Method evolve

src/attr/_make.py:2596–2625

Copy *self* and apply *changes*. This works similarly to `attrs.evolve` but that function does not work with :class:`attrs.Attribute`. It is mainly meant to be used for `transform-fields`. .. versionadded:: 20.3.0

(self, **changes)

    # Don't use attrs.evolve since fields(Attribute) doesn't work
    def evolve(self, **changes):
        """
        Copy *self* and apply *changes*.

        This works similarly to `attrs.evolve` but that function does not work
        with :class:`attrs.Attribute`.

        It is mainly meant to be used for `transform-fields`.

        .. versionadded:: 20.3.0
        """
        new = copy.copy(self)

        new._setattrs(changes.items())

        if "alias" in changes and "alias_is_default" not in changes:
            # Explicit alias provided -- no longer the default.
            _OBJ_SETATTR.__get__(new)("alias_is_default", False)
        elif (
            "name" in changes
            and "alias" not in changes
            # Don't auto-generate alias if the user picked picked the old one.
            and self.alias_is_default
        ):
            # Name changed, alias was auto-generated -- update it.
            _OBJ_SETATTR.__get__(new)(
                "alias", _default_init_alias_for(new.name)
            )

        return new

    # Don't use _add_pickle since fields(Attribute) doesn't work
    def __getstate__(self):