Encoding updates

[samschott]

This PR changes how paths are encoded and decoded on Unixes as follows:

1. Drops support for Python 2.7 to unify handling of paths (this can of course be changed if Python 2.7 support is important).
2. Use Python's builtin os.fsencode and os.fsdecode functions available from 3.2.

Those changes have significant advantages when creating the watches with a str path. Previously, events from paths which contain bytes that cannot be decoded in the file system encoding (sys.getfilesystemencoding()) would raise an unhandled UnicodeEncodingError in the inotify emitter thread. Now, the bytes are converted to Python's "surrogate escapes" and remain in the string. All os functions accept strings with such "escaped bytes" and will properly convert them back with os.fsencode.

[BoboTiG]

Great! I am completely for dropping Python 2.7. Even 3.4 and 3.5 if needed, by it seems not for now :)

Could you add lines in the changelog + your GH nickname? Also if you mind updating the README and/or just remove Python 2.7 everywhere (I could do it before the release though).

I will merge tomorrow, thanks for the patch 💪

[samschott]

Will do.

The Python 2.7 tests are predictably failing but also some Python 3.10 and Windows tests. From a brief glance, it doesn't look like anything introduced in this PR.

Before you merge, I'll also add an emitter test with invalid bytes in the filename. Just in case people are tempted to use bytes.decode instead of os.fsdecode.

[samschott]

Ok, this should be ready now. The remaining test failures are:

1. Failure of test_eventlet_monkey_patching on Python 3.10: TypeError when importing eventlet.
2. Failure of test_event_dispatcher on some macOS runs: A thread leak. Where is this coming from?
3. Failure to install Python 3.7 on Windows.

I am mostly concerned about the second one. Could this have anything to do with the changes from this PR?

[BoboTiG]

1 and 3 are OK.
I relaunched the job for 2, it happens from time to time ;)

[BoboTiG]

Passed, I wil merge after the nitpick in the test.

[BoboTiG]

Thanks a lot @samschott :)

[samschott]

Thanks for merging -- and for the very quick response times!