当一个类继承另一个类时，Pydantic 验证出错

Question

我定义了一个名为 MetaPersistent 的类：

class MetaPersistent(type(BaseModel)):

    Ref: ClassVar[type[RefBase[Self]]]

    Repository: ClassVar[type[RepositoryBase[Self]]]

    def __new__(cls, *args, skip_meta_init=False, **kwargs):
        return super().__new__(cls, *args, **kwargs)

    def __init__(self, *args, skip_meta_init=False, **kwargs):
        super().__init__(*args, **kwargs)
        # name, bases, dict = args

        if skip_meta_init is True:
            return

        # Make a repository class for the new persistent class

        rep_bases = tuple(
            {
                getattr(base, "Repository"): None
                for base in self.__mro__
                if hasattr(base, "Repository")
            }.keys()
        )

        rep_cls = type(
            "Repository",
            rep_bases,
            {
                "__module__": self.__module__,
                "__qualname__": f"{self.__qualname__}.Repository",
                "__persistent__": self,
            },
        )

        # Instance the repository
        repository = 
            rep_cls(_english_inflector.tableize(self.__qualname__))

        # Make a reference class for the new persistent class
        ref_bases = tuple(
            {
                getattr(base, "Ref"): None
                for base in self.__mro__
                if hasattr(base, "Ref")
            }.keys()
        )

        ref_cls = type(
            "Ref",
            ref_bases,
            {
                "__module__": self.__module__,
                "__qualname__": f"{self.__qualname__}.Ref",
                "__persistent__": self,
                "__repository__": repository,
            },
        )

        setattr(self, "Repository", rep_cls)
        setattr(self, "Ref", ref_cls)

        setattr(self, "__repository__", repository)

从中继承持久化：

class Persistent(BaseModel, metaclass=MetaPersistent, skip_meta_init=True):
    id: Optional[Id] = Field(None, title="Unique object Id", alias="_id")

    @property
    def ref(self) -> RefBase[Self]:
    return self.Ref(self.id)

    async def store(self) -> RefBase[Self]:
        if self.id:
            await repository_of(self).update_obj(self)
        else:
            await repository_of(self).insert_obj(self)

        return self.ref

然后，一个名为Vehicle的类继承自它：

class Vehicle(Persistent):
    tenant_ref: Optional[Tenant.Ref] = None  # Reference to the tenant (default is None)
    loadLimits: float  # Load limits of the vehicle
    startLocation: Location  # Starting location of the vehicle
    endLocation: Location  # Ending location of the vehicle

    class Config:
        arbitrary_types_allowed = True  # Allows arbitrary types

当我通过以下方式实例化车辆时出现问题：

vehicles = [Vehicle(
    loadLimits=vehicle["loadLimits"],
    startLocation=Location(**vehicle["startLocation"]),
    endLocation=Location(**vehicle["endLocation"])
        ) for vehicle in json_data_vehicles]

Pydantic投掷：

vehicles = [Vehicle(
            ^^^^^^^^
line 164, in __init__
__pydantic_self__.__pydantic_validator__.validate_python(data, 
self_instance=__pydantic_self__)
TypeError: BaseModel.validate() takes 2 positional arguments but 3 were given

另一方面，如果Vehicle像Vehicle(BaseModel)一样直接继承自BaseModel，则不会发现问题。猜测 Pydantic 验证继承的方式存在一些问题，但我无法修复它。

Answer 1

事实证明，Pydantic v1 和 v2 之间存在一些问题。由于我的一些导入依赖于 v1，代码因未知原因崩溃了。我通过从 v2（默认的 v2）导入所有内容来修复此问题：

from pydantic.v1 import BaseModel #importing from v1. Code crashes

from pydantic import BaseModel #importing from v2. Code runs ok