mypy v0.812 不兼容类型“str”；预期“联盟[文字['a']，联盟[文字['b']..]

Question

有没有办法让 mypy 对这段代码感到满意而无需更改class Config，目前我无法更改该类（对 cli 应用程序使用 typer）。我知道我可以使用# type: ignore ，但是还有其他解决方案吗？

"""
mypy --version
mypy 0.812
"""
from enum import Enum
from pathlib import Path

from typing_extensions import Literal


class Config(str, Enum):
  Debug = 'Debug'
  Release = 'Release'


BuildMode = Literal["ASAN", "UBSAN", "Coverage", "Release", "Debug"]


def run_c_tests(results_dir: Path, mode: BuildMode):
  ...


configuration = Config.Debug

# mypy error: Argument 2 to "run_c_tests" has incompatible type "str"; expected "Union[Literal['ASAN'], Literal['UBSAN'], Literal['Coverage'], Literal['Release'], Literal['Debug']]"
run_c_tests(Path('apath'), configuration.value)

Mypy v0.782 不会抱怨上面的代码，但 0.812 会抱怨。

Answer 1

我遇到了和你类似的问题，并通过使用Final注释修复了它。例如

from typing import Final

STRICT: Final = "strict"

我在这里找到提示：/sf/answers/4472467051/

Annotating a variable as Final indicates that its value will not be substituted for a value of similar type. This makes it correct to infer the type as the specific Literal value, instead of just the general type.