Some cleanups, fix memoryview support

[pitrou]

A couple assorted cleanups:

• save_global can use the default implementation most of the time
• save_buffer and save_memory needn't call Pickler.save_string directly
• use save_reduce instead of dumping opcodes by hand where possible
• remove Pandas from CI setup since it's not used anywhere in the test suite

Also, memoryviews should obviously serialize as bytes, not str.

[codecov-io]

Codecov Report

Merging #122 into master will decrease coverage by 2.37%.
The diff coverage is 90%.

@@            Coverage Diff             @@
##           master     #122      +/-   ##
==========================================
- Coverage   86.32%   83.94%   -2.38%     
==========================================
  Files           2        2              
  Lines         541      517      -24     
  Branches       98       90       -8     
==========================================
- Hits          467      434      -33     
- Misses         55       62       +7     
- Partials       19       21       +2

Impacted Files	Coverage Δ
cloudpickle/cloudpickle.py	83.85% <90%> (-2.4%)	⬇️

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[pitrou]

Predictably, Python 2.6 fails on memoryview. Should I fix this PR or should we ditch 2.6 (and 3.3)? :-)
@rgbkrk

[rgbkrk]

How about we finish making the release for v0.4.1 since it's still Python 2.6 compatible, then we merge this in noting that we'll drop 2.6 and 3.3 support for v0.5.0

[pitrou]

Works for me :-)

[rgbkrk]

I'm going to give @ssanderson a day or so to make the release then I'll ping again and go from there. 😉

[hugovk]

+1 to dropping 2.6 and 3.3.

Here's the pip installs for cloudpickle from PyPI for the last month -- they have very small numbers!

$ pypinfo --percent --pip cloudpickle pyversion
python_version percent download_count
-------------- ------- --------------
3.5              54.4%         41,113
2.7              30.5%         23,082
3.6              13.0%          9,834
3.4               1.9%          1,453
3.3               0.1%            103
3.7               0.1%             41
2.6               0.0%             12

[rgbkrk]

We have more Python3 downloads than Python2 downloads?!?! 😮

[mrocklin]

Woot

…

On Thu, Oct 26, 2017 at 5:32 PM, Kyle Kelley ***@***.***> wrote: We have more Python3 downloads than Python2 downloads?!?! 😮 — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#122 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AASszOVhifl_SkGpm9YqHWOJpYPuvAlZks5swPpcgaJpZM4QIAH7> .

[rgbkrk]

Alright, adjust that Travis matrix to get rid of 2.6 support and we can bring this in.