Version 0.14.0 allows pip to be installed on Python 2.7

[andy-maier]

Version 0.14.0 introduced the use of type hints, but its package definition does not require Python 3.6 or higher.

The Trove classifiers in the setup.py file state Python 2.7 and 3.6 and higher, but pip does not use that information, so pip happily installs 0.14.0 on Python 2.7, resulting in:

$ pip install voluptuous==0.14.0
Collecting voluptuous==0.14.0
  Downloading voluptuous-0.14.0.tar.gz (49 kB)
     |████████████████████████████████| 49 kB 2.7 MB/s 
    ERROR: Command errored out with exit status 1:
     command: /Users/maiera/virtualenvs/zhmc27/bin/python -c 'import sys, setuptools, tokenize; sys.argv[0] = '"'"'/private/var/folders/lh/v0_07k9d7dbfqdytfzzxks3r0000gn/T/pip-install-hJvLr2/voluptuous/setup.py'"'"'; __file__='"'"'/private/var/folders/lh/v0_07k9d7dbfqdytfzzxks3r0000gn/T/pip-install-hJvLr2/voluptuous/setup.py'"'"';f=getattr(tokenize, '"'"'open'"'"', open)(__file__);code=f.read().replace('"'"'\r\n'"'"', '"'"'\n'"'"');f.close();exec(compile(code, __file__, '"'"'exec'"'"'))' egg_info --egg-base /private/var/folders/lh/v0_07k9d7dbfqdytfzzxks3r0000gn/T/pip-pip-egg-info-u7zqr9
         cwd: /private/var/folders/lh/v0_07k9d7dbfqdytfzzxks3r0000gn/T/pip-install-hJvLr2/voluptuous/
    Complete output (10 lines):
    Traceback (most recent call last):
      File "<string>", line 1, in <module>
      File "/private/var/folders/lh/v0_07k9d7dbfqdytfzzxks3r0000gn/T/pip-install-hJvLr2/voluptuous/setup.py", line 6, in <module>
        version = __import__('voluptuous').__version__
      File "./voluptuous/__init__.py", line 3, in <module>
        from voluptuous.schema_builder import *
      File "./voluptuous/schema_builder.py", line 132
        def Self() -> None:
                   ^
    SyntaxError: invalid syntax
    ----------------------------------------
ERROR: Command errored out with exit status 1: python setup.py egg_info Check the logs for full command output.

I am well aware that Python 2.7 is no longer supported by the PSF, but we still need to support it in some of our projects for certain environments (including RedHat), and our builds currently break due to that.

The mitigation for us is to pin voluptuous on Python 2.7 to <0.14.0.

The vuluptuous project should do two things:

• correct the Trove classifiers to only the supported Python versions
• state the supported Python versions in the python_requires argument to setup()

The question is, what is the minimum Python 3.x version now for version 0.14.0, is 3.6 sufficient?

[andy-maier]

PR #493 fixes this issue (assuming that Python 3.6 is the intended minimum Python version). Let me know if you want a higher version, then I can adjust the PR.

[spacegaier]

Resolved via https://github.com/alecthomas/voluptuous/pull/494