diff -r ffa851df0825 -r 2fb8b9db1c86 symbian-qemu-0.9.1-12/python-2.6.1/Lib/test/crashers/mutation_inside_cyclegc.py --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/symbian-qemu-0.9.1-12/python-2.6.1/Lib/test/crashers/mutation_inside_cyclegc.py Fri Jul 31 15:01:17 2009 +0100 @@ -0,0 +1,31 @@ + +# The cycle GC collector can be executed when any GC-tracked object is +# allocated, e.g. during a call to PyList_New(), PyDict_New(), ... +# Moreover, it can invoke arbitrary Python code via a weakref callback. +# This means that there are many places in the source where an arbitrary +# mutation could unexpectedly occur. + +# The example below shows list_slice() not expecting the call to +# PyList_New to mutate the input list. (Of course there are many +# more examples like this one.) + + +import weakref + +class A(object): + pass + +def callback(x): + del lst[:] + + +keepalive = [] + +for i in range(100): + lst = [str(i)] + a = A() + a.cycle = a + keepalive.append(weakref.ref(a, callback)) + del a + while lst: + keepalive.append(lst[:])