Added a missing type error to void crashes under unlikely situations.

src/persistent/cPersistence.c

@@ -474,25 +474,25 @@ pickle___setstate__(PyObject *self, PyObject *state)
       PyObject **dict;
 
       dict = _PyObject_GetDictPtr(self);
-      if (dict)
+      
+      if (!dict)
         {
+          PyErr_SetString(PyExc_TypeError,
+                          "this object has no instance dictionary");
+          return NULL;
+        }
+
       if (!*dict)
         {
           *dict = PyDict_New();
           if (!*dict)
             return NULL;
         }
-        }
 
-      if (*dict)
-        {
       PyDict_Clear(*dict);
       if (PyDict_Update(*dict, state) < 0)
         return NULL;
     }
-      else if (pickle_setattrs_from_dict(self, state) < 0)
-        return NULL;
-    }
 
   if (slots && pickle_setattrs_from_dict(self, slots) < 0)
     return NULL;

src/persistent/tests/test_persistent.py

 ##############################################################################
 #
-# Copyright (c) 2001, 2002 Zope Corporation and Contributors.
+# Copyright (c) Zope Foundation and Contributors.
 # All Rights Reserved.
 #
 # This software is subject to the provisions of the Zope Public License,
-# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
+# Version 2.0 (ZPL).  A copy of the ZPL should accompany this distribution.
 # THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
 # WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 # WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
 # FOR A PARTICULAR PURPOSE.
 #
 ##############################################################################
+import unittest
 from zope.testing import doctest
 from persistent import Persistent
 
@@ -20,5 +21,23 @@ class P(Persistent):
     def inc(self):
         self.x += 1
 
+def cpersistent_setstate_pointer_sanity():
+    """
+    >>> Persistent().__setstate__({})
+    Traceback (most recent call last):
+    ...
+    TypeError: this object has no instance dictionary
+
+    >>> class C(Persistent): __slots__ = 'x', 'y'
+    >>> C().__setstate__(({}, {}))
+    Traceback (most recent call last):
+    ...
+    TypeError: this object has no instance dictionary
+    """
+
+
 def test_suite():
-    return doctest.DocFileSuite("persistent.txt", globs={"P": P})
+    return unittest.TestSuite((
+        doctest.DocFileSuite("persistent.txt", globs={"P": P}),
+        doctest.DocTestSuite(),
+        ))