Add new index version for inference metadata field

server/src/main/java/org/elasticsearch/index/IndexVersions.java

@@ -133,6 +133,7 @@ private static Version parseUnchecked(String version) {
     public static final IndexVersion V8_DEPRECATE_SOURCE_MODE_MAPPER = def(8_521_00_0, Version.LUCENE_9_12_0);
     public static final IndexVersion USE_SYNTHETIC_SOURCE_FOR_RECOVERY_BACKPORT = def(8_522_00_0, Version.LUCENE_9_12_0);
     public static final IndexVersion UPGRADE_TO_LUCENE_9_12_1 = def(8_523_00_0, parseUnchecked("9.12.1"));
+    public static final IndexVersion INFERENCE_METADATA_FIELDS_BACKPORT = def(8_524_00_0, parseUnchecked("9.12.1"));
     public static final IndexVersion UPGRADE_TO_LUCENE_10_0_0 = def(9_000_00_0, Version.LUCENE_10_0_0);
     public static final IndexVersion LOGSDB_DEFAULT_IGNORE_DYNAMIC_BEYOND_LIMIT = def(9_001_00_0, Version.LUCENE_10_0_0);
     public static final IndexVersion TIME_BASED_K_ORDERED_DOC_ID = def(9_002_00_0, Version.LUCENE_10_0_0);

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

@@ -86,8 +86,12 @@ public abstract ValueFetcher valueFetcher(
      * @return {@code true} if the new format is enabled; {@code false} otherwise
      */
     public static boolean isEnabled(Settings settings) {
-        return IndexMetadata.SETTING_INDEX_VERSION_CREATED.get(settings).onOrAfter(IndexVersions.INFERENCE_METADATA_FIELDS)
-            && USE_LEGACY_SEMANTIC_TEXT_FORMAT.get(settings) == false;
+        var version = IndexMetadata.SETTING_INDEX_VERSION_CREATED.get(settings);
+        if (version.before(IndexVersions.INFERENCE_METADATA_FIELDS)
+            && version.between(IndexVersions.INFERENCE_METADATA_FIELDS_BACKPORT, IndexVersions.UPGRADE_TO_LUCENE_10_0_0) == false) {
+            return false;
+        }
+        return USE_LEGACY_SEMANTIC_TEXT_FORMAT.get(settings) == false;
     }
 
     /**

x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/mapper/SemanticInferenceMetadataFieldMapperTests.java

@@ -9,10 +9,15 @@
 
 import org.apache.lucene.index.FieldInfo;
 import org.apache.lucene.index.FieldInfos;
+import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.index.IndexVersion;
+import org.elasticsearch.index.IndexVersions;
+import org.elasticsearch.index.mapper.InferenceMetadataFieldsMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
 import org.elasticsearch.index.mapper.MapperServiceTestCase;
 import org.elasticsearch.plugins.Plugin;
+import org.elasticsearch.test.index.IndexVersionUtils;
 import org.elasticsearch.xpack.inference.InferencePlugin;
 
 import java.util.Collection;
@@ -24,6 +29,32 @@ protected Collection<? extends Plugin> getPlugins() {
         return Collections.singletonList(new InferencePlugin(Settings.EMPTY));
     }
 
+    public void testIsEnabled() {
+        var settings = Settings.builder()
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), getRandomCompatibleIndexVersion(true))
+            .put(InferenceMetadataFieldsMapper.USE_LEGACY_SEMANTIC_TEXT_FORMAT.getKey(), true)
+            .build();
+        assertFalse(InferenceMetadataFieldsMapper.isEnabled(settings));
+
+        settings = Settings.builder()
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), getRandomCompatibleIndexVersion(true))
+            .put(InferenceMetadataFieldsMapper.USE_LEGACY_SEMANTIC_TEXT_FORMAT.getKey(), false)
+            .build();
+        assertFalse(InferenceMetadataFieldsMapper.isEnabled(settings));
+
+        settings = Settings.builder()
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), getRandomCompatibleIndexVersion(false))
+            .put(InferenceMetadataFieldsMapper.USE_LEGACY_SEMANTIC_TEXT_FORMAT.getKey(), true)
+            .build();
+        assertFalse(InferenceMetadataFieldsMapper.isEnabled(settings));
+
+        settings = Settings.builder()
+            .put(IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(), getRandomCompatibleIndexVersion(false))
+            .put(InferenceMetadataFieldsMapper.USE_LEGACY_SEMANTIC_TEXT_FORMAT.getKey(), false)
+            .build();
+        assertTrue(InferenceMetadataFieldsMapper.isEnabled(settings));
+    }
+
     @Override
     public void testFieldHasValue() {
         assertTrue(
@@ -42,4 +73,26 @@ public void testFieldHasValueWithEmptyFieldInfos() {
     public MappedFieldType getMappedFieldType() {
         return new SemanticInferenceMetadataFieldsMapper.FieldType();
     }
+
+    static IndexVersion getRandomCompatibleIndexVersion(boolean useLegacyFormat) {
+        if (useLegacyFormat) {
+            if (randomBoolean()) {
+                return IndexVersionUtils.randomVersionBetween(
+                    random(),
+                    IndexVersions.UPGRADE_TO_LUCENE_10_0_0,
+                    IndexVersionUtils.getPreviousVersion(IndexVersions.INFERENCE_METADATA_FIELDS)
+                );
+            }
+            return IndexVersionUtils.randomPreviousCompatibleVersion(random(), IndexVersions.INFERENCE_METADATA_FIELDS_BACKPORT);
+        } else {
+            if (randomBoolean()) {
+                return IndexVersionUtils.randomVersionBetween(random(), IndexVersions.INFERENCE_METADATA_FIELDS, IndexVersion.current());
+            }
+            return IndexVersionUtils.randomVersionBetween(
+                random(),
+                IndexVersions.INFERENCE_METADATA_FIELDS_BACKPORT,
+                IndexVersionUtils.getPreviousVersion(IndexVersions.UPGRADE_TO_LUCENE_10_0_0)
+            );
+        }
+    }
 }

x-pack/plugin/inference/src/test/java/org/elasticsearch/xpack/inference/mapper/SemanticTextFieldMapperTests.java

@@ -24,6 +24,7 @@
 import org.apache.lucene.search.join.QueryBitSetProducer;
 import org.apache.lucene.search.join.ScoreMode;
 import org.elasticsearch.action.admin.indices.mapping.put.PutMappingRequest;
+import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.common.CheckedBiConsumer;
 import org.elasticsearch.common.CheckedBiFunction;
 import org.elasticsearch.common.Strings;
@@ -112,6 +113,10 @@ protected Collection<? extends Plugin> getPlugins() {
 
     private MapperService createMapperService(XContentBuilder mappings, boolean useLegacyFormat) throws IOException {
         var settings = Settings.builder()
+            .put(
+                IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(),
+                SemanticInferenceMetadataFieldMapperTests.getRandomCompatibleIndexVersion(useLegacyFormat)
+            )
             .put(InferenceMetadataFieldsMapper.USE_LEGACY_SEMANTIC_TEXT_FORMAT.getKey(), useLegacyFormat)
             .build();
         return createMapperService(settings, mappings);