Pass over _routing value with more_like_this items to be retrieved (#24679)

When retrieving documents to extract terms from as part of a more like this query, the _routing value can be set, yet it gets lost. That leads to not being able to retrieve the documents, hence more_like_this used to return no matches all the time.

Closes #23699

core/src/main/java/org/elasticsearch/common/lucene/search/MoreLikeThisQuery.java

@@ -224,10 +224,6 @@ public class MoreLikeThisQuery extends Query {
         return likeText;
     }
 
-    public void setLikeText(String likeText) {
-        setLikeText(new String[]{likeText});
-    }
-
     public void setLikeText(String... likeText) {
         this.likeText = likeText;
     }
@@ -236,7 +232,7 @@ public class MoreLikeThisQuery extends Query {
         return likeFields;
     }
 
-    public void setLikeText(Fields... likeFields) {
+    public void setLikeFields(Fields... likeFields) {
         this.likeFields = likeFields;
     }
 
@@ -244,7 +240,7 @@ public class MoreLikeThisQuery extends Query {
         setLikeText(likeText.toArray(Strings.EMPTY_ARRAY));
     }
 
-    public void setUnlikeText(Fields... unlikeFields) {
+    public void setUnlikeFields(Fields... unlikeFields) {
         this.unlikeFields = unlikeFields;
     }
 

core/src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilder.java

@@ -178,6 +178,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
             this.index = copy.index;
             this.type = copy.type;
             this.id = copy.id;
+            this.routing = copy.routing;
             this.doc = copy.doc;
             this.xContentType = copy.xContentType;
             this.fields = copy.fields;
@@ -343,7 +344,7 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
         /**
          * Convert this to a {@link TermVectorsRequest} for fetching the terms of the document.
          */
-        public TermVectorsRequest toTermVectorsRequest() {
+        TermVectorsRequest toTermVectorsRequest() {
             TermVectorsRequest termVectorsRequest = new TermVectorsRequest(index, type, id)
                     .selectedFields(fields)
                     .routing(routing)
@@ -1085,14 +1086,14 @@ public class MoreLikeThisQueryBuilder extends AbstractQueryBuilder<MoreLikeThisQ
         // fetching the items with multi-termvectors API
         MultiTermVectorsResponse likeItemsResponse = fetchResponse(context.getClient(), likeItems);
         // getting the Fields for liked items
-        mltQuery.setLikeText(getFieldsFor(likeItemsResponse));
+        mltQuery.setLikeFields(getFieldsFor(likeItemsResponse));
 
         // getting the Fields for unliked items
         if (unlikeItems.length > 0) {
             MultiTermVectorsResponse unlikeItemsResponse = fetchResponse(context.getClient(), unlikeItems);
             org.apache.lucene.index.Fields[] unlikeFields = getFieldsFor(unlikeItemsResponse);
             if (unlikeFields.length > 0) {
-                mltQuery.setUnlikeText(unlikeFields);
+                mltQuery.setUnlikeFields(unlikeFields);
             }
         }
 

core/src/test/java/org/elasticsearch/index/query/MoreLikeThisQueryBuilderTests.java

@@ -23,6 +23,7 @@ import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
 import org.apache.lucene.index.Fields;
 import org.apache.lucene.index.MultiFields;
 import org.apache.lucene.index.memory.MemoryIndex;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.Query;
 import org.elasticsearch.ElasticsearchException;
@@ -61,6 +62,7 @@ import java.util.stream.Stream;
 import static org.elasticsearch.index.query.QueryBuilders.moreLikeThisQuery;
 import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.equalTo;
+import static org.hamcrest.Matchers.greaterThan;
 import static org.hamcrest.Matchers.instanceOf;
 
 public class MoreLikeThisQueryBuilderTests extends AbstractQueryTestCase<MoreLikeThisQueryBuilder> {
@@ -264,6 +266,13 @@ public class MoreLikeThisQueryBuilderTests extends AbstractQueryTestCase<MoreLik
     protected void doAssertLuceneQuery(MoreLikeThisQueryBuilder queryBuilder, Query query, SearchContext context) throws IOException {
         if (queryBuilder.likeItems() != null && queryBuilder.likeItems().length > 0) {
             assertThat(query, instanceOf(BooleanQuery.class));
+            BooleanQuery booleanQuery = (BooleanQuery) query;
+            for (BooleanClause booleanClause : booleanQuery) {
+                if (booleanClause.getQuery() instanceof MoreLikeThisQuery) {
+                    MoreLikeThisQuery moreLikeThisQuery = (MoreLikeThisQuery) booleanClause.getQuery();
+                    assertThat(moreLikeThisQuery.getLikeFields().length, greaterThan(0));
+                }
+            }
         } else {
             // we rely on integration tests for a deeper check here
             assertThat(query, instanceOf(MoreLikeThisQuery.class));
@@ -310,6 +319,12 @@ public class MoreLikeThisQueryBuilderTests extends AbstractQueryTestCase<MoreLik
         assertEquals(expectedItem, newItem);
     }
 
+    public void testItemCopy() throws IOException {
+        Item expectedItem = generateRandomItem();
+        Item newItem = new Item(expectedItem);
+        assertEquals(expectedItem, newItem);
+    }
+
     public void testItemFromXContent() throws IOException {
         Item expectedItem = generateRandomItem();
         String json = expectedItem.toXContent(XContentFactory.jsonBuilder(), ToXContent.EMPTY_PARAMS).string();

core/src/test/java/org/elasticsearch/search/morelikethis/MoreLikeThisIT.java

@@ -623,4 +623,18 @@ public class MoreLikeThisIT extends ESIntegTestCase {
         assertSearchResponse(response);
         assertHitCount(response, 1);
     }
+
+    public void testWithRouting() throws IOException {
+        client().prepareIndex("index", "type", "1").setRouting("3").setSource("text", "this is a document").get();
+        client().prepareIndex("index", "type", "2").setRouting("1").setSource("text", "this is another document").get();
+        client().prepareIndex("index", "type", "3").setRouting("4").setSource("text", "this is yet another document").get();
+        refresh("index");
+
+        Item item = new Item("index", "type", "2").routing("1");
+        MoreLikeThisQueryBuilder moreLikeThisQueryBuilder = new MoreLikeThisQueryBuilder(new String[]{"text"}, null, new Item[]{item});
+        moreLikeThisQueryBuilder.minTermFreq(1);
+        moreLikeThisQueryBuilder.minDocFreq(1);
+        SearchResponse searchResponse = client().prepareSearch("index").setQuery(moreLikeThisQueryBuilder).get();
+        assertEquals(2, searchResponse.getHits().totalHits);
+    }
 }