Fix inner hits retrieval when stored fields are disabled (_none_) (#33018)

Now that types are unique per mapping we can retrieve the document mapper
without referencing the type. This fixes an NPE when stored fields are disabled.
For 6x we'll need a different fix since mappings can still have multiple types.

Relates #32941

rest-api-spec/src/main/resources/rest-api-spec/test/search/100_stored_fields.yml

@@ -39,6 +39,5 @@ setup:
           stored_fields: "_none_"
 
   - is_false: hits.hits.0._id
-  - is_false: hits.hits.0._type
   - is_false: hits.hits.0._source
 

server/src/main/java/org/elasticsearch/search/fetch/FetchPhase.java

@@ -192,20 +192,15 @@ public class FetchPhase implements SearchPhase {
                                       int subDocId,
                                       Map<String, Set<String>> storedToRequestedFields,
                                       LeafReaderContext subReaderContext) {
+        DocumentMapper documentMapper = context.mapperService().documentMapper();
+        Text typeText = documentMapper.typeText();
         if (fieldsVisitor == null) {
-            return new SearchHit(docId);
+            return new SearchHit(docId, null, typeText, null);
         }
 
         Map<String, DocumentField> searchFields = getSearchFields(context, fieldsVisitor, subDocId,
             storedToRequestedFields, subReaderContext);
 
-        DocumentMapper documentMapper = context.mapperService().documentMapper(fieldsVisitor.uid().type());
-        Text typeText;
-        if (documentMapper == null) {
-            typeText = new Text(fieldsVisitor.uid().type());
-        } else {
-            typeText = documentMapper.typeText();
-        }
         SearchHit searchHit = new SearchHit(docId, fieldsVisitor.uid().id(), typeText, searchFields);
         // Set _source if requested.
         SourceLookup sourceLookup = context.lookup().source();
@@ -275,7 +270,7 @@ public class FetchPhase implements SearchPhase {
                 storedToRequestedFields, subReaderContext);
         }
 
-        DocumentMapper documentMapper = context.mapperService().documentMapper(uid.type());
+        DocumentMapper documentMapper = context.mapperService().documentMapper();
         SourceLookup sourceLookup = context.lookup().source();
         sourceLookup.setSegmentAndDocument(subReaderContext, nestedSubDocId);
 

server/src/test/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java

@@ -1052,7 +1052,7 @@ public class TopHitsIT extends ESIntegTestCase {
             for (SearchHit hit : hits) {
                 assertThat(hit.getSourceAsMap(), nullValue());
                 assertThat(hit.getId(), nullValue());
-                assertThat(hit.getType(), nullValue());
+                assertThat(hit.getType(), equalTo("type"));
             }
         }
     }

server/src/test/java/org/elasticsearch/search/source/MetadataFetchingIT.java

@@ -18,12 +18,20 @@
  */
 package org.elasticsearch.search.source;
 
+import org.apache.lucene.search.join.ScoreMode;
 import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.action.search.SearchPhaseExecutionException;
 import org.elasticsearch.action.search.SearchResponse;
+import org.elasticsearch.index.query.InnerHitBuilder;
+import org.elasticsearch.index.query.NestedQueryBuilder;
+import org.elasticsearch.index.query.TermQueryBuilder;
 import org.elasticsearch.search.SearchContextException;
+import org.elasticsearch.search.SearchHits;
+import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.test.ESIntegTestCase;
 
+import java.util.Collections;
+
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.hamcrest.Matchers.equalTo;
 import static org.hamcrest.Matchers.nullValue;
@@ -33,7 +41,7 @@ public class MetadataFetchingIT extends ESIntegTestCase {
         assertAcked(prepareCreate("test"));
         ensureGreen();
 
-        client().prepareIndex("test", "type1", "1").setSource("field", "value").execute().actionGet();
+        client().prepareIndex("test", "_doc", "1").setSource("field", "value").execute().actionGet();
         refresh();
 
