Python 2 incompatibility

Hello,

There seems to be an issue with the latest version of fastavro (1.0) on Python 2 after you dropped the Python 2 support from what I saw in your Changelog. Here is the error that I have when trying to install fastavro on Python 2 :

if sys.implementation.name != "pypy":
     AttributeError: 'module' object has no attribute 'implementation'

You dropped Python 2 support but you forgot to add python_requires='>=3.5' in your setup.py that will prevent users with Python 2 from downloading a sdist version they cannot build.

For more information about python_requires you can check the following details: Note: supporting python_requires requires setuptools>=24.2.0 and pip>=9.0.0 to benefit from it. Details here: https://packaging.python.org/guides/distributing-packages-using-setuptools/#python-requires

[scottbelden]

Okay, so I learned that there is a new yank feature on pypi which looks like it will do what I want. It effectively hides the 1.0.0 release so that it won’t be used by pip but is still technically installable if someone does pip install fastavro==1.0.0.

I was able to install correctly on Python 2 now:

pip install -U --no-cache fastavro
DEPRECATION: Python 2.7 reached the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 is no longer maintained. pip 21.0 will drop support for Python 2.7 in January 2021. More details about Python 2 support in pip can be found at https://pip.pypa.io/en/latest/development/release-process/#python-2-support
Collecting fastavro
  Downloading fastavro-0.24.2-cp27-cp27m-macosx_10_14_x86_64.whl (465 kB)
     |████████████████████████████████| 465 kB 804 kB/s
Requirement already satisfied, skipping upgrade: pytz in ... (from fastavro) (2020.1)
Installing collected packages: fastavro
Successfully installed fastavro-0.24.2

[scottbelden]

So I tried merging the PR and creating a 1.0.0.post release. I thought the idea of the post release was to effectively shadow the 1.0.0 release, but that doesn’t seem to happen. When I try to install on Python 2, pip skips the 1.0.0.post as expected because of the python_requires, but it still just tries to use the 1.0.0 tarball.

I could delete the 1.0.0 tarball from pypi… I’m a little worried about doing that as it sometimes causes issues for people that run their own mirrors or have the cached 1.0.0 version, but leaving it up also seems like a bad idea because now anyone on Python 2 that tries to install will hit an error at install time.