SOLR-6613: TextField.analyzeMultiTerm does not throw an exception when Analyzer returns no terms. (Bruno Roustant)

Closes #1146

solr/CHANGES.txt

@@ -212,6 +212,8 @@ Bug Fixes
 
 * SOLR-14163: SOLR_SSL_CLIENT_HOSTNAME_VERIFICATION needs to work with Jetty server/client SSL contexts (Kevin Risden)
 
+* SOLR-6613: TextField.analyzeMultiTerm does not throw an exception when Analyzer returns no terms. (Bruno Roustant)
+
 Other Changes
 ---------------------
 

solr/core/src/java/org/apache/solr/parser/SolrQueryParserBase.java

@@ -45,6 +45,7 @@ import org.apache.lucene.search.Query;
 import org.apache.lucene.search.QueryVisitor;
 import org.apache.lucene.search.RegexpQuery;
 import org.apache.lucene.search.WildcardQuery;
+import org.apache.lucene.util.BytesRef;
 import org.apache.lucene.util.QueryBuilder;
 import org.apache.lucene.util.automaton.Automata;
 import org.apache.lucene.util.automaton.Automaton;
@@ -997,8 +998,8 @@ public abstract class SolrQueryParserBase extends QueryBuilder {
 
     SchemaField sf = schema.getFieldOrNull((field));
     if (sf == null || ! (fieldType instanceof TextField)) return part;
-    String out = TextField.analyzeMultiTerm(field, part, ((TextField)fieldType).getMultiTermAnalyzer()).utf8ToString();
-    return out;
+    BytesRef out = TextField.analyzeMultiTerm(field, part, ((TextField)fieldType).getMultiTermAnalyzer());
+    return out == null ? part : out.utf8ToString();
   }
 
 

solr/core/src/java/org/apache/solr/schema/TextField.java

@@ -165,6 +165,16 @@ public class TextField extends FieldType {
     return new SolrRangeQuery(field.getName(), lower, upper, minInclusive, maxInclusive);
   }
 
+  /**
+   * Analyzes a text part using the provided {@link Analyzer} for a multi-term query.
+   * <p>
+   * Expects a single token to be used as multi-term term. This single token might also be filtered out
+   * so zero token is supported and null is returned in this case.
+   *
+   * @return The multi-term term bytes; or null if there is no multi-term terms.
+   * @throws SolrException If the {@link Analyzer} tokenizes more than one token;
+   * or if an underlying {@link IOException} occurs.
+   */
   public static BytesRef analyzeMultiTerm(String field, String part, Analyzer analyzerIn) {
     if (part == null || analyzerIn == null) return null;
 
@@ -173,8 +183,10 @@ public class TextField extends FieldType {
 
       TermToBytesRefAttribute termAtt = source.getAttribute(TermToBytesRefAttribute.class);
 
-      if (!source.incrementToken())
-        throw  new SolrException(SolrException.ErrorCode.BAD_REQUEST,"analyzer returned no terms for multiTerm term: " + part);
+      if (!source.incrementToken()) {
+        // Accept no tokens because it may have been filtered out by a StopFilter for example.
+        return null;
+      }
       BytesRef bytes = BytesRef.deepCopyOf(termAtt.getBytesRef());
       if (source.incrementToken())
         throw  new SolrException(SolrException.ErrorCode.BAD_REQUEST,"analyzer returned too many terms for multiTerm term: " + part);

solr/core/src/java/org/apache/solr/search/SimpleQParserPlugin.java

@@ -24,6 +24,7 @@ import org.apache.lucene.search.BooleanQuery;
 import org.apache.lucene.search.BoostQuery;
 import org.apache.lucene.search.FuzzyQuery;
 import org.apache.lucene.search.Query;
+import org.apache.lucene.util.BytesRef;
 import org.apache.solr.common.params.CommonParams;
 import org.apache.solr.common.params.SimpleParams;
 import org.apache.solr.common.params.SolrParams;
@@ -186,26 +187,30 @@ public class SimpleQParserPlugin extends QParserPlugin {
       for (Map.Entry<String, Float> entry : weights.entrySet()) {
         String field = entry.getKey();
         FieldType type = schema.getFieldType(field);
-        Query prefix;
+        Query prefix = null;
 
