changeset:   101068:15b20201cfa5
user:        Serhiy Storchaka <storchaka@gmail.com>
date:        Tue Apr 19 23:37:17 2016 +0300
files:       Python/ceval.c
description:
Issue #26802: Optimized calling a function with *args only positional arguments.
Patch by Joe Jevnik.


diff -r 75f40345d784 -r 15b20201cfa5 Python/ceval.c
--- a/Python/ceval.c	Tue Apr 19 22:29:11 2016 +0200
+++ b/Python/ceval.c	Tue Apr 19 23:37:17 2016 +0300
@@ -4890,6 +4890,21 @@
 {
     PyObject *callargs, *w;
 
+    if (!nstack) {
+        if (!stararg) {
+            /* There are no positional arguments on the stack and there is no
+               sequence to be unpacked. */
+            return PyTuple_New(0);
+        }
+        if (PyTuple_CheckExact(stararg)) {
+            /* No arguments are passed on the stack and the sequence is not a
+               tuple subclass so we can just pass the stararg tuple directly
+               to the function. */
+            Py_INCREF(stararg);
+            return stararg;
+        }
+    }
+
     callargs = PyTuple_New(nstack + nstar);
     if (callargs == NULL) {
         return NULL;