Python Pydantic v2 自定义类型验证器及信息

我正在try 将我的代码更新到PYDANIC v2，但在找到复制版本1中的自定义类型的好方法时遇到了困难.我将使用我的自定义日期类型作为示例.最初的实现和用法如下所示:

from datetime import date
from pydantic import BaseModel


class CustomDate(date):
    # Override POTENTIAL_FORMATS and fill it with date format strings to match your data
    POTENTIAL_FORMATS = []
    
    @classmethod
    def __get_validators__(cls):
        yield cls.validate_date
        
    @classmethod
    def validate_date(cls, field_value, values, field, config) -> date:
        if type(field_value) is date:
            return field_value
        return to_date(field.name, field_value, cls.POTENTIAL_FORMATS, return_str=False)

class ExampleModel(BaseModel):
    class MyDate(CustomDate):
        POTENTIAL_FORMATS = ['%Y-%m-%d', '%Y/%m/%d']
    dt: MyDate

我try 遵循下面列出的official docs和示例here，它基本上是有效的，但是info参数没有我需要的字段(data和field_name).try 访问它们时会出现AttributeError.

info.field_name
*** AttributeError: No attribute named 'field_name'

Annotated和__get_pydantic_core_schema__方法都有这个问题

from datetime import date
from typing import Annotated

from pydantic import BaseModel, BeforeValidator
from pydantic_core import core_schema  

class CustomDate:
    POTENTIAL_FORMATS = []

    @classmethod
    def validate(cls, field_value, info):
        if type(field_value) is date:
            return field_value
        return to_date(info.field_name, field_value, potential_formats, return_str=False)

    @classmethod
    def __get_pydantic_core_schema__(cls, source, handler) -> core_schema.CoreSchema:
        return core_schema.general_plain_validator_function(cls.validate)


def custom_date(potential_formats):
    """
    :param potential_formats: A list of datetime format strings
    """
    def validate_date(field_value, info) -> date:
        if type(field_value) is date:
            return field_value
        return to_date(info.field_name, field_value, potential_formats, return_str=False)
    CustomDate = Annotated[date, BeforeValidator(validate_date)]
    return CustomDate


class ExampleModel(BaseModel):
    class MyDate(CustomDate):
        POTENTIAL_FORMATS = ['%Y-%m-%d', '%Y/%m/%d']
    dt: MyDate
    dt2: custom_date(['%Y-%m-%d', '%Y/%m/%d'])

如果我只是将validate_date函数作为常规的field_validator来包含，我会得到info，其中包含我需要的所有字段，只有在将它与自定义类型一起使用时，我才会看到这个问题.如何编写可以访问以前验证的字段和正在验证的字段的名称的自定义类型？