Fixed #299 -- work on very old python2.7s :-(

[alex]

Tested on debian wheezy (which is a royal PITA). There's some other failing tests (all related to memoryview(array.array(...))), but this fixes all of the exceptions seen in #299

[alex]

FWIW, I structured the code like this so we only have the overhead of creating the buffer object on Pythons where it's relevant, and there's no additional branching in every single msgpack opcode.

[jfolz]

Looks like a really simple patch that's easy to remove when 2.7 support is dropped.

[alex]

Thanks!

[zsimic]

Note that the issue occurs on OSX with python 2.7.10... apparently this fix will not apply to OSX's /usr/bin/python

~: /usr/bin/python -c 'import sys; print(sys.version_info)'
sys.version_info(major=2, minor=7, micro=10, releaselevel='final', serial=0)

[alex]

Interesting, I wasn't able to reproduce this with a 2.7.6 from Ubuntu so I assumed that anything older was unaffected, that's unexpected.

…

On Mon, Apr 16, 2018 at 5:57 PM, Zoran Simic ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In msgpack/fallback.py <#300 (comment)> : > @@ -234,6 +234,12 @@ def __init__(self, file_like=None, read_size=0, use_list=True, raw=True, #: array of bytes fed. self._buffer = bytearray() + # Some very old pythons don't support `struct.unpack_from()` with a + # `bytearray`. So we wrap it in a `buffer()` there. + if sys.version_info < (2, 7, 6): Note that the issue occurs on OSX with python 2.7.10... apparently this fix will not apply to OSX's /usr/bin/python ~: /usr/bin/python -c 'import sys; print(sys.version_info)' sys.version_info(major=2, minor=7, micro=10, releaselevel='final', serial=0) — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#300 (review)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAADBAzV2PwMcoRNZJ3A4T8ximryHMlyks5tpRO7gaJpZM4TVSf2> .

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[zsimic]

I noticed it on OSX, with system python 2.7.10 pypa/pip#5259 On Mon, Apr 16, 2018 at 2:58 PM, Alex Gaynor <[email protected]> wrote:

…

Interesting, I wasn't able to reproduce this with a 2.7.6 from Ubuntu so I assumed that anything older was unaffected, that's unexpected. On Mon, Apr 16, 2018 at 5:57 PM, Zoran Simic ***@***.***> wrote: > ***@***.**** commented on this pull request. > ------------------------------ > > In msgpack/fallback.py > <#300# discussion_r181898068> > : > > > @@ -234,6 +234,12 @@ def __init__(self, file_like=None, read_size=0, use_list=True, raw=True, > > #: array of bytes fed. > self._buffer = bytearray() > + # Some very old pythons don't support `struct.unpack_from()` with a > + # `bytearray`. So we wrap it in a `buffer()` there. > + if sys.version_info < (2, 7, 6): > > Note that the issue occurs on OSX with python 2.7.10... apparently this > fix will not apply to OSX's /usr/bin/python > > ~: /usr/bin/python -c 'import sys; print(sys.version_info)' > sys.version_info(major=2, minor=7, micro=10, releaselevel='final', serial=0) > > — > You are receiving this because you authored the thread. > Reply to this email directly, view it on GitHub > <#300# pullrequestreview-112604053>, > or mute the thread > <https://github.com/notifications/unsubscribe-auth/ AAADBAzV2PwMcoRNZJ3A4T8ximryHMlyks5tpRO7gaJpZM4TVSf2> > . > -- "I disapprove of what you say, but I will defend to the death your right to say it." -- Evelyn Beatrice Hall (summarizing Voltaire) "The people's good is the highest law." -- Cicero GPG Key fingerprint: D1B3 ADC0 E023 8CA6 — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#300 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AAtmvYpcYXrgqwYrcAnqD1_OYby8zxSRks5tpRP6gaJpZM4TVSf2> .

[methane]

On 10.13.4 (High Sierra),

11:07 $ /usr/bin/python
Python 2.7.10 (default, Oct  6 2017, 22:29:07)
[GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
>>> struct.unpack_from("i", bytearray("1234"))
(875770417,)

unpack_from supports bytearray.
I have Sierra MacBook at my office. I'll try on it too.

[methane]

On 10.12.6 (Sierra):

$ /usr/bin/python2.7
Python 2.7.10 (default, Feb  7 2017, 00:08:15)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.34)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import struct
>>> struct.unpack_from("i", bytearray("1234"))
(875770417,)

@zsimic Is your python really 2.7.10?
virtualenv copies python. It means you may use old python if you created the virtualenv with old Python.
What .venv/bin/python -V prints?

[zsimic]

You're right @methane it does work with stock python 2.7.10

I have a pyenv-installed 2.7.0 (it's a recent pyenv install, don't know why it picked 2.7.0), and 2.7.0 was selected when I observed the issue, not my system python.

Sorry about the confusion