#!/usr/bin/env python

import os, time, threading


def worker():
    # Wait just a bit before forking so that the original thread makes it into
    # my_acquire.
    time.sleep(0.3)
    childpid = os.fork()
    if childpid != 0:
        # Parent process just waits for child.
        os.waitpid(childpid, 0)
    # Child process should just return.


w = threading.Thread(target=worker)

# Stub out the private condition variable's lock acquire method.  There is a
# race to acquire this between w.join() and w.__stop(), which is called when the
# thread returns.
orig_acquire = w._Thread__block.acquire
call_count = 0
def my_acquire():
    global call_count
    orig_acquire()
    if call_count == 0:
        # Make w.join() take longer between calls to self.__block.acquire() and
        # self.__block.wait(), which releases the lock.  w.__stop() should then
        # deadlock.
        time.sleep(1)
    call_count += 1
w._Thread__block.acquire = my_acquire

w.start()
w.join()