priority: backoffQ heap algorithm uses backoff completed time to sort bindings

[zhzhuang-zju]

What type of PR is this? /kind bug

What this PR does / why we need it: This PR includes:

1. The sorting of elements in the BackOff queue should be based on the binding's expiry rather than its priority. Otherwise, bindings whose BackOff period has ended might not be scheduled on time.

Which issue(s) this PR fixes: Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

[zhzhuang-zju]

cc @whitewindmills Please take a look~

[whitewindmills]

thanks, so quickly, I'll take a look tomorrow. /assign

[codecov-commenter]

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Codecov Report

Attention: Patch coverage is 63.63636% with 4 lines in your changes missing coverage. Please review.

Project coverage is 49.42%. Comparing base (e2f0e6e) to head (956b2c4).

Files with missing lines	Patch %	Lines
pkg/scheduler/internal/queue/scheduling_queue.go	55.55%	4 Missing :warning:

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Additional details and impacted files

@@            Coverage Diff             @@
##           master    #6216      +/-   ##
==========================================
+ Coverage   49.33%   49.42%   +0.08%     
==========================================
  Files         678      678              
  Lines       55122    55130       +8     
==========================================
+ Hits        27195    27247      +52     
+ Misses      26156    26110      -46     
- Partials     1771     1773       +2     

Flag	Coverage Δ
unittests	49.42% <63.63%> (+0.08%)	:arrow_up:

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[whitewindmills]

/lgtm /cc @RainbowMango do you want to take a look?

[RainbowMango]

ok. /assign

[karmada-bot]

New changes are detected. LGTM label has been removed.

[karmada-bot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: Once this PR has been reviewed and has the lgtm label, please ask for approval from rainbowmango. For more information see the Kubernetes Code Review Process.

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[zhzhuang-zju]

Will be tracked and completed by the new pr https://github.com/karmada-io/karmada/pull/6987

[rayo1uo]

@zhzhuang-zju Hey, I just realized this PR actually already fixes the incorrect sorting function in backoffQ — wondering why it hasn’t been merged yet? 🤣

[zhzhuang-zju]

@rayo1uo Hah, great minds think alike! I also discovered the issue by reading the source code back then, so when I saw your PR, it felt very familiar—and pleasantly surprising!

As for why it wasn’t merged, it was mainly because I didn’t follow up actively afterward—there’s no special reason behind it. I’ll gladly help review and push for your PR to get merged!

[RainbowMango]

I totally missed this after the first round of review. Sorry. But glad and thanks to @rayo1uo for bringing this up.