Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!feeds.phibee-telecom.net!newsfeed.xs4all.nl!newsfeed4.news.xs4all.nl!xs4all!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail Return-Path: X-Original-To: python-list@python.org Delivered-To: python-list@mail.python.org X-Spam-Status: OK 0.002 X-Spam-Evidence: '*H*': 1.00; '*S*': 0.00; 'classes.': 0.07; 'versions.': 0.07; 'backwards': 0.09; 'eat': 0.09; 'executes': 0.09; 'storage.': 0.09; 'subtle': 0.09; '\xe2\x80\x94': 0.09; 'cc:addr:python-list': 0.10; 'instead.': 0.15; 'output': 0.15; 'buffers,': 0.16; 'compatible.': 0.16; 'new-style': 0.16; 'old- style': 0.16; 'py3': 0.16; 'subject:make': 0.16; 'unsafe': 0.16; 'wrote:': 0.16; 'switched': 0.18; 'cc:addr:python.org': 0.21; 'cc:2**1': 0.22; 'environments': 0.22; 'subject:request': 0.22; 'programming': 0.23; 'am,': 0.23; 'code,': 0.23; 'bit': 0.23; '2015': 0.23; 'header:In-Reply-To:1': 0.24; 'cc:addr:gmail.com': 0.24; 'properties': 0.24; 'chris': 0.26; 'message- id:@mail.gmail.com': 0.28; 'subject:/': 0.29; 'pickle': 0.29; 'certainly': 0.31; 'e.g.': 0.31; 'url:mailman': 0.31; 'up.': 0.32; 'anyone': 0.32; 'url:python': 0.33; 'instead,': 0.33; 'languages': 0.34; 'file': 0.34; 'received:google.com': 0.34; 'url:listinfo': 0.35; 'could': 0.35; 'formats': 0.35; 'protocol': 0.35; 'something': 0.35; 'text': 0.36; 'url:org': 0.36; 'there': 0.36; 'should': 0.37; 'agree': 0.37; 'subject:: ': 0.37; 'delete': 0.37; 'tue,': 0.38; 'someone': 0.38; 'files': 0.38; 'means': 0.39; 'pm,': 0.39; 'data': 0.40; 'your': 0.60; 'more': 0.62; 'safe': 0.63; 'else.': 0.66; 'becker': 0.84; 'subject:read': 0.84; 'subject:write': 0.84; 'who,': 0.84; 'canonical': 0.91 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type:content-transfer-encoding; bh=myfS+qlDK1cYBGz6HOkwHIN57ax8osaNmRrxyGmi1G8=; b=RgOymUnozskC9W3cr848Skses6sTmE5MIFmxPUk/lEidm1v7QtxsF0gDvMhmGC+IIJ Sxy1Jst82V1Q6BE1KU9e20mrwbt4w773teUdTC9E5BNgV9Os9tEr7UY9ycVn3Bkc82/+ lWv/aM7Diz1QX+1CkVcEf9vBciC65ej0IA9B3aSqDUnjQZHYhmHf9bhHCP7iCCbFhTTz oij6DWPt88HvBs4UQBEb/26mYJlO/s6x0HcsGMg/i16u/+nKbi5Vo5XU1iBlVYGxkMlk RmQo9dX1ydcChGEYhFVWxGCs1P9Ty5NyR5lZ/slvS6zzsIpS/wpPZMuTVekrhct+ph23 7vuw== X-Received: by 10.194.172.130 with SMTP id bc2mr45911664wjc.85.1433880486725; Tue, 09 Jun 2015 13:08:06 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: From: Devin Jeanpierre Date: Tue, 9 Jun 2015 13:07:26 -0700 Subject: Re: enhancement request: make py3 read/write py2 pickle format To: Chris Warrick Cc: Neal Becker , "comp.lang.python" Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: python-list@python.org X-Mailman-Version: 2.1.20+ Precedence: list List-Id: General discussion list for the Python programming language List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Newsgroups: comp.lang.python Message-ID: Lines: 40 NNTP-Posting-Host: 2001:888:2000:d::a6 X-Trace: 1433880494 news.xs4all.nl 2968 [2001:888:2000:d::a6]:34908 X-Complaints-To: abuse@xs4all.nl Xref: csiph.com comp.lang.python:92369 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 wrote: > On Tue, Jun 9, 2015 at 8:08 PM, Neal Becker wrote: >> One of the most annoying problems with py2/3 interoperability is that th= e >> 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 form= at. >> You know, backward compatibility? > > Don=E2=80=99t use pickle. It=E2=80=99s unsafe =E2=80=94 it executes arbit= rary 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=E2=80=99s all you should know =E2=80=94 a= gain, don=E2=80=99t > use pickle. > > -- > Chris Warrick > PGP: 5EAAEA16 > -- > https://mail.python.org/mailman/listinfo/python-list