19 files changed, 319 insertions, 234 deletions

diff --git a/Doc/api/abstract.tex b/Doc/api/abstract.tex
index f740efb..9c39403 100644
--- a/Doc/api/abstract.tex
+++ b/Doc/api/abstract.tex
@@ -693,12 +693,31 @@ determination.
   \samp{float(\var{o})}.\bifuncindex{float}
 \end{cfuncdesc}
 
-\begin{cfuncdesc}{Py_ssize_t}{PyNumber_Index}{PyObject *o}
-  Returns the \var{o} converted to a Py_ssize_t integer on success, or
-  -1 with an exception raised on failure.
+\begin{cfuncdesc}{PyObject*}{PyNumber_Index}{PyObject *o}
+  Returns the \var{o} converted to a Python int or long on success or \NULL{}
+  with a TypeError exception raised on failure.
   \versionadded{2.5}
 \end{cfuncdesc}
 
+\begin{cfuncdesc}{Py_ssize_t}{PyNumber_AsSsize_t}{PyObject *o, PyObject *exc}
+  Returns \var{o} converted to a Py_ssize_t value if \var{o}
+  can be interpreted as an integer. If \var{o} can be converted to a Python
+  int or long but the attempt to convert to a Py_ssize_t value
+  would raise an \exception{OverflowError}, then the \var{exc} argument
+  is the type of exception that will be raised (usually \exception{IndexError}
+  or \exception{OverflowError}).  If \var{exc} is \NULL{}, then the exception
+  is cleared and the value is clipped to \var{PY_SSIZE_T_MIN}
+  for a negative integer or \var{PY_SSIZE_T_MAX} for a positive integer.
+  \versionadded{2.5}
+\end{cfuncdesc}
+
+\begin{cfuncdesc}{int}{PyIndex_Check}{PyObject *o}
+  Returns True if \var{o} is an index integer (has the nb_index slot of 
+  the tp_as_number structure filled in).  
+  \versionadded{2.5}
+\end{cfuncdesc}
+
+
 \section{Sequence Protocol \label{sequence}}
 
 \begin{cfuncdesc}{int}{PySequence_Check}{PyObject *o}
diff --git a/Include/abstract.h b/Include/abstract.h
index f96b297..9b0b3f0 100644
--- a/Include/abstract.h
+++ b/Include/abstract.h
@@ -758,13 +758,27 @@ xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx*/
 
        */
 
-     PyAPI_FUNC(Py_ssize_t) PyNumber_Index(PyObject *);
+#define PyIndex_Check(obj) \
+   ((obj)->ob_type->tp_as_number != NULL && \
+    PyType_HasFeature((obj)->ob_type, Py_TPFLAGS_HAVE_INDEX) && \
+    (obj)->ob_type->tp_as_number->nb_index != NULL)
+        
+     PyAPI_FUNC(PyObject *) PyNumber_Index(PyObject *o);
 
        /*
-	 Returns the object converted to Py_ssize_t on success 
-	 or -1 with an error raised on failure.
+	 Returns the object converted to a Python long or int
+	 or NULL with an error raised on failure.
        */
 
+     PyAPI_FUNC(Py_ssize_t) PyNumber_AsSsize_t(PyObject *o, PyObject *exc);
+
+       /*
+        Returns the object converted to Py_ssize_t by going through
+        PyNumber_Index first.  If an overflow error occurs while
+        converting the int-or-long to Py_ssize_t, then the second argument
+        is the error-type to return.  If it is NULL, then the overflow error
+        is cleared and the value is clipped. 
+       */
 
      PyAPI_FUNC(PyObject *) PyNumber_Int(PyObject *o);
 
diff --git a/Include/object.h b/Include/object.h
index 4b0e080..b0817e6 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -208,7 +208,7 @@ typedef struct {
 	binaryfunc nb_inplace_true_divide;
 
 	/* Added in release 2.5 */
-	lenfunc nb_index;
+	unaryfunc nb_index;
 } PyNumberMethods;
 
 typedef struct {
diff --git a/Lib/test/test_index.py b/Lib/test/test_index.py
index 45b3b2b..b224a50 100644
--- a/Lib/test/test_index.py
+++ b/Lib/test/test_index.py
@@ -1,6 +1,7 @@
 import unittest
 from test import test_support
 import operator
+from sys import maxint
 
 class oldstyle:
     def __index__(self):
@@ -10,68 +11,115 @@ class newstyle(object):
     def __index__(self):
         return self.ind
 
