bpo-37483: add _PyObject_CallOneArg() function (#14558)

20 files changed, 59 insertions, 80 deletions

diff --git a/Modules/_asynciomodule.c b/Modules/_asynciomodule.c
index 4caf3a4..443acc5 100644
--- a/Modules/_asynciomodule.c
+++ b/Modules/_asynciomodule.c
@@ -141,8 +141,7 @@ _is_coroutine(PyObject *coro)
        Do this check after 'future_init()'; in case we need to raise
        an error, __del__ needs a properly initialized object.
     */
-    PyObject *res = PyObject_CallFunctionObjArgs(
-        asyncio_iscoroutine_func, coro, NULL);
+    PyObject *res = _PyObject_CallOneArg(asyncio_iscoroutine_func, coro);
     if (res == NULL) {
         return -1;
     }
@@ -1286,8 +1285,7 @@ static PyObject *
 _asyncio_Future__repr_info_impl(FutureObj *self)
 /*[clinic end generated code: output=fa69e901bd176cfb input=f21504d8e2ae1ca2]*/
 {
-    return PyObject_CallFunctionObjArgs(
-        asyncio_future_repr_info_func, self, NULL);
+    return _PyObject_CallOneArg(asyncio_future_repr_info_func, (PyObject *)self);
 }
 
 static PyObject *
@@ -1364,7 +1362,7 @@ FutureObj_finalize(FutureObj *fut)
 
     func = _PyObject_GetAttrId(fut->fut_loop, &PyId_call_exception_handler);
     if (func != NULL) {
-        PyObject *res = PyObject_CallFunctionObjArgs(func, context, NULL);
+        PyObject *res = _PyObject_CallOneArg(func, context);
         if (res == NULL) {
             PyErr_WriteUnraisable(func);
         }
@@ -2104,13 +2102,13 @@ _asyncio_Task_current_task_impl(PyTypeObject *type, PyObject *loop)
             Py_DECREF(current_task_func);
             return NULL;
         }
-        ret = PyObject_CallFunctionObjArgs(current_task_func, loop, NULL);
+        ret = _PyObject_CallOneArg(current_task_func, loop);
         Py_DECREF(current_task_func);
         Py_DECREF(loop);
         return ret;
     }
     else {
-        ret = PyObject_CallFunctionObjArgs(current_task_func, loop, NULL);
+        ret = _PyObject_CallOneArg(current_task_func, loop);
         Py_DECREF(current_task_func);
         return ret;
     }
@@ -2146,7 +2144,7 @@ _asyncio_Task_all_tasks_impl(PyTypeObject *type, PyObject *loop)
         return NULL;
     }
 
-    res = PyObject_CallFunctionObjArgs(all_tasks_func, loop, NULL);
+    res = _PyObject_CallOneArg(all_tasks_func, loop);
     Py_DECREF(all_tasks_func);
     return res;
 }
@@ -2159,8 +2157,7 @@ static PyObject *
 _asyncio_Task__repr_info_impl(TaskObj *self)
 /*[clinic end generated code: output=6a490eb66d5ba34b input=3c6d051ed3ddec8b]*/
 {
-    return PyObject_CallFunctionObjArgs(
-        asyncio_task_repr_info_func, self, NULL);
+    return _PyObject_CallOneArg(asyncio_task_repr_info_func, (PyObject *)self);
 }
 
 /*[clinic input]
@@ -2411,7 +2408,7 @@ TaskObj_finalize(TaskObj *task)
 
     func = _PyObject_GetAttrId(task->task_loop, &PyId_call_exception_handler);
     if (func != NULL) {
-        PyObject *res = PyObject_CallFunctionObjArgs(func, context, NULL);
+        PyObject *res = _PyObject_CallOneArg(func, context);
         if (res == NULL) {
             PyErr_WriteUnraisable(func);
         }
@@ -2543,7 +2540,7 @@ task_set_error_soon(TaskObj *task, PyObject *et, const char *format, ...)
         return NULL;
     }
 
