MLT Query: Fix exclude with artificial documents

Artificial documents get assigned a random id. When include is set to false
(default), the ids of these documents also get included, when they should
rather be ignored.

Closes #8679

src/main/java/org/elasticsearch/index/query/MoreLikeThisQueryParser.java

@@ -27,6 +27,7 @@ import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.ConstantScoreQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.ElasticsearchIllegalArgumentException;
 import org.elasticsearch.action.termvectors.MultiTermVectorsRequest;
 import org.elasticsearch.action.termvectors.TermVectorsRequest;
@@ -37,7 +38,6 @@ import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.lucene.search.MoreLikeThisQuery;
 import org.elasticsearch.common.xcontent.XContentParser;
 import org.elasticsearch.index.analysis.Analysis;
-import org.elasticsearch.index.mapper.Uid;
 import org.elasticsearch.index.mapper.internal.UidFieldMapper;
 import org.elasticsearch.index.search.morelikethis.MoreLikeThisFetchService;
 
@@ -47,6 +47,8 @@ import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
 
+import static org.elasticsearch.index.mapper.Uid.createUidAsBytes;
+
 /**
  *
  */
@@ -257,9 +259,7 @@ public class MoreLikeThisQueryParser implements QueryParser {
             boolQuery.add(mltQuery, BooleanClause.Occur.SHOULD);
             // exclude the items from the search
             if (!include) {
-                TermsFilter filter = new TermsFilter(UidFieldMapper.NAME, Uid.createUids(items.getRequests()));
+                handleExclude(boolQuery, items);
-                ConstantScoreQuery query = new ConstantScoreQuery(filter);
-                boolQuery.add(query, BooleanClause.Occur.MUST_NOT);
             }
             return boolQuery;
         }
@@ -305,4 +305,20 @@ public class MoreLikeThisQueryParser implements QueryParser {
         }
         return moreLikeFields;
     }
+
+    private void handleExclude(BooleanQuery boolQuery, MultiTermVectorsRequest likeItems) {
+        // artificial docs get assigned a random id and should be disregarded
+        List<BytesRef> uids = new ArrayList<>();
+        for (TermVectorsRequest item : likeItems) {
+            if (item.doc() != null) {
+                continue;
+            }
+            uids.add(createUidAsBytes(item.type(), item.id()));
+        }
+        if (!uids.isEmpty()) {
+            TermsFilter filter = new TermsFilter(UidFieldMapper.NAME, uids.toArray(new BytesRef[0]));
+            ConstantScoreQuery query = new ConstantScoreQuery(filter);
+            boolQuery.add(query, BooleanClause.Occur.MUST_NOT);
+        }
+    }
 }

src/test/java/org/elasticsearch/mlt/MoreLikeThisActionTests.java

@@ -20,7 +20,6 @@
 package org.elasticsearch.mlt;
 
 import org.apache.lucene.util.ArrayUtil;
-import org.apache.lucene.util.LuceneTestCase;
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.action.admin.indices.create.CreateIndexRequestBuilder;
 import org.elasticsearch.action.index.IndexRequestBuilder;
@@ -569,17 +568,10 @@ public class MoreLikeThisActionTests extends ElasticsearchIntegrationTest {
     }
 
     @Test
-    @LuceneTestCase.AwaitsFix(bugUrl = "alex k working on it")
     public void testMoreLikeThisArtificialDocs() throws Exception {
         int numFields = randomIntBetween(5, 10);
 
-        logger.info("Creating an index with multiple fields ...");
+        createIndex("test");
-        XContentBuilder mapping = jsonBuilder().startObject().startObject("type1").startObject("properties");
-        for (int i = 0; i < numFields; i++) {
-            mapping.startObject("field"+i).field("type", "string").endObject();
-        }
-        mapping.endObject().endObject().endObject();
-        assertAcked(prepareCreate("test").addMapping("type1", mapping).get());
         ensureGreen();
 
         logger.info("Indexing a single document ...");
@@ -588,17 +580,15 @@ public class MoreLikeThisActionTests extends ElasticsearchIntegrationTest {
             doc.field("field"+i, generateRandomStringArray(5, 10));
         }
         doc.endObject();
-        List<IndexRequestBuilder> builders = new ArrayList<>();
+        indexRandom(true, client().prepareIndex("test", "type1", "0").setSource(doc));
-        builders.add(client().prepareIndex("test", "type1", "1").setSource(doc));
-        indexRandom(true, builders);
 
         logger.info("Checking the document matches ...");
         MoreLikeThisQueryBuilder mltQuery = moreLikeThisQuery()
-                .docs((Item) new Item().doc(doc).index("test").type("type1"))
+                .like((Item) new Item().doc(doc).index("test").type("type1"))
                 .minTermFreq(0)
                 .minDocFreq(0)
                 .maxQueryTerms(100)
-                .percentTermsToMatch(1); // strict all terms must match!
+                .minimumShouldMatch("100%"); // strict all terms must match!
         SearchResponse response = client().prepareSearch("test").setTypes("type1")
                 .setQuery(mltQuery).get();
         assertSearchResponse(response);