import sys, os
import time
import multiprocessing
import threading

def main():
    # Expected result when running this code:
    #   exits with output "thread_run got EOFError as expected"+"thread joined"
    # Actual result: deadlock in thread.join() / con.recv()
    print(f'main() using {sys.version}, pid={os.getpid()}', flush=True)
    pipe_read, pipe_write = multiprocessing.Pipe(duplex=False)
    p = multiprocessing.Process(
        target=worker_main,
        name='Worker',
        args=(
            pipe_write,
        ),
    )
    print('starting', flush=True)
    p.start()
    print('started', flush=True)
    pipe_write.close() # Close our copy of the worker's end of the connection ASAP
    thread = threading.Thread(target=lambda: thread_run(pipe_read))
    thread.start()
    print('running', flush=True)
    # time.sleep(1)   # Error no longer reproduces when adding this sleep
    print('killing', flush=True)
    p.kill()
    print('killed', flush=True)
    p.join()
    print('process joined', flush=True)
    thread.join()
    print('thread joined', flush=True)

def thread_run(con):
    try:
        msg = con.recv()
    except EOFError:
        print('thread_run got EOFError as expected', flush=True)
    else:
        print(f'thread_run received something: {msg}', flush=True)
    
def worker_main(con):
    print('worker_main()', flush=True)
    time.sleep(5)
    
if __name__ == '__main__':
    main()

# On deadlock, only the main process is alive, with the following stacks:
# Process 10632: c:\Python39\python.exe  z:\test\deadlock.py
# Python v3.9.1 (C:\Python39\python.exe)
# 
# Thread 7860 (active)
#     ntdll!NtWaitForSingleObject + 0x14   
#     KERNELBASE!WaitForSingleObjectEx + 0x8e   
#     python39!_PyCOND_WAIT_MS + 0x3c   
#     python39!PyCOND_WAIT + 0xf   
#     python39!EnterNonRecursiveMutex + 0x115   
#     python39!PyThread_acquire_lock_timed + 0x14d   
#     python39!acquire_timed + 0x90   
#     python39!lock_PyThread_acquire_lock + 0x31   
#     _wait_for_tstate_lock (threading.py:1049)
#     join (threading.py:1033)
#     main (deadlock.py:32)
#     <module> (deadlock.py:48)
# Thread 15344 (active)
#     ntdll!NtWaitForMultipleObjects + 0x14   
#     KERNELBASE!WaitForMultipleObjectsEx + 0xf0   
#     KERNELBASE!WaitForMultipleObjects + 0xe   
#     python39!_winapi_WaitForMultipleObjects_impl + 0x11c   
#     python39!_winapi_WaitForMultipleObjects + 0x53   
#     _recv_bytes (multiprocessing\connection.py:310)
#     recv (multiprocessing\connection.py:255)
#     thread_run (deadlock.py:37)
#     <lambda> (deadlock.py:23)
#     run (threading.py:892)
#     _bootstrap_inner (threading.py:954)
#     _bootstrap (threading.py:912)