+class TrapInt(int):
+    def __index__(self):
+        return self
+
+class TrapLong(long):
+    def __index__(self):
+        return self
+
 class BaseTestCase(unittest.TestCase):
     def setUp(self):
         self.o = oldstyle()
         self.n = newstyle()
-        self.o2 = oldstyle()
-        self.n2 = newstyle()
 
     def test_basic(self):
         self.o.ind = -2
         self.n.ind = 2
-        assert(self.seq[self.n] == self.seq[2])
-        assert(self.seq[self.o] == self.seq[-2])
-        assert(operator.index(self.o) == -2)
-        assert(operator.index(self.n) == 2)
+        self.assertEqual(operator.index(self.o), -2)
+        self.assertEqual(operator.index(self.n), 2)
+        
+    def test_slice(self):
+        self.o.ind = 1
+        self.n.ind = 2
+        slc = slice(self.o, self.o, self.o)
+        check_slc = slice(1, 1, 1)
+        self.assertEqual(slc.indices(self.o), check_slc.indices(1))
+        slc = slice(self.n, self.n, self.n)
+        check_slc = slice(2, 2, 2)
+        self.assertEqual(slc.indices(self.n), check_slc.indices(2))
 
+    def test_wrappers(self):
+        self.o.ind = 4
+        self.n.ind = 5
+        self.assertEqual(6 .__index__(), 6)
+        self.assertEqual(-7L.__index__(), -7)
+        self.assertEqual(self.o.__index__(), 4)
+        self.assertEqual(self.n.__index__(), 5)
+
+    def test_infinite_recursion(self):
+        self.failUnlessRaises(TypeError, operator.index, TrapInt())
+        self.failUnlessRaises(TypeError, operator.index, TrapLong())
+        self.failUnless(slice(TrapInt()).indices(0)==(0,0,1))
+        self.failUnlessRaises(TypeError, slice(TrapLong()).indices, 0)
+        
     def test_error(self):
         self.o.ind = 'dumb'
         self.n.ind = 'bad'
-        myfunc = lambda x, obj: obj.seq[x]
         self.failUnlessRaises(TypeError, operator.index, self.o)
         self.failUnlessRaises(TypeError, operator.index, self.n)
-        self.failUnlessRaises(TypeError, myfunc, self.o, self)
-        self.failUnlessRaises(TypeError, myfunc, self.n, self)
+        self.failUnlessRaises(TypeError, slice(self.o).indices, 0)
+        self.failUnlessRaises(TypeError, slice(self.n).indices, 0)
+
+
+class SeqTestCase(unittest.TestCase):
+    # This test case isn't run directly. It just defines common tests
+    # to the different sequence types below
+    def setUp(self):
+        self.o = oldstyle()
+        self.n = newstyle()
+        self.o2 = oldstyle()
+        self.n2 = newstyle()
+
+    def test_index(self):
+        self.o.ind = -2
+        self.n.ind = 2
+        self.assertEqual(self.seq[self.n], self.seq[2])
+        self.assertEqual(self.seq[self.o], self.seq[-2])
 
     def test_slice(self):
         self.o.ind = 1
         self.o2.ind = 3
         self.n.ind = 2
         self.n2.ind = 4
-        assert(self.seq[self.o:self.o2] == self.seq[1:3])
-        assert(self.seq[self.n:self.n2] == self.seq[2:4])
+        self.assertEqual(self.seq[self.o:self.o2], self.seq[1:3])
+        self.assertEqual(self.seq[self.n:self.n2], self.seq[2:4])
 
     def test_repeat(self):
         self.o.ind = 3
         self.n.ind = 2
-        assert(self.seq * self.o == self.seq * 3)
-        assert(self.seq * self.n == self.seq * 2)
-        assert(self.o * self.seq == self.seq * 3)
-        assert(self.n * self.seq == self.seq * 2)
+        self.assertEqual(self.seq * self.o, self.seq * 3)
+        self.assertEqual(self.seq * self.n, self.seq * 2)
+        self.assertEqual(self.o * self.seq, self.seq * 3)
+        self.assertEqual(self.n * self.seq, self.seq * 2)
 
     def test_wrappers(self):
-        n = self.n
-        n.ind = 5
-        assert n.__index__() == 5
-        assert 6 .__index__() == 6
-        assert -7L.__index__() == -7
-        assert self.seq.__getitem__(n) == self.seq[5]
-        assert self.seq.__mul__(n) == self.seq * 5
-        assert self.seq.__rmul__(n) == self.seq * 5
-
-    def test_infinite_recusion(self):
-        class Trap1(int):
-            def __index__(self):
-                return self
-        class Trap2(long):
-            def __index__(self):
-                return self
-        self.failUnlessRaises(TypeError, operator.getitem, self.seq, Trap1())
-        self.failUnlessRaises(TypeError, operator.getitem, self.seq, Trap2())
-
-
-class ListTestCase(BaseTestCase):
+        self.o.ind = 4
+        self.n.ind = 5
+        self.assertEqual(self.seq.__getitem__(self.o), self.seq[4])
+        self.assertEqual(self.seq.__mul__(self.o), self.seq * 4)
+        self.assertEqual(self.seq.__rmul__(self.o), self.seq * 4)
+        self.assertEqual(self.seq.__getitem__(self.n), self.seq[5])
+        self.assertEqual(self.seq.__mul__(self.n), self.seq * 5)
+        self.assertEqual(self.seq.__rmul__(self.n), self.seq * 5)
+
+    def test_infinite_recursion(self):
+        self.failUnlessRaises(TypeError, operator.getitem, self.seq, TrapInt())
+        self.failUnlessRaises(TypeError, operator.getitem, self.seq, TrapLong())
+
+    def test_error(self):
+        self.o.ind = 'dumb'
+        self.n.ind = 'bad'
+        indexobj = lambda x, obj: obj.seq[x]
+        self.failUnlessRaises(TypeError, indexobj, self.o, self)
+        self.failUnlessRaises(TypeError, indexobj, self.n, self)
+        sliceobj = lambda x, obj: obj.seq[x:]
+        self.failUnlessRaises(TypeError, sliceobj, self.o, self)
+        self.failUnlessRaises(TypeError, sliceobj, self.n, self)
+
+
+class ListTestCase(SeqTestCase):
     seq = [0,10,20,30,40,50]
 
