Static/dynamic type consistency for optional parameters, nargs? about datargs

[roee30]

Version 0.6.0 was released with this fix

[roee30]

I just released version 0.5.0 with nargs support, supporting List and Sequence exactly as you wrote.

Optional is not supported yet. Does it create a type-checking issue? If so, how can it be reproduced?

[brentyi]

Thanks for making a release!! Just updated and it works great.

Generally it feels a bit unsafe that a variable that's not typed as a None or Optional might contain a None value in it. Here's an example of where Optional might be nice:

import datargs

@dataclasses.dataclass(frozen=True)
class CliArgs:
    maybe_number: int = datargs.arg(default=None)

args = datargs.parse(CliArgs)

# Runtime error if `maybe_number` is None, even though according to static type this operation is safe
print("Your number plus 5 is:", args.maybe_number + 5)

If it was possible to type maybe_number with Optional[int], this kind of error could be flagged by mypy.

[brentyi]

That was lightning fast; really appreciate it.