[Python-Dev] are CObjects inherently unsafe? (original) (raw)

Michael Hudson mwh at python.net
Thu Dec 4 09:52:24 EST 2003

It seems to me that any time there are more than two CObjects around we have a good chance of causing mischief:

import cStringIO, _curses cStringIO.cStringIO_CAPI = _curses._C_API import cPickle cPickle.dumps(range(10)) Illegal instruction

(if you're trying this at home, starting python with -E might be necessary to make sure cPickle hasn't been imported already).

Question 1: do we care? I think we do: "no core dumps" is a pretty strong Pythonic principle, even though this is certainly a "doctor it hurts when I do this" situation. OTOH, Armin's gc.get_referrers hack was deemed allowable.

It seems to me that it would be more sensible to have a dict mapping names (maybe just module names...) to cobjects in the interpreter state. I guess there might be a way of getting ahold of the dict with the gc module (though I can't think of one off hand). This wouldn't be a difficult change, and if the CObjects are left in the module dicts, it shouldn't even do that much damage to binary compatibility.

Thoughts?

Cheers, mwh (who also notices that the cobject section in Doc/ext/ could do with being updated to use PyCObject_Import...)

More information about the Python-Dev mailing list