Hide debugger threads from being returned in the threading module

[jbelusic]

This code should go to end but in VS Code does not. In others IDE this run to the end.
Is this BUG or?

Code is:

import logging
import random
import threading
import time

logging.basicConfig(
    level=logging.DEBUG,
    format='(%(threadName)-10s) %(message)s',
)

class Counter(object):
    def __init__(self, start=0):
        self.lock = threading.Lock()
        self.value = start
    def increment(self):
        logging.debug('Waiting for lock')
        self.lock.acquire()
        try:
            logging.debug('Acquired lock')
            self.value = self.value + 1
        finally:
            logging.debug("Releasing")
            self.lock.release()

def worker(c):
    print('Entering worker...')
    for i in range(2):
        print('worker loop:', i)
        pause = random.random()
        logging.debug('Sleeping %0.02f', pause)
        time.sleep(pause)
        c.increment()
    logging.debug('Done')

counter = Counter()
for i in range(2):
    t = threading.Thread(target=worker, args=(counter,))
    t.start()

logging.debug('Waiting for worker threads')
main_thread = threading.currentThread()

try:
    for t in threading.enumerate():
        if t is not main_thread:
            t.join()
except Exception as e:
    print('exception: ', e)
finally:
    print('This is test')

logging.debug('Counter: %d', counter.value)

logging.debug('End of script')

[fabioz]

The problem is that you're waiting for all threads to finish (except the main thread) in:

for t in threading.enumerate():
    if t is not main_thread:
        t.join()

So, what happens is that some of the threads returned from threading.enumerate are debugger threads that will not finish until your own threads finish.

The fix for your own code would be joining just the threads that you created.

i.e.:

threads = []
for i in range(2):
    t = threading.Thread(target=worker, args=(counter,))
    threads.append(t)
    t.start()

...

for t in threads:
    t.join()

I'm leaving this open because we may want to hide the debugger threads in the future (I'll update the title to reflect that).

[jbelusic]

Great, it works, thanx.

[jbelusic]

Sorry I am new to GitHub and I accidentally closed this.