Function _update_func_cell_for__class__

Lib/dataclasses.py:1283–1301

(f, oldcls, newcls)

def _update_func_cell_for__class__(f, oldcls, newcls):
    # Returns True if we update a cell, else False.
    if f is None:
        # f will be None in the case of a property where not all of
        # fget, fset, and fdel are used.  Nothing to do in that case.
        return False
    try:
        idx = f.__code__.co_freevars.index("__class__")
    except ValueError:
        # This function doesn't reference __class__, so nothing to do.
        return False
    # Fix the cell to point to the new class, if it's already pointing
    # at the old class.  I'm not convinced that the "is oldcls" test
    # is needed, but other than performance can't hurt.
    closure = f.__closure__[idx]
    if closure.cell_contents is oldcls:
        closure.cell_contents = newcls
        return True
    return False


def _create_slots(defined_fields, inherited_slots, field_names, weakref_slot):