Use Py_ssize_t type for number of arguments

Issue #27848: use Py_ssize_t rather than C int for the number of function
positional and keyword arguments.

Include/abstract.h

@@ -280,7 +280,7 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
         Return the result on success. Raise an exception on return NULL on
         error. */
      PyAPI_FUNC(PyObject *) _PyObject_FastCallDict(PyObject *func,
-                                                   PyObject **args, int nargs,
+                                                   PyObject **args, Py_ssize_t nargs,
                                                    PyObject *kwargs);
 
 #define _PyObject_FastCall(func, args, nargs) \

Include/funcobject.h

@@ -61,7 +61,8 @@ PyAPI_FUNC(int) PyFunction_SetAnnotations(PyObject *, PyObject *);
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject *) _PyFunction_FastCallDict(
     PyObject *func,
-    PyObject **args, int nargs,
+    PyObject **args,
+    Py_ssize_t nargs,
     PyObject *kwargs);
 #endif
 

Include/methodobject.h

@@ -39,7 +39,8 @@ PyAPI_FUNC(PyObject *) PyCFunction_Call(PyObject *, PyObject *, PyObject *);
 
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject *) _PyCFunction_FastCallDict(PyObject *func,
-    PyObject **args, int nargs,
+    PyObject **args,
+    Py_ssize_t nargs,
     PyObject *kwargs);
 #endif
 

Objects/abstract.c

@@ -2255,7 +2255,7 @@ _PyStack_AsTuple(PyObject **stack, Py_ssize_t nargs)
 }
 
 PyObject *
-_PyObject_FastCallDict(PyObject *func, PyObject **args, int nargs,
+_PyObject_FastCallDict(PyObject *func, PyObject **args, Py_ssize_t nargs,
                        PyObject *kwargs)
 {
     ternaryfunc call;

Objects/methodobject.c

@@ -146,15 +146,20 @@ PyCFunction_Call(PyObject *func, PyObject *args, PyObject *kwds)
 }
 
 PyObject *
-_PyCFunction_FastCallDict(PyObject *func_obj, PyObject **args, int nargs,
+_PyCFunction_FastCallDict(PyObject *func_obj, PyObject **args, Py_ssize_t nargs,
                           PyObject *kwargs)
 {
-    PyCFunctionObject* func = (PyCFunctionObject*)func_obj;
+    PyCFunctionObject *func = (PyCFunctionObject*)func_obj;
     PyCFunction meth = PyCFunction_GET_FUNCTION(func);
     PyObject *self = PyCFunction_GET_SELF(func);
     PyObject *result;
     int flags;
 
+    assert(func != NULL);
+    assert(nargs >= 0);
+    assert(nargs == 0 || args != NULL);
+    assert(kwargs == NULL || PyDict_Check(kwargs));
+
     /* _PyCFunction_FastCallDict() must not be called with an exception set,
        because it may clear it (directly or indirectly) and so the
        caller loses its exception */

Python/bltinmodule.c

@@ -2095,7 +2095,7 @@ builtin_sorted(PyObject *self, PyObject *args, PyObject *kwds)
     PyObject *callable;
     static char *kwlist[] = {"iterable", "key", "reverse", 0};
     int reverse;
-    int nargs;
+    Py_ssize_t nargs;
 
     /* args 1-3 should match listsort in Objects/listobject.c */
     if (!PyArg_ParseTupleAndKeywords(args, kwds, "O|Oi:sorted",