PySequence_Tuple instead of PySequence_Fast and removed INCREF, DECREF

Author: priyanshu2282-cyber

Lib/test/test_socket.py

@@ -3577,7 +3577,7 @@ class SendmsgStreamTests(SendmsgTests):
                      "sendmsg not supported")
     def test_sendmsg_reentrant_ancillary_mutation(self):
         self._test_sendmsg_reentrant_ancillary_mutation()
-
+        
     def _test_sendmsg_reentrant_ancillary_mutation(self):
         import socket
 
@@ -3601,8 +3601,12 @@ def __index__(self):
         self.addCleanup(left.close)
         self.addCleanup(right.close)
 
-        with self.assertRaises(Exception):
-            left.sendmsg([b'x'], seq)
+        self.assertRaises(
+            (TypeError, OSError),
+            left.sendmsg,
+            [b'x'],
+            seq,
+        )
 
     def testSendmsgExplicitNoneAddr(self):
         # Check that peer address can be specified as None.

Modules/socketmodule.c

@@ -4977,11 +4977,13 @@ _socket_socket_sendmsg_impl(PySocketSockObject *s, PyObject *data_arg,
     if (cmsg_arg == NULL)
         ncmsgs = 0;
     else {
-        if ((cmsg_fast = PySequence_Fast(cmsg_arg,
-                                         "sendmsg() argument 2 must be an "
-                                         "iterable")) == NULL)
+        cmsg_fast = PySequence_Tuple(cmsg_arg);
+        if (cmsg_fast == NULL) {
+            PyErr_SetString(PyExc_TypeError,
+                "sendmsg() argument 2 must be an iterable");
             goto finally;
-        ncmsgs = PySequence_Fast_GET_SIZE(cmsg_fast);
+    }
+    ncmsgs = PyTuple_GET_SIZE(cmsg_fast);
     }
 
 #ifndef CMSG_SPACE
@@ -5003,18 +5005,15 @@ _socket_socket_sendmsg_impl(PySocketSockObject *s, PyObject *data_arg,
         size_t bufsize, space;
         PyObject *item;
 
-        item = PySequence_Fast_GET_ITEM(cmsg_fast, ncmsgbufs);
-        Py_INCREF(item);
+        item = PyTuple_GET_ITEM(cmsg_fast, ncmsgbufs);
 
         if (!PyArg_Parse(item,
                         "(iiy*):[sendmsg() ancillary data items]",
                         &cmsgs[ncmsgbufs].level,
                         &cmsgs[ncmsgbufs].type,
                         &cmsgs[ncmsgbufs].data)){
-            Py_DECREF(item);
             goto finally;
         }
-        Py_DECREF(item);
 
         bufsize = cmsgs[ncmsgbufs++].data.len;