Merge pull request #32 from piercefreeman/bug/fix-pydantic-setter-crash

Use settable __pydantic_fields__

Author: piercefreeman

iceaxe/base.py

@@ -34,8 +34,8 @@ def __new__(
         mcs._cached_args[cls] = raw_kwargs
 
         # If we have already set the class's fields, we should wrap them
-        if hasattr(cls, "model_fields"):
-            cls.model_fields = {
+        if hasattr(cls, "__pydantic_fields__"):
+            cls.__pydantic_fields__ = {
                 field: info
                 if isinstance(info, DBFieldInfo)
                 else DBFieldInfo.extend_field(
@@ -98,6 +98,14 @@ def _extract_kwarg(cls, kwargs: dict[str, Any], key: str, default: Any = None):
 
         return default
 
+    @property
+    def model_fields(self) -> dict[str, DBFieldInfo]:  # type: ignore
+        # model_fields must be reimplemented in our custom metaclass, otherwise
+        # clients will get the super typehinting signature when they try
+        # to access Model.model_fields. This overrides the ClassVar typehint
+        # that's placed in the TableBase itself.
+        return super().model_fields  # type: ignore
+
 
 class UniqueConstraint(BaseModel):
     columns: list[str]

iceaxe/field.py

@@ -25,6 +25,8 @@
 
 P = ParamSpec("P")
 
+_Unset: Any = PydanticUndefined
+
 
 class DBFieldInputs(_FieldInfoInputs, total=False):
     primary_key: bool
@@ -116,11 +118,16 @@ def func(
         index: bool = False,
         check_expression: str | None = None,
         is_json: bool = False,
-        default: Any = PydanticUndefined,
+        default: Any = _Unset,
+        default_factory: (
+            Callable[[], Any] | Callable[[dict[str, Any]], Any] | None
+        ) = _Unset,
         *args: P.args,
         **kwargs: P.kwargs,
     ):
-        raw_field = PydanticField(default=default, **kwargs)  # type: ignore
+        raw_field = PydanticField(
+            default=default, default_factory=default_factory, **kwargs
+        )  # type: ignore
 
         # The Any request is required for us to be able to assign fields to any
         # arbitrary type, like `value: str = Field()`