Drop Python2.7 support

[willmcgugan]

Python2.7 will be unsupported in a few months. We should drop Python2.7 before then.

I'm keen to do this as Python2.7 support has long been a headache. If anyone has a good reason to keep Py2.7 support, please make your case in this issue.

[zopyx]

May Python 2.7 rest forever.
No need for further Python 2.7 compatibility.

[althonos]

Fine by me, I'm not putting any particular effort for Python 2.7 support right now so I don't care about dropping support.
IMO you should make a last stable release so that all libraries can pin that version more easily in case some devs stuck in the past need to pin anything.

[bennr01]

Small suggestion: dropping py2 support is technically a backwards incompatible api change. When following semantic versioning, this should be indicated by a major version bump.

pyfilesystem2 currently has the major version 2, which would mean that the next major version would be 3. As most of you probably know, a python package ending with 3 usually indicates py3-only support, which would coincide with the change.

This would also allow py2-projects to specify fs < 3.0.0 as a dependency.

On the other hand, bumping the major version of a package in a repo called pyfilesystem2 may lead to confusion, so I am not sure whether this change should really be done in accordance with semantic versioning.

[dargueta]

a python package ending with 3 usually indicates py3-only support

Package name or package version? I agree with the name.

On the other hand, bumping the major version of a package in a repo called pyfilesystem2 may lead to confusion

I do agree that the 2 ending has put us in an unfortunate position, but we're going to have to bump the major version at some point. Otherwise we'll be violating the principle of semantic versioning.

[willmcgugan]

@bennr01 I concur 3.0.0 is the way to go when we drop Python2 support.

The name on Pypy is still fs. I hope the repos name containing a 2 doesn't confuse too many people. I can always put a note in the readme if it does.

[odgalvin]

@althonos I could go through and remove the Python 2 compatibility bits if you'd like a PR? Maybe after your next point release. It would tidy up the code a lot.

[althonos]

@odgalvin : as Will mentioned, we should make a new repository for that, probably forking this one into PyFilesystem/pyfilesystem3. Plus, it would be great to take advantage of this breaking change to actually address a lot of the breaking issues.

EDIT: I will have more time next week-end to start planning this, and to triage the current PyFilesystem2 issues.

[atollk]

Is this an ongoing discussion? Having worked quite a bit on different parts of the fs code base recently, I agree with @althonos that a chance to perform some breaking changes should be used to clean up as well. I feel like I could chime in with some ideas and would be willing to take up some of the resulting tasks, should we agree on the direction that PyFs3 wants to take.