enhancement request: make py3 read/write py2 pickle format

[Neal Becker]

Chris Warrick 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.
> 

I believe a good native serialization system is essential for any modern 
programming language.  If pickle isn't it, we need something else that can 
serialize all language objects.  Or, are you saying, it's impossible to do 
this safely?