     def test_setdelitem(self):
@@ -82,36 +130,36 @@ class ListTestCase(BaseTestCase):
         del lst[self.n]
         lst[self.o] = 'X'
         lst[self.n] = 'Y'
-        assert lst == list('abYdefghXj')
+        self.assertEqual(lst, list('abYdefghXj'))
 
         lst = [5, 6, 7, 8, 9, 10, 11]
         lst.__setitem__(self.n, "here")
-        assert lst == [5, 6, "here", 8, 9, 10, 11]
+        self.assertEqual(lst, [5, 6, "here", 8, 9, 10, 11])
         lst.__delitem__(self.n)
-        assert lst == [5, 6, 8, 9, 10, 11]
+        self.assertEqual(lst, [5, 6, 8, 9, 10, 11])
 
     def test_inplace_repeat(self):
         self.o.ind = 2
         self.n.ind = 3
         lst = [6, 4]
         lst *= self.o
-        assert lst == [6, 4, 6, 4]
+        self.assertEqual(lst, [6, 4, 6, 4])
         lst *= self.n
-        assert lst == [6, 4, 6, 4] * 3
+        self.assertEqual(lst, [6, 4, 6, 4] * 3)
 
         lst = [5, 6, 7, 8, 9, 11]
         l2 = lst.__imul__(self.n)
-        assert l2 is lst
-        assert lst == [5, 6, 7, 8, 9, 11] * 3
+        self.assert_(l2 is lst)
+        self.assertEqual(lst, [5, 6, 7, 8, 9, 11] * 3)
 
 
-class TupleTestCase(BaseTestCase):
+class TupleTestCase(SeqTestCase):
     seq = (0,10,20,30,40,50)
 
-class StringTestCase(BaseTestCase):
+class StringTestCase(SeqTestCase):
     seq = "this is a test"
 
-class UnicodeTestCase(BaseTestCase):
+class UnicodeTestCase(SeqTestCase):
     seq = u"this is a test"
 
 
@@ -120,17 +168,47 @@ class XRangeTestCase(unittest.TestCase):
     def test_xrange(self):
         n = newstyle()
         n.ind = 5
-        assert xrange(1, 20)[n] == 6
-        assert xrange(1, 20).__getitem__(n) == 6
+        self.assertEqual(xrange(1, 20)[n], 6)
+        self.assertEqual(xrange(1, 20).__getitem__(n), 6)
+
+class OverflowTestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.pos = 2**100
+        self.neg = -self.pos
+
+    def test_large_longs(self):
+        self.assertEqual(self.pos.__index__(), self.pos)
+        self.assertEqual(self.neg.__index__(), self.neg)
+
+    def test_getitem(self):
+        class GetItem(object):
+            def __len__(self):
+                return maxint
+            def __getitem__(self, key):
+                return key
+            def __getslice__(self, i, j):
+                return i, j
+        x = GetItem()
+        self.assertEqual(x[self.pos], self.pos)
+        self.assertEqual(x[self.neg], self.neg)
+        self.assertEqual(x[self.neg:self.pos], (-1, maxint))
+        self.assertEqual(x[self.neg:self.pos:1].indices(maxint), (0, maxint, 1))
+
+    def test_sequence_repeat(self):
+        self.failUnlessRaises(OverflowError, lambda: "a" * self.pos)
+        self.failUnlessRaises(OverflowError, lambda: "a" * self.neg)
 
 
 def test_main():
     test_support.run_unittest(
+        BaseTestCase,
         ListTestCase,
         TupleTestCase,
         StringTestCase,
         UnicodeTestCase,
         XRangeTestCase,
+        OverflowTestCase,
     )
 
 if __name__ == "__main__":
diff --git a/Misc/NEWS b/Misc/NEWS
index 26047f6..49de4b6 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,11 @@ What's New in Python 2.5 release candidate 1?
 Core and builtins
 -----------------
 
+- Patch #1538606, Fix __index__() clipping.  There were some problems
+  discovered with the API and how integers that didn't fit into Py_ssize_t
+  were handled.  This patch attempts to provide enough alternatives
+  to effectively use __index__.
+
 - Bug #1536021: __hash__ may now return long int; the final hash
   value is obtained by invoking hash on the long int.
 
