diff options
| -rw-r--r-- | Lib/argparse.py | 1 | ||||
| -rw-r--r-- | Lib/test/test_argparse.py | 10 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 14 insertions, 0 deletions
diff --git a/Lib/argparse.py b/Lib/argparse.py index 52ed3ab..fba6a26 100644 --- a/Lib/argparse.py +++ b/Lib/argparse.py @@ -1957,6 +1957,7 @@ class ArgumentParser(_AttributeHolder, _ActionsContainer): # 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 --git a/Lib/test/test_argparse.py b/Lib/test/test_argparse.py index a2f9a69..cd80dc6 100644 --- a/Lib/test/test_argparse.py +++ b/Lib/test/test_argparse.py @@ -4516,6 +4516,16 @@ class TestTypeFunctionCallWithNonStringDefault(TestCase): 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 # ====================== @@ -139,6 +139,9 @@ Library 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 |