[New-bugs-announce] [issue39681] pickle.load expects an object that implements readinto

[Nathan Goldbaum]

New submission from Nathan Goldbaum <nathan12343 at gmail.com>:

As of https://github.com/python/cpython/pull/7076, it looks like at least the C implementation of pickle.load expects the file argument to implement readinto:

https://github.com/python/cpython/blob/ffd9753a944916ced659b2c77aebe66a6c9fbab5/Modules/_pickle.c#L1617-L1622

This is a change in behavior relative to previous versions of Python and I don't see it mentioned in PEP 574 or in the pull request so I'm not sure why it was changed.

This change breaks some PyTorch tests (see https://github.com/pytorch/pytorch/issues/32289) and, at least one PyTorch user, although I don't have full details there.

I can try to fix this on the PyTorch side but I first want to check that this was an intentional change on the Python side of things.

----------
components: Library (Lib)
messages: 362242
nosy: Nathan.Goldbaum
priority: normal
severity: normal
status: open
title: pickle.load expects an object that implements readinto
versions: Python 3.8

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