diff --git a/Modules/arraymodule.c b/Modules/arraymodule.c
index 14e5e5d..efa7835 100644
--- a/Modules/arraymodule.c
+++ b/Modules/arraymodule.c
@@ -1572,14 +1572,11 @@ array_repr(arrayobject *a)
 	return s;
 }
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
-
 static PyObject*
 array_subscr(arrayobject* self, PyObject* item)
 {
-	PyNumberMethods *nb = item->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(item);
+	if (PyIndex_Check(item)) {
+		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
 		if (i==-1 && PyErr_Occurred()) {
 			return NULL;
 		}
@@ -1627,9 +1624,8 @@ array_subscr(arrayobject* self, PyObject* item)
 static int
 array_ass_subscr(arrayobject* self, PyObject* item, PyObject* value)
 {
-	PyNumberMethods *nb = item->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(item);
+	if (PyIndex_Check(item)) {
+		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
 		if (i==-1 && PyErr_Occurred()) 
 			return -1;
 		if (i < 0)
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index b2dd675..53df275 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -808,8 +808,6 @@ static PyTypeObject mmap_object_type = {
 };
 
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
-
 /* extract the map size from the given PyObject
 
    Returns -1 on error, with an appropriate Python exception raised. On
@@ -817,31 +815,19 @@ static PyTypeObject mmap_object_type = {
 static Py_ssize_t
 _GetMapSize(PyObject *o)
 {
-	PyNumberMethods *nb = o->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(o) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(o);
+	if (PyIndex_Check(o)) {
+		Py_ssize_t i = PyNumber_AsSsize_t(o, PyExc_OverflowError);
 		if (i==-1 && PyErr_Occurred()) 
 			return -1;
-		if (i < 0)
-			goto onnegoverflow;
-		if (i==PY_SSIZE_T_MAX)
-			goto onposoverflow;
+		if (i < 0) {	 
+			PyErr_SetString(PyExc_OverflowError,
+					"memory mapped size must be positive");
+			return -1;
+		}
 		return i;
 	}
-	else {
-		PyErr_SetString(PyExc_TypeError,
-				"map size must be an integral value");
-		return -1;
-	}
-
-  onnegoverflow:
-	PyErr_SetString(PyExc_OverflowError,
-			"memory mapped size must be positive");
-	return -1;
 
-  onposoverflow:
-	PyErr_SetString(PyExc_OverflowError,
-			"memory mapped size is too large (limited by C int)");
+	PyErr_SetString(PyExc_TypeError, "map size must be an integral value");
 	return -1;
 }
 
diff --git a/Modules/operator.c b/Modules/operator.c
index 7fc1f8a..7479a53 100644
--- a/Modules/operator.c
+++ b/Modules/operator.c
@@ -139,15 +139,7 @@ op_ipow(PyObject *s, PyObject *a)
 static PyObject *
 op_index(PyObject *s, PyObject *a)
 {
-	Py_ssize_t i;
-	PyObject *a1;
-	if (!PyArg_UnpackTuple(a,"index", 1, 1, &a1))
-		return NULL;		
-	i = PyNumber_Index(a1);
-	if (i == -1 && PyErr_Occurred())
-		return NULL;
-	else
-		return PyInt_FromSsize_t(i);
+	return PyNumber_Index(a);
 }
 
 static PyObject*
@@ -249,7 +241,7 @@ spam1o(isMappingType,
 
 spam1(is_, "is_(a, b) -- Same as a is b.")
 spam1(is_not, "is_not(a, b) -- Same as a is not b.")
-spam2(index, __index__, "index(a) -- Same as a.__index__()")
+spam2o(index, __index__, "index(a) -- Same as a.__index__()")
 spam2(add,__add__, "add(a, b) -- Same as a + b.")
 spam2(sub,__sub__, "sub(a, b) -- Same as a - b.")
 spam2(mul,__mul__, "mul(a, b) -- Same as a * b.")
diff --git a/Objects/abstract.c b/Objects/abstract.c
index bad9f96..c8e9ddc 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -8,8 +8,6 @@
 #define NEW_STYLE_NUMBER(o) PyType_HasFeature((o)->ob_type, \
 				Py_TPFLAGS_CHECKTYPES)
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
-
 
