1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
|
import gc
import sys
import unittest
import weakref
import greenlet
class GCTests(unittest.TestCase):
def test_dead_circular_ref(self):
o = weakref.ref(greenlet.greenlet(greenlet.getcurrent).switch())
gc.collect()
self.assertTrue(o() is None)
self.assertFalse(gc.garbage, gc.garbage)
if greenlet.GREENLET_USE_GC:
# These only work with greenlet gc support
def test_circular_greenlet(self):
class circular_greenlet(greenlet.greenlet):
pass
o = circular_greenlet()
o.self = o
o = weakref.ref(o)
gc.collect()
self.assertTrue(o() is None)
self.assertFalse(gc.garbage, gc.garbage)
def test_inactive_ref(self):
class inactive_greenlet(greenlet.greenlet):
def __init__(self):
greenlet.greenlet.__init__(self, run=self.run)
def run(self):
pass
o = inactive_greenlet()
o = weakref.ref(o)
gc.collect()
self.assertTrue(o() is None)
self.assertFalse(gc.garbage, gc.garbage)
def test_finalizer_crash(self):
# This test is designed to crash when active greenlets
# are made garbage collectable, until the underlying
# problem is resolved. How does it work:
# - order of object creation is important
# - array is created first, so it is moved to unreachable first
# - we create a cycle between a greenlet and this array
# - we create an object that participates in gc, is only
# referenced by a greenlet, and would corrupt gc lists
# on destruction, the easiest is to use an object with
# a finalizer
# - because array is the first object in unreachable it is
# cleared first, which causes all references to greenlet
# to disappear and causes greenlet to be destroyed, but since
# it is still live it causes a switch during gc, which causes
# an object with finalizer to be destroyed, which causes stack
# corruption and then a crash
class object_with_finalizer(object):
def __del__(self):
pass
array = []
parent = greenlet.getcurrent()
def greenlet_body():
greenlet.getcurrent().object = object_with_finalizer()
try:
parent.switch()
finally:
del greenlet.getcurrent().object
g = greenlet.greenlet(greenlet_body)
g.array = array
array.append(g)
g.switch()
del array
del g
greenlet.getcurrent()
gc.collect()
|
