src/snakia/field/auto.py

@@ -1,5 +1,7 @@
 import pickle
-from typing import Final, Generic, TypeVar
+from typing import Callable, Final, Generic, TypeVar, overload
+
+from typing_extensions import Self
 
 from .field import Field
 
@@ -9,8 +11,28 @@ T = TypeVar("T")
 class AutoField(Field[T], Generic[T]):
     __slots__ = ("__target_type",)
 
-    def __init__(self, default_value: T, *, target_type: type[T] | None = None) -> None:
+    @overload
-        super().__init__(default_value)
+    def __init__(
+        self, default_value: T, *, target_type: type[T] | None = None
+    ) -> None: ...
+    @overload
+    def __init__(
+        self,
+        *,
+        default_factory: Callable[[Self], T],
+        target_type: type[T] | None = None,
+    ) -> None: ...
+    def __init__(
+        self,
+        default_value: T | None = None,
+        *,
+        default_factory: Callable[[Self], T] | None = None,
+        target_type: type[T] | None = None,
+    ) -> None:
+        if default_factory is not None and default_value is None:
+            super().__init__(default_factory=default_factory)
+        elif default_value is not None and default_factory is None:
+            super().__init__(default_value)
         self.__target_type: Final = target_type
 
     def serialize(self, value: T, /) -> bytes:
@@ -19,5 +41,5 @@ class AutoField(Field[T], Generic[T]):
     def deserialize(self, serialized: bytes, /) -> T:
         value = pickle.loads(serialized)
         if not isinstance(value, self.__target_type or object):
-            return self.default_value
+            return self._get_default()
         return value  # type: ignore