Fix double invocation of postCollection when MultiBucketCollector is present

[jed326]

Description

Fixes a bug where postCollection would be called twice when a MultiBucketCollector is present. This was resulting in double counting the docs in the last segment for deferred bucket collectors.

Related Issues

Resolves #14000

Check List

• Functionality includes testing.
• API changes companion pull request created, if applicable.
• Public documentation issue/PR created, if applicable.

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[github-actions]

❌ Gradle check result for 2d9e52d: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[jed326]

@sohami @reta @dennisoelkers could you please take a look?

Thanks!

[github-actions]

❌ Gradle check result for 9b2ebbd: FAILURE

Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green. Is the failure a flaky test unrelated to your change?

[github-actions]

✅ Gradle check result for 9b2ebbd: SUCCESS

[codecov]

Codecov Report

Attention: Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.

Project coverage is 71.56%. Comparing base (b15cb0c) to head (9b2ebbd).
Report is 351 commits behind head on main.

Files	Patch %	Lines
...egations/bucket/BestBucketsDeferringCollector.java	50.00%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #14015      +/-   ##
============================================
+ Coverage     71.42%   71.56%   +0.13%     
- Complexity    59978    61344    +1366     
============================================
  Files          4985     5066      +81     
  Lines        282275   288263    +5988     
  Branches      40946    41754     +808     
============================================
+ Hits         201603   206281    +4678     
- Misses        63999    64963     +964     
- Partials      16673    17019     +346     

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[dennisoelkers]

@jed326: Tested it locally and it fixes the problem. Great work! Many thanks for the quick investigation and fix, as well as providing a workaround for 2.14!

[dennisoelkers]

Fixes the problem described in #14000.

[reta]

Thank you @jed326 !

[jed326]

https://build.ci.opensearch.org/job/gradle-check/39912/

• [BUG] Flakey test org.opensearch.common.joda.JavaJodaTimeDuellingTests.testIncompatiblePatterns #14045