rhbz#2097411 Avoid obsolete PyThreadState_Delete crashing Python 3.11

1fb53a637597f76bea86514b62ddfad34f60c889 "pyuno_loader::CreateInstance: delete
the initial PyThreadState" had added the PyThreadState_Delete for claimed
benefits but whose details appear lost to history (cf. the comment thread
starting at
<https://gerrit.libreoffice.org/c/core/+/3452/2#message-602ff52abdd1c95fd5c13cfe405b5fadd0048c5f>
"pyuno_loader::CreateInstance: delete the initial PyThreadState").  And at least
a recent master Linux --enable-python=fully-internal build with the bundled
Python 3.8.12 appears to succeed `make check` just fine with the
PyThreadState_Delete temporarily removed.

But on the other hand, building against upcoming Python 3.11 now started to make
CppunitTest_services fail with

> Fatal Python error: init_threadstate: thread state already initialized
> Python runtime state: initialized
> Thread 0x0000ffff81c8b020 (most recent call first):
>   <no Python frame>
> Fatal exception: Signal 6
> Stack:
> /builddir/build/BUILD/libreoffice-7.3.4.2/instdir/program/libuno_sal.so.3(+0x37c28)[0xffff81be7c28]
> /builddir/build/BUILD/libreoffice-7.3.4.2/instdir/program/libuno_sal.so.3(+0x37e40)[0xffff81be7e40]
> linux-vdso.so.1(__kernel_rt_sigreturn+0x0)[0xffff81ccb7ec]
> /lib64/libc.so.6(+0x82878)[0xffff81742878]
> /lib64/libc.so.6(raise+0x20)[0xffff816fae00]
> /lib64/libc.so.6(abort+0xe8)[0xffff816e72b8]
> /lib64/libpython3.11.so.1.0(+0x104e28)[0xfffee4de4e28]
> /lib64/libpython3.11.so.1.0(+0x105200)[0xfffee4de5200]
> /lib64/libpython3.11.so.1.0(PyThread_get_thread_native_id+0x0)[0xfffee4ed6764]
> /lib64/libpython3.11.so.1.0(PyThreadState_New+0x14)[0xfffee4ed6628]
> /builddir/build/BUILD/libreoffice-7.3.4.2/instdir/program/libpyuno.so(_ZN5pyuno14PyThreadAttachC2EP3_is+0x78)[0xfffee4c8c52c]
> /builddir/build/BUILD/libreoffice-7.3.4.2/instdir/program/libpythonloaderlo.so(pyuno_Loader_get_implementation+0x5c)[0xfffee5243060]
> /builddir/build/BUILD/libreoffice-7.3.4.2/instdir/program/libuno_cppuhelpergcc3.so.3(+0x544b4)[0xffff815544b4]

because of the PyThreadState_Delete.  (The deleted PyThreadState, while not
reused again directly, is still recorded in the state obtained from
PyInterpreterState_Head() later.)

So conservatively keep the PyThreadState_Delete of unclear benefit for older
Python versions and only drop it for 3.11 where it is known to have negative
effects now.

Change-Id: I9b99f1e947f0b165ddc95c2bfbd764858dda39db
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/136006
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/pyuno/source/loader/pyuno_loader.cxx b/pyuno/source/loader/pyuno_loader.cxx
index c9b8248c1b25..da0467f450c6 100644
--- a/pyuno/source/loader/pyuno_loader.cxx
+++ b/pyuno/source/loader/pyuno_loader.cxx
@@ -229,10 +229,12 @@ void pythonInit() {
 
     PyThreadState *tstate = PyThreadState_Get();
     PyEval_ReleaseThread( tstate );
+#if PY_VERSION_HEX < 0x030B0000
     // This tstate is never used again, so delete it here.
     // This prevents an assertion in PyThreadState_Swap on the
     // PyThreadAttach below.
     PyThreadState_Delete(tstate);
+#endif
 }
 
 }