thread_inheritence.py

"""The challenge here is to make grand children print out the value set by child, without modifying cannot_modify or grand_child"""
from threading import Thread, local

var = local()

def peek(from_name):
    print(f"{from_name}: {getattr(var, 'value', None)}\n", end="")

def master():
    var.value = "master"
    peek("master")
    children = [Thread(target=child, name=name, args=(name,)) for name in ("A", "B")]
    [t.start() for t in children]
    [t.join() for t in children]


def child(name):
    var.value = name
    peek(name)
    cannot_modify(name)

def cannot_modify(name):
    thread = Thread(target=grand_child, name=f"{name}-{0}", args=(f"{name}-{0}",))
    thread.start()
    thread.join()

def grand_child(name):
    peek(name)

master()

"""
Current behaviour:

master: master
A: A
A-0: None
B: B
B-0: None
"""