Roundup Robot devn...@psf.upfronthosting.co.za added the comment:
New changeset 14695b4825dc by Alexandre Vassalotti in branch '3.2':
Issue #13505: Make pickling of bytes object compatible with Python 2.
http://hg.python.org/cpython/rev/14695b4825dc
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nosy: +python-dev
Alexandre Vassalotti alexan...@peadrop.com added the comment:
Fixed. Thanks for the patch!
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assignee: - alexandre.vassalotti
resolution: - fixed
stage: needs patch - committed/rejected
status: open - closed
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Python tracker
Antoine Pitrou pit...@free.fr added the comment:
Only worry is that codecs.latin_1_encode.__module__ is '_codecs', and
_codecs is undocumented.
It seems we have to choose between two evils here. Given that the
codecs.latin_1_encode produces more compact pickles, I'd say go for it.
Note that
sbt shibt...@gmail.com added the comment:
I now realise latin_1_encode won't work because it returns a pair (bytes_obj,
length).
I have done a patch using _codecs.encode instead -- the pickles turn out to be
exactly the same size anyway.
pickletools.dis(pickle.dumps(babc, 2))
0: \x80
Meador Inge mead...@gmail.com added the comment:
On Sun, Dec 11, 2011 at 12:17 PM, sbt rep...@bugs.python.org wrote:
I don't really know that much about pickle, but Antoine mentioned that
'bytearray'
works fine going from 3.2 to 2.7. Given that, can't we just compose 'bytes'
with
sbt shibt...@gmail.com added the comment:
Which is fine. 'bytes' and byte literals were not introduced until
2.6 [1,2]. So *any* solution we come
up with is for = 2.6.
In 2.6 and 2.7, bytes is just an alias for str. In all 2.x versions with
codecs.encode, the result will be str.
sbt shibt...@gmail.com added the comment:
I don't really know that much about pickle, but Antoine mentioned that
'bytearray'
works fine going from 3.2 to 2.7. Given that, can't we just compose 'bytes'
with
'bytearray'?
Yes, although it would only work for 2.6 and 2.7.
codecs.encode()
Meador Inge mead...@gmail.com added the comment:
I don't really know that much about pickle, but Antoine mentioned that
'bytearray'
works fine going from 3.2 to 2.7. Given that, can't we just compose 'bytes'
with
'bytearray'? Something like:
Python 3.3.0a0 (default:aab45b904141+, Dec 10
sbt shibt...@gmail.com added the comment:
sbt, the bug is not that the encoding is inefficient. The problem is we
cannot unpickle bytes streams from Python 3 using Python 2.
Ah. Well you can do it using codecs.encode.
Python 3.3.0a0 (default, Dec 8 2011, 17:56:13) [MSC v.1500 32 bit
Antoine Pitrou pit...@free.fr added the comment:
sbt, the bug is not that the encoding is inefficient. The problem is we
cannot unpickle bytes streams from Python 3 using Python 2.
Ah. Well you can do it using codecs.encode.
Great. A bit hackish but functional and not too inefficient
Alexandre Vassalotti alexan...@peadrop.com added the comment:
sbt, the bug is not that the encoding is inefficient. The problem is we cannot
unpickle bytes streams from Python 3 using Python 2.
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Python tracker rep...@bugs.python.org
sbt shibt...@gmail.com added the comment:
One *dirty* trick I am thinking about would be to use something like
array.tostring() to construct the byte string.
array('B', ...) objects are pickled using two bytes per character, so there
would be no advantage:
pickle.dumps(array.array('B',
Alexandre Vassalotti alexan...@peadrop.com added the comment:
I think we are kind of stuck here. I might need to rely on some clever hack to
generate the desired str object in 2.7 without breaking the bytes support in
3.3 and without changing 2.7 itself.
One *dirty* trick I am thinking about
Antoine Pitrou pit...@free.fr added the comment:
After a bit of testing, my idea was flawed, as str() doesn't accept an encoding
parameter in 2.x: `str(u'foo', 'latin1')` simply raises a TypeError.
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Python tracker rep...@bugs.python.org
New submission from Antoine Pitrou pit...@free.fr:
In Python 3.2:
pickle.dumps(b'xyz', protocol=2)
b'\x80\x02c__builtin__\nbytes\nq\x00]q\x01(KxKyKze\x85q\x02Rq\x03.'
In Python 2.7:
pickle.loads(b'\x80\x02c__builtin__\nbytes\nq\x00]q\x01(KxKyKze\x85q\x02Rq\x03.')
'[120, 121, 122]'
The
Changes by Meador Inge mead...@gmail.com:
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nosy: +meador.inge
stage: - needs patch
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Python tracker rep...@bugs.python.org
http://bugs.python.org/issue13505
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