gh-140550: Enable limited C API tests on Free Threading in test_cext

[vstinner]

Enable limited C API tests on Free Threading in test_cext and test_cppext: test Py_TARGET_ABI3T macro.

• Convert test_cppext to PySlot API using PySlot_PTR_STATIC().
• Define Py_MOD_GIL_NOT_USED in test_cext and test_cppext.
• Disable C++ test_virtual_object() if Py_TARGET_ABI3T is defined.
• Remove ";" from PyABIInfo_VAR macro definition, since "PyABIInfo_VAR(abi_info);" added two ";;" which is illegal in C++03.

• Issue: Implement PEP 793 – PyModExport #140550

[vstinner]

cc @encukou

[vstinner]

!buildbot

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @vstinner for commit 9bed8d3 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F157493%2Fmerge

If you want to schedule another build, you need to add the 🔨 test-with-buildbots label again.

[vstinner]

test_limited_cpp03ext() of test_cppext failed on ARM64 macOS:

  /usr/bin/clang++ -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -fno-strict-overflow -Wsign-compare -g -Og -Wall -I/Users/buildbot/buildarea/pull_request.pablogsal-macos-m1.macos-with-brew/build/build/test_python_61414æ/tempcwd/env/include -I/Users/buildbot/buildarea/pull_request.pablogsal-macos-m1.macos-with-brew/build/Include -I/Users/buildbot/buildarea/pull_request.pablogsal-macos-m1.macos-with-brew/build -c extension.cpp -o build/temp.macosx-26.6-arm64-cpython-316-pydebug/extension.o -Werror -DMODULE_NAME=_test_limited_cpp03ext -std=c++03 -pedantic-errors -Wno-long-long -DPy_LIMITED_API=0x31000a0
  extension.cpp:332:36: error: cast between pointer-to-function and pointer-to-object is an extension [-Werror,-Wpedantic]
    332 |     PySlot_PTR_STATIC(Py_mod_exec, (void*)_testcppext_exec),
        |                                    ^~~~~~~~~~~~~~~~~~~~~~~
  /Users/buildbot/buildarea/pull_request.pablogsal-macos-m1.macos-with-brew/build/Include/slots.h:54:59: note: expanded from macro 'PySlot_PTR_STATIC'
     54 |     {(NAME), PySlot_INTPTR | PySlot_STATIC, {0}, {(void*)(VALUE)}}
        |                                                           ^~~~~

test.pythoninfo logs CC.version: Apple clang version 21.0.0 (clang-2100.1.1.101), so I guess that it's clang++ 21.0.0. test.pythoninfo should also lox CXX.version.

I supposed that we should disable -Wpedantic on PySlot defintions, as do already on the PyModuleDef_Slot definitions.

[encukou]

I supposed that we should disable -Wpedantic on PySlot defintions

Only on PySlot_PTR & PySlot_PTR_STATIC (that is, the shims added for compatibility with C++11, but trade off pedantic type safety -- exactly as the test found out).

[vstinner]

x86-64 MacOS Intel NoGIL PR failed the same way: test_limited_cpp03ext() of test_cppext failed with:

  /usr/bin/clang++ -fno-omit-frame-pointer -mno-omit-leaf-frame-pointer -fno-strict-overflow -Wsign-compare -g -Og -Wall -I/Users/buildbot/buildarea/pull_request.itamaro-macos-intel-aws.nogil/build/build/test_python_58460æ/tempcwd/env/include -I/Users/buildbot/buildarea/pull_request.itamaro-macos-intel-aws.nogil/build/Include -I/Users/buildbot/buildarea/pull_request.itamaro-macos-intel-aws.nogil/build -c extension.cpp -o build/temp.macosx-13.7-x86_64-cpython-316t-pydebug/extension.o -Werror -DMODULE_NAME=_test_limited_cpp03ext -std=c++03 -pedantic-errors -Wno-long-long -DPy_LIMITED_API=0x31000a0
  extension.cpp:332:36: error: cast between pointer-to-function and pointer-to-object is an extension [-Werror,-Wpedantic]
      PySlot_PTR_STATIC(Py_mod_exec, (void*)_testcppext_exec),
                                     ^~~~~~~~~~~~~~~~~~~~~~~
  /Users/buildbot/buildarea/pull_request.itamaro-macos-intel-aws.nogil/build/Include/slots.h:54:59: note: expanded from macro 'PySlot_PTR_STATIC'
      {(NAME), PySlot_INTPTR | PySlot_STATIC, {0}, {(void*)(VALUE)}}
                                                            ^~~~~

test_cppext uses clang++. test.pythoninfo says CC.version: Apple clang version 15.0.0 (clang-1500.1.0.2.5).

[vstinner]

!buildbot ARM64 macOS PR

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @vstinner for commit 5b05582 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F157493%2Fmerge

The command will test the builders whose names match following regular expression: ARM64 macOS PR

The builders matched are:

• ARM64 macOS PR

[vstinner]

!buildbot x86-64 MacOS Intel NoGIL PR

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @vstinner for commit 5b05582 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F157493%2Fmerge

The command will test the builders whose names match following regular expression: x86-64 MacOS Intel NoGIL PR

The builders matched are:

• x86-64 MacOS Intel NoGIL PR

[vstinner]

I pushed a fix for the warning on "cast between pointer-to-function and pointer-to-object is an extension" in pedantic mode.

[vstinner]

!buildbot x86-64 MacOS Intel NoGIL PR

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @vstinner for commit 5b05582 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F157493%2Fmerge

The command will test the builders whose names match following regular expression: x86-64 MacOS Intel NoGIL PR

The builders matched are:

• x86-64 MacOS Intel NoGIL PR

[vstinner]

Good, the test suite passed on "buildbot/ARM64 macOS PR" and "buildbot/x86-64 MacOS Intel NoGIL PR".

[vstinner]

I will wait until #157539 is merged, and then merge this change on top of it.

[miss-islington-app]

Thanks @vstinner for the PR 🌮🎉.. I'm working now to backport this PR to: 3.15.
🐍🍒⛏🤖

[bedevere-app]

GH-157560 is a backport of this pull request to the 3.15 branch.