 /* Shorthands to return certain errors */
 
@@ -122,9 +120,9 @@ PyObject_GetItem(PyObject *o, PyObject *key)
 		return m->mp_subscript(o, key);
 
 	if (o->ob_type->tp_as_sequence) {
-		PyNumberMethods *nb = key->ob_type->tp_as_number;
-		if (nb != NULL && HASINDEX(key) && nb->nb_index != NULL) {
-			Py_ssize_t key_value = nb->nb_index(key);
+		if (PyIndex_Check(key)) {
+			Py_ssize_t key_value;
+			key_value = PyNumber_AsSsize_t(key, PyExc_IndexError);
 			if (key_value == -1 && PyErr_Occurred())
 				return NULL;
 			return PySequence_GetItem(o, key_value);
@@ -151,9 +149,9 @@ PyObject_SetItem(PyObject *o, PyObject *key, PyObject *value)
 		return m->mp_ass_subscript(o, key, value);
 
 	if (o->ob_type->tp_as_sequence) {
-		PyNumberMethods *nb = key->ob_type->tp_as_number;
-		if (nb != NULL && HASINDEX(key) && nb->nb_index != NULL) {
-			Py_ssize_t key_value = nb->nb_index(key);
+		if (PyIndex_Check(key)) {
+			Py_ssize_t key_value;
+			key_value = PyNumber_AsSsize_t(key, PyExc_IndexError);
 			if (key_value == -1 && PyErr_Occurred())
 				return -1;
 			return PySequence_SetItem(o, key_value, value);
@@ -183,9 +181,9 @@ PyObject_DelItem(PyObject *o, PyObject *key)
 		return m->mp_ass_subscript(o, key, (PyObject*)NULL);
 
 	if (o->ob_type->tp_as_sequence) {
-		PyNumberMethods *nb = key->ob_type->tp_as_number;
-		if (nb != NULL && HASINDEX(key) && nb->nb_index != NULL) {
-			Py_ssize_t key_value = nb->nb_index(key);
+		if (PyIndex_Check(key)) {
+			Py_ssize_t key_value;
+			key_value = PyNumber_AsSsize_t(key, PyExc_IndexError);
 			if (key_value == -1 && PyErr_Occurred())
 				return -1;
 			return PySequence_DelItem(o, key_value);
@@ -653,9 +651,8 @@ static PyObject *
 sequence_repeat(ssizeargfunc repeatfunc, PyObject *seq, PyObject *n)
 {
 	Py_ssize_t count;
-	PyNumberMethods *nb = n->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(n) && nb->nb_index != NULL) {
-		count = nb->nb_index(n);
+	if (PyIndex_Check(n)) {
+		count = PyNumber_AsSsize_t(n, PyExc_OverflowError);
 		if (count == -1 && PyErr_Occurred())
 			return NULL;
 	}
@@ -938,23 +935,89 @@ int_from_string(const char *s, Py_ssize_t len)
 	return x;
 }
 
-/* Return a Py_ssize_t integer from the object item */
-Py_ssize_t 
+/* Return a Python Int or Long from the object item 
+   Raise TypeError if the result is not an int-or-long
+   or if the object cannot be interpreted as an index. 
+*/
+PyObject *
 PyNumber_Index(PyObject *item)
 {
-	Py_ssize_t value = -1;
-	PyNumberMethods *nb = item->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		value = nb->nb_index(item);
+	PyObject *result = NULL;
+	if (item == NULL)
+		return null_error();
+	/* XXX(nnorwitz): should these be CheckExact?  Aren't subclasses ok? */
+	if (PyInt_CheckExact(item) || PyLong_CheckExact(item)) {
+		Py_INCREF(item);
+		return item;
+	}
+	if (PyIndex_Check(item)) {
+		result = item->ob_type->tp_as_number->nb_index(item);
+		/* XXX(nnorwitz): Aren't subclasses ok here too? */
+		if (result &&
+		    !PyInt_CheckExact(result) && !PyLong_CheckExact(result)) {
+			PyErr_Format(PyExc_TypeError,
+				     "__index__ returned non-(int,long) " \
+				     "(type %.200s)",
+				     result->ob_type->tp_name);
+			Py_DECREF(result);
+			return NULL;
+		}
 	}
 	else {
 		PyErr_Format(PyExc_TypeError,
 			     "'%.200s' object cannot be interpreted "
 			     "as an index", item->ob_type->tp_name);
 	}
-	return value;
+	return result;
+}
+
+/* Return an error on Overflow only if err is not NULL*/
+
+Py_ssize_t
+PyNumber_AsSsize_t(PyObject *item, PyObject *err)
+{
+	Py_ssize_t result;
+	PyObject *runerr;
+	PyObject *value = PyNumber_Index(item);
+	if (value == NULL)
+		return -1;
+
+	/* We're done if PyInt_AsSsize_t() returns without error. */
+	result = PyInt_AsSsize_t(value);
+	if (result != -1 || !(runerr = PyErr_Occurred()))
+		goto finish;
+
+	/* Error handling code -- only manage OverflowError differently */
+	if (!PyErr_GivenExceptionMatches(runerr, PyExc_OverflowError)) 
+		goto finish;
+
+	PyErr_Clear();
+	/* If no error-handling desired then the default clipping 
+	   is sufficient.
+	 */
+	if (!err) {
+		assert(PyLong_Check(value));
+		/* Whether or not it is less than or equal to 
+		   zero is determined by the sign of ob_size
+		*/
+		if (_PyLong_Sign(value) < 0) 
+			result = PY_SSIZE_T_MIN;
+		else
+			result = PY_SSIZE_T_MAX;
+	}
+	else {
+		/* Otherwise replace the error with caller's error object. */
+		PyErr_Format(err,
+			     "cannot fit '%.200s' into an index-sized integer", 
+			     item->ob_type->tp_name); 
+	}
+	
+ finish:
+	Py_DECREF(value);
+	return result;
 }
 
