Issue #8268: Old-style classes (not just instances) now support weak
references.
diff --git a/Include/classobject.h b/Include/classobject.h
index 118dd09..bc03e0d 100644
--- a/Include/classobject.h
+++ b/Include/classobject.h
@@ -18,6 +18,7 @@
PyObject *cl_getattr;
PyObject *cl_setattr;
PyObject *cl_delattr;
+ PyObject *cl_weakreflist; /* List of weak references */
} PyClassObject;
typedef struct {
diff --git a/Lib/test/test_sys.py b/Lib/test/test_sys.py
index d106fe7..1720875 100644
--- a/Lib/test/test_sys.py
+++ b/Lib/test/test_sys.py
@@ -544,7 +544,7 @@
class class_oldstyle():
def method():
pass
- check(class_oldstyle, size(h + '6P'))
+ check(class_oldstyle, size(h + '7P'))
# instance (old-style class)
check(class_oldstyle(), size(h + '3P'))
# instancemethod (old-style class)
diff --git a/Lib/test/test_weakref.py b/Lib/test/test_weakref.py
index 536a987..bc2982f 100644
--- a/Lib/test/test_weakref.py
+++ b/Lib/test/test_weakref.py
@@ -685,6 +685,26 @@
# No exception should be raised here
gc.collect()
+ def test_classes(self):
+ # Check that both old-style classes and new-style classes
+ # are weakrefable.
+ class A(object):
+ pass
+ class B:
+ pass
+ l = []
+ weakref.ref(int)
+ a = weakref.ref(A, l.append)
+ A = None
+ gc.collect()
+ self.assertEqual(a(), None)
+ self.assertEqual(l, [a])
+ b = weakref.ref(B, l.append)
+ B = None
+ gc.collect()
+ self.assertEqual(b(), None)
+ self.assertEqual(l, [a, b])
+
class SubclassableWeakrefTestCase(TestBase):
diff --git a/Misc/NEWS b/Misc/NEWS
index 09d07f2..80f1d2e 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@
Core and Builtins
-----------------
+- Issue #8268: Old-style classes (not just instances) now support weak
+ references.
+
- Issue #8211: Save/restore CFLAGS around AC_PROG_CC in configure.in, compiler
optimizations are disabled when --with-pydebug is used.
diff --git a/Objects/classobject.c b/Objects/classobject.c
index 3f51c0f..032d354 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -123,6 +123,7 @@
op->cl_dict = dict;
Py_XINCREF(name);
op->cl_name = name;
+ op->cl_weakreflist = NULL;
op->cl_getattr = class_lookup(op, getattrstr, &dummy);
op->cl_setattr = class_lookup(op, setattrstr, &dummy);
@@ -188,6 +189,8 @@
class_dealloc(PyClassObject *op)
{
_PyObject_GC_UNTRACK(op);
+ if (op->cl_weakreflist != NULL)
+ PyObject_ClearWeakRefs((PyObject *) op);
Py_DECREF(op->cl_bases);
Py_DECREF(op->cl_dict);
Py_XDECREF(op->cl_name);
@@ -454,7 +457,7 @@
(traverseproc)class_traverse, /* tp_traverse */
0, /* tp_clear */
0, /* tp_richcompare */
- 0, /* tp_weaklistoffset */
+ offsetof(PyClassObject, cl_weakreflist), /* tp_weaklistoffset */
0, /* tp_iter */
0, /* tp_iternext */
0, /* tp_methods */