[Python-checkins] python/dist/src/Lib/test test_weakref.py, 1.28, 1.28.6.1

[tim_one at users.sourceforge.net]

Update of /cvsroot/python/python/dist/src/Lib/test
In directory sc8-pr-cvs1:/tmp/cvs-serv22584/Lib/test

Modified Files:
      Tag: release23-maint
	test_weakref.py 
Log Message:
Backport of fix for SF bug 840829, memory corruption in some cases of
weakref callbacks.

This is a critical bugfix.  It's already been fixed on the trunk (2.4
development).  I don't intend to backport it to the 22 line, but if a
2.2.4 ever gets released, this should be in it.


Index: test_weakref.py
===================================================================
RCS file: /cvsroot/python/python/dist/src/Lib/test/test_weakref.py,v
retrieving revision 1.28
retrieving revision 1.28.6.1
diff -C2 -d -r1.28 -r1.28.6.1
*** test_weakref.py	14 Jul 2003 21:37:17 -0000	1.28
--- test_weakref.py	13 Nov 2003 01:17:55 -0000	1.28.6.1
***************
*** 299,302 ****
--- 299,322 ----
              self.fail("exception not properly restored")
  
+     def test_sf_bug_840829(self):
+         # "weakref callbacks and gc corrupt memory"
+         # subtype_dealloc erroneously exposed a new-style instance
+         # already in the process of getting deallocated to gc,
+         # causing double-deallocation if the instance had a weakref
+         # callback that triggered gc.
+         # If the bug exists, there probably won't be an obvious symptom
+         # in a release build.  In a debug build, a segfault will occur
+         # when the second attempt to remove the instance from the "list
+         # of all objects" occurs.
+ 
+         import gc
+ 
+         class C(object):
+             pass
+ 
+         c = C()
+         wr = weakref.ref(c, lambda ignore: gc.collect())
+         del c
+ 
  
  class Object: