bpo-40792: Make the result of PyNumber_Index() always having exact type int. (GH-20443)

Previously, the result could have been an instance of a subclass of int.

Also revert bpo-26202 and make attributes start, stop and step of the range
object having exact type int.

Add private function _PyNumber_Index() which preserves the old behavior
of PyNumber_Index() for performance to use it in the conversion functions
like PyLong_AsLong().

1 files changed, 3 insertions, 3 deletions

diff --git a/Modules/clinic/_struct.c.h b/Modules/clinic/_struct.c.h
index 874f30a..1cfaef3 100644
--- a/Modules/clinic/_struct.c.h
+++ b/Modules/clinic/_struct.c.h
@@ -126,7 +126,7 @@ Struct_unpack_from(PyStructObject *self, PyObject *const *args, Py_ssize_t nargs
     }
     {
         Py_ssize_t ival = -1;
-        PyObject *iobj = PyNumber_Index(args[1]);
+        PyObject *iobj = _PyNumber_Index(args[1]);
         if (iobj != NULL) {
             ival = PyLong_AsSsize_t(iobj);
             Py_DECREF(iobj);
@@ -312,7 +312,7 @@ unpack_from(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject
     }
     {
         Py_ssize_t ival = -1;
-        PyObject *iobj = PyNumber_Index(args[2]);
+        PyObject *iobj = _PyNumber_Index(args[2]);
         if (iobj != NULL) {
             ival = PyLong_AsSsize_t(iobj);
             Py_DECREF(iobj);
@@ -376,4 +376,4 @@ exit:
 
     return return_value;
 }
-/*[clinic end generated code: output=1205daf7f616f0cf input=a9049054013a1b77]*/
+/*[clinic end generated code: output=8089792d8ed0c1be input=a9049054013a1b77]*/