incompatible requirements

[dimbleby]

oldest-supported-numpy/setup.cfg

Line 45 in b0b3376

numpy==1.21.0; python_version=='3.8' and platform_machine=='arm64' and platform_system=='Darwin'

and

oldest-supported-numpy/setup.cfg

Line 70 in b0b3376

numpy==1.22.2; python_version=='3.8' and platform_machine!='loongarch64' and platform_python_implementation=='PyPy'

would both apply for users of pypy on macos, but require different versions of numpy. There may be other examples.

[rgommers]

Hmm, this is tested, but the tests say that PyPy is only supported on x86-64 and aarch64:

oldest-supported-numpy/tests/test_dependencies.py

Line 52 in b0b3376

if platform_python_implementation == "PyPy" and (platform_machine not in ["x86_64", "aarch64"]):

macOS uses arm64 rather than aarch64. I'm not sure if this was an oversight in the test or PyPy is indeed not supported. I'm guessing the former, and we need to fix the metadata and add arm64 to that line.

Cc @mattip as our PyPy expert.

[dimbleby]

Another pair that are at least logically incompatible - though possibly not in practice - is

oldest-supported-numpy/setup.cfg

Line 54 in b0b3376

numpy==1.22.2; platform_machine=='loongarch64' and python_version<'3.11'

and

oldest-supported-numpy/setup.cfg

Line 32 in b0b3376

numpy==1.23.3; python_version=='3.9' and platform_system=='OS400'

I was experimenting with the use of this package via poetry, which is trying to build cross-platform solutions. So it can't rely on out-of-band knowledge about which combinations actually exist in the real world; but it may be that for an installer that only cares about the current platform these conflicts are never realised.

[rgommers]

Does Poetry actually error out on this? If so, I'm curious how and what "build cross-platform solutions" means exactly.

It's very difficult to make sure this is all logically consistent; the best way is to extend the platform/OS/interpreter combos being tested.

[dimbleby]

Does Poetry actually error out on this?

Well it will do, once it has been fixed to behave properly! I chanced across this project and thought - rightly, it turns out - that it would be an interesting testcase for some ongoing work in poetry to correct the handling of overlapping markers...

"build cross-platform solutions" means that poetry is supposed to build a portable lockfile. ie installation from this lockfile might take place on any arbitrary platform, and poetry promises that regardless of the environment at install-time, it will be able to satisfy the top-level requirements using the details it has written in the lockfile.

Of course that's impossible if there are environments which have incompatible requirements: there can never be any solution for those environments.

[mattip]

PyPy does support macOS arm64 (i.e. Apple silicon). This is supported by cibuildwheel but rarely used in practice.