gh-108014: Add Py_IsFinalizing() function (#108032)

Co-authored-by: Serhiy Storchaka <[email protected]>

Doc/c-api/init.rst

@@ -373,6 +373,14 @@ Initializing and finalizing the interpreter
    :c:func:`Py_Initialize` is called again.
 
 
+.. c:function:: int Py_IsFinalizing()
+
+   Return true (non-zero) if the main Python interpreter is
+   :term:`shutting down <interpreter shutdown>`. Return false (zero) otherwise.
+
+   .. versionadded:: 3.13
+
+
 .. c:function:: int Py_FinalizeEx()
 
    Undo all initializations made by :c:func:`Py_Initialize` and subsequent use of
@@ -852,7 +860,7 @@ code, or when embedding the Python interpreter:
    .. note::
       Calling this function from a thread when the runtime is finalizing
       will terminate the thread, even if the thread was not created by Python.
-      You can use :c:func:`!_Py_IsFinalizing` or :func:`sys.is_finalizing` to
+      You can use :c:func:`Py_IsFinalizing` or :func:`sys.is_finalizing` to
       check if the interpreter is in process of being finalized before calling
       this function to avoid unwanted termination.
 
@@ -898,7 +906,7 @@ with sub-interpreters:
    .. note::
       Calling this function from a thread when the runtime is finalizing
       will terminate the thread, even if the thread was not created by Python.
-      You can use :c:func:`!_Py_IsFinalizing` or :func:`sys.is_finalizing` to
+      You can use :c:func:`Py_IsFinalizing` or :func:`sys.is_finalizing` to
       check if the interpreter is in process of being finalized before calling
       this function to avoid unwanted termination.
 
@@ -1180,7 +1188,7 @@ All of the following functions must be called after :c:func:`Py_Initialize`.
    .. note::
       Calling this function from a thread when the runtime is finalizing
       will terminate the thread, even if the thread was not created by Python.
-      You can use :c:func:`!_Py_IsFinalizing` or :func:`sys.is_finalizing` to
+      You can use :c:func:`Py_IsFinalizing` or :func:`sys.is_finalizing` to
       check if the interpreter is in process of being finalized before calling
       this function to avoid unwanted termination.
 

Doc/library/sys.rst

@@ -1121,8 +1121,8 @@ always available.
 
 .. function:: is_finalizing()
 
-   Return :const:`True` if the Python interpreter is
-   :term:`shutting down <interpreter shutdown>`, :const:`False` otherwise.
+   Return :const:`True` if the main Python interpreter is
+   :term:`shutting down <interpreter shutdown>`. Return :const:`False` otherwise.
 
    .. versionadded:: 3.5
 

Doc/whatsnew/3.13.rst

@@ -832,6 +832,10 @@ New Features
   not needed.
   (Contributed by Victor Stinner in :gh:`106004`.)
 
+* Add :c:func:`Py_IsFinalizing` function: check if the main Python interpreter is
+  :term:`shutting down <interpreter shutdown>`.
+  (Contributed by Victor Stinner in :gh:`108014`.)
+
 Porting to Python 3.13
 ----------------------
 

Include/cpython/pylifecycle.h

@@ -81,3 +81,5 @@ PyAPI_FUNC(PyStatus) Py_NewInterpreterFromConfig(
 typedef void (*atexit_datacallbackfunc)(void *);
 PyAPI_FUNC(int) PyUnstable_AtExit(
         PyInterpreterState *, atexit_datacallbackfunc, void *);
+
+PyAPI_FUNC(int) Py_IsFinalizing(void);

Include/internal/pycore_pylifecycle.h

@@ -98,7 +98,6 @@ extern int _Py_FdIsInteractive(FILE *fp, PyObject *filename);
 extern const char* _Py_gitidentifier(void);
 extern const char* _Py_gitversion(void);
 
-extern int _Py_IsFinalizing(void);
 PyAPI_FUNC(int) _Py_IsInterpreterFinalizing(PyInterpreterState *interp);
 
 /* Random */

Misc/NEWS.d/next/C API/2023-08-16-17-16-19.gh-issue-108014.wXN3CF.rst

@@ -0,0 +1,2 @@
+Add :c:func:`Py_IsFinalizing` function: check if the main Python interpreter is
+:term:`shutting down <interpreter shutdown>`. Patch by Victor Stinner.

Modules/_asynciomodule.c

@@ -529,7 +529,7 @@ future_init(FutureObj *fut, PyObject *loop)
     }
     if (is_true && !_Py_IsInterpreterFinalizing(_PyInterpreterState_GET())) {
         /* Only try to capture the traceback if the interpreter is not being
-           finalized.  The original motivation to add a `_Py_IsFinalizing()`
+           finalized.  The original motivation to add a `Py_IsFinalizing()`
            call was to prevent SIGSEGV when a Future is created in a __del__
            method, which is called during the interpreter shutdown and the
            traceback module is already unloaded.

Python/pylifecycle.c

@@ -129,7 +129,7 @@ _PyRuntime_Finalize(void)
 }
 
 int
-_Py_IsFinalizing(void)
+Py_IsFinalizing(void)
 {
     return _PyRuntimeState_GetFinalizing(&_PyRuntime) != NULL;
 }

Python/sysmodule.c

@@ -2095,7 +2095,7 @@ static PyObject *
 sys_is_finalizing_impl(PyObject *module)
 /*[clinic end generated code: output=735b5ff7962ab281 input=f0df747a039948a5]*/
 {
-    return PyBool_FromLong(_Py_IsFinalizing());
+    return PyBool_FromLong(Py_IsFinalizing());
 }
 
 #ifdef Py_STATS