[BUG] test failure: test_unicode.UnicodeTest.test_raiseMemError on 32bit in Debian CI about cython HOT 6 CLOSED

I'm guessing is is because we're running in a 32bit container on a 64bit kernel, so processes can allocate 4GiB

This is non-trivial to detect from userspace, I can't think of a reliable way to do so offhand.

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Is Python itself passing it's test-suite?

This is a test that's ultimately copied from CPython (https://github.com/python/cpython/blob/f108468970bf4e70910862476900f924fb701399/Lib/test/test_str.py#L2451) so it'd be interesting to know if that version of the same test is passing/failing/being skipped.

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Yep, seems to be passing: https://ci.debian.net/packages/p/python3.12/unstable/i386/40342642/#L2130 (until 3.13, it's called test_unicode)

I will say that I couldn't reproduce this one locally (an i386 container on an amd64 host), but it seems to be failing reliably on our CI infra.

from cython.

Thanks for confirming it.

I'm not too worried about this test since it's mostly testing Cpython internals rather than anything we're doing so I think it's fine to ignore.

This kind of bug (where it's very very platform specific) always ends up fairly hard for us to reproduce unfortunately.

from cython.

One of the maintainers of ci.debian.net here. If there is a particular command you'd like me to run in the testbed where the test failed, let me know and I'll see what I can do.

from cython.

My view is we should just skip this test.

The original test I think was designed to allocate a string that's just too big and is thus guaranteed to fail. However, it's based on struct sizes that are version dependent and have shrunk a little since we copied the test. So it's possible that the test is now testing something that's probably too big but might just is possible.

It's testing a CPython implementation detail that's tested properly as part of CPython. I don't think there's much value to Cython in having this test and I don't think it's worth you spend time debugging it.

I'll make a PR to remove it shortly

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