(google-cloud-vision) enum34 should not be installed on Python 3.4+

[matrixl]

The enum34 breaks my code (python3.6), it is a known issue that enum34 doesn't work on Python 3.4+

Please refer to the discussion over here:
https://bitbucket.org/stoneleaf/enum34/issues/5/enum34-incompatible-with-python-35#comment-19462547

suggested fix in vision/setup.py

REQUIREMENTS = [
-    'enum34',
    'google-cloud-core >= 0.24.0, < 0.25dev',
    'gapic-google-cloud-vision-v1 >= 0.90.3, < 0.91dev',
]

+if sys.version_info < (3, 4):
+    # Backport of Python 3.4 enums to earlier versions
+   REQUIREMENTS.append('enum34')

setup(
    name='google-cloud-vision',
    version='0.24.0',
    description='Python Client for Google Cloud Vision',
    long_description=README,
    namespace_packages=[
        'google',
        'google.cloud',
    ],
    packages=find_packages(exclude=('tests*',)),
    install_requires=REQUIREMENTS,
    **SETUP_BASE
)

[dhermes]

@matrixl Can you link to the known issue? Our unit tests run in Python 3.4, 3.5, 3.6 and our system tests run in 3.6 without any issue at all.

[matrixl]

Here is the issue reported in other project.
donnemartin/saws#55

Also some discussion over here.
https://bitbucket.org/stoneleaf/enum34/issues/5/enum34-incompatible-with-python-35#comment-19462547

[dhermes]

Both of this indicate that the incompatibility was resolved 2 years ago. Am I somehow misreading?

[matrixl]

Yes, those issues have been fixed, but the way they fixed it is to only install enum34 with Python < 3.4.

donnemartin/saws@f109bc8

Here is the latest post in 2017.
https://bitbucket.org/stoneleaf/enum34/issues/19/enum34-isnt-compatible-with-python-36

Issue #19 WONTFIX
enum34 isn't compatible with python 3.6

It was tagged as "WONTFIX", so the only way to fix it is to only require it with Python < 3.4

[dhermes]

Gotcha, thanks for digging @matrixl. So the issue isn't that our code is broken on it's own, just that it steps in front of import enum and stops you from using the newest features of enum?

@jonparrott WDYT of adding enum34;python_version<"3.4" in our requirements?

[theacodes]

@dhermes I'm fine with that.

[tseaver]

@matrixl If what you report is true, I don't understand how our system and unit tests could be working with enum34 unconditionally installed.

[dhermes]

@tseaver He didn't say it doesn't work with our code, he said: "enum34 breaks my code (python3.6)".

The point is that enum34 steps in front of the native import enum and so users and up with the wrong package, and the backport one has fewer features.