String hinted arguments passed numerical values should not be coerced #733

Observed behavior

If a callable command function defines an argument with a string hint, e.g. arg: str, and a value of 1.10 is passed to it, then it receives an argument of type float with value 1.1 which has different meaning than the passed value.

This is particularly troublesome when dealing with versions since 1.1 is much different than 1.10.

Expected behavior

Fire should not coerce the value to a type different than the type hint, regardless of its format.

Reproduction

Code

# tp.py
import fire


def main(arg: str):
    print(f"Hello! {type(arg)} {arg}")


if __name__ == "__main__":
    fire.Fire(main)

Execution

$ python tp.py 1.10
Hello! <class 'float'> 1.1

or

$ python tp.py '1.10'
Hello! <class 'float'> 1.1

Metadata

fire version v0.7.1