issues with doctest and threads

[Michele Simionato]

I am getting a strange error with this script:

$ cat doctest-threads.py
"""
>>> import time, threading
>>> def example():
...     thread.out = []
...     while thread.running:
...         time.sleep(.01)
...         thread.out.append(".")
>>> thread = threading.Thread(None, example)
>>> thread.running = True; thread.start()
>>> time.sleep(.1)
>>> thread.running = False
>>> print thread.out
['.', '.', '.', '.', '.', '.', '.', '.', '.']
"""

if __name__ == "__main__":
    import doctest; doctest.testmod()

$ python doctest-threads.py
Exception in thread Thread-1:
Traceback (most recent call last):
  File "/usr/lib/python2.4/threading.py", line 442, in __bootstrap
    self.run()
  File "/usr/lib/python2.4/threading.py", line 422, in run
    self.__target(*self.__args, **self.__kwargs)
  File "<doctest __main__[1]>", line 5, in example
NameError: global name 'thread' is not defined

I have found out a workaround, putting 'thread' in the main program
(i.e.
in the globals):

$ cat doctest-threads2.py
"""
>>> thread.running = True
>>> thread.start()
>>> time.sleep(.1)
>>> thread.running = False
>>> print thread.out
['.', '.', '.', '.', '.', '.', '.', '.', '.']
"""
import time, threading

def example():
    thread.out = []
    while thread.running:
        time.sleep(.01)
        thread.out.append(".")

thread = threading.Thread(None, example)

if __name__ == "__main__":
    import doctest; doctest.testmod()

However this is strange, since replacing in the first script

>>> globals()["thread"] = threading.Thread(None, example)

does NOT work, so it is not just putting stuff in the globals.
Also, it seems that I cannot reproduce the same error in absense of
threads.
Any idea of what is happening?
Thanks for sharing,

              Michele Simionato