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Author andrei.avk
Recipients BTaskaya, Mark.Shannon, andrei.avk, christian.heimes, josh.r, mark.dickinson, pablogsal, rhettinger, serhiy.storchaka, terry.reedy
Date 2021-04-12.04:09:08
SpamBayes Score -1.0
Marked as misclassified Yes
Message-id <1618200548.75.0.00871119849192.issue42454@roundup.psfhosted.org>
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One possibility for this being a breaking change is this scenario: some codebase may have logic that takes a list and uses a slice operation on it; in a rare circumstance the list is really a dict and a TypeError is caught upstream and dealt with; with this change it will no longer be caught/logged and the dict will be unexpectedly modified. It might also be hard to debug. 

I don't remember seeing such code but it's conceivable.

The change might still be worth it for performance improvement though - I'm not sure.
History
Date User Action Args
2021-04-12 04:09:08andrei.avksetrecipients: + andrei.avk, rhettinger, terry.reedy, mark.dickinson, christian.heimes, Mark.Shannon, serhiy.storchaka, josh.r, pablogsal, BTaskaya
2021-04-12 04:09:08andrei.avksetmessageid: <1618200548.75.0.00871119849192.issue42454@roundup.psfhosted.org>
2021-04-12 04:09:08andrei.avklinkissue42454 messages
2021-04-12 04:09:08andrei.avkcreate