+
 PyObject *
 PyNumber_Int(PyObject *o)
 {
diff --git a/Objects/classobject.c b/Objects/classobject.c
index 56bf29c..1e93908 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -1670,40 +1670,28 @@ instance_nonzero(PyInstanceObject *self)
 	return outcome > 0;
 }
 
-static Py_ssize_t
+static PyObject *
 instance_index(PyInstanceObject *self)
 {
 	PyObject *func, *res;
-	Py_ssize_t outcome;
 	static PyObject *indexstr = NULL;
 
 	if (indexstr == NULL) {
 		indexstr = PyString_InternFromString("__index__");
 		if (indexstr == NULL)
-			return -1;
+			return NULL;
 	}	
 	if ((func = instance_getattr(self, indexstr)) == NULL) {
 		if (!PyErr_ExceptionMatches(PyExc_AttributeError))
-			return -1;
+			return NULL;
 		PyErr_Clear();
 		PyErr_SetString(PyExc_TypeError, 
 				"object cannot be interpreted as an index");
-		return -1;
+		return NULL;
 	}
 	res = PyEval_CallObject(func, (PyObject *)NULL);
 	Py_DECREF(func);
-	if (res == NULL)
-		return -1;
-	if (PyInt_Check(res) || PyLong_Check(res)) {
-		outcome = res->ob_type->tp_as_number->nb_index(res);
-	}
-	else {
-		PyErr_SetString(PyExc_TypeError, 
-				"__index__ must return an int or a long");
-		outcome = -1;
-	}
-	Py_DECREF(res);
-	return outcome;
+	return res;
 }
 
 
@@ -2026,7 +2014,7 @@ static PyNumberMethods instance_as_number = {
 	instance_truediv,		/* nb_true_divide */
 	instance_ifloordiv,		/* nb_inplace_floor_divide */
 	instance_itruediv,		/* nb_inplace_true_divide */
-	(lenfunc)instance_index,	/* nb_index */
+	(unaryfunc)instance_index,	/* nb_index */
 };
 
 PyTypeObject PyInstance_Type = {
diff --git a/Objects/intobject.c b/Objects/intobject.c
index 2062bee..c7137df 100644
--- a/Objects/intobject.c
+++ b/Objects/intobject.c
@@ -193,16 +193,21 @@ PyInt_AsSsize_t(register PyObject *op)
 	PyIntObject *io;
 	Py_ssize_t val;
 #endif
-	if (op && !PyInt_CheckExact(op) && PyLong_Check(op))
+
+	if (op == NULL) {
+		PyErr_SetString(PyExc_TypeError, "an integer is required");
+		return -1;
+	}
+
+	if (PyInt_Check(op))
+		return PyInt_AS_LONG((PyIntObject*) op);
+	if (PyLong_Check(op))
 		return _PyLong_AsSsize_t(op);
 #if SIZEOF_SIZE_T == SIZEOF_LONG
 	return PyInt_AsLong(op);
 #else
 
-	if (op && PyInt_Check(op))
-		return PyInt_AS_LONG((PyIntObject*) op);
-
-	if (op == NULL || (nb = op->ob_type->tp_as_number) == NULL ||
+	if ((nb = op->ob_type->tp_as_number) == NULL ||
 	    (nb->nb_int == NULL && nb->nb_long == 0)) {
 		PyErr_SetString(PyExc_TypeError, "an integer is required");
 		return -1;
@@ -1079,7 +1084,7 @@ static PyNumberMethods int_as_number = {
 	int_true_divide,	/* nb_true_divide */
 	0,			/* nb_inplace_floor_divide */
 	0,			/* nb_inplace_true_divide */
-	PyInt_AsSsize_t,	/* nb_index */
+	(unaryfunc)int_int,	/* nb_index */
 };
 
 PyTypeObject PyInt_Type = {
diff --git a/Objects/listobject.c b/Objects/listobject.c
index f917385..ad27644 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2450,14 +2450,13 @@ PyDoc_STRVAR(list_doc,
 "list() -> new list\n"
 "list(sequence) -> new list initialized from sequence's items");
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
 
 static PyObject *
 list_subscript(PyListObject* self, PyObject* item)
 {
-	PyNumberMethods *nb = item->ob_type->tp_as_number;	
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(item);
+	if (PyIndex_Check(item)) {
+		Py_ssize_t i;
+		i = PyNumber_AsSsize_t(item, PyExc_IndexError);
 		if (i == -1 && PyErr_Occurred())
 			return NULL;
 		if (i < 0)
@@ -2504,9 +2503,8 @@ list_subscript(PyListObject* self, PyObject* item)
 static int
 list_ass_subscript(PyListObject* self, PyObject* item, PyObject* value)
 {
-	PyNumberMethods *nb = item->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(item);
+	if (PyIndex_Check(item)) {
+		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
 		if (i == -1 && PyErr_Occurred())
 			return -1;
 		if (i < 0)
diff --git a/Objects/longobject.c b/Objects/longobject.c
index 4ce9479..e32c425 100644
--- a/Objects/longobject.c
+++ b/Objects/longobject.c
@@ -240,8 +240,11 @@ PyLong_AsLong(PyObject *vv)
 	return -1;
 }
 
