[ML] Exclude analysis fields with core field names from anomaly results (#41093)

Added "_index", "_type", "_id" to list of reserved fields.

Closes #39406

Author: yana2301

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/job/results/ReservedFieldNames.java

@@ -5,6 +5,7 @@
  */
 package org.elasticsearch.xpack.core.ml.job.results;
 
+import org.elasticsearch.index.get.GetResult;
 import org.elasticsearch.xpack.core.ml.datafeed.ChunkingConfig;
 import org.elasticsearch.xpack.core.ml.datafeed.DatafeedConfig;
 import org.elasticsearch.xpack.core.ml.datafeed.DelayedDataCheckConfig;
@@ -171,8 +172,12 @@ public final class ReservedFieldNames {
 
             Result.RESULT_TYPE.getPreferredName(),
             Result.TIMESTAMP.getPreferredName(),
-            Result.IS_INTERIM.getPreferredName()
-    };
+            Result.IS_INTERIM.getPreferredName(),
+
+            GetResult._ID,
+            GetResult._INDEX,
+            GetResult._TYPE
+   };
 
     /**
      * This array should be updated to contain all the field names that appear
@@ -256,7 +261,11 @@ public final class ReservedFieldNames {
             ChunkingConfig.MODE_FIELD.getPreferredName(),
             ChunkingConfig.TIME_SPAN_FIELD.getPreferredName(),
 
-            ElasticsearchMappings.CONFIG_TYPE
+            ElasticsearchMappings.CONFIG_TYPE,
+
+            GetResult._ID,
+            GetResult._INDEX,
+            GetResult._TYPE
     };
 
     /**

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/job/persistence/ElasticsearchMappingsTests.java

@@ -19,6 +19,7 @@
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.XContentParser;
+import org.elasticsearch.index.get.GetResult;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.test.VersionUtils;
 import org.elasticsearch.xpack.core.ml.datafeed.DatafeedConfig;
@@ -63,6 +64,12 @@ public class ElasticsearchMappingsTests extends ESTestCase {
             ElasticsearchMappings.WHITESPACE
     );
 
+    private static List<String> INTERNAL_FIELDS = Arrays.asList(
+            GetResult._ID,
+            GetResult._INDEX,
+            GetResult._TYPE
+    );
+
     public void testResultsMapppingReservedFields() throws Exception {
         Set<String> overridden = new HashSet<>(KEYWORDS);
 
@@ -76,6 +83,7 @@ public void testResultsMapppingReservedFields() throws Exception {
 
         Set<String> expected = collectResultsDocFieldNames();
         expected.removeAll(overridden);
+        expected.addAll(INTERNAL_FIELDS);
 
         compareFields(expected, ReservedFieldNames.RESERVED_RESULT_FIELD_NAMES);
     }
@@ -91,6 +99,7 @@ public void testConfigMapppingReservedFields() throws Exception {
 
         Set<String> expected = collectConfigDocFieldNames();
         expected.removeAll(overridden);
+        expected.addAll(INTERNAL_FIELDS);
 
         compareFields(expected, ReservedFieldNames.RESERVED_CONFIG_FIELD_NAMES);
     }

x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/job/results/ReservedFieldNamesTests.java

@@ -5,6 +5,7 @@
  */
 package org.elasticsearch.xpack.ml.job.results;
 
+import org.elasticsearch.index.get.GetResult;
 import org.elasticsearch.test.ESTestCase;
 import org.elasticsearch.xpack.core.ml.job.results.AnomalyRecord;
 import org.elasticsearch.xpack.core.ml.job.results.ReservedFieldNames;
@@ -16,5 +17,8 @@ public void testIsValidFieldName() {
         assertTrue(ReservedFieldNames.isValidFieldName("host.actual"));
         assertFalse(ReservedFieldNames.isValidFieldName("actual.host"));
         assertFalse(ReservedFieldNames.isValidFieldName(AnomalyRecord.BUCKET_SPAN.getPreferredName()));
+        assertFalse(ReservedFieldNames.isValidFieldName(GetResult._INDEX));
+        assertFalse(ReservedFieldNames.isValidFieldName(GetResult._TYPE));
+        assertFalse(ReservedFieldNames.isValidFieldName(GetResult._ID));
     }
-}
+}