Apply boost only once for distance_feature query (#63767)

Currently if distance_feature query contains boost,
it incorrectly  gets applied twice: in AbstractQueryBuilder::toQuery and
we also pass this boost to Lucene's LongPoint.newDistanceFeatureQuery.
As a result we get incorrect scores.

This fixes this error to ensure that boost is applied only once.

Closes #63691

Author: mayya-sharipova

docs/reference/release-notes/7.10.asciidoc

@@ -1,3 +1,14 @@
+[[release-notes-7.10.1]]
+== {es} version 7.10.1
+
+[[bug-7.10.1]]
+[float]
+=== Bug fixes
+
+Search::
+* Apply boost only once for distance_feature query {es-pull}63767[#63767]
+
+
 [[release-notes-7.10.0]]
 == {es} version 7.10.0
 

server/src/main/java/org/elasticsearch/index/query/DistanceFeatureQueryBuilder.java

@@ -112,7 +112,8 @@ protected Query doToQuery(QueryShardContext context) throws IOException {
         if (fieldType == null) {
             return Queries.newMatchNoDocsQuery("Can't run [" + NAME + "] query on unmapped fields!");
         }
-        return fieldType.distanceFeatureQuery(origin.origin(), pivot, boost, context);
+        // As we already apply boost in AbstractQueryBuilder::toQuery, we always passing a boost of 1.0 to distanceFeatureQuery
+        return fieldType.distanceFeatureQuery(origin.origin(), pivot, 1.0f, context);
     }
 
     String fieldName() {

server/src/test/java/org/elasticsearch/index/query/DistanceFeatureQueryBuilderTests.java

@@ -78,12 +78,11 @@ protected void doAssertLuceneQuery(DistanceFeatureQueryBuilder queryBuilder,
         String fieldName = expectedFieldName(queryBuilder.fieldName());
         Object origin = queryBuilder.origin().origin();
         String pivot = queryBuilder.pivot();
-        float boost = queryBuilder.boost;
         final Query expectedQuery;
         if (fieldName.equals(GEO_POINT_FIELD_NAME)) {
             GeoPoint originGeoPoint = (origin instanceof GeoPoint)? (GeoPoint) origin : GeoUtils.parseFromString((String) origin);
             double pivotDouble = DistanceUnit.DEFAULT.parse(pivot, DistanceUnit.DEFAULT);
-            expectedQuery = LatLonPoint.newDistanceFeatureQuery(fieldName, boost, originGeoPoint.lat(), originGeoPoint.lon(), pivotDouble);
+            expectedQuery = LatLonPoint.newDistanceFeatureQuery(fieldName, 1.0f, originGeoPoint.lat(), originGeoPoint.lon(), pivotDouble);
         } else { // if (fieldName.equals(DATE_FIELD_NAME))
             MapperService mapperService = context.getMapperService();
             DateFieldType fieldType = (DateFieldType) mapperService.fieldType(fieldName);
@@ -95,7 +94,7 @@ protected void doAssertLuceneQuery(DistanceFeatureQueryBuilder queryBuilder,
             } else { // NANOSECONDS
                 pivotLong = pivotVal.getNanos();
             }
-            expectedQuery = LongPoint.newDistanceFeatureQuery(fieldName, boost, originLong, pivotLong);
+            expectedQuery = LongPoint.newDistanceFeatureQuery(fieldName, 1.0f, originLong, pivotLong);
         }
         assertEquals(expectedQuery, query);
     }