Issue 15702: Multiprocessing Pool deadlocks on join after empty map operation (original) (raw)

Following code deadlocks on Windows 7 64-bit, Python 3.2.3

If you have a pool issue a map operation over an empty iterable then try to join later, it will deadlock. If there is no map operation or blah in the code below isn't empty, it does not deadlock

from multiprocessing import Pool

def main(): p = Pool(); blah = []; print("Mapping"); p.map(dummy, blah); p.close(); p.join(); # deadlocks here print("Done");

def dummy(x): pass;

if name == "main": main();