-static Py_ssize_t
-_long_as_ssize_t(PyObject *vv) {
+/* Get a Py_ssize_t from a long int object.
+   Returns -1 and sets an error condition if overflow occurs. */
+
+Py_ssize_t
+_PyLong_AsSsize_t(PyObject *vv) {
 	register PyLongObject *v;
 	size_t x, prev;
 	Py_ssize_t i;
@@ -277,45 +280,7 @@ _long_as_ssize_t(PyObject *vv) {
  overflow:
 	PyErr_SetString(PyExc_OverflowError,
 			"long int too large to convert to int");
-	if (sign > 0)
-		return PY_SSIZE_T_MAX;
-	else
-		return PY_SSIZE_T_MIN;
-}
-
-/* Get a Py_ssize_t from a long int object.
-   Returns -1 and sets an error condition if overflow occurs. */
-
-Py_ssize_t
-_PyLong_AsSsize_t(PyObject *vv)
-{
-	Py_ssize_t x;
-
-	x = _long_as_ssize_t(vv);
-	if (PyErr_Occurred()) return -1;
-	return x;
-}
-
-
-/* Get a Py_ssize_t from a long int object.
-   Silently reduce values larger than PY_SSIZE_T_MAX to PY_SSIZE_T_MAX,
-   and silently boost values less than -PY_SSIZE_T_MAX-1 to -PY_SSIZE_T_MAX-1.
-   On error, return -1 with an exception set.
-*/
-
-static Py_ssize_t
-long_index(PyObject *vv)
-{
-	Py_ssize_t x;
-
-	x = _long_as_ssize_t(vv);
-	if (PyErr_Occurred()) {
-		/* If overflow error, ignore the error */
-		if (x != -1) {
-			PyErr_Clear();
-		}
-	}
-	return x;
+	return -1;
 }
 
 /* Get a C unsigned long int from a long int object.
@@ -3405,7 +3370,7 @@ static PyNumberMethods long_as_number = {
 	long_true_divide,		/* nb_true_divide */
 	0,				/* nb_inplace_floor_divide */
 	0,				/* nb_inplace_true_divide */
-	long_index,			/* nb_index */
+	long_long,			/* nb_index */
 };
 
 PyTypeObject PyLong_Type = {
diff --git a/Objects/sliceobject.c b/Objects/sliceobject.c
index 271a9ad..d8a2465 100644
--- a/Objects/sliceobject.c
+++ b/Objects/sliceobject.c
@@ -252,7 +252,7 @@ slice_indices(PySliceObject* self, PyObject* len)
 {
 	Py_ssize_t ilen, start, stop, step, slicelength;
 
-	ilen = PyInt_AsSsize_t(len);
+	ilen = PyNumber_AsSsize_t(len, PyExc_OverflowError);
 
 	if (ilen == -1 && PyErr_Occurred()) {
 		return NULL;
diff --git a/Objects/stringobject.c b/Objects/stringobject.c
index 91f0103..bbbeaa6 100644
--- a/Objects/stringobject.c
+++ b/Objects/stringobject.c
@@ -1184,14 +1184,11 @@ string_hash(PyStringObject *a)
 	return x;
 }
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
-
 static PyObject*
 string_subscript(PyStringObject* self, PyObject* item)
 {
-	PyNumberMethods *nb = item->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(item);
+	if (PyIndex_Check(item)) {
+		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
 		if (i == -1 && PyErr_Occurred())
 			return NULL;
 		if (i < 0)
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 2161ab9..6f3711f 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -577,14 +577,11 @@ static PySequenceMethods tuple_as_sequence = {
 	(objobjproc)tuplecontains,		/* sq_contains */
 };
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
-
 static PyObject*
 tuplesubscript(PyTupleObject* self, PyObject* item)
 {
-	PyNumberMethods *nb = item->ob_type->tp_as_number;
-	if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-		Py_ssize_t i = nb->nb_index(item);
+	if (PyIndex_Check(item)) {
+		Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
 		if (i == -1 && PyErr_Occurred())
 			return NULL;
 		if (i < 0)
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 485d2bb..517d4db 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -3527,7 +3527,7 @@ wrap_indexargfunc(PyObject *self, PyObject *args, void *wrapped)
 
 	if (!PyArg_UnpackTuple(args, "", 1, 1, &o))
 		return NULL;
-	i = PyNumber_Index(o);
+	i = PyNumber_AsSsize_t(o, PyExc_OverflowError);
 	if (i == -1 && PyErr_Occurred())
 		return NULL;
 	return (*func)(self, i);
@@ -3538,7 +3538,7 @@ getindex(PyObject *self, PyObject *arg)
 {
 	Py_ssize_t i;
 
