[issue38241] Pickle with protocol=0 in python 3 does not produce a 'human-readable' format
New submission from Nicholas Neumann :
The docs for pickle, in python 2, say that the default pickle protocol, 0,
produces ASCII. In the python 3 docs, this has changed to "human-readable".
While the pickle output with protocol 0 loads fine in python2, it is definitely
not human-readable, as it is not valid ASCII and contains every possible byte.
To see a simple example, run this in both python 2 and 3
import pickle
a = bytearray(range(255)) #bytes containing 0..255
b = bytes(a)
c = pickle.dumps(b,protocol=0)
print(c)#human readable in 2, not in 3
c.decode('ascii')#throws in 3, not in 2
--
messages: 352907
nosy: aggieNick02
priority: normal
severity: normal
status: open
title: Pickle with protocol=0 in python 3 does not produce a 'human-readable'
format
type: behavior
versions: Python 3.7
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[issue38241] Pickle with protocol=0 in python 3 does not produce a 'human-readable' format
Nicholas Neumann added the comment: Wow, that's a great catch with bytearray on py2. Protocols 0-2 are all actually supposed to work with python 2, and I was using 0 from Py3 as it's the default for Py2, and what I want to use during a short transition where both Py3 and Py2 are operating on my pickled data. I was surprised when Py3's protocol 0 output was so different than Py2's protocol 0. To be "human-readable", I think the protocol would have to be even stricter, omitting the non-printable ASCII characters. I wonder if protocol 0 was initially ASCII (or even stricter), and then this went out the window or was unintentionally not adhered to when new things like bytearray (2.6) were introduced. -- ___ Python tracker <https://bugs.python.org/issue38241> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
[issue38241] Pickle with protocol=0 in python 3 does not produce a 'human-readable' format
Nicholas Neumann added the comment: Apologies as I'm not super-familiar with Latin1 or how Python refers to Latin1, but it seems a little odd to even call it Latin1. It can be decoded as Latin1, but it can contain every possible byte, including 0x7f through 0x9f, which aren't really Latin1. It is human readable when pickling certain data types, but when others are involved, it sure seems like binary to me. I think that is fine, and perhaps all that needs to be done is to update the documentation to say something like: "Protocol level 0 is the original pickling format. It is the default for Python 2 and is now a binary format; it originally was an ASCII format but this ceased to be true as support for new datatypes was added to Python." -- ___ Python tracker <https://bugs.python.org/issue38241> ___ ___ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
