Python 2 deprecation

[mykola-mokhnach]

January 1st of 2020 is the EOL for Python2. I would say it makes sense to start working on python client version 2 (for us this is going to be 1.0.0), which only supports python 3 (preferably Python 3.7+)

List of things I would like to see in the new major release (suggestion are highly welcome):

• Explicit types declarations (use typing module) -> High priority
• asyncio and async/await usage (for both network and file system i/o operations) -> Medium to Low priority, this might be a serious change and might require the users to update a lot of their code
• Proper exceptions inheritance (use raise from) -> High priority
• Ordered dictionaries usage -> High priority
• Proper strings/bytearrays usage -> High priority
• Proper super usage -> High priority
• pytest usage -> Medium priority

[ki4070ma]

High priority

• Explicit types declarations (use typing module)
• Proper exceptions inheritance (use raise from)
• Ordered dictionaries usage
  • By https://github.com/appium/python-client/pull/482/files#diff-728408031f247e6ab31468d14d7efdceL46-R30
• Proper strings/bytearrays usage
  • By https://github.com/appium/python-client/pull/482/files#diff-728408031f247e6ab31468d14d7efdceL20-L36
• Proper super usage

Medium priority

• pytest usage
• asyncio and async/await usage (for both network and file system i/o operations) -> Medium to Low priority, this might be a serious change and might require the users to update a lot of their code

As internal tasks

• Remove py2 from travis ci and run py38
  • https://github.com/appium/python-client/blob/master/.travis.yml
• Upgrade dependencies
  • https://github.com/appium/python-client/blob/master/Pipfile

[manoj9788]

Thanks @mykola-mokhnach Absolutely makes sense to start this work now!

[ki4070ma]

Action sequence for branch strategy

#478 (comment)

[mykola-mokhnach]

One more useful thing which is present since Python 3.7 and which we could use:

• Data classes

[ki4070ma]

Might need to add py.typed file to repository. Will check later.

https://www.python.org/dev/peps/pep-0561/

-> Done by #508

[KazuCocoa]

Python 2.7.18 came out

[ki4070ma]

Done