SOLR-6271: fix StringDistance comparison in CSSC. ( This closes #135 )

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1717999 13f79535-47bb-0310-9956-ffa450edef68

solr/CHANGES.txt

@@ -199,6 +199,9 @@ Bug Fixes
 
 * SOLR-8366: ConcurrentUpdateSolrClient attempts to use response's content type as charset encoding
   for parsing exception. (shalin)
+  
+* SOLR-6271: fix ConjunctionSolrSpellChecker to not compare StringDistance by instance.
+  (Igor Kostromin via James Dyer)
 
 Other Changes
 ----------------------

solr/core/src/java/org/apache/solr/spelling/ConjunctionSolrSpellChecker.java

@@ -57,7 +57,7 @@ public class ConjunctionSolrSpellChecker extends SolrSpellChecker {
     try {
       if (stringDistance == null) {
         stringDistance = checker.getStringDistance();
-      } else if (stringDistance != checker.getStringDistance()) {
+      } else if (!stringDistance.equals(checker.getStringDistance())) {
         throw new IllegalArgumentException(
             "All checkers need to use the same StringDistance.");
       }

solr/core/src/test/org/apache/solr/spelling/ConjunctionSolrSpellCheckerTest.java

@@ -0,0 +1,74 @@
+package org.apache.solr.spelling;
+
+import java.io.IOException;
+
+import org.apache.lucene.search.spell.LevensteinDistance;
+import org.apache.lucene.search.spell.NGramDistance;
+import org.apache.lucene.search.spell.StringDistance;
+import org.apache.lucene.util.LuceneTestCase;
+import org.apache.solr.core.SolrCore;
+import org.apache.solr.search.SolrIndexSearcher;
+import org.junit.Test;
+
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class ConjunctionSolrSpellCheckerTest extends LuceneTestCase {
+  
+  @Test
+  public void test() throws Exception {
+    ConjunctionSolrSpellChecker cssc = new ConjunctionSolrSpellChecker();
+    MockSolrSpellChecker levenstein1 = new MockSolrSpellChecker(new LevensteinDistance());
+    MockSolrSpellChecker levenstein2 = new MockSolrSpellChecker(new LevensteinDistance());
+    MockSolrSpellChecker ngram = new MockSolrSpellChecker(new NGramDistance());
+    
+    cssc.addChecker(levenstein1);
+    cssc.addChecker(levenstein2);
+    try {
+      cssc.addChecker(ngram);
+      fail("ConjunctionSolrSpellChecker should have thrown an exception about non-identical StringDistances.");
+    } catch (IllegalArgumentException iae) {
+      // correct behavior
+    }
+  }
+  
+  class MockSolrSpellChecker extends SolrSpellChecker {
+    
+    final StringDistance sd;
+    
+    MockSolrSpellChecker(StringDistance sd) {
+      this.sd = sd;
+    }
+    
+    @Override
+    protected StringDistance getStringDistance() {
+      return sd;
+    }
+    
+    @Override
+    public void reload(SolrCore core, SolrIndexSearcher searcher) throws IOException {}
+    
+    @Override
+    public void build(SolrCore core, SolrIndexSearcher searcher) throws IOException {}
+    
+    @Override
+    public SpellingResult getSuggestions(SpellingOptions options) throws IOException {
+      return null;
+    }
+    
+  }
+}