enhancement request: make py3 read/write py2 pickle format

[Devin Jeanpierre]

There's a lot of subtle issues with pickle compatibility. e.g.
old-style vs new-style classes. It's kinda hard and it's better to
give up. I definitely agree it's better to use something else instead.
For example, we switched to using protocol buffers, which have much
better compatibility properties and are a bit more testable to boot
(since text format protobufs are always output in a canonical (sorted)
form.)

-- Devin

On Tue, Jun 9, 2015 at 11:35 AM, Chris Warrick <kwpolska at gmail.com> wrote:
> On Tue, Jun 9, 2015 at 8:08 PM, Neal Becker <ndbecker2 at gmail.com> wrote:
>> One of the most annoying problems with py2/3 interoperability is that the
>> pickle formats are not compatible.  There must be many who, like myself,
>> often use pickle format for data storage.
>>
>> It certainly would be a big help if py3 could read/write py2 pickle format.
>> You know, backward compatibility?
>
> Don’t use pickle. It’s unsafe — it executes arbitrary code, which
> means someone can give you a pickle file that will delete all your
> files or eat your cat.
>
> Instead, use a safe format that has no ability to execute code, like
> JSON. It will also work with other programming languages and
> environments if you ever need to talk to anyone else.
>
> But, FYI: there is backwards compatibility if you ask for it, in the
> form of protocol versions. That’s all you should know — again, don’t
> use pickle.
>
> --
> Chris Warrick <https://chriswarrick.com/>
> PGP: 5EAAEA16
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