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Issue 3110: Crash with weakref subclass,

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seen after a "import multiprocessing.reduction"

An instance of a weakref subclass can have attributes.
If such a weakref holds the only strong reference to the object,
deleting the weakref will delete the object. In this case,
the callback must not be called, because the ref object is being deleted!
This commit is contained in:
Amaury Forgeot d'Arc 2008-06-16 19:12:42 +00:00
parent 305480c9dc
commit a8919fe631
3 changed files with 55 additions and 5 deletions
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16
Objects/weakrefobject.c
View file

@ -907,7 +907,8 @@ PyObject_ClearWeakRefs(PyObject *object)
current->wr_callback = NULL;
clear_weakref(current);
if (callback != NULL) {
handle_callback(current, callback);
if (current->ob_refcnt > 0)
handle_callback(current, callback);
Py_DECREF(callback);
}
}
@ -925,9 +926,15 @@ PyObject_ClearWeakRefs(PyObject *object)
for (i = 0; i < count; ++i) {
PyWeakReference *next = current->wr_next;
Py_INCREF(current);
PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
if (current->ob_refcnt > 0)
{
Py_INCREF(current);
PyTuple_SET_ITEM(tuple, i * 2, (PyObject *) current);
PyTuple_SET_ITEM(tuple, i * 2 + 1, current->wr_callback);
}
else {
Py_DECREF(current->wr_callback);
}
current->wr_callback = NULL;
clear_weakref(current);
current = next;
@ -935,6 +942,7 @@ PyObject_ClearWeakRefs(PyObject *object)
for (i = 0; i < count; ++i) {
PyObject *callback = PyTuple_GET_ITEM(tuple, i * 2 + 1);
/* The tuple may have slots left to NULL */
if (callback != NULL) {
PyObject *item = PyTuple_GET_ITEM(tuple, i * 2);
handle_callback((PyWeakReference *)item, callback);