         if (type instanceof TextField) {
           // If the field type is a TextField then use the multi term analyzer.
           Analyzer analyzer = ((TextField)type).getMultiTermAnalyzer();
-          String term = TextField.analyzeMultiTerm(field, text, analyzer).utf8ToString();
+          BytesRef termBytes = TextField.analyzeMultiTerm(field, text, analyzer);
+          if (termBytes != null) {
+            String term = termBytes.utf8ToString();
             SchemaField sf = schema.getField(field);
             prefix = sf.getType().getPrefixQuery(qParser, sf, term);
+          }
         } else {
           // If the type is *not* a TextField don't do any analysis.
           SchemaField sf = schema.getField(field);
           prefix = type.getPrefixQuery(qParser, sf, text);
         }
-
+        if (prefix != null) {
           float boost = entry.getValue();
           if (boost != 1f) {
             prefix = new BoostQuery(prefix, boost);
           }
           bq.add(prefix, BooleanClause.Occur.SHOULD);
         }
+      }
 
       return simplify(bq.build());
     }
@@ -217,24 +222,28 @@ public class SimpleQParserPlugin extends QParserPlugin {
       for (Map.Entry<String, Float> entry : weights.entrySet()) {
         String field = entry.getKey();
         FieldType type = schema.getFieldType(field);
-        Query fuzzy;
+        Query fuzzy = null;
 
         if (type instanceof TextField) {
           // If the field type is a TextField then use the multi term analyzer.
           Analyzer analyzer = ((TextField)type).getMultiTermAnalyzer();
-          String term = TextField.analyzeMultiTerm(field, text, analyzer).utf8ToString();
+          BytesRef termBytes = TextField.analyzeMultiTerm(field, text, analyzer);
+          if (termBytes != null) {
+            String term = termBytes.utf8ToString();
             fuzzy = new FuzzyQuery(new Term(entry.getKey(), term), fuzziness);
+          }
         } else {
           // If the type is *not* a TextField don't do any analysis.
           fuzzy = new FuzzyQuery(new Term(entry.getKey(), text), fuzziness);
         }
-
+        if (fuzzy != null) {
           float boost = entry.getValue();
           if (boost != 1f) {
             fuzzy = new BoostQuery(fuzzy, boost);
           }
           bq.add(fuzzy, BooleanClause.Occur.SHOULD);
         }
+      }
 
       return simplify(bq.build());
     }

solr/core/src/test/org/apache/solr/schema/TestTextField.java

@@ -0,0 +1,50 @@
+/*
+ * 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.
+ */
+
+package org.apache.solr.schema;
+
+import org.apache.lucene.analysis.core.StopAnalyzer;
+import org.apache.lucene.analysis.core.WhitespaceAnalyzer;
+import org.apache.lucene.analysis.en.EnglishAnalyzer;
+import org.apache.lucene.util.BytesRef;
+import org.apache.solr.SolrTestCaseJ4;
+import org.apache.solr.common.SolrException;
+import org.junit.Test;
+
+/**
+ * Tests directly {@link org.apache.solr.schema.TextField} methods.
+ */
+public class TestTextField extends SolrTestCaseJ4 {
+
+  @Test
+  public void testAnalyzeMultiTerm() {
+    // No terms provided by the StopFilter (stop word) for the multi-term part.
+    // This is supported. Check TextField.analyzeMultiTerm returns null (and does not throw an exception).
+    BytesRef termBytes = TextField.analyzeMultiTerm("field", "the", new StopAnalyzer(EnglishAnalyzer.ENGLISH_STOP_WORDS_SET));
+    assertNull(termBytes);
+
+    // One term provided by the WhitespaceTokenizer for the multi-term part.
+    // This is the regular case. Check TextField.analyzeMultiTerm returns it (and does not throw an exception).
+    termBytes = TextField.analyzeMultiTerm("field", "Sol", new WhitespaceAnalyzer());
+    assertEquals("Sol", termBytes.utf8ToString());
+
+    // Two terms provided by the WhitespaceTokenizer for the multi-term part.
+    // This is not allowed. Expect an exception.
+    SolrException exception = expectThrows(SolrException.class, () -> TextField.analyzeMultiTerm("field", "term1 term2", new WhitespaceAnalyzer()));
+    assertEquals("Unexpected error code", SolrException.ErrorCode.BAD_REQUEST.code, exception.code());
+  }
+}