Treat Setting value with empty array string as empty array

[machenity]

Description

According to the documentation, to create a dedicated coordinating node , empty array ([]) should be set as node.roles setting in the opensearch.yml document. The problem is that when I pass the setting value "[]"(env variables are always strings) via an environment variable, OpenSearch's environment variable parser does not determine it as an empty array and uses it as a string of "[]". As a result, it was not possible to create a dedicated coordinating node using an environment variable.

This PR fixes this so that if a listSetting value that is "[]" + any whitespaces, it is treated as an empty array.

Related Issues

Resolves #3412

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Commits are signed per the DCO using --signoff
• Commit changes are listed out in CHANGELOG.md file (See: Changelog)
• Public documentation issue/PR created

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[github-actions]

Compatibility status:

Checks if related components are compatible with change 6f21088

Incompatible components

Incompatible components: [https://github.com/opensearch-project/performance-analyzer.git]

Skipped components

Compatible components

Compatible components: [https://github.com/opensearch-project/asynchronous-search.git, https://github.com/opensearch-project/security-analytics.git, https://github.com/opensearch-project/observability.git, https://github.com/opensearch-project/notifications.git, https://github.com/opensearch-project/reporting.git, https://github.com/opensearch-project/job-scheduler.git, https://github.com/opensearch-project/common-utils.git, https://github.com/opensearch-project/neural-search.git, https://github.com/opensearch-project/opensearch-oci-object-storage.git, https://github.com/opensearch-project/custom-codecs.git, https://github.com/opensearch-project/anomaly-detection.git, https://github.com/opensearch-project/geospatial.git, https://github.com/opensearch-project/ml-commons.git, https://github.com/opensearch-project/index-management.git, https://github.com/opensearch-project/security.git, https://github.com/opensearch-project/alerting.git, https://github.com/opensearch-project/cross-cluster-replication.git, https://github.com/opensearch-project/k-nn.git, https://github.com/opensearch-project/performance-analyzer-rca.git, https://github.com/opensearch-project/sql.git]

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/27890/
• CommitID: 35515a7
  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?

[msfroh]

I'm concerned about the potential blast-radius of this change. Setting is used everywhere, so this may have unintended consequences. The string "[]" is not the same thing as the empty array.

Can we apply this logic only when reading settings from environment variables instead?

[machenity]

The change is in classListSetting, the subclass of Setting, and only applies to one of the static factory methods below it.
I think any settings which is an instance of ListSetting, expect its value to be either a yaml array or a string of comma-separated values.
The only settings that instantiated by that certain factor method are affected by the change, so I don't think the blast-radius would be that large.

Also, as far as I understand, the code that reads in the environment variable is located in ResolvePlaceholder, and I don't think it makes any checks or judgments about the content of the value of the retrieved environment variable. Rather, I'm concerned that reading the content, determining that it's an empty array of strings or something else and changing it might exceed its responsibility range.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/28267/
• CommitID: 7855ce2
  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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/28279/
• CommitID: 178bf08
  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 (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/28280/
• CommitID: fe32d29
  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?

[reta]

• URL: https://build.ci.opensearch.org/job/gradle-check/28280/

Broken by https://github.com/opensearch-project/OpenSearch/pull/10696/files#r1364151268

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: UNSTABLE ❕
• TEST FAILURES:

      1 org.opensearch.search.SearchWeightedRoutingIT.testSearchAggregationWithNetworkDisruption_FailOpenEnabled

• URL: https://build.ci.opensearch.org/job/gradle-check/28908/
• CommitID: 8144ee7
  Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[codecov]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (3ff7e97) 71.15% compared to head (6f21088) 71.17%.
Report is 8 commits behind head on main.

Files	Patch %	Lines
.../java/org/opensearch/common/settings/Settings.java	77.77%	1 Missing and 3 partials ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##               main   #10625      +/-   ##
============================================
+ Coverage     71.15%   71.17%   +0.01%     
- Complexity    58783    58797      +14     
============================================
  Files          4885     4885              
  Lines        277199   277216      +17     
  Branches      40285    40290       +5     
============================================
+ Hits         197247   197308      +61     
- Misses        63448    63474      +26     
+ Partials      16504    16434      -70     

☔ View full report in Codecov by Sentry.
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[reta]

@msfroh friendly ping please

[github-actions]

❌ Gradle check result for 6f21088: 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 6f21088: 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?

[reta]

❌ Gradle check result for 6f21088: FAILURE

#11208

[github-actions]

✅ Gradle check result for 6f21088: SUCCESS