Allow @InternalApi annotation on classes not meant to be constructed outside of the OpenSearch core

[reta]

Description

Allow @InternalApi annotation on classes not meant to be constructed outside of the OpenSearch core. Just one of the examples where it is useful is IndexShard, it has pretty verbose constructor but the instances of IndexShard are not supposed to be created outside of core.

The functionality was already implemented [1] but without proper test cases and usage examples.

[1] https://github.com/opensearch-project/OpenSearch/blob/main/libs/common/src/main/java/org/opensearch/common/annotation/processor/ApiAnnotationProcessor.java#L229

Related Issues

Part of #13308

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 f2e6370: 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 d7c83e1: SUCCESS

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 71.78%. Comparing base (2be25bb) to head (d7c83e1).
Report is 1 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #14575      +/-   ##
============================================
+ Coverage     71.71%   71.78%   +0.06%     
- Complexity    62179    62218      +39     
============================================
  Files          5125     5125              
  Lines        292444   292444              
  Branches      42257    42257              
============================================
+ Hits         209720   209919     +199     
+ Misses        65434    65227     -207     
- Partials      17290    17298       +8     

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[opensearch-trigger-bot]

The backport to 2.x failed:

The process '/usr/bin/git' failed with exit code 128

To backport manually, run these commands in your terminal:

# Navigate to the root of your repository
cd $(git rev-parse --show-toplevel)
# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add ../.worktrees/OpenSearch/backport-2.x 2.x
# Navigate to the new working tree
pushd ../.worktrees/OpenSearch/backport-2.x
# Create a new branch
git switch --create backport/backport-14575-to-2.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick -x --mainline 1 391dee23aa2e8a808821389c379499e91ee2d550
# Push it to GitHub
git push --set-upstream origin backport/backport-14575-to-2.x
# Go back to the original working tree
popd
# Delete the working tree
git worktree remove ../.worktrees/OpenSearch/backport-2.x

Then, create a pull request where the base branch is 2.x and the compare/head branch is backport/backport-14575-to-2.x.