-    PyObject *e = PyObject_CallFunctionObjArgs(et, msg, NULL);
+    PyObject *e = _PyObject_CallOneArg(et, msg);
     Py_DECREF(msg);
     if (e == NULL) {
         return NULL;
diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 45169ec..cc7d3cf 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -512,8 +512,7 @@ deque_copy(PyObject *deque, PyObject *Py_UNUSED(ignored))
         return NULL;
     }
     if (old_deque->maxlen < 0)
-        result = PyObject_CallFunctionObjArgs((PyObject *)(Py_TYPE(deque)),
-                                              deque, NULL);
+        result = _PyObject_CallOneArg((PyObject *)(Py_TYPE(deque)), deque);
     else
         result = PyObject_CallFunction((PyObject *)(Py_TYPE(deque)), "Oi",
                                        deque, old_deque->maxlen, NULL);
diff --git a/Modules/_csv.c b/Modules/_csv.c
index 014cbb4..9653ff9 100644
--- a/Modules/_csv.c
+++ b/Modules/_csv.c
@@ -1240,7 +1240,7 @@ csv_writerow(WriterObj *self, PyObject *seq)
     if (line == NULL) {
         return NULL;
     }
-    result = PyObject_CallFunctionObjArgs(self->write, line, NULL);
+    result = _PyObject_CallOneArg(self->write, line);
     Py_DECREF(line);
     return result;
 }
diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c
index 6766524..973a654 100644
--- a/Modules/_ctypes/callproc.c
+++ b/Modules/_ctypes/callproc.c
@@ -925,7 +925,7 @@ static PyObject *GetResult(PyObject *restype, void *result, PyObject *checker)
     if (!checker || !retval)
         return retval;
 
-    v = PyObject_CallFunctionObjArgs(checker, retval, NULL);
+    v = _PyObject_CallOneArg(checker, retval);
     if (v == NULL)
         _PyTraceback_Add("GetResult", "_ctypes/callproc.c", __LINE__-2);
     Py_DECREF(retval);
@@ -1118,7 +1118,7 @@ PyObject *_ctypes_callproc(PPROC pProc,
         if (argtypes && argtype_count > i) {
             PyObject *v;
             converter = PyTuple_GET_ITEM(argtypes, i);
-            v = PyObject_CallFunctionObjArgs(converter, arg, NULL);
+            v = _PyObject_CallOneArg(converter, arg);
             if (v == NULL) {
                 _ctypes_extend_error(PyExc_ArgError, "argument %zd: ", i+1);
                 goto cleanup;
@@ -1795,7 +1795,7 @@ pointer(PyObject *self, PyObject *arg)
 
     typ = PyDict_GetItemWithError(_ctypes_ptrtype_cache, (PyObject *)Py_TYPE(arg));
     if (typ) {
-        return PyObject_CallFunctionObjArgs(typ, arg, NULL);
+        return _PyObject_CallOneArg(typ, arg);
     }
     else if (PyErr_Occurred()) {
         return NULL;
@@ -1803,7 +1803,7 @@ pointer(PyObject *self, PyObject *arg)
     typ = POINTER(NULL, (PyObject *)Py_TYPE(arg));
     if (typ == NULL)
         return NULL;
-    result = PyObject_CallFunctionObjArgs(typ, arg, NULL);
+    result = _PyObject_CallOneArg(typ, arg);
     Py_DECREF(typ);
     return result;
 }
diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index ee1b5e5..b93ec3d 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -2696,7 +2696,7 @@ treebuilder_append_event(TreeBuilderObject *self, PyObject *action,
         PyObject *event = PyTuple_Pack(2, action, node);
         if (event == NULL)
             return -1;
-        res = _PyObject_FastCall(self->events_append, &event, 1);
+        res = _PyObject_CallOneArg(self->events_append, event);
         Py_DECREF(event);
         if (res == NULL)
             return -1;
@@ -2859,7 +2859,7 @@ treebuilder_handle_comment(TreeBuilderObject* self, PyObject* text)
     }
 
     if (self->comment_factory) {
-        comment = _PyObject_FastCall(self->comment_factory, &text, 1);
+        comment = _PyObject_CallOneArg(self->comment_factory, text);
         if (!comment)
             return NULL;
 
