Pycharm provide unreachable code because of NoReturn type hint

October 25, 2023

I am writing a test for a code that will raise an exception.

with pytest.raises(Exception) as exception:
    A.b()

assert str(exception.value) == "exception"

The function b will never return a thing and may raise an exception.
Once I put the return type of b() to def b() -> NoReturn: I am getting that the assertion will never be reached "This code is unreachable". Either I did not get the purpose of NoReturn or It is a bug in Pycharm, because once I debug it, the line is reachable.

An example of b is

def b(a: int) -> NoReturn:
    if a < 0:
        raise Exception('Negative numbers are not accepted)

>Solution :

"will never return a thing and may raise an exception" contradicts itself. A function can’t "never return a thing" and "may raise an exception" at the same time.

Even if a function does not explicitly use the return statement, None is implicitly returned.

You should change NoReturn in the type hint to None.