FYI: fix buglet in Frame comparison function

[Tom Tromey <tromey@redhat.com>]

I'm checking this in.

This fixes a bug in the gdb.Frame richcompare function.  The '!='
operator was not handled.  This also fixes the comparison function to
return Py_NotImplemented, as specified in the Python docs.

Built and regtested on x86-64 (compile farm).
A new test case is included.

Tom

2009-04-13  Tom Tromey  <tromey@redhat.com>

	* python/python-frame.c (frapy_richcompare): Return
	Py_NotImplemented, not an error.  Handle Py_NE as well.
	* python/lib/gdb/FrameIterator.py (FrameIterator.next): Use 'is'.

diff --git a/gdb/python/python-frame.c b/gdb/python/python-frame.c
index 8d6127e..a97009f 100644
--- a/gdb/python/python-frame.c
+++ b/gdb/python/python-frame.c
@@ -415,21 +415,23 @@ gdbpy_frame_stop_reason_string (PyObject *self, PyObject *args)
 static PyObject *
 frapy_richcompare (PyObject *self, PyObject *other, int op)
 {
-  if (!PyObject_TypeCheck (other, &frame_object_type))
-    {
-      PyErr_SetString (PyExc_TypeError, "Frame object expected in comparison.");
-      return NULL;
-    }
-  else if (op != Py_EQ)
+  int result;
+
+  if (!PyObject_TypeCheck (other, &frame_object_type)
+      || (op != Py_EQ && op != Py_NE))
     {
-      PyErr_SetString (PyExc_TypeError, "Invalid comparison for gdb.Frame.");
-      return NULL;
+      Py_INCREF (Py_NotImplemented);
+      return Py_NotImplemented;
     }
 
   if (frame_id_eq (((frame_object *) self)->frame_id,
 		   ((frame_object *) other)->frame_id))
-    Py_RETURN_TRUE;
+    result = Py_EQ;
+  else
+    result = Py_NE;
 
+  if (op == result)
+    Py_RETURN_TRUE;
   Py_RETURN_FALSE;
 }
 
diff --git a/gdb/testsuite/gdb.python/python-frame.exp b/gdb/testsuite/gdb.python/python-frame.exp
index b1ee9be..82b526e 100644
--- a/gdb/testsuite/gdb.python/python-frame.exp
+++ b/gdb/testsuite/gdb.python/python-frame.exp
@@ -70,6 +70,8 @@ gdb_py_test_silent_cmd "python f0 = f1.newer ()" "get first frame" 0
 
 gdb_test "python print 'result =', f0 == f1" " = False" "test equality comparison (false)"
 gdb_test "python print 'result =', f0 == f0" " = True" "test equality comparison (true)"
+gdb_test "python print 'result =', f0 != f1" " = True" "test inequality comparison (true)"
+gdb_test "python print 'result =', f0 != f0" " = False" "test inequality comparison (false)"
 gdb_test "python print 'result =', f0.is_valid ()" " = True" "test Frame.is_valid"
 gdb_test "python print 'result =', f0.name ()" " = f2" "test Frame.name"
 gdb_test "python print 'result =', f0.type () == gdb.NORMAL_FRAME" " = True" "test Frame.type"