This is effectively an un-revert of #11617 and #12024 (reverted in #12159). Portions of those were merged in other PRs (with lower risk) and this represents the remainder. Note that I found 3 different bugs in the original PRs and have fixed them here.
The function has no return value.
Fix the following warning on Windows:
python\ceval.c(180): warning C4098: 'PyEval_InitThreads':
'void' function returning a value
* Revert "bpo-36097: Use only public C-API in the_xxsubinterpreters module (adding as necessary). (#12003)"
This reverts commit bcfa450f21.
* Revert "bpo-33608: Simplify ceval's DISPATCH by hoisting eval_breaker ahead of time. (gh-12062)"
This reverts commit bda918bf65.
* Revert "bpo-33608: Use _Py_AddPendingCall() in _PyCrossInterpreterData_Release(). (gh-12024)"
This reverts commit b05b711a2c.
* Revert "bpo-33608: Factor out a private, per-interpreter _Py_AddPendingCall(). (GH-11617)"
This reverts commit ef4ac967e2.
Ensure that the main interpreter is active (in the main thread) for signal-handling operations. This is increasingly relevant as people use subinterpreters more.
https://bugs.python.org/issue35724
This change separates the signal handling trigger in the eval loop from the "pending calls" machinery. There is no semantic change and the difference in performance is insignificant.
The change makes both components less confusing. It also eliminates the risk of changes to the pending calls affecting signal handling. This is particularly relevant for some upcoming pending calls changes I have in the works.
In _localemodule.c and selectmodule.c, remove dead code that would
cause double decrefs if run.
In addition, replace PyList_SetItem() with PyList_SET_ITEM() in cases
where a new list is populated and there is no possibility of an error.
In addition, check if the list changed size in the loop in array_array_fromlist().
* _PyTuple_ITEMS() gives access to the tuple->ob_item field and cast the
first argument to PyTupleObject*. This internal macro is only usable if
Py_BUILD_CORE is defined.
* Replace &PyTuple_GET_ITEM(ob, 0) with _PyTuple_ITEMS(ob).
* Replace PyTuple_GET_ITEM(op, 1) with &_PyTuple_ITEMS(ob)[1].
