1 files changed, 47 insertions, 44 deletions

diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 55d88a8c9f..6ff241e7dd 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -157,15 +157,12 @@ groupby_setstate(groupbyobject *lz, PyObject *state)
     PyObject *currkey, *currvalue, *tgtkey;
     if (!PyArg_ParseTuple(state, "OOO", &currkey, &currvalue, &tgtkey))
         return NULL;
-    Py_CLEAR(lz->currkey);
-    lz->currkey = currkey;
-    Py_INCREF(lz->currkey);
-    Py_CLEAR(lz->currvalue);
-    lz->currvalue = currvalue;
-    Py_INCREF(lz->currvalue);
-    Py_CLEAR(lz->tgtkey);
-    lz->tgtkey = tgtkey;
-    Py_INCREF(lz->tgtkey);
+    Py_INCREF(currkey);
+    Py_XSETREF(lz->currkey, currkey);
+    Py_INCREF(currvalue);
+    Py_XSETREF(lz->currvalue, currvalue);
+    Py_INCREF(tgtkey);
+    Py_XSETREF(lz->tgtkey, tgtkey);
     Py_RETURN_NONE;
 }
 
@@ -634,8 +631,7 @@ tee_next(teeobject *to)
         link = teedataobject_jumplink(to->dataobj);
         if (link == NULL)
             return NULL;
-        Py_DECREF(to->dataobj);
-        to->dataobj = (teedataobject *)link;
+        Py_SETREF(to->dataobj, (teedataobject *)link);
         to->index = 0;
     }
     value = teedataobject_getitem(to->dataobj, to->index);
@@ -746,9 +742,8 @@ tee_setstate(teeobject *to, PyObject *state)
         PyErr_SetString(PyExc_ValueError, "Index out of range");
         return NULL;
     }
-    Py_CLEAR(to->dataobj);
-    to->dataobj = tdo;
-    Py_INCREF(to->dataobj);
+    Py_INCREF(tdo);
+    Py_XSETREF(to->dataobj, tdo);
     to->index = index;
     Py_RETURN_NONE;
 }
@@ -973,9 +968,8 @@ cycle_setstate(cycleobject *lz, PyObject *state)
     int firstpass;
     if (!PyArg_ParseTuple(state, "Oi", &saved, &firstpass))
         return NULL;
-    Py_CLEAR(lz->saved);
-    lz->saved = saved;
-    Py_XINCREF(lz->saved);
+    Py_XINCREF(saved);
+    Py_XSETREF(lz->saved, saved);
     lz->firstpass = firstpass != 0;
     Py_RETURN_NONE;
 }
@@ -1900,12 +1894,10 @@ chain_setstate(chainobject *lz, PyObject *state)
     if (! PyArg_ParseTuple(state, "O|O", &source, &active))
         return NULL;
 
-    Py_CLEAR(lz->source);
-    lz->source = source;
-    Py_INCREF(lz->source);
-    Py_CLEAR(lz->active);
-    lz->active = active;
-    Py_XINCREF(lz->active);
+    Py_INCREF(source);
+    Py_XSETREF(lz->source, source);
+    Py_XINCREF(active);
+    Py_XSETREF(lz->active, active);
     Py_RETURN_NONE;
 }
 
@@ -1919,7 +1911,7 @@ iterable, until all of the iterables are exhausted.");
 PyDoc_STRVAR(chain_from_iterable_doc,
 "chain.from_iterable(iterable) --> chain object\n\
 \n\
-Alternate chain() contructor taking a single iterable argument\n\
+Alternate chain() constructor taking a single iterable argument\n\
 that evaluates lazily.");
 
 static PyMethodDef chain_methods[] = {
@@ -2087,7 +2079,7 @@ product_sizeof(productobject *lz, void *unused)
 {
     Py_ssize_t res;
 
-    res = sizeof(productobject);
+    res = _PyObject_SIZE(Py_TYPE(lz));
     res += PyTuple_GET_SIZE(lz->pools) * sizeof(Py_ssize_t);
     return PyLong_FromSsize_t(res);
 }
@@ -2261,8 +2253,7 @@ product_setstate(productobject *lz, PyObject *state)
         Py_INCREF(element);
         PyTuple_SET_ITEM(result, i, element);
     }
-    Py_CLEAR(lz->result);
-    lz->result = result;
+    Py_XSETREF(lz->result, result);
     Py_RETURN_NONE;
 }
 
@@ -2418,7 +2409,7 @@ combinations_sizeof(combinationsobject *co, void *unused)
 {
     Py_ssize_t res;
 
-    res = sizeof(combinationsobject);
+    res = _PyObject_SIZE(Py_TYPE(co));
     res += co->r * sizeof(Py_ssize_t);
     return PyLong_FromSsize_t(res);
 }
@@ -2584,8 +2575,7 @@ combinations_setstate(combinationsobject *lz, PyObject *state)
         PyTuple_SET_ITEM(result, i, element);
     }
 
