Thread without join (ARCH2041)

Key python.async.thread-without-join · Severity warning · Category async

When a thread is created and started with no corresponding join(), the spawning scope may exit before the thread finishes and the thread’s exceptions vanish unobserved.

Incorrect

import threading

def process(items):
    t = threading.Thread(target=work, args=(items,))
    t.start()  # no join, work unobserved

Correct

import threading

def process(items):
    t = threading.Thread(target=work, args=(items,))
    t.start()
    t.join()  # wait for completion

Fix

Call join() for every thread you start, or manage daemon lifetimes explicitly.