如何基于IntEnum创建保留自动补全的字符串Enum？

现有如下IntEnum定义：

from enum import IntEnum

class TransactionTypeIntEnum(IntEnum):
    UNKNOWN = 0
    ADMINISTRATIVE = 1
    PAYMENT = 2
    TRADE = 3

需要创建一个字符串Enum，成员名称与上述IntEnum完全一致，值为成员名称本身，形式如下：

from enum import Enum

class TransactionType(Enum):
    UNKNOWN = "UNKNOWN"
    ADMINISTRATIVE = "ADMINISTRATIVE"
    PAYMENT = "PAYMENT" 
    TRADE = "TRADE"

当前通过BaseEnum.from_iterable动态生成该字符串Enum：

from enum import Enum
from typing import Type, Iterable, TypeVar

TBaseEnum = TypeVar("TBaseEnum", bound=BaseEnum, covariant=True)

class BaseEnum(Enum):
    @classmethod
    def from_iterable(cls: Type[TBaseEnum], name: str, values: Iterable[str]) -> Type[TBaseEnum]:
        return cls(name, {value: value for value in values})

TransactionType = BaseEnum.from_iterable("TransactionType", [element.name for element in TransactionTypeIntEnum])

但该实现存在问题：动态生成的TransactionType丢失了IDE自动补全功能，无法直接提示成员名称，必须查看TransactionTypeIntEnum才能知晓可用成员。

方法一：类型检查分支+动态生成（推荐） #

利用typing.TYPE_CHECKING常量，在IDE类型检查阶段提供显式的枚举类定义用于自动补全，运行时则动态从IntEnum生成字符串枚举，既保证补全功能，又避免手动同步两个枚举的成员：

from enum import Enum, IntEnum
from typing import TYPE_CHECKING

# 定义原始IntEnum
class TransactionTypeIntEnum(IntEnum):
    UNKNOWN = 0
    ADMINISTRATIVE = 1
    PAYMENT = 2
    TRADE = 3

if TYPE_CHECKING:
    # 仅用于IDE类型检查和自动补全的假枚举类
    class TransactionType(Enum):
        UNKNOWN = "UNKNOWN"
        ADMINISTRATIVE = "ADMINISTRATIVE"
        PAYMENT = "PAYMENT"
        TRADE = "TRADE"
else:
    # 运行时动态生成的真实枚举类，与IntEnum成员完全同步
    TransactionType = Enum(
        "TransactionType",
        {member.name: member.name for member in TransactionTypeIntEnum}
    )

方法二：代码生成（显式成员定义） #

通过exec动态生成枚举类的代码，让IDE能识别到显式的成员定义，同时保证与IntEnum同步：

from enum import Enum, IntEnum

class TransactionTypeIntEnum(IntEnum):
    UNKNOWN = 0
    ADMINISTRATIVE = 1
    PAYMENT = 2
    TRADE = 3

# 生成字符串枚举的代码并执行
transaction_type_code = f"""
class TransactionType(Enum):
    {chr(10).join([f"{member.name} = '{member.name}'" for member in TransactionTypeIntEnum])}
"""
exec(transaction_type_code)

方法三：元类+类型提示 #

自定义元类从IntEnum同步成员，同时结合Literal类型提示让IDE识别成员：

from enum import Enum, IntEnum, EnumMeta
from typing import Literal, Type, TypeVar

TIntEnum = TypeVar("TIntEnum", bound=IntEnum)

class StringEnumMeta(EnumMeta):
    def __new__(cls, name, bases, namespace, source_int_enum: Type[TIntEnum]):
        # 从IntEnum提取成员名称和值
        enum_members = {member.name: member.name for member in source_int_enum}
        # 创建枚举类
        enum_cls = super().__new__(cls, name, bases, enum_members)
        # 添加Literal类型提示，让IDE识别成员
        enum_cls.__annotations__['__members__'] = Literal[tuple(enum_members.keys())]
        return enum_cls

# 定义IntEnum
class TransactionTypeIntEnum(IntEnum):
    UNKNOWN = 0
    ADMINISTRATIVE = 1
    PAYMENT = 2
    TRADE = 3

# 生成字符串枚举
class TransactionType(Enum, metaclass=StringEnumMeta, source_int_enum=TransactionTypeIntEnum):
    pass

内容的提问来源于stack exchange，提问作者Henrique Andrade