-    Py_CLEAR(lz->result);
-    lz->result = result;
+    Py_XSETREF(lz->result, result);
     Py_RETURN_NONE;
 }
 
@@ -2759,7 +2749,7 @@ cwr_sizeof(cwrobject *co, void *unused)
 {
     Py_ssize_t res;
 
-    res = sizeof(cwrobject);
+    res = _PyObject_SIZE(Py_TYPE(co));
     res += co->r * sizeof(Py_ssize_t);
     return PyLong_FromSsize_t(res);
 }
@@ -2915,8 +2905,7 @@ cwr_setstate(cwrobject *lz, PyObject *state)
         Py_INCREF(element);
         PyTuple_SET_ITEM(result, i, element);
     }
-    Py_CLEAR(lz->result);
-    lz->result = result;
+    Py_XSETREF(lz->result, result);
     Py_RETURN_NONE;
 }
 
@@ -3108,7 +3097,7 @@ permutations_sizeof(permutationsobject *po, void *unused)
 {
     Py_ssize_t res;
 
-    res = sizeof(permutationsobject);
+    res = _PyObject_SIZE(Py_TYPE(po));
     res += PyTuple_GET_SIZE(po->pool) * sizeof(Py_ssize_t);
     res += po->r * sizeof(Py_ssize_t);
     return PyLong_FromSsize_t(res);
@@ -3309,8 +3298,7 @@ permutations_setstate(permutationsobject *po, PyObject *state)
         Py_INCREF(element);
         PyTuple_SET_ITEM(result, i, element);
     }
-    Py_CLEAR(po->result);
-    po->result = result;
+    Py_XSETREF(po->result, result);
     Py_RETURN_NONE;
 }
 
@@ -3472,6 +3460,23 @@ accumulate_next(accumulateobject *lz)
 static PyObject *
 accumulate_reduce(accumulateobject *lz)
 {
+    if (lz->total == Py_None) {
+        PyObject *it;
+
+        if (PyType_Ready(&chain_type) < 0)
+            return NULL;
+        if (PyType_Ready(&islice_type) < 0)
+            return NULL;
+        it = PyObject_CallFunction((PyObject *)&chain_type, "(O)O",
+                                   lz->total, lz->it);
+        if (it == NULL)
+            return NULL;
+        it = PyObject_CallFunction((PyObject *)Py_TYPE(lz), "NO",
+                                   it, lz->binop ? lz->binop : Py_None);
+        if (it == NULL)
+            return NULL;
+        return Py_BuildValue("O(NiO)", &islice_type, it, 1, Py_None);
+    }
     return Py_BuildValue("O(OO)O", Py_TYPE(lz),
                             lz->it, lz->binop?lz->binop:Py_None,
                             lz->total?lz->total:Py_None);
@@ -3480,9 +3485,8 @@ accumulate_reduce(accumulateobject *lz)
 static PyObject *
 accumulate_setstate(accumulateobject *lz, PyObject *state)
 {
-    Py_CLEAR(lz->total);
-    lz->total = state;
-    Py_INCREF(lz->total);
+    Py_INCREF(state);
+    Py_XSETREF(lz->total, state);
     Py_RETURN_NONE;
 }
 
@@ -3882,7 +3886,7 @@ typedef struct {
 
 fast_mode:  when cnt an integer < PY_SSIZE_T_MAX and no step is specified.
 
-    assert(cnt != PY_SSIZE_T_MAX && long_cnt == NULL && long_step==PyInt(1));
+    assert(cnt != PY_SSIZE_T_MAX && long_cnt == NULL && long_step==PyLong(1));
     Advances with:  cnt += 1
     When count hits Y_SSIZE_T_MAX, switch to slow_mode.
 
@@ -4463,9 +4467,8 @@ zip_longest_reduce(ziplongestobject *lz)
 static PyObject *
 zip_longest_setstate(ziplongestobject *lz, PyObject *state)
 {
-    Py_CLEAR(lz->fillvalue);
-    lz->fillvalue = state;
-    Py_INCREF(lz->fillvalue);
+    Py_INCREF(state);
+    Py_XSETREF(lz->fillvalue, state);
     Py_RETURN_NONE;
 }
 
@@ -4480,7 +4483,7 @@ static PyMethodDef zip_longest_methods[] = {
 PyDoc_STRVAR(zip_longest_doc,
 "zip_longest(iter1 [,iter2 [...]], [fillvalue=None]) --> zip_longest object\n\
 \n\
-Return an zip_longest object whose .__next__() method returns a tuple where\n\
+Return a zip_longest object whose .__next__() method returns a tuple where\n\
 the i-th element comes from the i-th iterable argument.  The .__next__()\n\
 method continues until the longest iterable in the argument sequence\n\
 is exhausted and then it raises StopIteration.  When the shorter iterables\n\