MAINT: python 3.11 support

[tylerjereddy]

Python 3.11 RC1 is guaranteed to be ABI stable, so it is safe to start thinking/testing for compatibility there.

Currently, I see some pybind11-related failures like this during pykokkos-base build:

| [ 75%] Building CXX object CMakeFiles/libpykokkos-core.dir/Unity/unity_1_cxx.cxx.o
| In file included from /tmp/pykokkos-base/external/pybind11/include/pybind11/cast.h:16,
|                  from /tmp/pykokkos-base/external/pybind11/include/pybind11/attr.h:13,
|                  from /tmp/pykokkos-base/external/pybind11/include/pybind11/pybind11.h:45,
|                  from /tmp/pykokkos-base/include/common.hpp:54,
|                  from /tmp/pykokkos-base/include/traits.hpp:47,
|                  from /tmp/pykokkos-base/_skbuild/linux-x86_64-3.11/cmake-build/src/variants/views.cpp:3,
|                  from /tmp/pykokkos-base/_skbuild/linux-x86_64-3.11/cmake-build/CMakeFiles/libpykokkos-core.dir/Unity/unity_1_cxx.cxx:3:
| /tmp/pykokkos-base/external/pybind11/include/pybind11/detail/type_caster_base.h: In function ‘std::string pybind11::detail::error_string()’:
| /tmp/pykokkos-base/external/pybind11/include/pybind11/detail/type_caster_base.h:448:36: error: invalid use of incomplete type ‘PyFrameObject’ {aka ‘struct _frame’}
|   448 |                 "  " + handle(frame->f_code->co_filename).cast<std::string>() +
|       |                                

If you want to reproduce you can i.e., modify the pykokkos repo CI:

--- a/.github/workflows/main_ci.yml
+++ b/.github/workflows/main_ci.yml
@@ -13,7 +13,7 @@ jobs:
     strategy:
       matrix:
         platform: [ubuntu-latest]
-        python-version: ["3.8", "3.9", "3.10"]
+        python-version: ["3.11.0-rc.1"]
     runs-on: ${{ matrix.platform }}
     steps:
       - uses: actions/checkout@v3

and run act -j test_pykokkos

[jrmadsen]

$20 says that's fixed in 3.11.0-rc2. This has nothing to do with the ABI, it's a header include issue. They aren't going to break every package which uses pybind11 for that.

[tylerjereddy]

How old is /tmp/pykokkos-base/external/pybind11 that gets vendored?

My first bet would have been that pybind11 would have shimmed around that by now. I'll try to check that later tonight. Most other large packages I've seen are already passing tests with pybind11 + 3.11, so it is a safe bet that we just need to bump pybind11 I think.

[jrmadsen]

I think I just used the current main or stable branch when I create the repo. No special changes, you probably just need to do a git pull inside the submodule. Looks like it was noted and fixed in Oct 2021:

pybind/pybind11#3367

pybind/pybind11#3368

[tylerjereddy]

Looks all good with 3.11rc1 over in kokkos/pykokkos#74 now. I'll leave this open as a reminder to update the submodule in this repo, then can remove the manual submodule update over there.

[tylerjereddy]

I guess we might want a single 3.11rc1 job in this repo as well? I'll try to help resolve the current CI issues here first though, before expanding more.