bpo-29935: Fixed error messages in the index() method of tuple and list (#887) (#907) (#910)

when pass indices of wrong type.
(cherry picked from commit d4edfc9)
(cherry picked from commit bf4bb2e)

Author: serhiy-storchaka

Include/ceval.h

@@ -145,6 +145,7 @@ PyAPI_FUNC(void) PyEval_ReInitThreads(void);
 #endif /* !WITH_THREAD */
 
 PyAPI_FUNC(int) _PyEval_SliceIndex(PyObject *, Py_ssize_t *);
+PyAPI_FUNC(int) _PyEval_SliceIndexNotNone(PyObject *, Py_ssize_t *);
 
 
 #ifdef __cplusplus

Misc/NEWS

@@ -10,6 +10,9 @@ What's New in Python 2.7.14?
 Core and Builtins
 -----------------
 
+- bpo-29935: Fixed error messages in the index() method of tuple and list
+  when pass indices of wrong type.
+
 - bpo-28598: Support __rmod__ for subclasses of str being called before
   str.__mod__.  Patch by Martijn Pieters.
 

Objects/listobject.c

@@ -2284,8 +2284,8 @@ listindex(PyListObject *self, PyObject *args)
     static PyObject *err_format = NULL;
 
     if (!PyArg_ParseTuple(args, "O|O&O&:index", &v,
-                                _PyEval_SliceIndex, &start,
-                                _PyEval_SliceIndex, &stop))
+                                _PyEval_SliceIndexNotNone, &start,
+                                _PyEval_SliceIndexNotNone, &stop))
         return NULL;
     if (start < 0) {
         start += Py_SIZE(self);

Objects/tupleobject.c

@@ -515,8 +515,8 @@ tupleindex(PyTupleObject *self, PyObject *args)
     PyObject *v;
 
     if (!PyArg_ParseTuple(args, "O|O&O&:index", &v,
-                                _PyEval_SliceIndex, &start,
-                                _PyEval_SliceIndex, &stop))
+                                _PyEval_SliceIndexNotNone, &start,
+                                _PyEval_SliceIndexNotNone, &stop))
         return NULL;
     if (start < 0) {
         start += Py_SIZE(self);

Python/ceval.c

@@ -4689,7 +4689,7 @@ ext_do_call(PyObject *func, PyObject ***pp_stack, int flags, int na, int nk)
 int
 _PyEval_SliceIndex(PyObject *v, Py_ssize_t *pi)
 {
-    if (v != NULL) {
+    if (v != NULL && v != Py_None) {
         Py_ssize_t x;
         if (PyInt_Check(v)) {
             /* XXX(nnorwitz): I think PyInt_AS_LONG is correct,
@@ -4714,6 +4714,26 @@ _PyEval_SliceIndex(PyObject *v, Py_ssize_t *pi)
     return 1;
 }
 
+int
+_PyEval_SliceIndexNotNone(PyObject *v, Py_ssize_t *pi)
+{
+    Py_ssize_t x;
+    if (PyIndex_Check(v)) {
+        x = PyNumber_AsSsize_t(v, NULL);
+        if (x == -1 && PyErr_Occurred())
+            return 0;
+    }
+    else {
+        PyErr_SetString(PyExc_TypeError,
+                        "slice indices must be integers or "
+                        "have an __index__ method");
+        return 0;
+    }
+    *pi = x;
+    return 1;
+}
+
+
 #undef ISINDEX
 #define ISINDEX(x) ((x) == NULL || \
                     PyInt_Check(x) || PyLong_Check(x) || PyIndex_Check(x))