[Code scan] Non-string variant choices raise raw TypeError

[njzjz]

This issue was found by a Codex global code scan of the repository.

Affected code:

dargs/dargs/dargs.py

Lines 898 to 913 in b4db564

	def get_choice(self, argdict: dict, path: list[str] | None = None) -> Argument:
	if self.flag_name in argdict:
	tag = argdict[self.flag_name]
	if tag in self.choice_dict:
	return self.choice_dict[tag]
	elif tag in self.choice_alias:
	return self.choice_dict[self.choice_alias[tag]]
	else:
	raise ArgumentValueError(
	path,
	f"get invalid choice `{tag}` for flag key `{self.flag_name}`."
	+ did_you_mean(
	tag,
	list(self.choice_dict.keys()) + list(self.choice_alias.keys()),
	),
	)

dargs/dargs/dargs.py

Lines 1273 to 1289 in b4db564

	def did_you_mean(choice: str, choices: Iterable[str]) -> str:
	"""Get did you mean message.
	Parameters
	----------
	choice : str
	the user's wrong choice
	choices : list[str]
	all the choices
	Returns
	-------
	str
	did you mean error message
	"""
	matches = difflib.get_close_matches(choice, choices)
	return f"Did you mean: {matches[0]}?" if matches else ""

Problem:
When a variant flag value is not a string, Variant.get_choice() passes it to did_you_mean(), which calls difflib.get_close_matches(). Non-string values such as 1 or None raise raw TypeError from inside difflib instead of a structured dargs ArgumentError.

Reproducer:

from dargs import Argument, Variant

arg = Argument("base", dict, sub_variants=[Variant("kind", [Argument("a", dict)])])
arg.check_value({"kind": 1})

Observed behavior:

TypeError: 'int' object is not iterable

Expected behavior:
Invalid non-string variant tags should raise a dargs ArgumentTypeError or ArgumentValueError with the argument path and expected choices.