Function _frozen_get_del_attr

Lib/dataclasses.py:728–748

(cls, fields, func_builder)

def _frozen_get_del_attr(cls, fields, func_builder):
    locals = {'cls': cls,
              'FrozenInstanceError': FrozenInstanceError}
    condition = 'type(self) is cls'
    if fields:
        condition += ' or name in {' + ', '.join(repr(f.name) for f in fields) + '}'

    func_builder.add_fn('__setattr__',
                        ('self', 'name', 'value'),
                        (f'  if {condition}:',
                          '   raise FrozenInstanceError(f"cannot assign to field {name!r}")',
                         f'  super(cls, self).__setattr__(name, value)'),
                        locals=locals,
                        overwrite_error=True)
    func_builder.add_fn('__delattr__',
                        ('self', 'name'),
                        (f'  if {condition}:',
                          '   raise FrozenInstanceError(f"cannot delete field {name!r}")',
                         f'  super(cls, self).__delattr__(name)'),
                        locals=locals,
                        overwrite_error=True)


def _is_classvar(a_type, typing):