[BUG] Sorted Order Assertion in LongHashSet.java is incorrect

[Shailesh-Kumar-Singh]

Describe the bug

The assertion logic in LongHashSet.java assumes signed long values, which leads to incorrect validation when dealing with unsigned long values. The sorted order check fails because value >= previousValue does not correctly handle unsigned comparisons.

Related component

Search

To Reproduce

1. Run ./gradlew run
2. Create the Index
   PUT test_index

{
  "settings": {
    "index": {
      "number_of_shards": 1,
      "number_of_replicas": 0
    }
  },
  "mappings": {
    "properties": {
      "stat": {
        "type": "unsigned_long"
      },
      "latency": {
        "type": "long"
      }
    }
  }
}

3. Ingest sample documents
4. Run Query -
   POST test_index/_search

{
  "query": {
    "terms": {
      "stat": [
        "9223372036854775814",
        "9223372036854775812",
        "9223372036854775811",
        "1"
      ]
    }
  },
  "aggs": {
    "sum_size": {
      "sum": {
        "field": "latency"
      }
    }
  }
}

5. We get - [Please check Additional Details below for Stack trace]

»  fatal error in thread [opensearch[runTask-0][search][T#1]], exiting
»  java.lang.AssertionError: values must be provided in sorted order
FAILURE: Build failed with an exception. 

Expected behavior

In the normal flow, the query should correctly apply Terms aggregations without assertion errors.

Additional Details

Stack Trace

»  java.lang.AssertionError: values must be provided in sorted order
»       at org.apache.lucene.util.LongHashSet.assertBasedOnDataType(LongHashSet.java:68)
»       at org.apache.lucene.util.LongHashSet.<init>(LongHashSet.java:55)
»       at org.opensearch.index.document.SortedUnsignedLongDocValuesSetQuery.<init>(SortedUnsignedLongDocValuesSetQuery.java:48)
»       at org.opensearch.index.document.SortedUnsignedLongDocValuesSetQuery$2.<init>(SortedUnsignedLongDocValuesSetQuery.java:150)
»       at org.opensearch.index.document.SortedUnsignedLongDocValuesSetQuery.newSlowSetQuery(SortedUnsignedLongDocValuesSetQuery.java:150)
»       at org.opensearch.index.mapper.NumberFieldMapper$NumberType$8.termsQuery(NumberFieldMapper.java:1168)
»       at org.opensearch.index.mapper.NumberFieldMapper$NumberFieldType.termsQuery(NumberFieldMapper.java:1577)
»       at org.opensearch.index.query.TermsQueryBuilder.doToQuery(TermsQueryBuilder.java:556)
»       at org.opensearch.index.query.AbstractQueryBuilder.toQuery(AbstractQueryBuilder.java:117)
»       at org.opensearch.index.query.QueryShardContext.lambda$toQuery$3(QueryShardContext.java:575)
»       at org.opensearch.index.query.QueryShardContext.toQuery(QueryShardContext.java:587)
»       at org.opensearch.index.query.QueryShardContext.toQuery(QueryShardContext.java:574)
»       at org.opensearch.search.SearchService.parseSource(SearchService.java:1374)
»       at org.opensearch.search.SearchService.createContext(SearchService.java:1110)
»       at org.opensearch.search.SearchService.executeQueryPhase(SearchService.java:707)
»       at org.opensearch.search.SearchService$2.lambda$onResponse$0(SearchService.java:680)
»       at org.opensearch.action.ActionRunnable.lambda$supply$0(ActionRunnable.java:74)
»       at org.opensearch.action.ActionRunnable$2.doRun(ActionRunnable.java:89)
»       at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52)
»       at org.opensearch.threadpool.TaskAwareRunnable.doRun(TaskAwareRunnable.java:78)
»       at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52)
»       at org.opensearch.common.util.concurrent.TimedRunnable.doRun(TimedRunnable.java:59)
»       at org.opensearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:994)
»       at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52)
»       at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1144)
»       at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:642)
»       at java.base/java.lang.Thread.run(Thread.java:1583)