Interpreter: Python 3.1.2

Sample:

===== first.py =====

import sys
import second 

if 'second' in sys.modules:
  print ('in sys modules')
  del sys.modules['second']

del second

===== second.py =====

class A:
 def __init__(self):
   print('created')

 def __del__(self):
   print('destroyed')

a = A()

Result: 'destroyed' isn't printed
With Python 2.6.5 it worked fine

This also reproduces in 2.7.
2.6 and 2.7 have a different behaviour.

Probably bpo-7140, which will disable clearing of the module dict if it's caught in a reference cycle (which it is here, since A.__init__ and A.__del__ will reference it as their globals dict).

Tricky. I think the only way to do this properly is to call _PyModule_Clear when the dict is destroyed. However, there's no good way to flag a dictionary as a "module" dict. Therefore, I propose we remove the Py_REFCNT == 1 guard in module_dealloc, and simply leave as an open bug that modules will clear their dictionaries on deallocation. Thoughts?

Therefore, I propose we remove the Py_REFCNT == 1 guard in
module_dealloc, and simply leave as an open bug that modules will clear
their dictionaries on deallocation.

Yes, I think it's the best solution. People can easily copy the dict if they want to keep it around after the module gets destroyed.

r85392.

r85393 introduced a regression in test_runpy of Python 2.7.

test_runpy fails also on Python 3.2.

r85398