On Tue, Mar 13, 2012 at 12:42 PM, Michael Foord <fuzzy...@voidspace.org.uk> wrote: > > On 13 Mar 2012, at 04:44, Merlijn van Deen wrote: > >> http://bugs.python.org/issue6784 ("byte/unicode pickle >> incompatibilities between python2 and python3") >> >> Hello all, >> >> Currently, pickle unpickles python2 'str' objects as python3 'str' >> objects, where the encoding to use is passed to the Unpickler. >> However, there are cases where it makes more sense to unpickle a >> python2 'str' as python3 'bytes' - for instance when it is actually >> binary data, and not text. >> >> Currently, the mapping is as follows, when reading a pickle: >> python2 'str' -> python3 'str' (using an encoding supplied to Unpickler) >> python2 'unicode' -> python3 'str' >> >> or, when creating a pickle using protocol <= 2: >> python3 'str' -> python2 'unicode' >> python3 'bytes' -> python2 '__builtins__.bytes object' >> > > > It does seem unfortunate that by default it is impossible for a developer to > "do the right thing" as regards pickling / unpickling here. Binary data on > Python 2 being unpickled as Unicode on Python 3 is presumably for the > convenience of developers doing the *wrong thing* (and only works for ascii > anyway).
Well, since trying to migrate data between versions using pickle is the "wrong" thing anyway, I think the status quo is just fine. Developers doing the "right" thing don't use pickle for this purpose. -- --Guido van Rossum (python.org/~guido) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
