bpo-34204: Use pickle.DEFAULT_PROTOCOL in shelve (GH-19639)

Use pickle.DEFAULT_PROTOCOL (currently 5) in shelve instead of a
hardcoded 3.
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Zackery Spytz 2020-10-29 03:44:35 -06:00 committed by GitHub
parent 4173320920
commit df59273c7a
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5 changed files with 29 additions and 8 deletions

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@ -25,8 +25,9 @@ lots of shared sub-objects. The keys are ordinary strings.
database file is opened for reading and writing. The optional *flag* parameter
has the same interpretation as the *flag* parameter of :func:`dbm.open`.
By default, version 3 pickles are used to serialize values. The version of the
pickle protocol can be specified with the *protocol* parameter.
By default, pickles created with :data:`pickle.DEFAULT_PROTOCOL` are used
to serialize values. The version of the pickle protocol can be specified
with the *protocol* parameter.
Because of Python semantics, a shelf cannot know when a mutable
persistent-dictionary entry is modified. By default modified objects are
@ -40,6 +41,10 @@ lots of shared sub-objects. The keys are ordinary strings.
determine which accessed entries are mutable, nor which ones were actually
mutated).
.. versionchanged:: 3.10
:data:`pickle.DEFAULT_PROTOCOL` is now used as the default pickle
protocol.
.. note::
Do not rely on the shelf being closed automatically; always call
@ -108,9 +113,10 @@ Restrictions
A subclass of :class:`collections.abc.MutableMapping` which stores pickled
values in the *dict* object.
By default, version 3 pickles are used to serialize values. The version of the
pickle protocol can be specified with the *protocol* parameter. See the
:mod:`pickle` documentation for a discussion of the pickle protocols.
By default, pickles created with :data:`pickle.DEFAULT_PROTOCOL` are used
to serialize values. The version of the pickle protocol can be specified
with the *protocol* parameter. See the :mod:`pickle` documentation for a
discussion of the pickle protocols.
If the *writeback* parameter is ``True``, the object will hold a cache of all
entries accessed and write them back to the *dict* at sync and close times.
@ -130,6 +136,10 @@ Restrictions
.. versionchanged:: 3.4
Added context manager support.
.. versionchanged:: 3.10
:data:`pickle.DEFAULT_PROTOCOL` is now used as the default pickle
protocol.
.. class:: BsdDbShelf(dict, protocol=None, writeback=False, keyencoding='utf-8')

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@ -210,6 +210,13 @@ py_compile
Added ``--quiet`` option to command-line interface of :mod:`py_compile`.
(Contributed by Gregory Schevchenko in :issue:`38731`.)
shelve
------
The :mod:`shelve` module now uses :data:`pickle.DEFAULT_PROTOCOL` by default
instead of :mod:`pickle` protocol ``3`` when creating shelves.
(Contributed by Zackery Spytz in :issue:`34204`.)
sys
---

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@ -56,7 +56,7 @@ entries in the cache, and empty the cache (d.sync() also synchronizes
the persistent dictionary on disk, if feasible).
"""
from pickle import Pickler, Unpickler
from pickle import DEFAULT_PROTOCOL, Pickler, Unpickler
from io import BytesIO
import collections.abc
@ -85,7 +85,7 @@ class Shelf(collections.abc.MutableMapping):
keyencoding="utf-8"):
self.dict = dict
if protocol is None:
protocol = 3
protocol = DEFAULT_PROTOCOL
self._protocol = protocol
self.writeback = writeback
self.cache = {}

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@ -1,6 +1,8 @@
import unittest
import shelve
import glob
import pickle
from test import support
from test.support import os_helper
from collections.abc import MutableMapping
@ -160,7 +162,7 @@ class TestCase(unittest.TestCase):
def test_default_protocol(self):
with shelve.Shelf({}) as s:
self.assertEqual(s._protocol, 3)
self.assertEqual(s._protocol, pickle.DEFAULT_PROTOCOL)
from test import mapping_tests

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@ -0,0 +1,2 @@
The :mod:`shelve` module now uses :data:`pickle.DEFAULT_PROTOCOL` by default
instead of :mod:`pickle` protocol ``3``.