Index: Objects/object.c
===================================================================
--- Objects/object.c	(révision 69678)
+++ Objects/object.c	(copie de travail)
@@ -1926,6 +1926,7 @@
 PyObject_Dir(PyObject *obj)
 {
 	PyObject * result;
+	Py_ssize_t i, len;
 
 	if (obj == NULL)
 		/* no object -- introspect the locals */
@@ -1934,9 +1935,25 @@
 		/* object -- introspect the object */
 		result = _dir_object(obj);
 
-	assert(result == NULL || PyList_Check(result));
+	if (result == NULL)
+		return NULL;
+
+	assert(PyList_Check(result));
+
+	len = PyList_GET_SIZE(result);
+	for (i = 0; i < len; i++) {
+		PyObject *v = PyList_GET_ITEM(result, i);
+		if (!PyString_Check(v)) {
+			PyErr_Format(PyExc_TypeError,
+				"__dir__() must return a list of string, "
+				"not a list of %.200s",
+				Py_TYPE(v)->tp_name);
+			Py_DECREF(result);
+			return NULL;
+		}
+	}
 
-	if (result != NULL && PyList_Sort(result) != 0) {
+	if (PyList_Sort(result) != 0) {
 		/* sorting the list failed */
 		Py_DECREF(result);
 		result = NULL;
Index: Lib/test/test_builtin.py
===================================================================
--- Lib/test/test_builtin.py	(révision 69678)
+++ Lib/test/test_builtin.py	(copie de travail)
@@ -290,6 +290,13 @@
         f = Foo()
         self.assertRaises(TypeError, dir, f)
 
+        # issue 1056293: list of non-string
+        class Foo(object):
+            def __dir__(self):
+                return [7]
+        f = Foo()
+        self.assertRaises(TypeError, dir, f)
+
     def test_divmod(self):
         self.assertEqual(divmod(12, 7), (1, 5))
         self.assertEqual(divmod(-12, 7), (-2, 2))