review comments

Author: eendebakpt

Modules/itertoolsmodule.c

@@ -3531,25 +3531,26 @@ count_traverse(PyObject *op, visitproc visit, void *arg)
 static PyObject *
 count_nextlong(countobject *lz)
 {
-    PyObject *long_cnt;
-    PyObject *stepped_up;
-
-    long_cnt = lz->long_cnt;
-    if (long_cnt == NULL) {
+    if (lz->long_cnt == NULL) {
         /* Switch to slow_mode */
-        long_cnt = PyLong_FromSsize_t(PY_SSIZE_T_MAX);
-        if (long_cnt == NULL) {
+        lz->long_cnt = PyLong_FromSsize_t(PY_SSIZE_T_MAX);
+        if (lz->long_cnt == NULL) {
             return NULL;
         }
-        lz->long_cnt = long_cnt;
     }
-    assert(lz->cnt == PY_SSIZE_T_MAX && long_cnt != NULL);
+    assert(lz->cnt == PY_SSIZE_T_MAX && lz->long_cnt != NULL);
+
+    // We hold one reference to "result" (a.k.a. the old value of
+    // lz->long_cnt); we'll either return it or keep it in lz->long_cnt.
+    PyObject *result = lz->long_cnt;
 
-    stepped_up = PyNumber_Add(long_cnt, lz->long_step);
-    if (stepped_up == NULL)
+    PyObject *stepped_up = PyNumber_Add(result, lz->long_step);
+    if (stepped_up == NULL) {
         return NULL;
+    }
     lz->long_cnt = stepped_up;
-    return long_cnt;
+
+    return result;
 }
 
 static PyObject *