@@ -3197,7 +3197,7 @@ expat_set_error(enum XML_Error error_code, Py_ssize_t line, Py_ssize_t column,
     if (errmsg == NULL)
         return;
 
-    error = _PyObject_FastCall(st->parseerror_obj, &errmsg, 1);
+    error = _PyObject_CallOneArg(st->parseerror_obj, errmsg);
     Py_DECREF(errmsg);
     if (!error)
         return;
@@ -3260,7 +3260,7 @@ expat_default_handler(XMLParserObject* self, const XML_Char* data_in,
                 (TreeBuilderObject*) self->target, value
                 );
         else if (self->handle_data)
-            res = _PyObject_FastCall(self->handle_data, &value, 1);
+            res = _PyObject_CallOneArg(self->handle_data, value);
         else
             res = NULL;
         Py_XDECREF(res);
@@ -3371,7 +3371,7 @@ expat_data_handler(XMLParserObject* self, const XML_Char* data_in,
         /* shortcut */
         res = treebuilder_handle_data((TreeBuilderObject*) self->target, data);
     else if (self->handle_data)
-        res = _PyObject_FastCall(self->handle_data, &data, 1);
+        res = _PyObject_CallOneArg(self->handle_data, data);
     else
         res = NULL;
 
@@ -3398,7 +3398,7 @@ expat_end_handler(XMLParserObject* self, const XML_Char* tag_in)
     else if (self->handle_end) {
         tag = makeuniversal(self, tag_in);
         if (tag) {
-            res = _PyObject_FastCall(self->handle_end, &tag, 1);
+            res = _PyObject_CallOneArg(self->handle_end, tag);
             Py_DECREF(tag);
         }
     }
@@ -3485,7 +3485,7 @@ expat_end_ns_handler(XMLParserObject* self, const XML_Char* prefix_in)
         if (!prefix)
             return;
 
-        res = _PyObject_FastCall(self->handle_end_ns, &prefix, 1);
+        res = _PyObject_CallOneArg(self->handle_end_ns, prefix);
         Py_DECREF(prefix);
     }
 
@@ -3515,7 +3515,7 @@ expat_comment_handler(XMLParserObject* self, const XML_Char* comment_in)
         if (!comment)
             return;
 
-        res = _PyObject_FastCall(self->handle_comment, &comment, 1);
+        res = _PyObject_CallOneArg(self->handle_comment, comment);
     }
 
     Py_XDECREF(res);
diff --git a/Modules/_io/iobase.c b/Modules/_io/iobase.c
index fab4509..82cc776 100644
--- a/Modules/_io/iobase.c
+++ b/Modules/_io/iobase.c
@@ -557,7 +557,7 @@ _io__IOBase_readline_impl(PyObject *self, Py_ssize_t limit)
         PyObject *b;
 
         if (peek != NULL) {
-            PyObject *readahead = PyObject_CallFunctionObjArgs(peek, _PyLong_One, NULL);
+            PyObject *readahead = _PyObject_CallOneArg(peek, _PyLong_One);
             if (readahead == NULL) {
                 /* NOTE: PyErr_SetFromErrno() calls PyErr_CheckSignals()
                    when EINTR occurs so we needn't do it ourselves. */
diff --git a/Modules/_json.c b/Modules/_json.c
index e3aa997..38beb6f 100644
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -818,14 +818,14 @@ _parse_object_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t idx, Py_ss
     *next_idx_ptr = idx + 1;
 
     if (has_pairs_hook) {
-        val = PyObject_CallFunctionObjArgs(s->object_pairs_hook, rval, NULL);
+        val = _PyObject_CallOneArg(s->object_pairs_hook, rval);
         Py_DECREF(rval);
         return val;
     }
 
