DEP: Add 'python_requires' to setup.py to drop 3.4 support

[djhoese]

• closes pip install panadas fails on numpy version #20697
• tests added / passed
• passes git diff upstream/master -u -- "*.py" | flake8 --diff
• whatsnew entry

This is a small change to the setup.py that should stop newer versions of pandas from being downloaded in environments with older/unsupported versions of python. I followed the instructions here: https://packaging.python.org/guides/dropping-older-python-versions/

[jreback]

hmm, there has to be a better way to write this, to signify only 2.7 or >=3.5

[djhoese]

I was following numpy (https://github.com/numpy/numpy/blob/master/setup.py#L368) and the link I mentioned.

[djhoese]

https://packaging.python.org/tutorials/distributing-packages/?highlight=python_requires#python-requires

[djhoese]

I agree that it should be simpler but wasn't sure what conditionals were allowed.

[djhoese]

Oh, I do notice a big mistake. It should be >=2.7 not >2.7. Researching to see if there is a shorter way.

[djhoese]

In [15]: from pip.utils.packaging import specifiers, version

In [16]: version.parse('3.5.0') in specifiers.SpecifierSet('==2.7,>=3.5.*')
Out[16]: False

[jreback]

I think you can do >=3.5 ?

[jreback]

cc @TomAugspurger

[codecov]

Codecov Report

Merging #20698 into master will increase coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #20698      +/-   ##
==========================================
+ Coverage   91.81%   91.81%   +<.01%     
==========================================
  Files         153      153              
  Lines       49275    49279       +4     
==========================================
+ Hits        45241    45245       +4     
  Misses       4034     4034

Flag	Coverage Δ
#multiple	90.2% <ø> (ø)	⬆️
#single	41.9% <ø> (-0.01%)	⬇️

Impacted Files	Coverage Δ
pandas/core/frame.py	97.16% <0%> (ø)	⬆️
pandas/core/indexes/multi.py	95.06% <0%> (ø)	⬆️

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[djhoese]

Moving the discussion outside of the commits in case more changes are done. Simple test for a simpler python_requires:

In [15]: from pip.utils.packaging import specifiers, version

In [16]: version.parse('3.5.0') in specifiers.SpecifierSet('==2.7,>=3.5.*')
Out[16]: False

# later I did:
In [2]: version.parse('3.5.0') in specifiers.SpecifierSet('==2.7,>=3.5')
Out[2]: False

[djhoese]

I read the source for SpecifierSet and Specifier. The condition is basically all(my_version in specifier for specifier in specifiers) where the __contains__ is doing the individual condition for each version specifier (my_version == 2.7 and my_version >=3.5).

I guess you'll just have to drop python 2.7 sooner /s

Source: https://github.com/pypa/pip/blob/master/src/pip/_vendor/packaging/specifiers.py#L180
https://github.com/pypa/pip/blob/master/src/pip/_vendor/packaging/specifiers.py#L724

[jreback]

@davidh-ssec ok this looks ok. can you change our min for setuptools to 24.2.0, see here (which is pretty old anyhow). and update the Dependencies in install.rst & in the whatsnew.

[djhoese]

@jreback You want the setuptools version in setup_requires? Or is there somewhere else it is currently specified?

[djhoese]

Oh you meant set the min version in install.rst and update the deps in the 0.23 whatsnew. For the deps do you want it added to the min version table of deps?

[jreback]

yes + in

(pandas) bash-3.2$ grep setuptools ci/*
ci/environment-dev.yaml:  - setuptools>=3.3
ci/requirements_dev.txt:setuptools>=3.3

(just update these)

[jreback]

thanks @davidh-ssec

[TomAugspurger]

We’re hoping to do a release in about 1 week.

…

________________________________ From: Jeff Reback <[email protected]> Sent: Monday, April 16, 2018 5:34:51 AM To: pandas-dev/pandas Cc: Tom Augspurger; Mention Subject: Re: [pandas-dev/pandas] DEP: Add 'python_requires' to setup.py to drop 3.4 support (#20698) thanks @davidh-ssec<https://github.com/davidh-ssec> — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub<#20698 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/ABQHIhVLiRg70pbG07q8GryTC7zmZ2vYks5tpHPLgaJpZM4TVRcb>.

[jorisvandenbossche]

Should we remove our pyproject.toml alltogether for upcoming 0.23.0 until support in pip is more mature? It seems that also the varying numpy version depending on the python version is not yet supported (cfr scipy/scipy#8734)