Use PyThreadState_GetUnchecked on Python 3.13

(cherry picked from commit f3face0)

Author: filmor

src/runtime/Runtime.Delegates.cs

@@ -23,7 +23,17 @@ static Delegates()
             Py_EndInterpreter = (delegate* unmanaged[Cdecl]<PyThreadState*, void>)GetFunctionByName(nameof(Py_EndInterpreter), GetUnmanagedDll(_PythonDll));
             PyThreadState_New = (delegate* unmanaged[Cdecl]<PyInterpreterState*, PyThreadState*>)GetFunctionByName(nameof(PyThreadState_New), GetUnmanagedDll(_PythonDll));
             PyThreadState_Get = (delegate* unmanaged[Cdecl]<PyThreadState*>)GetFunctionByName(nameof(PyThreadState_Get), GetUnmanagedDll(_PythonDll));
-            _PyThreadState_UncheckedGet = (delegate* unmanaged[Cdecl]<PyThreadState*>)GetFunctionByName(nameof(_PyThreadState_UncheckedGet), GetUnmanagedDll(_PythonDll));
+            try
+            {
+                // Up until Python 3.13, this function was private and named
+                // slightly differently.
+                PyThreadState_GetUnchecked = (delegate* unmanaged[Cdecl]<PyThreadState*>)GetFunctionByName("_PyThreadState_UncheckedGet", GetUnmanagedDll(_PythonDll));
+            }
+            catch (MissingMethodException)
+            {
+
+                PyThreadState_GetUnchecked = (delegate* unmanaged[Cdecl]<PyThreadState*>)GetFunctionByName(nameof(PyThreadState_GetUnchecked), GetUnmanagedDll(_PythonDll));
+            }
             try
             {
                 PyGILState_Check = (delegate* unmanaged[Cdecl]<int>)GetFunctionByName(nameof(PyGILState_Check), GetUnmanagedDll(_PythonDll));
@@ -316,7 +326,7 @@ static Delegates()
         internal static delegate* unmanaged[Cdecl]<PyThreadState*, void> Py_EndInterpreter { get; }
         internal static delegate* unmanaged[Cdecl]<PyInterpreterState*, PyThreadState*> PyThreadState_New { get; }
         internal static delegate* unmanaged[Cdecl]<PyThreadState*> PyThreadState_Get { get; }
-        internal static delegate* unmanaged[Cdecl]<PyThreadState*> _PyThreadState_UncheckedGet { get; }
+        internal static delegate* unmanaged[Cdecl]<PyThreadState*> PyThreadState_GetUnchecked { get; }
         internal static delegate* unmanaged[Cdecl]<int> PyGILState_Check { get; }
         internal static delegate* unmanaged[Cdecl]<PyGILState> PyGILState_Ensure { get; }
         internal static delegate* unmanaged[Cdecl]<PyGILState, void> PyGILState_Release { get; }

src/runtime/Runtime.cs

@@ -319,7 +319,7 @@ internal static void Shutdown()
                 // Then release the GIL for good, if there is somehting to release
                 // Use the unchecked version as the checked version calls `abort()`
                 // if the current state is NULL.
-                if (_PyThreadState_UncheckedGet() != (PyThreadState*)0)
+                if (PyThreadState_GetUnchecked() != (PyThreadState*)0)
                 {
                     PyEval_SaveThread();
                 }
@@ -745,7 +745,7 @@ internal static T TryUsingDll<T>(Func<T> op)
         internal static PyThreadState* PyThreadState_Get() => Delegates.PyThreadState_Get();
 
 
-        internal static PyThreadState* _PyThreadState_UncheckedGet() => Delegates._PyThreadState_UncheckedGet();
+        internal static PyThreadState* PyThreadState_GetUnchecked() => Delegates.PyThreadState_GetUnchecked();
 
 
         internal static int PyGILState_Check() => Delegates.PyGILState_Check();