     /* if object_hook is not None: rval = object_hook(rval) */
     if (s->object_hook != Py_None) {
-        val = PyObject_CallFunctionObjArgs(s->object_hook, rval, NULL);
+        val = _PyObject_CallOneArg(s->object_hook, rval);
         Py_DECREF(rval);
         return val;
     }
@@ -931,7 +931,7 @@ _parse_constant(PyScannerObject *s, const char *constant, Py_ssize_t idx, Py_ssi
         return NULL;
 
     /* rval = parse_constant(constant) */
-    rval = PyObject_CallFunctionObjArgs(s->parse_constant, cstr, NULL);
+    rval = _PyObject_CallOneArg(s->parse_constant, cstr);
     idx += PyUnicode_GET_LENGTH(cstr);
     Py_DECREF(cstr);
     *next_idx_ptr = idx;
@@ -1030,7 +1030,7 @@ _match_number_unicode(PyScannerObject *s, PyObject *pystr, Py_ssize_t start, Py_
                                            idx - start);
         if (numstr == NULL)
             return NULL;
-        rval = PyObject_CallFunctionObjArgs(custom_func, numstr, NULL);
+        rval = _PyObject_CallOneArg(custom_func, numstr);
     }
     else {
         Py_ssize_t i, n;
@@ -1440,7 +1440,7 @@ encoder_encode_string(PyEncoderObject *s, PyObject *obj)
     if (s->fast_encode) {
         return s->fast_encode(NULL, obj);
     }
-    encoded = PyObject_CallFunctionObjArgs(s->encoder, obj, NULL);
+    encoded = _PyObject_CallOneArg(s->encoder, obj);
     if (encoded != NULL && !PyUnicode_Check(encoded)) {
         PyErr_Format(PyExc_TypeError,
                      "encoder() must return a string, not %.80s",
@@ -1526,7 +1526,7 @@ encoder_listencode_obj(PyEncoderObject *s, _PyAccu *acc,
                 return -1;
             }
         }
-        newobj = PyObject_CallFunctionObjArgs(s->defaultfn, obj, NULL);
+        newobj = _PyObject_CallOneArg(s->defaultfn, obj);
         if (newobj == NULL) {
             Py_XDECREF(ident);
             return -1;
diff --git a/Modules/_pickle.c b/Modules/_pickle.c
index 3adece0..d6d1250 100644
--- a/Modules/_pickle.c
+++ b/Modules/_pickle.c
@@ -359,7 +359,7 @@ _Pickle_FastCall(PyObject *func, PyObject *obj)
 {
     PyObject *result;
 
-    result = PyObject_CallFunctionObjArgs(func, obj, NULL);
+    result = _PyObject_CallOneArg(func, obj);
     Py_DECREF(obj);
     return result;
 }
@@ -420,7 +420,7 @@ call_method(PyObject *func, PyObject *self, PyObject *obj)
         return PyObject_CallFunctionObjArgs(func, self, obj, NULL);
     }
     else {
-        return PyObject_CallFunctionObjArgs(func, obj, NULL);
+        return _PyObject_CallOneArg(func, obj);
     }
 }
 
@@ -2296,7 +2296,7 @@ _Pickler_write_bytes(PicklerObject *self,
                 return -1;
             }
         }
-        result = PyObject_CallFunctionObjArgs(self->write, payload, NULL);
+        result = _PyObject_CallOneArg(self->write, payload);
         Py_XDECREF(mem);
         if (result == NULL) {
             return -1;
@@ -2504,8 +2504,7 @@ save_picklebuffer(PicklerObject *self, PyObject *obj)
     }
     int in_band = 1;
     if (self->buffer_callback != NULL) {
-        PyObject *ret = PyObject_CallFunctionObjArgs(self->buffer_callback,
-                                                     obj, NULL);
+        PyObject *ret = _PyObject_CallOneArg(self->buffer_callback, obj);
         if (ret == NULL) {
             return -1;
         }
@@ -4322,8 +4321,7 @@ save(PicklerObject *self, PyObject *obj, int pers_save)
      * regular reduction mechanism.
      */
     if (self->reducer_override != NULL) {
-        reduce_value = PyObject_CallFunctionObjArgs(self->reducer_override,
-                                                    obj, NULL);
+        reduce_value = _PyObject_CallOneArg(self->reducer_override, obj);
         if (reduce_value == NULL) {
             goto error;
         }
diff --git a/Modules/_sqlite/cache.c b/Modules/_sqlite/cache.c
index 4d41804..7552d1b 100644
--- a/Modules/_sqlite/cache.c
+++ b/Modules/_sqlite/cache.c
@@ -112,9 +112,8 @@ void pysqlite_cache_dealloc(pysqlite_Cache* self)
     Py_TYPE(self)->tp_free((PyObject*)self);
 }
 
