Make the various iterators' "setstate" sliently and consistently clip the

index.  This avoids the possibility of setting an iterator to an invalid
state.

Lib/test/test_range.py

@@ -381,6 +381,18 @@ class RangeTest(unittest.TestCase):
                 self.assertEqual(list(it), data[1:])
 
     def test_exhausted_iterator_pickling(self):
+        r = range(2**65, 2**65+2)
+        i = iter(r)
+        while True:
+            r = next(i)
+            if r == 2**65+1:
+                break
+        d = pickle.dumps(i)
+        i2 = pickle.loads(d)
+        self.assertEqual(list(i), [])
+        self.assertEqual(list(i2), [])
+
+    def test_large_exhausted_iterator_pickling(self):
         r = range(20)
         i = iter(r)
         while True:

Modules/arraymodule.c

@@ -2838,6 +2838,8 @@ arrayiter_setstate(arrayiterobject *it, PyObject *state)
         return NULL;
     if (index < 0)
         index = 0;
+    else if (index > Py_SIZE(it->ao))
+        index = Py_SIZE(it->ao); /* iterator exhausted */
     it->index = index;
     Py_RETURN_NONE;
 }

Objects/bytearrayobject.c

@@ -3025,9 +3025,13 @@ bytearrayiter_setstate(bytesiterobject *it, PyObject *state)
     Py_ssize_t index = PyLong_AsSsize_t(state);
     if (index == -1 && PyErr_Occurred())
         return NULL;
+    if (it->it_seq != NULL) {
         if (index < 0)
             index = 0;
+        else if (index > PyByteArray_GET_SIZE(it->it_seq))
+            index = PyByteArray_GET_SIZE(it->it_seq); /* iterator exhausted */
         it->it_index = index;
+    }
     Py_RETURN_NONE;
 }
 

Objects/bytesobject.c

@@ -2937,9 +2937,13 @@ striter_setstate(striterobject *it, PyObject *state)
     Py_ssize_t index = PyLong_AsSsize_t(state);
     if (index == -1 && PyErr_Occurred())
         return NULL;
+    if (it->it_seq != NULL) {
         if (index < 0)
             index = 0;
+        else if (index > PyBytes_GET_SIZE(it->it_seq))
+            index = PyBytes_GET_SIZE(it->it_seq); /* iterator exhausted */
         it->it_index = index;
+    }
     Py_RETURN_NONE;
 }
 

Objects/listobject.c

@@ -2811,6 +2811,8 @@ listiter_setstate(listiterobject *it, PyObject *state)
     if (it->it_seq != NULL) {
         if (index < 0)
             index = 0;
+        else if (index > PyList_GET_SIZE(it->it_seq))
+            index = PyList_GET_SIZE(it->it_seq); /* iterator exhausted */
         it->it_index = index;
     }
     Py_RETURN_NONE;

Objects/rangeobject.c

@@ -807,10 +807,11 @@ rangeiter_setstate(rangeiterobject *r, PyObject *state)
     long index = PyLong_AsLong(state);
     if (index == -1 && PyErr_Occurred())
         return NULL;
-    if (index < 0 || index > r->len) {
-        PyErr_SetString(PyExc_ValueError, "index out of range");
-        return NULL;
-    }
+    /* silently clip the index value */
+    if (index < 0)
+        index = 0;
+    else if (index > r->len)
+        index = r->len; /* exhausted iterator */
     r->index = index;
     Py_RETURN_NONE;
 }
@@ -985,6 +986,28 @@ longrangeiter_reduce(longrangeiterobject *r)
 static PyObject *
 longrangeiter_setstate(longrangeiterobject *r, PyObject *state)
 {
+    int cmp;
+   
+    /* clip the value */
+    PyObject *zero = PyLong_FromLong(0);
+    if (zero == NULL)
+        return NULL;
+    cmp = PyObject_RichCompareBool(state, zero, Py_LT);
+    if (cmp > 0) {
+        Py_CLEAR(r->index);
+        r->index = zero;
+        Py_RETURN_NONE;
+    }
+    Py_DECREF(zero);
+    if (cmp < 0)
+        return NULL;
+
+    cmp = PyObject_RichCompareBool(r->len, state, Py_LT);
+    if (cmp < 0)
+        return NULL;
+    if (cmp > 0)
+        state = r->len;
+    
     Py_CLEAR(r->index);
     r->index = state;
     Py_INCREF(r->index);

Objects/tupleobject.c

@@ -1011,8 +1011,8 @@ tupleiter_setstate(tupleiterobject *it, PyObject *state)
     if (it->it_seq != NULL) {
         if (index < 0)
             index = 0;
-        else if (it->it_seq != NULL && index > PyTuple_GET_SIZE(it->it_seq))
-            index = PyTuple_GET_SIZE(it->it_seq);
+        else if (index > PyTuple_GET_SIZE(it->it_seq))
+            index = PyTuple_GET_SIZE(it->it_seq); /* exhausted iterator */
         it->it_index = index;
     }
     Py_RETURN_NONE;

Objects/unicodeobject.c

@@ -15196,9 +15196,13 @@ unicodeiter_setstate(unicodeiterobject *it, PyObject *state)
     Py_ssize_t index = PyLong_AsSsize_t(state);
     if (index == -1 && PyErr_Occurred())
         return NULL;
+    if (it->it_seq != NULL) {
         if (index < 0)
             index = 0;
+        else if (index > PyUnicode_GET_LENGTH(it->it_seq))
+            index = PyUnicode_GET_LENGTH(it->it_seq); /* iterator truncated */
         it->it_index = index;
+    }
     Py_RETURN_NONE;
 }