-	i = PyNumber_Index(arg);
+	i = PyNumber_AsSsize_t(arg, PyExc_OverflowError);
 	if (i == -1 && PyErr_Occurred())
 		return -1;
 	if (i < 0) {
@@ -4344,26 +4344,11 @@ slot_nb_nonzero(PyObject *self)
 }
 
 
-static Py_ssize_t 
+static PyObject *
 slot_nb_index(PyObject *self)
 {
 	static PyObject *index_str;
-	PyObject *temp = call_method(self, "__index__", &index_str, "()");
-	Py_ssize_t result;
-
-	if (temp == NULL)
-		return -1;
-	if (PyInt_CheckExact(temp) || PyLong_CheckExact(temp)) {
-		result = temp->ob_type->tp_as_number->nb_index(temp);
-	}
-	else {
-		PyErr_Format(PyExc_TypeError, 
-			     "__index__ must return an int or a long, "
-			     "not '%.200s'", temp->ob_type->tp_name);
-		result = -1;
-	}
-	Py_DECREF(temp);
-	return result;
+	return call_method(self, "__index__", &index_str, "()");
 }
 
 
@@ -5109,7 +5094,7 @@ static slotdef slotdefs[] = {
 	       "oct(x)"),
 	UNSLOT("__hex__", nb_hex, slot_nb_hex, wrap_unaryfunc,
 	       "hex(x)"),
-	NBSLOT("__index__", nb_index, slot_nb_index, wrap_lenfunc, 
+	NBSLOT("__index__", nb_index, slot_nb_index, wrap_unaryfunc, 
 	       "x[y:z] <==> x[y.__index__():z.__index__()]"),
 	IBSLOT("__iadd__", nb_inplace_add, slot_nb_inplace_add,
 	       wrap_binaryfunc, "+"),
diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 096dfc6..ababda1 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -6985,14 +6985,11 @@ static PySequenceMethods unicode_as_sequence = {
     PyUnicode_Contains, 		/* sq_contains */
 };
 
-#define HASINDEX(o) PyType_HasFeature((o)->ob_type, Py_TPFLAGS_HAVE_INDEX)
-
 static PyObject*
 unicode_subscript(PyUnicodeObject* self, PyObject* item)
 {
-    PyNumberMethods *nb = item->ob_type->tp_as_number;
-    if (nb != NULL && HASINDEX(item) && nb->nb_index != NULL) {
-        Py_ssize_t i = nb->nb_index(item);
+    if (PyIndex_Check(item)) {
+        Py_ssize_t i = PyNumber_AsSsize_t(item, PyExc_IndexError);
         if (i == -1 && PyErr_Occurred())
             return NULL;
         if (i < 0)
diff --git a/Python/ceval.c b/Python/ceval.c
index a0e8b30..cd8ff9b 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -3866,12 +3866,14 @@ _PyEval_SliceIndex(PyObject *v, Py_ssize_t *pi)
 	if (v != NULL) {
 		Py_ssize_t x;
 		if (PyInt_Check(v)) {
-			x = PyInt_AsSsize_t(v);
+			/* XXX(nnorwitz): I think PyInt_AS_LONG is correct,
+			   however, it looks like it should be AsSsize_t.
+			   There should be a comment here explaining why.
+			*/
+			x = PyInt_AS_LONG(v);
 		}
-		else if (v->ob_type->tp_as_number &&
-			 PyType_HasFeature(v->ob_type, Py_TPFLAGS_HAVE_INDEX)
-			 && v->ob_type->tp_as_number->nb_index) {
-			x = v->ob_type->tp_as_number->nb_index(v);
+		else if (PyIndex_Check(v)) {
+			x = PyNumber_AsSsize_t(v, NULL);
 			if (x == -1 && PyErr_Occurred())
 				return 0;
 		}
@@ -3887,10 +3889,8 @@ _PyEval_SliceIndex(PyObject *v, Py_ssize_t *pi)
 }
 
 #undef ISINDEX
-#define ISINDEX(x) ((x) == NULL || PyInt_Check(x) || PyLong_Check(x) || \
-		    ((x)->ob_type->tp_as_number && \
-                     PyType_HasFeature((x)->ob_type, Py_TPFLAGS_HAVE_INDEX) \
-		     && (x)->ob_type->tp_as_number->nb_index))
+#define ISINDEX(x) ((x) == NULL || \
+		    PyInt_Check(x) || PyLong_Check(x) || PyIndex_Check(x))
 
 static PyObject *
 apply_slice(PyObject *u, PyObject *v, PyObject *w) /* return u[v:w] */