-PyObject* pysqlite_cache_get(pysqlite_Cache* self, PyObject* args)
+PyObject* pysqlite_cache_get(pysqlite_Cache* self, PyObject* key)
 {
-    PyObject* key = args;
     pysqlite_Node* node;
     pysqlite_Node* ptr;
     PyObject* data;
@@ -184,6 +183,9 @@ PyObject* pysqlite_cache_get(pysqlite_Cache* self, PyObject* args)
             }
         }
 
+        /* We cannot replace this by _PyObject_CallOneArg() since
+         * PyObject_CallFunction() has a special case when using a
+         * single tuple as argument. */
         data = PyObject_CallFunction(self->factory, "O", key);
 
         if (!data) {
diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index 5ceeaf9..08604b9 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -310,7 +310,7 @@ PyObject* pysqlite_connection_cursor(pysqlite_Connection* self, PyObject* args,
         factory = (PyObject*)&pysqlite_CursorType;
     }
 
-    cursor = PyObject_CallFunctionObjArgs(factory, (PyObject *)self, NULL);
+    cursor = _PyObject_CallOneArg(factory, (PyObject *)self);
     if (cursor == NULL)
         return NULL;
     if (!PyObject_TypeCheck(cursor, &pysqlite_CursorType)) {
@@ -970,7 +970,7 @@ static void _trace_callback(void* user_arg, const char* statement_string)
     py_statement = PyUnicode_DecodeUTF8(statement_string,
             strlen(statement_string), "replace");
     if (py_statement) {
-        ret = PyObject_CallFunctionObjArgs((PyObject*)user_arg, py_statement, NULL);
+        ret = _PyObject_CallOneArg((PyObject*)user_arg, py_statement);
         Py_DECREF(py_statement);
     }
 
@@ -1465,16 +1465,9 @@ pysqlite_connection_iterdump(pysqlite_Connection* self, PyObject* args)
         goto finally;
     }
 
-    args = PyTuple_New(1);
-    if (!args) {
-        goto finally;
-    }
-    Py_INCREF(self);
-    PyTuple_SetItem(args, 0, (PyObject*)self);
-    retval = PyObject_CallObject(pyfn_iterdump, args);
+    retval = _PyObject_CallOneArg(pyfn_iterdump, (PyObject *)self);
 
 finally:
-    Py_XDECREF(args);
     Py_XDECREF(module);
     return retval;
 }
diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
index 38d94b2..e6fcac8 100644
--- a/Modules/_sqlite/cursor.c
+++ b/Modules/_sqlite/cursor.c
@@ -266,7 +266,7 @@ _pysqlite_fetch_one_row(pysqlite_Cursor* self)
                 item = PyBytes_FromStringAndSize(val_str, nbytes);
                 if (!item)
                     goto error;
-                converted = PyObject_CallFunction(converter, "O", item);
+                converted = _PyObject_CallOneArg(converter, item);
                 Py_DECREF(item);
             }
         } else {
diff --git a/Modules/_sqlite/microprotocols.c b/Modules/_sqlite/microprotocols.c
index c23b09f..59a5e22 100644
--- a/Modules/_sqlite/microprotocols.c
+++ b/Modules/_sqlite/microprotocols.c
@@ -92,7 +92,7 @@ pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
     Py_DECREF(key);
     if (adapter) {
         Py_INCREF(adapter);
-        adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
+        adapted = _PyObject_CallOneArg(adapter, obj);
         Py_DECREF(adapter);
         return adapted;
     }
@@ -105,7 +105,7 @@ pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
         return NULL;
     }
     if (adapter) {
-        adapted = PyObject_CallFunctionObjArgs(adapter, obj, NULL);
+        adapted = _PyObject_CallOneArg(adapter, obj);
         Py_DECREF(adapter);
 
