[Python-Dev] Strange error importing a Pickle from 2.7 to 3.2

[Alexander Belopolsky]

On Tue, Feb 22, 2011 at 11:34 PM, Jesus Cea <jcea at jcea.es> wrote:
..
> Issue filed. It already has a patch. That was fast!. Now I can sit back
> waiting for 3.2.1 before touching my project again :). Mixed feelings
> about the waiting. I hope it is short.

It looks like you don't need delay your project: if you spell encoding
as "latin-1", your pickle loads just fine:


>>> with open("z.pickle", mode="rb") as f: pickle.load(f, encoding="latin-1")
...
{'ya_volcados': {'comment': ''}}


With encoding="latin1", it does fail:

>>> with open("z.pickle", mode="rb") as f: pickle.load(f, encoding="latin1")
...
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: operation forbidden on released memoryview object

(For those not following the tracker issue, the z.pickle file was
posted at <http://bugs.python.org/file20839/z.pickle>.)

There is still a bug, which is best demonstrated by

>>> pickle.loads(b'\x80\x02U\x00.', encoding='latin1')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: operation forbidden on released memoryview object

The fact that the above works with encoding='latin-1',

>>> pickle.loads(b'\x80\x02U\x00.', encoding='latin-1')
''

shows that there is probably more than one bug.