[PR #10151/7c12b1a9 backport][3.11] Fix infinite callback loop when time is not moving forward

[patchback]

This is a backport of PR #10151 as merged into master (7c12b1a).

What do these changes do?

If the keepalive handler is called too soon, it reschedules itself. The test used now <= close_time, which means that an exactly on-time notification is treated as "too soon", causing an automatic rescheduling. For real systems the time will eventually advance and break the loop, but with async-solipsism, time doesn't advance until there is some reason to sleep and the loop is infinite.

Are there changes in behavior for the user?

This will fix infinite loops when using async-solipsism.

Is it a substantial burden for the maintainers to support this?

No. This does not increase the amount of code at all.

Related issue number

Fixes #10149.

Checklist

• I think the code is well written
• Unit tests for the changes exist (I am assuming that the keepalive functionality has existing test coverage)
• Documentation reflects the changes (no documentation change needed)
• If you provide code modification, please add yourself to CONTRIBUTORS.txt (already there)
  • The format is <Name> <Surname>.
  • Please keep alphabetical order, the file is sorted by names.
• Add a new news fragment into the CHANGES/ folder

  • name it <issue_or_pr_num>.<type>.rst (e.g. 588.bugfix.rst)

  • if you don't have an issue number, change it to the pull request
    number after creating the PR

    • .bugfix: A bug fix for something the maintainers deemed an
      improper undesired behavior that got corrected to match
      pre-agreed expectations.
    • .feature: A new behavior, public APIs. That sort of stuff.
    • .deprecation: A declaration of future API removals and breaking
      changes in behavior.
    • .breaking: When something public is removed in a breaking way.
      Could be deprecated in an earlier release.
    • .doc: Notable updates to the documentation structure or build
      process.
    • .packaging: Notes for downstreams about unobvious side effects
      and tooling. Changes in the test invocation considerations and
      runtime assumptions.
    • .contrib: Stuff that affects the contributor experience. e.g.
      Running tests, building the docs, setting up the development
      environment.
    • .misc: Changes that are hard to assign to any of the above
      categories.

  • Make sure to use full sentences with correct case and punctuation,
    for example:

    Fixed issue with non-ascii contents in doctest text files
    -- by :user:`contributor-gh-handle`.

    Use the past tense or the present tense a non-imperative mood,
    referring to what's changed compared to the last released version
    of this project.

[codspeed-hq]

CodSpeed Performance Report

Merging #10173 will not alter performance

_{Comparing patchback/backports/3.11/7c12b1a9c8b2a9e33fb559229a4c4695de39f08c/pr-10151 (d226c05) with 3.11 (3680479)}

Summary

✅ 47 untouched benchmarks

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.06%. Comparing base (3680479) to head (d226c05).
Report is 1 commits behind head on 3.11.

✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             3.11   #10173   +/-   ##
=======================================
  Coverage   98.06%   98.06%           
=======================================
  Files         123      123           
  Lines       37156    37177   +21     
  Branches     4468     4469    +1     
=======================================
+ Hits        36436    36457   +21     
  Misses        542      542           
  Partials      178      178           

Flag	Coverage Δ
CI-GHA	97.95% <100.00%> (+<0.01%)	⬆️
OS-Linux	97.65% <95.45%> (+<0.01%)	⬆️
OS-Windows	94.58% <100.00%> (+<0.01%)	⬆️
OS-macOS	96.77% <95.45%> (-0.01%)	⬇️
Py-3.10.11	96.62% <100.00%> (+<0.01%)	⬆️
Py-3.10.15	97.21% <95.45%> (+0.04%)	⬆️
Py-3.11.10	?
Py-3.11.11	97.23% <95.45%> (?)
Py-3.11.9	96.70% <100.00%> (+<0.01%)	⬆️
Py-3.12.7	?
Py-3.12.8	97.72% <100.00%> (?)
Py-3.13.0	?
Py-3.13.1	97.71% <95.45%> (+0.02%)	⬆️
Py-3.9.13	96.55% <100.00%> (+<0.01%)	⬆️
Py-3.9.20	97.13% <95.45%> (+0.03%)	⬆️
Py-pypy7.3.16	96.70% <95.45%> (+<0.01%)	⬆️
VM-macos	96.77% <95.45%> (-0.01%)	⬇️
VM-ubuntu	97.65% <95.45%> (+<0.01%)	⬆️
VM-windows	94.58% <100.00%> (+<0.01%)	⬆️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.