light cleanups

Author: markjhoy

server/src/main/java/org/elasticsearch/index/mapper/vectors/SparseVectorFieldMapper.java

@@ -516,7 +516,7 @@ public static Boolean parseIndexOptionsPruneValue(Map<String, Object> indexOptio
         public static PruningConfig parseIndexOptionsPruningConfig(Boolean prune, Map<String, Object> indexOptionsMap) {
             Object pruningConfiguration = indexOptionsMap.remove(IndexOptions.PRUNING_CONFIG_FIELD_NAME);
             if (pruningConfiguration == null) {
-                return new PruningConfig(PruningConfig.DEFAULT_TOKENS_FREQ_RATIO_THRESHOLD, PruningConfig.DEFAULT_TOKENS_WEIGHT_THRESHOLD);
+                return null;
             }
             if ((pruningConfiguration instanceof Map) == false) {
                 throw new MapperParsingException("[index_options] field [pruning_config] should be a map");

server/src/test/java/org/elasticsearch/index/mapper/vectors/SparseVectorFieldMapperTests.java

@@ -151,8 +151,7 @@ public void testDefaults() throws Exception {
     public void testWithIndexOptionsPrune() throws Exception {
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::mappingWithIndexOptionsPrune));
         String expectedMapping = "{\"_doc\":{\"properties\":{\"field\":{\"type\":\"sparse_vector\",\"index_options\":"
-            + "{\"prune\":true,\"pruning_config\":{\"tokens_freq_ratio_threshold\":5.0,\"tokens_weight_threshold\":0.4}}"
-            + "}}}}";
+            + "{\"prune\":true}}}}}";
         assertEquals(expectedMapping, mapper.mappingSource().toString());
 
         ParsedDocument doc1 = mapper.parse(source(this::writeField));