This is all about current (3.6) trunk.
In Objects/weakrefobject.c, we have the function
PyObject_ClearWeakRefs(). This is called when a generic object that
supports weakrefs is destroyed; this is the code that calls the
callbacks. Here's a little paragraph of code from the center:
for (i = 0; i < count; ++i) {
PyWeakReference *next = current->wr_next;
if (((PyObject *)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;
}
"current" is the doubly-linked list of PyWeakReference objects stored
inside the object that's getting destroyed.
My question: under what circumstances would ob_refcnt ever be 0? The
tp_dealloc handler for PyWeakReference * objects removes it from this
list and frees the memory. How could the reference count reach 0
without tp_dealloc being called and it being removed from the list?
Scratching my head like crazy,
//arry/
p.s. If you're thinking "why does he care?", understanding this would
maybe help with the Gilectomy. So yes there's a point to this question.
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