Merged revisions 78141-78142 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/trunk

........
  r78141 | r.david.murray | 2010-02-10 20:38:42 -0500 (Wed, 10 Feb 2010) | 6 lines

  Issue 5754:  tweak shelve doc wording to make it clearer that even when
  writeback=True values are written to the backing store when assigned to
  the shelf.  Add test to confirm that this happens.  Doc patch and added
  test by Robert Lehmann.  I also fixed the cross references to the sync
  and close methods.
........
  r78142 | r.david.murray | 2010-02-10 20:56:42 -0500 (Wed, 10 Feb 2010) | 3 lines

  Improve issue 7835 fix per MAL to handle the case that the
  module dictionary has also been cleared.
........

Lib/shelve.py

@@ -145,11 +145,12 @@ class Shelf(UserDict.DictMixin):
             self.dict.close()
         except AttributeError:
             pass
-        # _ClosedDict can be None when close is called from __del__ during shutdown
-        if _ClosedDict is None:
-            self.dict = None
-        else:
+        # Catch errors that may happen when close is called from __del__
+        # because CPython is in interpreter shutdown.
+        try:
             self.dict = _ClosedDict()
+        except (NameError, TypeError):
+            self.dict = None
 
     def __del__(self):
         if not hasattr(self, 'writeback'):

Lib/test/test_shelve.py

@@ -88,6 +88,17 @@ class TestCase(unittest.TestCase):
         self.assertEqual(len(d1), 1)
         self.assertEqual(len(d2), 1)
 
+    def test_writeback_also_writes_immediately(self):
+        # Issue 5754
+        d = {}
+        s = shelve.Shelf(d, writeback=True)
+        s['key'] = [1]
+        p1 = d['key']  # Will give a KeyError if backing store not updated
+        s['key'].append(2)
+        s.close()
+        p2 = d['key']
+        self.assertNotEqual(p1, p2)  # Write creates new object in store
+
 
 from test import mapping_tests