# -*- coding: utf-8 -*-

"""Demonstrate broken descriptor `__set_name__` feature for `dataclass` descriptor fields."""

class D:
    """A descriptor class that knows its name."""
    def __set_name__(self, owner, name):
        self.name = name
    def __get__(self, instance, owner):
        if instance is not None:
            return 1
        return self

if __name__ == "__main__":
    from dataclasses import dataclass, field
    
    @dataclass
    class C:
        d: int = field(default=D(), init=False)

    print(f"Instance attribute access works as expected: C().d -> {C().d}")
    print(f"Class object attribute access works as expected: C.d -> {C.d}")
    print("However, the descriptor (`D`) object name was never set; C.d.name raises `AttributeError`:")
    C.d.name