Import ABC from collections.abc for Python 3.10 compatibility.

[tirkarthi]

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What does this PR do and why is it necessary?

Importing ABC directly from collections has been deprecated and removed in Python 3.10 . This PR updates the relevant places

How was it tested? How can it be tested by the reviewer?

Any background context you want to provide?

What are the relevant tickets if any?

Similar to #3735

Screenshots (if appropriate)

Further notes

[cp2004]

Would it be possible for these to be behind error handled blocks and against the maintenance branch, so it can go out before the 2.0.0 release dropping Python 2? That would be the ideal here, using some error handling to make it work on Python 2.7 as well.

Also, as a side note - these were finally removed in Py 3.10? It's been warning about it being removed for Py3.8, then 3.9, then 3.10....

[cp2004]

I tried to give this a test, while it probably works on Python 3.10 there's a slightly larger issue with frozendict:

Traceback (most recent call last):
  File "C:\Users\charl.TERRANCE\Development\venv310\Scripts\octoprint-script.py", line 33, in <module>
    sys.exit(load_entry_point('OctoPrint', 'console_scripts', 'octoprint')())
  File "c:\users\charl.terrance\development\octoprint core\octoprint\src\octoprint\__init__.py", line 913, in main
    from octoprint.cli import octo
  File "c:\users\charl.terrance\development\octoprint core\octoprint\src\octoprint\cli\__init__.py", line 282, in <module>
    from .dev import dev_commands  # noqa: E402
  File "c:\users\charl.terrance\development\octoprint core\octoprint\src\octoprint\cli\dev.py", line 259, in <module>
    def dev():
  File "c:\users\charl.terrance\development\venv310\lib\site-packages\click\core.py", line 1377, in decorator
    cmd = group(*args, **kwargs)(f)
  File "c:\users\charl.terrance\development\venv310\lib\site-packages\click\decorators.py", line 130, in decorator
    cmd = _make_command(f, name, attrs, cls)
  File "c:\users\charl.terrance\development\venv310\lib\site-packages\click\decorators.py", line 98, in _make_command
    return cls(
  File "c:\users\charl.terrance\development\octoprint core\octoprint\src\octoprint\cli\dev.py", line 26, in __init__
    from octoprint.util.commandline import CommandlineCaller
  File "c:\users\charl.terrance\development\octoprint core\octoprint\src\octoprint\util\__init__.py", line 27, in <module>
    import frozendict
  File "c:\users\charl.terrance\development\venv310\lib\site-packages\frozendict\__init__.py", line 16, in <module>
    class frozendict(collections.Mapping):
AttributeError: module 'collections' has no attribute 'Mapping'

It does not appear to be maintained any longer, though there are alternatives around and people trying to claim the frozen dict project to bring it up to speed.

[tirkarthi]

Thanks added try/except and rebased. This was delayed couple of times and removed in python/cpython#23754 for Python 3.10

[cp2004]

That looks good to me - obviously the problem of frozendict dependency will have to be solved as well (and maybe something else) but this is at least part of it. 3.10 is still in alpha, so we have 6 months or so to come up with a solution 🙂.

I did poke about and saw there was a request for the frozendict package to be adopted on PyPi that was approved, the original maintainer is OK for it to be transferred. So once they get through the backlog it may be simple enough to upgrade - though my bets are it won't support Python 2. Maybe by then we will be closer to a working 2.0 release 😉

[foosel]

Took the liberty to squash and change base to maintenance (since devel is Py3 only the Py2 fallback otherwise wouldn't really make sense either).