changeset: 79000:bc342cd7ed96 branch: 3.2 parent: 78996:957e1eef3296 user: Barry Warsaw date: Tue Sep 11 22:38:47 2012 -0400 files: Lib/argparse.py Lib/test/test_argparse.py Misc/NEWS description: - Issue #15906: Fix a regression in argparse caused by the preceding change, when action='append', type='str' and default=[]. diff -r 957e1eef3296 -r bc342cd7ed96 Lib/argparse.py --- a/Lib/argparse.py Tue Sep 11 13:01:43 2012 -0400 +++ b/Lib/argparse.py Tue Sep 11 22:38:47 2012 -0400 @@ -1957,6 +1957,7 @@ # twice (which may fail) if the argument was given, but # only if it was defined already in the namespace if (action.default is not None and + isinstance(action, _StoreAction) and hasattr(namespace, action.dest) and action.default is getattr(namespace, action.dest)): setattr(namespace, action.dest, diff -r 957e1eef3296 -r bc342cd7ed96 Lib/test/test_argparse.py --- a/Lib/test/test_argparse.py Tue Sep 11 13:01:43 2012 -0400 +++ b/Lib/test/test_argparse.py Tue Sep 11 22:38:47 2012 -0400 @@ -4516,6 +4516,16 @@ args = parser.parse_args([]) self.assertEqual(NS(foo='foo_converted'), args) + def test_issue_15906(self): + # Issue #15906: When action='append', type=str, default=[] are + # providing, the dest value was the string representation "[]" when it + # should have been an empty list. + parser = argparse.ArgumentParser() + parser.add_argument('--test', dest='test', type=str, + default=[], action='append') + args = parser.parse_args([]) + self.assertEqual(args.test, []) + # ====================== # parse_known_args tests # ====================== diff -r 957e1eef3296 -r bc342cd7ed96 Misc/NEWS --- a/Misc/NEWS Tue Sep 11 13:01:43 2012 -0400 +++ b/Misc/NEWS Tue Sep 11 22:38:47 2012 -0400 @@ -139,6 +139,9 @@ especially problematic for the FileType type, as a default file would always be opened, even if a file argument was specified on the command line. +- Issue #15906: Fix a regression in argparse caused by the preceding change, + when action='append', type='str' and default=[]. + - Issue #13370: Ensure that ctypes works on Mac OS X when Python is compiled using the clang compiler