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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 issue7140, 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