From 5abaa2b139fb75a76933fb5437e09021fd080fae Mon Sep 17 00:00:00 2001
From: Victor Stinner <victor.stinner@gmail.com>
Date: Fri, 9 Dec 2016 16:22:32 +0100
Subject: [PATCH] Use PyObject_CallFunctionObjArgs()

Issue #28915: Replace PyObject_CallFunction() with
PyObject_CallFunctionObjArgs() when the format string was only made of "O"
formats, PyObject* arguments.

PyObject_CallFunctionObjArgs() avoids the creation of a temporary tuple and
doesn't have to parse a format string.
---
 Modules/_elementtree.c | 22 ++++++++++++++--------
 Objects/abstract.c     |  2 +-
 Objects/descrobject.c  |  2 +-
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/Modules/_elementtree.c b/Modules/_elementtree.c
index 8678c0a3701..ba827e667f6 100644
--- a/Modules/_elementtree.c
+++ b/Modules/_elementtree.c
@@ -2496,11 +2496,13 @@ treebuilder_handle_start(TreeBuilderObject* self, PyObject* tag,
         attrib = PyDict_New();
         if (!attrib)
             return NULL;
-        node = PyObject_CallFunction(self->element_factory, "OO", tag, attrib);
+        node = PyObject_CallFunctionObjArgs(self->element_factory,
+                                            tag, attrib, NULL);
         Py_DECREF(attrib);
     }
     else {
-        node = PyObject_CallFunction(self->element_factory, "OO", tag, attrib);
+        node = PyObject_CallFunctionObjArgs(self->element_factory,
+                                            tag, attrib, NULL);
     }
     if (!node) {
         return NULL;
@@ -2977,7 +2979,8 @@ expat_start_handler(XMLParserObject* self, const XML_Char* tag_in,
                 return;
             }
         }
-        res = PyObject_CallFunction(self->handle_start, "OO", tag, attrib);
+        res = PyObject_CallFunctionObjArgs(self->handle_start,
+                                           tag, attrib, NULL);
     } else
         res = NULL;
 
@@ -3143,8 +3146,9 @@ expat_start_doctype_handler(XMLParserObject *self,
 
     /* If the target has a handler for doctype, call it. */
     if (self->handle_doctype) {
-        res = PyObject_CallFunction(self->handle_doctype, "OOO",
-                                    doctype_name_obj, pubid_obj, sysid_obj);
+        res = PyObject_CallFunctionObjArgs(self->handle_doctype,
+                                           doctype_name_obj, pubid_obj,
+                                           sysid_obj, NULL);
         Py_CLEAR(res);
     }
     else {
@@ -3163,8 +3167,9 @@ expat_start_doctype_handler(XMLParserObject *self,
             if (!res)
                 goto clear;
             Py_DECREF(res);
-            res = PyObject_CallFunction(parser_doctype, "OOO",
-                                        doctype_name_obj, pubid_obj, sysid_obj);
+            res = PyObject_CallFunctionObjArgs(parser_doctype,
+                                               doctype_name_obj, pubid_obj,
+                                               sysid_obj, NULL);
             Py_CLEAR(res);
         }
     }
@@ -3191,7 +3196,8 @@ expat_pi_handler(XMLParserObject* self, const XML_Char* target_in,
         target = PyUnicode_DecodeUTF8(target_in, strlen(target_in), "strict");
         data = PyUnicode_DecodeUTF8(data_in, strlen(data_in), "strict");
         if (target && data) {
-            res = PyObject_CallFunction(self->handle_pi, "OO", target, data);
+            res = PyObject_CallFunctionObjArgs(self->handle_pi,
+                                               target, data, NULL);
             Py_XDECREF(res);
             Py_DECREF(data);
             Py_DECREF(target);
diff --git a/Objects/abstract.c b/Objects/abstract.c
index 2c5057d133e..d3b9ec0d19c 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2549,7 +2549,7 @@ _PyObject_CallFunctionVa(PyObject *callable, const char *format,
     }
 
     if (nargs == 1 && PyTuple_Check(stack[0])) {
-        /* Special cases:
+        /* Special cases for backward compatibility:
            - PyObject_CallFunction(func, "O", tuple) calls func(*tuple)
            - PyObject_CallFunction(func, "(OOO)", arg1, arg2, arg3) calls
              func(*(arg1, arg2, arg3)): func(arg1, arg2, arg3) */
diff --git a/Objects/descrobject.c b/Objects/descrobject.c
index ee356b1bf40..090c9cdd047 100644
--- a/Objects/descrobject.c
+++ b/Objects/descrobject.c
@@ -1454,7 +1454,7 @@ property_copy(PyObject *old, PyObject *get, PyObject *set, PyObject *del)
         doc = pold->prop_doc ? pold->prop_doc : Py_None;
     }
 
-    new =  PyObject_CallFunction(type, "OOOO", get, set, del, doc);
+    new =  PyObject_CallFunctionObjArgs(type, get, set, del, doc, NULL);
     Py_DECREF(type);
     if (new == NULL)
         return NULL;