Remove support for type, fields, copy_to and boost in metadata field definition (#116944)

Support for type, fields, copy_to and boost in metadata field definition has been
deprecated in #90989. Such fields have been long parsed and silently ignored.

Author: javanna

docs/changelog/116944.yaml

@@ -0,0 +1,11 @@
+pr: 116944
+summary: "Remove support for type, fields, `copy_to` and boost in metadata field definition"
+area: Mapping
+type: breaking
+issues: []
+breaking:
+  title: "Remove support for type, fields, copy_to and boost in metadata field definition"
+  area: Mapping
+  details: The type, fields, copy_to and boost parameters are no longer supported in metadata field definition
+  impact: Users providing type, fields, copy_to or boost as part of metadata field definition should remove them from their mappings.
+  notable: false

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

@@ -10,16 +10,13 @@
 package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.common.Explicit;
-import org.elasticsearch.common.logging.DeprecationCategory;
 import org.elasticsearch.common.util.Maps;
 import org.elasticsearch.common.xcontent.support.XContentMapValues;
-import org.elasticsearch.index.IndexVersions;
 import org.elasticsearch.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Iterator;
 import java.util.Map;
-import java.util.Set;
 import java.util.function.Function;
 
 /**
@@ -135,8 +132,6 @@ public final MetadataFieldMapper build(MapperBuilderContext context) {
             return build();
         }
 
-        private static final Set<String> UNSUPPORTED_PARAMETERS_8_6_0 = Set.of("type", "fields", "copy_to", "boost");
-
         public final void parseMetadataField(String name, MappingParserContext parserContext, Map<String, Object> fieldNode) {
             final Parameter<?>[] params = getParameters();
             Map<String, Parameter<?>> paramsMap = Maps.newHashMapWithExpectedSize(params.length);
@@ -149,20 +144,6 @@ public final void parseMetadataField(String name, MappingParserContext parserCon
                 final Object propNode = entry.getValue();
                 Parameter<?> parameter = paramsMap.get(propName);
                 if (parameter == null) {
-                    if (UNSUPPORTED_PARAMETERS_8_6_0.contains(propName)) {
-                        if (parserContext.indexVersionCreated().onOrAfter(IndexVersions.V_8_6_0)) {
-                            // silently ignore type, and a few other parameters: sadly we've been doing this for a long time
-                            deprecationLogger.warn(
-                                DeprecationCategory.API,
-                                propName,
-                                "Parameter [{}] has no effect on metadata field [{}] and will be removed in future",
-                                propName,
-                                name
-                            );
-                        }
-                        iterator.remove();
-                        continue;
-                    }
                     throw new MapperParsingException("unknown parameter [" + propName + "] on metadata field [" + name + "]");
                 }
                 parameter.parse(name, parserContext, propNode);

test/framework/src/main/java/org/elasticsearch/index/mapper/MetadataMapperTestCase.java

@@ -12,7 +12,6 @@
 import org.elasticsearch.common.compress.CompressedXContent;
 import org.elasticsearch.core.CheckedConsumer;
 import org.elasticsearch.index.IndexVersion;
-import org.elasticsearch.index.IndexVersions;
 import org.elasticsearch.index.mapper.MapperService.MergeReason;
 import org.elasticsearch.test.index.IndexVersionUtils;
 import org.elasticsearch.xcontent.XContentBuilder;
@@ -142,52 +141,4 @@ public final void testFixedMetaFieldsAreNotConfigurable() throws IOException {
         );
         assertEquals("Failed to parse mapping: " + fieldName() + " is not configurable", exception.getMessage());
     }
-
-    public void testTypeAndFriendsAreSilentlyIgnoredBefore_8_6_0() throws IOException {
-        assumeTrue("Metadata field " + fieldName() + " isn't configurable", isConfigurable());
-        IndexVersion previousVersion = IndexVersionUtils.getPreviousVersion(IndexVersions.V_8_6_0);
-        IndexVersion version = IndexVersionUtils.randomVersionBetween(random(), IndexVersions.MINIMUM_COMPATIBLE, previousVersion);
-        assumeTrue("Metadata field " + fieldName() + " is not supported on version " + version, isSupportedOn(version));
-        MapperService mapperService = createMapperService(version, mapping(b -> {}));
-        // these parameters were previously silently ignored, they will still be ignored in existing indices
-        String[] unsupportedParameters = new String[] { "fields", "copy_to", "boost", "type" };
-        for (String param : unsupportedParameters) {
-            String mappingAsString = "{\n"
-                + "    \"_doc\" : {\n"
-                + "      \""
-                + fieldName()
-                + "\" : {\n"
-                + "        \""
-                + param
-                + "\" : \"any\"\n"
-                + "      }\n"
-                + "    }\n"
-                + "}";
-            assertNotNull(mapperService.parseMapping("_doc", MergeReason.MAPPING_UPDATE, new CompressedXContent(mappingAsString)));
-        }
-    }
-
-    public void testTypeAndFriendsAreDeprecatedFrom_8_6_0() throws IOException {
-        assumeTrue("Metadata field " + fieldName() + " isn't configurable", isConfigurable());
-        IndexVersion version = IndexVersionUtils.randomVersionBetween(random(), IndexVersions.V_8_6_0, IndexVersion.current());
-        assumeTrue("Metadata field " + fieldName() + " is not supported on version " + version, isSupportedOn(version));
-        MapperService mapperService = createMapperService(version, mapping(b -> {}));
-        // these parameters were previously silently ignored, they are now deprecated in new indices
-        String[] unsupportedParameters = new String[] { "fields", "copy_to", "boost", "type" };
-        for (String param : unsupportedParameters) {
-            String mappingAsString = "{\n"
-                + "    \"_doc\" : {\n"
-                + "      \""
-                + fieldName()
-                + "\" : {\n"
-                + "        \""
-                + param
-                + "\" : \"any\"\n"
-                + "      }\n"
-                + "    }\n"
-                + "}";
-            assertNotNull(mapperService.parseMapping("_doc", MergeReason.MAPPING_UPDATE, new CompressedXContent(mappingAsString)));
-            assertWarnings("Parameter [" + param + "] has no effect on metadata field [" + fieldName() + "] and will be removed in future");
-        }
-    }
 }