Message161339
multiprocessing.dummy crashes when attempting to create a ThreadPool from a Thread.
The following code will crush on 2.7.3:
import multiprocessing.dummy
import threading
class Worker(threading.Thread):
def __init__(self):
threading.Thread.__init__(self)
def run(self):
poll = multiprocessing.dummy.Pool(5)
print str(poll)
w = Worker()
w.start()
will crush with the following traceback:
poll = multiprocessing.dummy.Pool(5)
File "C:\Python27\lib\multiprocessing\dummy\__init__.py", line 150, in Pool
return ThreadPool(processes, initializer, initargs)
File "C:\Python27\lib\multiprocessing\pool.py", line 685, in __init__
Pool.__init__(self, processes, initializer, initargs)
File "C:\Python27\lib\multiprocessing\pool.py", line 136, in __init__
self._repopulate_pool()
File "C:\Python27\lib\multiprocessing\pool.py", line 199, in _repopulate_pool
w.start()
File "C:\Python27\lib\multiprocessing\dummy\__init__.py", line 73, in start
self._parent._children[self] = None
AttributeError: 'Worker' object has no attribute '_children'
If you have access to the thread itself, you can set the _children attribute youself (w._children = weakref.WeakKeyDictionary()), but it is not possible with threads different from threading.thread (Such as PyQt4's QThread thread, which is essential for GUI programming).
The fix that I found is to edit the Python27\Lib\multiprocessing\dummy\__init__.py file. The crashing code is line number 73.
This line should be nested in an if block:
if hasattr(self._parent, '_children'):
self._parent._children[self] = None
That way the code is fixed.
Thanks! |
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Date |
User |
Action |
Args |
2012-05-22 08:51:11 | Itay.Brandes | set | recipients:
+ Itay.Brandes |
2012-05-22 08:51:10 | Itay.Brandes | set | messageid: <1337676670.99.0.0296506896441.issue14881@psf.upfronthosting.co.za> |
2012-05-22 08:51:10 | Itay.Brandes | link | issue14881 messages |
2012-05-22 08:51:10 | Itay.Brandes | create | |
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