OK, how about using encoding=bytes (yes, the type object!)? Or 'bytes' ?
--Guido van Rossum (sent from Android phone)
On Mar 16, 2012 2:19 PM, "Merlijn van Deen" <valhall...@arctus.nl> wrote:
> Hi Guido,
>
> Let me start with thanking you for your long reply. It has clarified
> some points to me, but I am still not certain about some others. I
> hope I can clarify why I'm confused about this issue in the following.
>
> First of all, let me clarify that I wrote my original mail not as 'the
> guy who wants to serialize stuff' but as 'the guy who wonders what the
> best way to implement it in python is'. Of course, 'not' is a
> reasonable answer to that question.
>
> On 13 March 2012 23:08, Guido van Rossum <gu...@python.org> wrote:
> > That was probably written before Python 3. Python 3 also dropped the
> > long-term backwards compatibilities for the language and stdlib. I am
> > certainly fine with adding a warning to the docs that this guarantee
> > does not apply to the Python 2/3 boundary. But I don't think we should
> > map 8-bit str instances from Python 2 to bytes in Python 3.
>
> Yes, backwards compatibility was dropped, but the current pickle
> module tries to work around this by using a module mapping [1] and
> aids in loading 8-bit str instances by asking for an encoding [2].
> Last, but not least, we can /write/ old version pickles, for which
> the same module mapping is used, but in reverse. As such, the module
> suggests in many ways that it should be possible to interchange
> pickles between python 2 and python 3.
>
> > My snipe was mostly in reference to the many other things that can go
> > wrong with pickled data as your environment evolves (...)
> I understand your point. However, my interpretation of this issue
> always was 'if you only pickle built-in types, you'll be fine' - which
> is apparently wrong.
>
>
> Essentially - my point is this: considering the pickle module is
> already using several compatibility tricks and considering I am not
> the only one who would like to read binary data from a pickle in
> python 3 - even though it might not be the 'right' way to do it - what
> is there /against/ adding the possibility?
>
> Last but not least, this is what people are now doing instead: [1]
> s = pickle.load(f, encoding='latin1')
> b = s.encode('latin1')
> print(zlib.decompress(b))
>
> Which hurts my eyes.
>
> In any case - again, thanks for taking the time to respond. I hope I
> somewhat clarified why I was/am somewhat confused on the issue, and
> the reasons why I think that it is still a good idea ;-)
>
> Best,
> Merlijn
>
> [1] http://hg.python.org/cpython/file/8b2668e60aef/Lib/_compat_pickle.py
> [2] http://docs.python.org/dev/library/pickle.html#module-interface
> [3]
> http://stackoverflow.com/questions/4281619/unpicking-data-pickled-in-python-2-5-in-python-3-1-then-uncompressing-with-zlib
>
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