Fix flat_object long field error

[naomichi-y]

Description

Fixed an error 'Preview of field's value: 'null' that occurred when using flat_object with long field names in OpenSearch version 2.12 and later.

Related Issues

#13184

Check List

• New functionality includes testing.
  • All tests pass
• New functionality has been documented.
  • New functionality has javadoc added
• Failing checks are inspected and point to the corresponding known issue(s) (See: Troubleshooting Failing Builds)
• 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]

❌ Gradle check result for 5aa3812: 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 5e00cb7: FAILURE

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[dblock]

What are the values of path and currentFieldName that we end up with in the changed code and what is that code trying to do? I am just wondering what the side effects of setting path to blank are.

@msfroh take a look pls

[dblock]

* What went wrong:
Execution failed for task ':server:spotlessJavaCheck'.
> The following files had format violations:
      src/test/java/org/opensearch/index/mapper/FlatObjectFieldDataTests.java
          @@ -73,8 +73,12 @@
           ············.startObject("field")
           ············.startObject("detail")
           ············.startArray("fooooooooooo")
          -············.startObject().field("name",·"baz").endObject()
          -············.startObject().field("name",·"baz").endObject()
          +············.startObject()
          +············.field("name",·"baz")
          +············.endObject()
          +············.startObject()
          +············.field("name",·"baz")
          +············.endObject()
           ············.endArray()
           ············.endObject()
           ············.endObject()
          @@ -93,7 +97,6 @@
           ········assertEquals(1,·valueReaders.size());
           ····}
           
          -
           ····@Override
           ····protected·String·getFieldDataType()·{
           ········return·FIELD_TYPE;
  Run './gradlew :server:spotlessApply' to fix these violations.

^

[github-actions]

❌ Gradle check result for 5c276f0: FAILURE

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[github-actions]

❌ Gradle check result for 4b58495: FAILURE

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[naomichi-y]

@msfroh
Thank you. I have changed the path.lastIndexOf argument, please confirm.
The other bug was confirmed in my environment. I guess a new Issue needs to be made.

[dblock]

❌ Gradle check result for 4b58495: 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?

org.opensearch.indices.store.IndicesStoreIntegrationIT.testShardActiveElseWhere {p0={"cluster.remote_store.state.enabled":"true"}}

#12788

[dblock]

@msfroh Thank you. I have changed the path.lastIndexOf argument, please confirm. The other bug was confirmed in my environment. I guess a new Issue needs to be made.

Please do open an issue or add a fix/test to this PR @naomichi-y. Appreciate it.

I propose we get this change in first as is? @msfroh wdyt?

[naomichi-y]

I've opened a new issue.
#13351

[github-actions]

❌ Gradle check result for 4b58495: 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?

[dblock]

❌ Gradle check result for 4b58495: FAILURE

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Test Result (4 failures / +4)
org.opensearch.cluster.coordination.AwarenessAttributeDecommissionIT.testConcurrentDecommissionAction
org.opensearch.cluster.coordination.AwarenessAttributeDecommissionIT.testConcurrentDecommissionAction
org.opensearch.cluster.coordination.AwarenessAttributeDecommissionIT.testConcurrentDecommissionAction
org.opensearch.cluster.coordination.AwarenessAttributeDecommissionIT.testConcurrentDecommissionAction

#12197

[github-actions]

❕ Gradle check result for 4b58495: UNSTABLE

• TEST FAILURES:

      1 org.opensearch.cluster.MinimumClusterManagerNodesIT.testThreeNodesNoClusterManagerBlock
      1 org.opensearch.action.admin.indices.create.CreateIndexIT.testCreateAndDeleteIndexConcurrently
      1 org.opensearch.action.admin.indices.create.CreateIndexIT.classMethod

Please review all flaky tests that succeeded after retry and create an issue if one does not already exist to track the flaky failure.

[msfroh]

Thanks for tackling this, @naomichi-y! If you're willing to address the follow-up issue, that would be great!

Please feel free to steal the unit test that I posted above.

[kkewwei]

@naomichi-y @dblock @msfroh, It seems that in some case, null values ​​will cause an infinite loop with this PR. I will fix it in the #14069， and make it merged as soon as possible.

Example:

PUT demo-text
{
  "mappings": {
    "properties": {
      "record": {
        "type": "flat_object"
      }
    }
  }
}

PUT demo-text/_doc/3
{
  "record": {
    "name": null,
    "age":"5",
    "name1": null
  }
}