> FTR I thought the consensus was not to backport these fixes unless there was a demonstrated problem: <https://bugs.python.org/issue1621#msg144499>, though personally, I would be in favour of backporting in many cases.

Sorry not know that. :-( Another benefit of the change is it actually backports the codes from 3.x so it's easy for later maintainence and it doesn't add additional work.

> I included a test case that works on 32-bit platforms, which you may use.

Thanks. But I don't get such an environment to test so I prefer not to add it now. I adjust my patch according to yours. :-)