Message 382357 - Python tracker

➜

This issue tracker has been migrated to GitHub, and is currently read-only.
For more information, see the GitHub FAQs in the Python's Developer Guide.

Author	vstinner
Recipients	rhettinger, serhiy.storchaka, vstinner
Date	2020-12-02.23:50:25
SpamBayes Score	-1.0
Marked as misclassified	Yes
Message-id	<1606953025.93.0.400102099548.issue42536@roundup.psfhosted.org>
In-reply-to

Content
Raymond Hettinger: > If this is new, pairwise() is the most likely cause. I reproduced the issue without involving the itertools module. It seems to be a zip_next() micro-optimization which keeps an object alive longer than epxected. This micro-optimization is not new. It's just really hard to trigger the issue. It seems to depend if the zip object is deleted or not. The builtin zip type implements a traverse function which visits Py_VISIT(lz->result). The GC is supposed to be able to break such cycle, no?

Raymond Hettinger:
> If this is new, pairwise() is the most likely cause.

I reproduced the issue without involving the itertools module. It seems to be a zip_next() micro-optimization which keeps an object alive longer than epxected. This micro-optimization is not new. It's just really hard to trigger the issue.

It seems to depend if the zip object is deleted or not. The builtin zip type implements a traverse function which visits Py_VISIT(lz->result). The GC is supposed to be able to break such cycle, no?

History
Date	User	Action	Args
2020-12-02 23:50:25	vstinner	set	recipients: + vstinner, rhettinger, serhiy.storchaka
2020-12-02 23:50:25	vstinner	set	messageid: <1606953025.93.0.400102099548.issue42536@roundup.psfhosted.org>
2020-12-02 23:50:25	vstinner	link	issue42536 messages
2020-12-02 23:50:25	vstinner	create