refactor: better fabrication of Inputs/Outputs from Context object(s)

src/cipy/common.py

@@ -12,6 +12,7 @@ from types import SimpleNamespace, NoneType
 from typing import Annotated, Any, Callable, Iterator, Literal, overload
 
 from pydantic import BaseModel, Field
+from pydantic_core import PydanticUndefined
 
 type Scalar = bool | int | float | str
 type Computed = Ref | Factory
@@ -129,28 +130,20 @@ class Context(SimpleNamespace):
         if extra is None:
             extra = {}
 
-        model = getattr(state, attr)
-        if model is None:
-            annotation = state.__pydantic_fields__[attr].annotation
-            assert annotation is not None
-            model = annotation()
+        fields: dict[str, Any] = {}
+        if (model := getattr(state, attr)) is not None:
+            fields = vars(model)
 
-        value: Value | None = None
-        for k, value in extra.items():
-            setattr(model, k, self(value))
+        annotation = state.__pydantic_fields__[attr].annotation
+        assert annotation is not None
 
-        for k, fld in model.__pydantic_fields__.items():
-            value = getattr(model, k)
-            if fld.annotation is None:
-                continue
-
-            if k in extra:
-                pass
-
-            value = self(value)
-            if value is not None:
-                setattr(model, k, fld.annotation(value))
+        for name, fld in annotation.__pydantic_fields__.items():
+            if name in extra:
+                fields[name] = self(extra[name])
+            elif fld.default is not PydanticUndefined:
+                fields[name] = self(fld.default)
 
+        model = annotation(**fields)
         _validate(model)
         setattr(state, attr, model)
         return model