utils.py

from .interfaces import AllSemanticsFleafAPI

__all__ = ["inherit_annotations"]


def inherit_annotations(property_method=None, from_class=AllSemanticsFleafAPI):
    """Return a decorator to inherit method annotations from a given class.

    If this is used to inherit annotations for a property method, the property decorator
    needs to be above/outside this decorator, and property_method should be set appropiately.

    Args:
        property_method: An optional string of either "fget", "fset", "fdel".
            If this is not None, this will instead copy the annotations from either
            the getter, setter or deleter of a property with the same name.
        from_class: A class to search for a method with the same name that defines annotations.
    """
    def decorator(method):
        for cls in from_class.__mro__:
            parent_method = getattr(cls, method.__name__, None)
            if property_method:
                parent_method = getattr(parent_method, property_method, None)
            if parent_method:
                parent_annotations = getattr(parent_method, "__annotations__", {})
                if parent_annotations:
                    setattr(method, "__annotations__", parent_annotations)
                    break
        return method
    return decorator