         if (adapted == Py_None) {
@@ -124,7 +124,7 @@ pysqlite_microprotocols_adapt(PyObject *obj, PyObject *proto, PyObject *alt)
         return NULL;
     }
     if (adapter) {
-        adapted = PyObject_CallFunctionObjArgs(adapter, proto, NULL);
+        adapted = _PyObject_CallOneArg(adapter, proto);
         Py_DECREF(adapter);
 
         if (adapted == Py_None) {
diff --git a/Modules/_sre.c b/Modules/_sre.c
index d4fe588..f4f9d01 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -1082,7 +1082,7 @@ pattern_subx(PatternObject* self, PyObject* ptemplate, PyObject* string,
             match = pattern_new_match(self, &state, 1);
             if (!match)
                 goto error;
-            item = PyObject_CallFunctionObjArgs(filter, match, NULL);
+            item = _PyObject_CallOneArg(filter, match);
             Py_DECREF(match);
             if (!item)
                 goto error;
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 9281c68..d1c635a 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -2098,7 +2098,7 @@ cache_struct_converter(PyObject *fmt, PyStructObject **ptr)
         return 0;
     }
 
-    s_object = PyObject_CallFunctionObjArgs((PyObject *)(&PyStructType), fmt, NULL);
+    s_object = _PyObject_CallOneArg((PyObject *)(&PyStructType), fmt);
     if (s_object != NULL) {
         if (PyDict_GET_SIZE(cache) >= MAXCACHE)
             PyDict_Clear(cache);
diff --git a/Modules/_xxtestfuzz/fuzzer.c b/Modules/_xxtestfuzz/fuzzer.c
index 16104e4..2446e71 100644
--- a/Modules/_xxtestfuzz/fuzzer.c
+++ b/Modules/_xxtestfuzz/fuzzer.c
@@ -104,7 +104,7 @@ static int fuzz_json_loads(const char* data, size_t size) {
     if (input_bytes == NULL) {
         return 0;
     }
-    PyObject* parsed = PyObject_CallFunctionObjArgs(json_loads_method, input_bytes, NULL);
+    PyObject* parsed = _PyObject_CallOneArg(json_loads_method, input_bytes);
     if (parsed == NULL) {
         /* Ignore ValueError as the fuzzer will more than likely
            generate some invalid json and values */
@@ -263,7 +263,7 @@ static int fuzz_sre_match(const char* data, size_t size) {
     PyObject* pattern = compiled_patterns[idx];
     PyObject* match_callable = PyObject_GetAttrString(pattern, "match");
 
-    PyObject* matches = PyObject_CallFunctionObjArgs(match_callable, to_match, NULL);
+    PyObject* matches = _PyObject_CallOneArg(match_callable, to_match);
 
     Py_XDECREF(matches);
     Py_DECREF(match_callable);
diff --git a/Modules/cjkcodecs/cjkcodecs.h b/Modules/cjkcodecs/cjkcodecs.h
index b67f348..7ed8365 100644
--- a/Modules/cjkcodecs/cjkcodecs.h
+++ b/Modules/cjkcodecs/cjkcodecs.h
@@ -291,7 +291,7 @@ getcodec(PyObject *self, PyObject *encoding)
     if (codecobj == NULL)
         return NULL;
 
