Issue #22995: Instances of extension types with a state that aren't

subclasses of list or dict and haven't implemented any pickle-related
methods (__reduce__, __reduce_ex__, __getnewargs__, __getnewargs_ex__,
or __getstate__), can no longer be pickled.  Including memoryview.

Lib/test/test_buffer.py

@@ -4,6 +4,8 @@ For now, tests just new or changed functionality.
 
 """
 
+import copy
+import pickle
 import sys
 import unittest
 from test import test_support
@@ -35,6 +37,17 @@ class BufferTests(unittest.TestCase):
         buf = buffer(data, sys.maxsize, sys.maxsize)
         self.assertEqual(buf[:4096], "")
 
+    def test_copy(self):
+        buf = buffer(b'abc')
+        with self.assertRaises(TypeError):
+            copy.copy(buf)
+
+    def test_pickle(self):
+        buf = buffer(b'abc')
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises(TypeError):
+                pickle.dumps(buf, proto)
+
 
 def test_main():
     with test_support.check_py3k_warnings(("buffer.. not supported",

Lib/test/test_csv.py

@@ -2,6 +2,7 @@
 # Copyright (C) 2001,2002 Python Software Foundation
 # csv package unit tests
 
+import copy
 import sys
 import os
 import unittest
@@ -10,6 +11,7 @@ import tempfile
 import csv
 import gc
 import io
+import pickle
 from test import test_support
 
 class Test_Csv(unittest.TestCase):
@@ -466,6 +468,17 @@ class TestDialectRegistry(unittest.TestCase):
         self.assertRaises(TypeError, csv.reader, [], quoting = -1)
         self.assertRaises(TypeError, csv.reader, [], quoting = 100)
 
+    def test_copy(self):
+        for name in csv.list_dialects():
+            dialect = csv.get_dialect(name)
+            self.assertRaises(TypeError, copy.copy, dialect)
+
+    def test_pickle(self):
+        for name in csv.list_dialects():
+            dialect = csv.get_dialect(name)
+            for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+                self.assertRaises(TypeError, pickle.dumps, dialect, proto)
+
 class TestCsvBase(unittest.TestCase):
     def readerAssertEqual(self, input, expected_result):
         fd, name = tempfile.mkstemp()

Lib/test/test_memoryview.py

@@ -10,6 +10,8 @@ import weakref
 import array
 from test import test_support
 import io
+import copy
+import pickle
 
 
 class AbstractMemoryTests:
@@ -354,6 +356,19 @@ class BytesMemorySliceSliceTest(unittest.TestCase,
     #pass
 
 
+class OtherTest(unittest.TestCase):
+    def test_copy(self):
+        m = memoryview(b'abc')
+        with self.assertRaises(TypeError):
+            copy.copy(m)
+
+    def test_pickle(self):
+        m = memoryview(b'abc')
+        for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+            with self.assertRaises(TypeError):
+                pickle.dumps(m, proto)
+
+
 def test_main():
     test_support.run_unittest(__name__)
 

Misc/NEWS

@@ -10,6 +10,11 @@ What's New in Python 2.7.12?
 Core and Builtins
 -----------------
 
+- Issue #22995: Instances of extension types with a state that aren't
+  subclasses of list or dict and haven't implemented any pickle-related
+  methods (__reduce__, __reduce_ex__, __getnewargs__, __getnewargs_ex__,
+  or __getstate__), can no longer be pickled.  Including memoryview.
+
 - Issue #20440: Massive replacing unsafe attribute setting code with special
   macro Py_SETREF.
 

Objects/typeobject.c

@@ -3207,6 +3207,7 @@ reduce_2(PyObject *obj)
     PyObject *slots = NULL, *listitems = NULL, *dictitems = NULL;
     PyObject *copyreg = NULL, *newobj = NULL, *res = NULL;
     Py_ssize_t i, n;
+    int required_state = 0;
 
     cls = PyObject_GetAttrString(obj, "__class__");
     if (cls == NULL)
@@ -3214,7 +3215,7 @@ reduce_2(PyObject *obj)
 
     if (PyType_Check(cls) && ((PyTypeObject *)cls)->tp_new == NULL) {
         PyErr_Format(PyExc_TypeError,
-                     "can't pickle %s objects",
+                     "can't pickle %.200s objects",
                      ((PyTypeObject *)cls)->tp_name);
         return NULL;
     }
@@ -3223,7 +3224,9 @@ reduce_2(PyObject *obj)
     if (getnewargs != NULL) {
         args = PyObject_CallObject(getnewargs, NULL);
         Py_DECREF(getnewargs);
-        if (args != NULL && !PyTuple_Check(args)) {
+        if (args == NULL)
+            goto end;
+        if (!PyTuple_Check(args)) {
             PyErr_Format(PyExc_TypeError,
                 "__getnewargs__ should return a tuple, "
                 "not '%.200s'", Py_TYPE(args)->tp_name);
@@ -3232,10 +3235,8 @@ reduce_2(PyObject *obj)
     }
     else {
         PyErr_Clear();
-        args = PyTuple_New(0);
+        required_state = !PyList_Check(obj) && !PyDict_Check(obj);
     }
-    if (args == NULL)
-        goto end;
 
     getstate = PyObject_GetAttrString(obj, "__getstate__");
     if (getstate != NULL) {
@@ -3246,6 +3247,14 @@ reduce_2(PyObject *obj)
     }
     else {
         PyErr_Clear();
+
+        if (required_state && obj->ob_type->tp_itemsize) {
+            PyErr_Format(PyExc_TypeError,
+                         "can't pickle %.200s objects",
+                         Py_TYPE(obj)->tp_name);
+            goto end;
+        }
+
         state = PyObject_GetAttrString(obj, "__dict__");
         if (state == NULL) {
             PyErr_Clear();
@@ -3255,8 +3264,24 @@ reduce_2(PyObject *obj)
         names = slotnames(cls);
         if (names == NULL)
             goto end;
+        assert(names == Py_None || PyList_Check(names));
+        if (required_state) {
+            Py_ssize_t basicsize = PyBaseObject_Type.tp_basicsize;
+            if (obj->ob_type->tp_dictoffset)
+                basicsize += sizeof(PyObject *);
+            if (obj->ob_type->tp_weaklistoffset)
+                basicsize += sizeof(PyObject *);
+            if (names != Py_None)
+                basicsize += sizeof(PyObject *) * Py_SIZE(names);
+            if (obj->ob_type->tp_basicsize > basicsize) {
+                PyErr_Format(PyExc_TypeError,
+                             "can't pickle %.200s objects",
+                             Py_TYPE(obj)->tp_name);
+                goto end;
+            }
+        }
+
         if (names != Py_None) {
-            assert(PyList_Check(names));
             slots = PyDict_New();
             if (slots == NULL)
                 goto end;
@@ -3318,7 +3343,7 @@ reduce_2(PyObject *obj)
     if (newobj == NULL)
         goto end;
 
-    n = PyTuple_GET_SIZE(args);
+    n = args ? PyTuple_GET_SIZE(args) : 0;
     args2 = PyTuple_New(n+1);
     if (args2 == NULL)
         goto end;