changeset:   98575:4b2a2688d2ad
parent:      98570:db782c81bba9
parent:      98574:e02e4afcce6a
user:        Benjamin Peterson <benjamin@python.org>
date:        Tue Oct 06 19:42:46 2015 -0700
files:       Misc/NEWS Objects/typeobject.c
description:
merge 3.5 (closes #24806)


diff -r db782c81bba9 -r 4b2a2688d2ad Lib/test/test_descr.py
--- a/Lib/test/test_descr.py	Tue Oct 06 15:29:09 2015 -0500
+++ b/Lib/test/test_descr.py	Tue Oct 06 19:42:46 2015 -0700
@@ -3798,6 +3798,37 @@
         else:
             assert 0, "best_base calculation found wanting"
 
+    def test_unsubclassable_types(self):
+        with self.assertRaises(TypeError):
+            class X(type(None)):
+                pass
+        with self.assertRaises(TypeError):
+            class X(object, type(None)):
+                pass
+        with self.assertRaises(TypeError):
+            class X(type(None), object):
+                pass
+        class O(object):
+            pass
+        with self.assertRaises(TypeError):
+            class X(O, type(None)):
+                pass
+        with self.assertRaises(TypeError):
+            class X(type(None), O):
+                pass
+
+        class X(object):
+            pass
+        with self.assertRaises(TypeError):
+            X.__bases__ = type(None),
+        with self.assertRaises(TypeError):
+            X.__bases__ = object, type(None)
+        with self.assertRaises(TypeError):
+            X.__bases__ = type(None), object
+        with self.assertRaises(TypeError):
+            X.__bases__ = O, type(None)
+        with self.assertRaises(TypeError):
+            X.__bases__ = type(None), O
 
     def test_mutable_bases_with_failing_mro(self):
         # Testing mutable bases with failing mro...
diff -r db782c81bba9 -r 4b2a2688d2ad Misc/NEWS
--- a/Misc/NEWS	Tue Oct 06 15:29:09 2015 -0500
+++ b/Misc/NEWS	Tue Oct 06 19:42:46 2015 -0700
@@ -10,6 +10,9 @@
 Core and Builtins
 -----------------
 
+- Issue #24806: Prevent builtin types that are not allowed to be subclassed from
+  being subclassed through multiple inheritance.
+
 * Issue #25301: The UTF-8 decoder is now up to 15 times as fast for error
   handlers: ``ignore``, ``replace`` and ``surrogateescape``.
 
diff -r db782c81bba9 -r 4b2a2688d2ad Objects/typeobject.c
--- a/Objects/typeobject.c	Tue Oct 06 15:29:09 2015 -0500
+++ b/Objects/typeobject.c	Tue Oct 06 19:42:46 2015 -0700
@@ -1973,6 +1973,12 @@
             if (PyType_Ready(base_i) < 0)
                 return NULL;
         }
+        if (!PyType_HasFeature(base_i, Py_TPFLAGS_BASETYPE)) {
+            PyErr_Format(PyExc_TypeError,
+                         "type '%.100s' is not an acceptable base type",
+                         base_i->tp_name);
+            return NULL;
+        }
         candidate = solid_base(base_i);
         if (winner == NULL) {
             winner = candidate;
@@ -2353,12 +2359,6 @@
     if (base == NULL) {
         goto error;
     }
-    if (!PyType_HasFeature(base, Py_TPFLAGS_BASETYPE)) {
-        PyErr_Format(PyExc_TypeError,
-                     "type '%.100s' is not an acceptable base type",
-                     base->tp_name);
-        goto error;
-    }
 
     dict = PyDict_Copy(orig_dict);
     if (dict == NULL)