Issue 3689: list_reverseiterator should support __length_hint__ instead of __len__.
diff --git a/Lib/test/list_tests.py b/Lib/test/list_tests.py
index 6250908..5b1aa75 100644
--- a/Lib/test/list_tests.py
+++ b/Lib/test/list_tests.py
@@ -93,6 +93,8 @@
self.assertRaises(StopIteration, next, r)
self.assertEqual(list(reversed(self.type2test())),
self.type2test())
+ # Bug 3689: make sure list-reversed-iterator doesn't have __len__
+ self.assertRaises(TypeError, len, reversed([1,2,3]))
def test_setitem(self):
a = self.type2test([0, 1])
diff --git a/Misc/NEWS b/Misc/NEWS
index a8565c9..b1bd085 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -16,6 +16,9 @@
interpreter to abort ("Fatal Python error: Could not reset the stack!")
instead of throwing a MemoryError.
+- Issue #3689: The list reversed iterator now supports __length_hint__
+ instead of __len__. Behavior now matches other reversed iterators.
+
- Issue #4367: Python would segfault during compiling when the unicodedata
module couldn't be imported and \N escapes were present.
diff --git a/Objects/listobject.c b/Objects/listobject.c
index d5acec1..40077a1 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2736,11 +2736,11 @@
static void listreviter_dealloc(listreviterobject *);
static int listreviter_traverse(listreviterobject *, visitproc, void *);
static PyObject *listreviter_next(listreviterobject *);
-static Py_ssize_t listreviter_len(listreviterobject *);
+static PyObject *listreviter_len(listreviterobject *);
-static PySequenceMethods listreviter_as_sequence = {
- (lenfunc)listreviter_len, /* sq_length */
- 0, /* sq_concat */
+static PyMethodDef listreviter_methods[] = {
+ {"__length_hint__", (PyCFunction)listreviter_len, METH_NOARGS, length_hint_doc},
+ {NULL, NULL} /* sentinel */
};
PyTypeObject PyListRevIter_Type = {
@@ -2756,7 +2756,7 @@
0, /* tp_compare */
0, /* tp_repr */
0, /* tp_as_number */
- &listreviter_as_sequence, /* tp_as_sequence */
+ 0, /* tp_as_sequence */
0, /* tp_as_mapping */
0, /* tp_hash */
0, /* tp_call */
@@ -2772,6 +2772,7 @@
0, /* tp_weaklistoffset */
PyObject_SelfIter, /* tp_iter */
(iternextfunc)listreviter_next, /* tp_iternext */
+ listreviter_methods, /* tp_methods */
0,
};
@@ -2827,12 +2828,12 @@
return NULL;
}
-static Py_ssize_t
+static PyObject *
listreviter_len(listreviterobject *it)
{
Py_ssize_t len = it->it_index + 1;
if (it->it_seq == NULL || PyList_GET_SIZE(it->it_seq) < len)
- return 0;
- return len;
+ len = 0;
+ return PyLong_FromSsize_t(len);
}