From b92a305d2ad46cc7ba918da8d21531677d48862c Mon Sep 17 00:00:00 2001 From: "R. David Murray" Date: Thu, 11 Feb 2010 02:01:02 +0000 Subject: [PATCH] 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. ........ --- Doc/library/shelve.rst | 17 +++++++++-------- Lib/shelve.py | 9 +++++---- Lib/test/test_shelve.py | 11 +++++++++++ Misc/ACKS | 1 + 4 files changed, 26 insertions(+), 12 deletions(-) diff --git a/Doc/library/shelve.rst b/Doc/library/shelve.rst index 5d82dc42d5..c0bcb80f19 100644 --- a/Doc/library/shelve.rst +++ b/Doc/library/shelve.rst @@ -30,14 +30,15 @@ lots of shared sub-objects. The keys are ordinary strings. Because of Python semantics, a shelf cannot know when a mutable persistent-dictionary entry is modified. By default modified objects are - written only when assigned to the shelf (see :ref:`shelve-example`). If the - optional *writeback* parameter is set to *True*, all entries accessed are - cached in memory, and written back on :meth:`sync` and :meth:`close`; this - can make it handier to mutate mutable entries in the persistent dictionary, - but, if many entries are accessed, it can consume vast amounts of memory for - the cache, and it can make the close operation very slow since all accessed - entries are written back (there is no way to determine which accessed entries - are mutable, nor which ones were actually mutated). + written *only* when assigned to the shelf (see :ref:`shelve-example`). If the + optional *writeback* parameter is set to *True*, all entries accessed are also + cached in memory, and written back on :meth:`~Shelf.sync` and + :meth:`~Shelf.close`; this can make it handier to mutate mutable entries in + the persistent dictionary, but, if many entries are accessed, it can consume + vast amounts of memory for the cache, and it can make the close operation + very slow since all accessed entries are written back (there is no way to + determine which accessed entries are mutable, nor which ones were actually + mutated). .. note:: diff --git a/Lib/shelve.py b/Lib/shelve.py index 8055f42e22..c8cba8582d 100644 --- a/Lib/shelve.py +++ b/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'): diff --git a/Lib/test/test_shelve.py b/Lib/test/test_shelve.py index ffcc98da56..f03457f978 100644 --- a/Lib/test/test_shelve.py +++ b/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 diff --git a/Misc/ACKS b/Misc/ACKS index 6562b7e75a..1d2daac96b 100644 --- a/Misc/ACKS +++ b/Misc/ACKS @@ -418,6 +418,7 @@ Luc Lefebvre Vincent Legoll Kip Lehman Joerg Lehmann +Robert Lehmann Luke Kenneth Casson Leighton Marc-Andre Lemburg John Lenton -- 2.40.0