On 2016-10-10 10:45, Chris Angelico wrote:
On Mon, Oct 10, 2016 at 8:35 PM, Larry Hastings <la...@hastings.org> wrote:
Huh? In all other circumstances, a "borrowed" reference is exactly that: X
has a reference, and you are relying on X's reference to keep the object
alive. Borrowing from a borrowed reference is simply a chain of these; Z
borrows from Y, Y borrows from X, and X is the original person who did the
incref. But you're borrowing from something specific, somebody who the API
guarantees has a legitimate reference on the object and won't drop it while
you're using it. I bet for every other spot in the API I can tell you from
whom you're borrowing the reference.
Okay. Here's a test:
PyObject* PyList_GetItem(PyObject *list, Py_ssize_t index)
Return value: Borrowed reference.
Presumably you own a reference to the list itself before you call
this, and the list has a reference to its items. But suppose another
thread clear()s the list immediately after you call this; whose
reference are you borrowing now? The list's is gone.
Or is this another API that will have to change post gilectomy?
Couldn't the reference to the list also be borrowed?
If you lookup something in a dict, it'll be a borrowed reference.
If the dict is globals() and there's no GIL, another thread could delete
the item while your code had the borrowed reference.
It looks like there might be a lot that will need to changed post gilectomy!
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
https://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
