fix: set as default type for factory only if model is defined

polyfactory/factories/base.py

@@ -223,7 +223,7 @@ def __init_subclass__(cls, *args: Any, **kwargs: Any) -> None:  # noqa: C901
         if random_seed is not None:
             cls.seed_random(random_seed)
 
-        if cls.__set_as_default_factory_for_type__:
+        if cls.__set_as_default_factory_for_type__ and hasattr(cls, "__model__"):
             BaseFactory._factory_type_mapping[cls.__model__] = cls
 
     @classmethod

tests/test_factory_configuration.py

@@ -0,0 +1,20 @@
+from typing import Any, Type
+
+from typing_extensions import TypeGuard
+
+from polyfactory.factories.base import BaseFactory, T
+
+
+def test_setting_set_as_default_factory_for_type_on_base_factory() -> None:
+    """Setting the value to `True` shouldn't raise exception when initializing."""
+
+    class CustomBaseFactory(BaseFactory[T]):
+        __is_base_factory__ = True
+        __set_as_default_factory_for_type__ = True
+
+        @classmethod
+        def is_supported_type(cls, value: Any) -> TypeGuard[Type[T]]:
+            # Set this as false since this factory will be injected into the
+            # list of base factories, but this obviously shouldn't be ran
+            # for any of the types.
+            return False