[8.19] Backport Semantic Text Format Tests (#127967)

Author: Mikep86

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

@@ -9,9 +9,11 @@
 
 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;
@@ -27,6 +29,59 @@ 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(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));
+
+        // Test that index.mapping.semantic_text.use_legacy_format == false is ignored when the index version is too old to support the new
+        // format
+        settings = Settings.builder()
+            .put(
+                IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(),
+                IndexVersionUtils.randomVersionBetween(
+                    random(),
+                    IndexVersions.SEMANTIC_TEXT_FIELD_TYPE,
+                    IndexVersionUtils.getPreviousVersion(IndexVersions.INFERENCE_METADATA_FIELDS_BACKPORT)
+                )  // 8.x version range prior to the introduction of the new format
+            )
+            .put(InferenceMetadataFieldsMapper.USE_LEGACY_SEMANTIC_TEXT_FORMAT.getKey(), false)
+            .build();
+        assertFalse(InferenceMetadataFieldsMapper.isEnabled(settings));
+    }
+
+    public void testIsEnabledByDefault() {
+        var settings = Settings.builder()
+            .put(
+                IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(),
+                IndexVersionUtils.randomPreviousCompatibleVersion(random(), IndexVersions.INFERENCE_METADATA_FIELDS_BACKPORT)
+            )
+            .build();
+        assertFalse(InferenceMetadataFieldsMapper.isEnabled(settings));
+
+        settings = Settings.builder()
+            .put(
+                IndexMetadata.SETTING_INDEX_VERSION_CREATED.getKey(),
+                IndexVersionUtils.randomVersionBetween(random(), IndexVersions.INFERENCE_METADATA_FIELDS_BACKPORT, IndexVersion.current())
+            )
+            .build();
+        assertTrue(InferenceMetadataFieldsMapper.isEnabled(settings));
+    }
+
     @Override
     public void testFieldHasValue() {
         assertTrue(