diff options
| -rw-r--r-- | Lib/test/test_descr.py | 19 | ||||
| -rw-r--r-- | Misc/NEWS | 3 | ||||
| -rw-r--r-- | Objects/typeobject.c | 9 |
3 files changed, 27 insertions, 4 deletions
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py index d64af69..45fd05d 100644 --- a/Lib/test/test_descr.py +++ b/Lib/test/test_descr.py @@ -1,8 +1,10 @@ import builtins +import gc import sys import types import math import unittest +import weakref from copy import deepcopy from test import support @@ -1186,7 +1188,6 @@ order (MRO) for bases """ self.assertEqual(Counted.counter, 0) # Test lookup leaks [SF bug 572567] - import gc if hasattr(gc, 'get_objects'): class G(object): def __eq__(self, other): @@ -4387,7 +4388,6 @@ order (MRO) for bases """ self.assertRaises(AttributeError, getattr, C(), "attr") self.assertEqual(descr.counter, 4) - import gc class EvilGetattribute(object): # This used to segfault def __getattr__(self, name): @@ -4484,6 +4484,21 @@ order (MRO) for bases """ ns = {'__qualname__': 1} self.assertRaises(TypeError, type, 'Foo', (), ns) + def test_cycle_through_dict(self): + # See bug #1469629 + class X(dict): + def __init__(self): + dict.__init__(self) + self.__dict__ = self + x = X() + x.attr = 42 + wr = weakref.ref(x) + del x + support.gc_collect() + self.assertIsNone(wr()) + for o in gc.get_objects(): + self.assertIsNot(type(o), X) + class DictProxyTests(unittest.TestCase): def setUp(self): @@ -10,6 +10,9 @@ What's New in Python 3.3.0 Alpha 2? Core and Builtins ----------------- +- Issue #1469629: Allow cycles through an object's __dict__ slot to be + collected. (For example if ``x.__dict__ is x``). + - Issue #14205: dict lookup raises a RuntimeError if the dict is modified during a lookup. diff --git a/Objects/typeobject.c b/Objects/typeobject.c index 50b9723..dae7ff8 100644 --- a/Objects/typeobject.c +++ b/Objects/typeobject.c @@ -862,8 +862,13 @@ subtype_clear(PyObject *self) assert(base); } - /* There's no need to clear the instance dict (if any); - the collector will call its tp_clear handler. */ + /* Clear the instance dict (if any), to break cycles involving only + __dict__ slots (as in the case 'self.__dict__ is self'). */ + if (type->tp_dictoffset != base->tp_dictoffset) { + PyObject **dictptr = _PyObject_GetDictPtr(self); + if (dictptr && *dictptr) + Py_CLEAR(*dictptr); + } if (baseclear) return baseclear(self); |