GH-98363: Slicing isn't necessary. A resize will suffice.

rhettinger · rhettinger · commit 7c890ed19c7b · 2022-10-22T01:19:36.000-05:00
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
@@ -181,9 +181,9 @@ batched_next(batchedobject *bo)
         Py_DECREF(result);
         return NULL;
     }
-    PyObject *short_list = PyList_GetSlice(result, 0, i);
-    Py_DECREF(result);
-    return short_list;
+    /* Elements in result[i:] are still NULL */
+    Py_SET_SIZE(result, i);
+    return result;
 }
 
 static PyTypeObject batched_type = {

Original file line number	Diff line number	Diff line change
`@@ -181,9 +181,9 @@ batched_next(batchedobject *bo)`
`181`	`181`	`Py_DECREF(result);`
`182`	`182`	`return NULL;`
`183`	`183`	`}`
`184`		`- PyObject *short_list = PyList_GetSlice(result, 0, i);`
`185`		`- Py_DECREF(result);`
`186`		`- return short_list;`
	`184`	`+ /* Elements in result[i:] are still NULL */`
	`185`	`+ Py_SET_SIZE(result, i);`
	`186`	`+ return result;`
`187`	`187`	`}`
`188`	`188`
`189`	`189`	`static PyTypeObject batched_type = {`