Fix compatibility with Python 3.10, refs #358

[simonw]

What do these changes do?

Tests now also run against Python 3.10, and code incorporates a workaround for a bug in Python 3.10 that affects Janus.

Related issue number

• Error with Python 3.10: "ValueError: loop argument must agree with lock" #358

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes - (not needed)
• Add a new news fragment into the CHANGES folder (skipped, not sure how to do this)

[simonw]

Necessary to use strings rather than floating point numbers here, because otherwise 3.10 is interpreted as 3.1

[webknjaz]

I'd say only wrap "3.10" and keep others as is.

[achimnol]

I think it's better to wrap them all for consistency, but have no strong opinion on this as long as it would not make future confusion.

[asvetlov]

Both variants work technically.
I prefer the current version; if we process 3.10 as a string -- why others should be numbers? Again, technically the version is not a number but a string.

[webknjaz]

LGTM but I'll leave this to the maintainers to merge.

[codecov]

Codecov Report

Merging #359 (5f2a387) into master (d7970f8) will decrease coverage by 0.06%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master     #359      +/-   ##
==========================================
- Coverage   95.52%   95.45%   -0.07%     
==========================================
  Files           4        4              
  Lines        1274     1277       +3     
  Branches       84       86       +2     
==========================================
+ Hits         1217     1219       +2     
  Misses         50       50              
- Partials        7        8       +1     

Flag	Coverage Δ
unit	95.30% <33.33%> (-0.15%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
janus/__init__.py	99.36% <66.66%> (-0.32%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update d7970f8...5f2a387. Read the comment docs.

[achimnol]

I've confirmed the symptom reported in #358 and that this PR well handles it.

[achimnol]

I think it's better to wrap them all for consistency, but have no strong opinion on this as long as it would not make future confusion.

[achimnol]

@asvetlov Could you review & merge this PR to release a new version?
I think this is a major blocker for many asyncio projects to run with Python 3.10 and it is expected that we still need to wait for about 1.5 months to get Python 3.10.1 which will fix the issue in the upstream.

[asvetlov]

Thanks!