为什么这个函数没有正确注释（错误：泛型类型缺少类型参数）？

Question

此功能类型是否正确注释？

import subprocess
from os import PathLike
from typing import Union, Sequence, Any


def run(shell_command: Union[bytes, str, Sequence[Union[bytes, str, PathLike]]], **subprocess_run_kwargs: Any) -> int:
    return subprocess.run(shell_command, check=True, shell=True, **subprocess_run_kwargs).returncode

我猜它不是，因为我得到了：

he\other.py:6: error: Missing type parameters for generic type

要获得相同的错误，请将以上代码保存在other.py中，然后：

$ pip install mypy

$ mypy --strict other.py

Answer 1

PathLike是泛型类型，因此您需要将其与类型参数（例如AnyStr）一起使用：

import subprocess
from os import PathLike
from typing import Union, Sequence, Any, AnyStr


def run(shell_command: Union[bytes, str, Sequence[Union[bytes, str, PathLike[AnyStr]]]], **subprocess_run_kwargs: Any) -> int:
    return subprocess.run(shell_command, check=True, shell=True, **subprocess_run_kwargs).returncode

相关问题：

• https://github.com/python/mypy/issues/6112
• https://github.com/python/mypy/issues/6128

UPDATE

对不起，我没有在运行时检查此代码。通过一些技巧，可以编写一个变通方法：

import subprocess
from os import PathLike as BasePathLike
from typing import Union, Sequence, Any, AnyStr, TYPE_CHECKING
import abc


if TYPE_CHECKING:
    PathLike = BasePathLike
else:
    class FakeGenericMeta(abc.ABCMeta):
        def __getitem__(self, item):
            return self

    class PathLike(BasePathLike, metaclass=FakeGenericMeta):
        pass

def run(shell_command: Union[bytes, str, Sequence[Union[bytes, str, PathLike[AnyStr]]]], **subprocess_run_kwargs: Any) -> int:
    return subprocess.run(shell_command, check=True, shell=True, **subprocess_run_kwargs).returncode

与此解决方法相关的问题：

• mypy: how to define a generic subclass
• https://github.com/python/mypy/issues/5264