哪个 python 静态检查器可以捕获 'forgotten await' 问题？

Question

代码：

from typing import AsyncIterable

import asyncio


async def agen() -> AsyncIterable[str]:
    print('agen start')
    yield '1'
    yield '2'


async def agenmaker() -> AsyncIterable[str]:
    print('agenmaker start')
    return agen()


async def amain():
    print('amain')
    async for item in agen():
        pass
    async for item in await agenmaker():
        pass
    # Error:
    async for item in agenmaker():
        pass


def main():
    asyncio.get_event_loop().run_until_complete(amain())


if __name__ == '__main__':
    main()

如您所见，它带有类型注释，并且包含一个容易被忽略的错误。

但是，pylint 和 mypy 都没有发现该错误。

除了单元测试之外，还有哪些选项可以捕获此类错误？

Answer 1

MyPy 完全有能力发现这个问题。问题在于未检查未注释的函数。将有问题的函数注释为 -> None，它会被正确检查并拒绝。

# annotated with return type
async def amain() -> None:
    print('amain')
    async for item in agen():
        pass
    async for item in await agenmaker():
        pass
    # Error:
    async for item in agenmaker(): # error: "Coroutine[Any, Any, AsyncIterable[str]]" has no attribute "__aiter__" (not async iterable)

        pass

如果您想消除此类漏掉的问题，请使用标志 --disallow-untyped-defs or --check-untyped-defs。

MyPy: Function signatures and dynamic vs static typing

A function without type annotations is considered to be dynamically typed by mypy:
def greeting(name):
    return 'Hello ' + name
By default, mypy will not type check dynamically typed functions. This means that with a few exceptions, mypy will not report any errors with regular unannotated Python.

哪个 python 静态检查器可以捕获 'forgotten await' 问题？

Which python static checker can catch 'forgotten await' problems?

python

pylint

mypy

MyPy: Function signatures and dynamic vs static typing