Field capabilities - make keyword a family of field types (#58315)

Introduces a new method on `MappedFieldType` to return a family type name which defaults to the field type.
Changes `wildcard` and `constant_keyword` field types to return `keyword` for field capabilities.

Relates to #53175

docs/reference/search/field-caps.asciidoc

@@ -67,6 +67,13 @@ query rewrites to `match_none` on every shard.
 ==== {api-response-body-title}
 
 
+The types used in the response describe _families_ of field types.
+Normally a family type is the same as the field type declared in the mapping,
+but to simplify matters certain field types that behave identically are
+described using a family type. For example, `keyword`, `constant_keyword` and `wildcard`
+field types are all described as the `keyword` family type.
+
+
 
 `searchable`::
  Whether this field is indexed for search on all indices.
@@ -75,8 +82,8 @@ query rewrites to `match_none` on every shard.
  Whether this field can be aggregated on all indices.
 
 `indices`::
- The list of indices where this field has the same type, or null if all indices
- have the same type for the field.
+ The list of indices where this field has the same family type, or null if all indices
+ have the same family type for the field.
 
 `non_searchable_indices`::
  The list of indices where this field is not searchable, or null if all indices

server/src/main/java/org/elasticsearch/action/fieldcaps/TransportFieldCapabilitiesIndexAction.java

@@ -124,7 +124,7 @@ private FieldCapabilitiesIndexResponse shardOperation(final FieldCapabilitiesInd
  if (ft != null) {
  if (indicesService.isMetadataField(mapperService.getIndexSettings().getIndexVersionCreated(), field)
  || fieldPredicate.test(ft.name())) {
- IndexFieldCapabilities fieldCap = new IndexFieldCapabilities(field, ft.typeName(),
+ IndexFieldCapabilities fieldCap = new IndexFieldCapabilities(field, ft.familyTypeName(),
  ft.isSearchable(), ft.isAggregatable(), ft.meta());
  responseMap.put(field, fieldCap);
  } else {

server/src/main/java/org/elasticsearch/index/mapper/MappedFieldType.java

@@ -135,6 +135,11 @@ public int hashCode() {
 
  /** Returns the name of this type, as would be specified in mapping properties */
  public abstract String typeName();
+
+ /** Returns the field family type, as used in field capabilities */
+ public String familyTypeName() {
+ return typeName();
+ }
 
  public String name() {
  return name;

x-pack/plugin/mapper-constant-keyword/src/main/java/org/elasticsearch/xpack/constantkeyword/mapper/ConstantKeywordFieldMapper.java

@@ -30,6 +30,7 @@
 import org.elasticsearch.index.fielddata.plain.ConstantIndexFieldData;
 import org.elasticsearch.index.mapper.ConstantFieldType;
 import org.elasticsearch.index.mapper.FieldMapper;
+import org.elasticsearch.index.mapper.KeywordFieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.mapper.MapperParsingException;
@@ -151,6 +152,11 @@ public String value() {
  public String typeName() {
  return CONTENT_TYPE;
  }
+
+ @Override
+ public String familyTypeName() {
+ return KeywordFieldMapper.CONTENT_TYPE;
+ } 
 
  @Override
  public IndexFieldData.Builder fielddataBuilder(String fullyQualifiedIndexName) {

x-pack/plugin/sql/qa/server/src/main/java/org/elasticsearch/xpack/sql/qa/FieldExtractorTestCase.java

@@ -128,7 +128,7 @@ public void testConstantKeywordField() throws IOException {
  Map<String, Object> expected = new HashMap<>();
  expected.put(
  "columns",
- Arrays.asList(columnInfo("plain", "constant_keyword_field", "constant_keyword", JDBCType.VARCHAR, Integer.MAX_VALUE))
+ Arrays.asList(columnInfo("plain", "constant_keyword_field", "keyword", JDBCType.VARCHAR, Integer.MAX_VALUE))
  );
  expected.put("rows", singletonList(singletonList(value)));
  assertResponse(expected, runSql("SELECT constant_keyword_field FROM test"));

x-pack/plugin/sql/qa/server/src/main/resources/alias.csv-spec

@@ -41,7 +41,7 @@ emp_no |INTEGER |integer
 extra |STRUCT |object
 extra.info |STRUCT |object
 extra.info.gender |VARCHAR |keyword
-extra_gender |VARCHAR |constant_keyword
+extra_gender |VARCHAR |keyword
 extra_no |INTEGER |integer
 first_name |VARCHAR |text
 first_name.keyword |VARCHAR |keyword
@@ -50,7 +50,7 @@ hire_date |TIMESTAMP |datetime
 languages |TINYINT |byte
 last_name |VARCHAR |text
 last_name.keyword |VARCHAR |keyword
-null_constant |VARCHAR |constant_keyword
+null_constant |VARCHAR |keyword
 salary |INTEGER |integer
 ;
 
@@ -70,7 +70,7 @@ emp_no |INTEGER |integer
 extra |STRUCT |object
 extra.info |STRUCT |object
 extra.info.gender |VARCHAR |keyword
-extra_gender |VARCHAR |constant_keyword
+extra_gender |VARCHAR |keyword
 extra_no |INTEGER |integer
 first_name |VARCHAR |text
 first_name.keyword |VARCHAR |keyword
@@ -79,7 +79,7 @@ hire_date |TIMESTAMP |datetime
 languages |TINYINT |byte
 last_name |VARCHAR |text
 last_name.keyword |VARCHAR |keyword
-null_constant |VARCHAR |constant_keyword
+null_constant |VARCHAR |keyword
 salary |INTEGER |integer
 ;
 

x-pack/plugin/sql/qa/server/src/main/resources/command.csv-spec

@@ -281,7 +281,7 @@ emp_no |INTEGER |integer
 extra |STRUCT |object
 extra.info |STRUCT |object
 extra.info.gender |VARCHAR |keyword
-extra_gender |VARCHAR |constant_keyword
+extra_gender |VARCHAR |keyword
 extra_no |INTEGER |integer
 first_name |VARCHAR |text
 first_name.keyword |VARCHAR |keyword
@@ -290,7 +290,7 @@ hire_date |TIMESTAMP |datetime
 languages |TINYINT |byte
 last_name |VARCHAR |text
 last_name.keyword |VARCHAR |keyword
-null_constant |VARCHAR |constant_keyword
+null_constant |VARCHAR |keyword
 salary |INTEGER |integer
 ;
 
@@ -310,7 +310,7 @@ emp_no |INTEGER |integer
 extra |STRUCT |object
 extra.info |STRUCT |object
 extra.info.gender |VARCHAR |keyword
-extra_gender |VARCHAR |constant_keyword
+extra_gender |VARCHAR |keyword
 extra_no |INTEGER |integer
 first_name |VARCHAR |text
 first_name.keyword |VARCHAR |keyword
@@ -319,7 +319,7 @@ hire_date |TIMESTAMP |datetime
 languages |TINYINT |byte
 last_name |VARCHAR |text
 last_name.keyword |VARCHAR |keyword
-null_constant |VARCHAR |constant_keyword
+null_constant |VARCHAR |keyword
 salary |INTEGER |integer
 ;