "/home/barry/projects/python/cpython/Lib/test/test_argparse.py", line 4608, in test_type_function_call_with_non_string_default
 self.assertEqual(NS(foo='foo_converted'), args)
 File "/home/barry/projects/python/cpython/Lib/test/test_argparse.py", line 29, in assertEqual
 super(TestCase, self).assertEqual(obj1, obj2)
AssertionError: NS(foo='foo_converted') != Namespace(foo=0)
This test was added for the issue #12776 and #11839 fix, and it's pretty
obvious why it fails. In the test, default=0 (i.e. a non-string).
Do you think test_type_function_call_with_non_string_default() is a valid test
of expected semantics? If not, then the test should be removed, and the
changeset for #12667 and #11839 should be re-evaluated, at least to determine
whether accurate tests of those bugs were applied.
If that test is removed, then the above suggested change can be made to fix
#15906.