bpo-29298: Fix crash for required subparsers in argparse by BenSokol · Pull Request #18564 · python/cpython (original) (raw)
When an instance of subparsers is has required=True, and no subparser is found,
an uncaught exception was thrown.
OS: Windows - Cygwin
Python Version: 3.8.0b4
This issue still appears to be present in master
Fixes the following stack trace:
...
File "/usr/lib/python3.8/argparse.py", line 1760, in parse_args
args, argv = self.parse_known_args(args, namespace)
File "/usr/lib/python3.8/argparse.py", line 1792, in parse_known_args
namespace, args = self._parse_known_args(args, namespace)
File "/usr/lib/python3.8/argparse.py", line 2027, in _parse_known_args
', '.join(required_actions))
TypeError: sequence item 0: expected str instance, NoneType found