-    r = PyObject_CallFunctionObjArgs(cofunc, codecobj, NULL);
+    r = _PyObject_CallOneArg(cofunc, codecobj);
     Py_DECREF(codecobj);
 
     return r;
diff --git a/Modules/cjkcodecs/multibytecodec.c b/Modules/cjkcodecs/multibytecodec.c
index c01a0e5..052ed88 100644
--- a/Modules/cjkcodecs/multibytecodec.c
+++ b/Modules/cjkcodecs/multibytecodec.c
@@ -81,7 +81,7 @@ internal_error_callback(const char *errors)
 static PyObject *
 call_error_callback(PyObject *errors, PyObject *exc)
 {
-    PyObject *args, *cb, *r;
+    PyObject *cb, *r;
     const char *str;
 
     assert(PyUnicode_Check(errors));
@@ -92,17 +92,7 @@ call_error_callback(PyObject *errors, PyObject *exc)
     if (cb == NULL)
         return NULL;
 
-    args = PyTuple_New(1);
-    if (args == NULL) {
-        Py_DECREF(cb);
-        return NULL;
-    }
-
-    PyTuple_SET_ITEM(args, 0, exc);
-    Py_INCREF(exc);
-
-    r = PyObject_CallObject(cb, args);
-    Py_DECREF(args);
+    r = _PyObject_CallOneArg(cb, exc);
     Py_DECREF(cb);
     return r;
 }
diff --git a/Modules/gcmodule.c b/Modules/gcmodule.c
index 0cf00e8..2ee7651 100644
--- a/Modules/gcmodule.c
+++ b/Modules/gcmodule.c
@@ -763,7 +763,7 @@ handle_weakrefs(PyGC_Head *unreachable, PyGC_Head *old)
         _PyObject_ASSERT(op, callback != NULL);
 
         /* copy-paste of weakrefobject.c's handle_callback() */
-        temp = PyObject_CallFunctionObjArgs(callback, wr, NULL);
+        temp = _PyObject_CallOneArg(callback, (PyObject *)wr);
         if (temp == NULL)
             PyErr_WriteUnraisable(callback);
         else
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 00e3cbb..781d0cc 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -134,7 +134,7 @@ groupby_step(groupbyobject *gbo)
         newkey = newvalue;
         Py_INCREF(newvalue);
     } else {
-        newkey = PyObject_CallFunctionObjArgs(gbo->keyfunc, newvalue, NULL);
+        newkey = _PyObject_CallOneArg(gbo->keyfunc, newvalue);
         if (newkey == NULL) {
             Py_DECREF(newvalue);
             return -1;
@@ -1210,7 +1210,7 @@ dropwhile_next(dropwhileobject *lz)
         if (lz->start == 1)
             return item;
 
-        good = PyObject_CallFunctionObjArgs(lz->func, item, NULL);
+        good = _PyObject_CallOneArg(lz->func, item);
         if (good == NULL) {
             Py_DECREF(item);
             return NULL;
@@ -1373,7 +1373,7 @@ takewhile_next(takewhileobject *lz)
     if (item == NULL)
         return NULL;
 
-    good = PyObject_CallFunctionObjArgs(lz->func, item, NULL);
+    good = _PyObject_CallOneArg(lz->func, item);
     if (good == NULL) {
         Py_DECREF(item);
         return NULL;
@@ -3906,7 +3906,7 @@ filterfalse_next(filterfalseobject *lz)
             ok = PyObject_IsTrue(item);
         } else {
             PyObject *good;
-            good = PyObject_CallFunctionObjArgs(lz->func, item, NULL);
+            good = _PyObject_CallOneArg(lz->func, item);
             if (good == NULL) {
                 Py_DECREF(item);
                 return NULL;
diff --git a/Modules/pyexpat.c b/Modules/pyexpat.c
index 45a1e68..3d193e7 100644
--- a/Modules/pyexpat.c
+++ b/Modules/pyexpat.c
@@ -119,7 +119,7 @@ set_error(xmlparseobject *self, enum XML_Error code)
                                   XML_ErrorString(code), lineno, column);
     if (buffer == NULL)
         return NULL;
-    err = PyObject_CallFunctionObjArgs(ErrorObject, buffer, NULL);
+    err = _PyObject_CallOneArg(ErrorObject, buffer);
     Py_DECREF(buffer);
     if (  err != NULL
           && set_error_attr(err, "code", code)