def deserialization() -> Conversion:
annotations: dict[str, Any] = {}
deserialization_namespace: dict[str, Any] = {
"__annotations__": annotations
}
for sub in rec_subclasses(cls):
annotations[sub.__name__] = Tagged[sub] # type: ignore
# Add tagged fields for all its alternative constructors
for constructor in _alternative_constructors.get(sub, ()):
# Build the alias of the field
alias = to_pascal_case(constructor.__name__)
# object_deserialization uses get_type_hints, but the constructor
# return type is stringified and the class not defined yet,
# so it must be assigned manually
constructor.__annotations__["return"] = sub
# Add constructor tagged field with its conversion
annotations[alias] = Tagged[sub] # type: ignore
deserialization_namespace[alias] = Tagged(
conversion(
# Use object_deserialization to wrap constructor as deserializer
deserialization=object_deserialization(
constructor, type_name(alias))))
# Create the deserialization tagged union class
deserialization_union = new_class(
cls.__name__,
(TaggedUnion, ),
exec_body=lambda ns: ns.update(deserialization_namespace),
)
return Conversion(lambda obj: get_tagged(obj)[1],
source=deserialization_union,
target=cls)
class Data2:
data_field2: Field2 = field(
metadata=flattened | conversion(Field2.from_field, Field2.to_field))