静态类型检查器（mypy、pytype、pyright）抱怨动态生成的`Union`

Question

如何从动态

Union

创建 TypeAdapter 而不会遇到 linting 错误？

from pydantic import BaseModel, TypeAdapter

class Lion(BaseModel):
    roar: str


class Tiger(BaseModel):
    roar: str


ZOO = {
    "lion": Lion,
    "tiger": Tiger,
    # ...
}

Animal = Union[*[animal for animal in ZOO.values()]]    # Error: Invalid type alias: expression is not a valid type

AnimalTypeAdapter: TypeAdapter[Animal] = TypeAdapter(Animal)    # Error: Variable "Animal" is not valid as a type

Answer 1

你不能。

您应该首先定义联合，然后将其转换回运行时结构：

from typing import Union, get_args

Animal = Union[Tiger, Lion]

ZOO = dict(zip(['tiger', 'lion'], get_args(Animal)))
# {'tiger': Tiger, 'lion': Lion}