Open Zac-HD opened 1 year ago
Just randomly reading this.
but we need the yield statement there to make the method into a generator!
May I ask what the yield
makes for a difference? So where does it break if it is missing? Runtime, type checking, other static checkers or just that the developer knows about it?
I am just asking such that I can think about other possible solutions.
Runtime (e.g. inspect.isgeneratorfunction()
as well as static typechecking. I guess it's also useful for human readers but the runtime requirement is the hard one.
I agree that that type checker and code readability can probably easily be managed (type annotation, custom decorator, custom exception).
For runtime checks I thought about the following:
class AbstractFoo(ABC):
@abstractmethod
def some_generator(self):
yield from GeneratorNotImplemented()
where GeneratorNotImplemented
is something like
class GeneratorNotImplemented:
def __init__(self):
raise NotImplementedError
However, I guess it it less readable than the original code.
Sorry, if this goes into a wrong direction for you. I am not maintainer of this project.
Bye the way, the more I think about it, the more sense it makes to me to not mark them as unreachable yields
(similar to yield
followed by a return
to create an empty iterator). Because the yield
was put there on purpose and changes the behavior of the program.
I also checked mypy
and PyCharm
both of them will mark the code as unreachable (like vulture
).
Don't raise NotImplementedError
(class) but NotImplementedError()
(instance).
It's not documented in the README, but you can suppress unreachable-code errors for a line with noqa: V201
. Vulture should perhaps handle this case automatically though.
Here's another use case. I don't force a child class to implement the method and I have a default empty one.
def my_generator(self) -> Generator[str, None, None]:
return
yield # I have to add "noqa: V201"
Consider the following example, where an abstract method is a generator:
We want to
raise NotImplementedError
to prevent accidental calls, but then Vulture errors out because theyield
is unreachable. Indeed it is unreachable - but we need theyield
statement there to make the method into a generator!Decent solutions might include supporting some way to ignore unreachable-code warnings (as is possible for unused variables), or more direct heuristics like "ignore an unreachable bare yield if there are no following statements and only a
raise
statement preceding" - I'm not attached to any particular solution, but would love something to unblock this so I can enforce Vulture rather than just running it by hand occasionally 🙂