         SearchResponse response = client()
@@ -42,7 +50,7 @@ public class MetadataFetchingIT extends ESIntegTestCase {
             .setFetchSource(false)
             .get();
         assertThat(response.getHits().getAt(0).getId(), nullValue());
-        assertThat(response.getHits().getAt(0).getType(), nullValue());
+        assertThat(response.getHits().getAt(0).getType(),  equalTo("_doc"));
         assertThat(response.getHits().getAt(0).getSourceAsString(), nullValue());
 
         response = client()
@@ -50,15 +58,45 @@ public class MetadataFetchingIT extends ESIntegTestCase {
             .storedFields("_none_")
             .get();
         assertThat(response.getHits().getAt(0).getId(), nullValue());
-        assertThat(response.getHits().getAt(0).getType(), nullValue());
+        assertThat(response.getHits().getAt(0).getType(),  equalTo("_doc"));
+        assertThat(response.getHits().getAt(0).getSourceAsString(), nullValue());
+    }
+
+    public void testInnerHits() {
+        assertAcked(prepareCreate("test").addMapping("_doc", "nested", "type=nested"));
+        ensureGreen();
+        client().prepareIndex("test", "_doc", "1")
+            .setSource("field", "value", "nested", Collections.singletonMap("title", "foo")).execute().actionGet();
+        refresh();
+
+        SearchResponse response = client()
+            .prepareSearch("test")
+            .storedFields("_none_")
+            .setFetchSource(false)
+            .setQuery(
+                new NestedQueryBuilder("nested", new TermQueryBuilder("nested.title", "foo"), ScoreMode.Total)
+                    .innerHit(new InnerHitBuilder()
+                        .setStoredFieldNames(Collections.singletonList("_none_"))
+                        .setFetchSourceContext(new FetchSourceContext(false)))
+            )
+            .get();
+        assertThat(response.getHits().totalHits, equalTo(1L));
+        assertThat(response.getHits().getAt(0).getId(), nullValue());
+        assertThat(response.getHits().getAt(0).getType(), equalTo("_doc"));
         assertThat(response.getHits().getAt(0).getSourceAsString(), nullValue());
+        assertThat(response.getHits().getAt(0).getInnerHits().size(), equalTo(1));
+        SearchHits hits = response.getHits().getAt(0).getInnerHits().get("nested");
+        assertThat(hits.totalHits, equalTo(1L));
+        assertThat(hits.getAt(0).getId(), nullValue());
+        assertThat(hits.getAt(0).getType(), equalTo("_doc"));
+        assertThat(hits.getAt(0).getSourceAsString(), nullValue());
     }
 
     public void testWithRouting() {
         assertAcked(prepareCreate("test"));
         ensureGreen();
 
-        client().prepareIndex("test", "type1", "1").setSource("field", "value").setRouting("toto").execute().actionGet();
+        client().prepareIndex("test", "_doc", "1").setSource("field", "value").setRouting("toto").execute().actionGet();
         refresh();
 
         SearchResponse response = client()
@@ -67,7 +105,7 @@ public class MetadataFetchingIT extends ESIntegTestCase {
             .setFetchSource(false)
             .get();
         assertThat(response.getHits().getAt(0).getId(), nullValue());
-        assertThat(response.getHits().getAt(0).getType(), nullValue());
+        assertThat(response.getHits().getAt(0).getType(),  equalTo("_doc"));
         assertThat(response.getHits().getAt(0).field("_routing"), nullValue());
         assertThat(response.getHits().getAt(0).getSourceAsString(), nullValue());
 
@@ -76,7 +114,7 @@ public class MetadataFetchingIT extends ESIntegTestCase {
             .storedFields("_none_")
             .get();
         assertThat(response.getHits().getAt(0).getId(), nullValue());
-        assertThat(response.getHits().getAt(0).getType(), nullValue());
+        assertThat(response.getHits().getAt(0).getType(),  equalTo("_doc"));
         assertThat(response.getHits().getAt(0).getSourceAsString(), nullValue());
     }
 

test/framework/src/main/java/org/elasticsearch/search/aggregations/AggregatorTestCase.java

@@ -37,6 +37,7 @@ import org.elasticsearch.common.lease.Releasable;
 import org.elasticsearch.common.lease.Releasables;
 import org.elasticsearch.common.lucene.index.ElasticsearchDirectoryReader;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.text.Text;
 import org.elasticsearch.common.util.MockBigArrays;
 import org.elasticsearch.common.util.MockPageCacheRecycler;
 import org.elasticsearch.index.Index;
@@ -137,6 +138,7 @@ public abstract class AggregatorTestCase extends ESTestCase {
         when(mapperService.getIndexSettings()).thenReturn(indexSettings);
         when(mapperService.hasNested()).thenReturn(false);
         DocumentMapper mapper = mock(DocumentMapper.class);
+        when(mapper.typeText()).thenReturn(new Text(TYPE_NAME));
         when(mapper.type()).thenReturn(TYPE_NAME);
         when(mapperService.documentMapper()).thenReturn(mapper);
         when(searchContext.mapperService()).thenReturn(mapperService);