LUCENE-6121: QueryBuilder put 2nd reset() to where it was, and add test to ensure no double-reset if there is no term attribute.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1646794 13f79535-47bb-0310-9956-ffa450edef68

lucene/core/src/java/org/apache/lucene/util/QueryBuilder.java

@@ -225,19 +225,25 @@ public class QueryBuilder {
         } catch (IOException e) {
           // ignore
         }
-
-        // rewind the buffer stream
-        buffer.reset();//will never through on subsequent reset calls
       }
     } catch (IOException e) {
       throw new RuntimeException("Error analyzing query text", e);
     }
 
+    // rewind the buffer stream
+    try {
+      if (numTokens > 0) {
+        buffer.reset();//will never throw; the buffer is cached
+      }
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+
     BytesRef bytes = termAtt == null ? null : termAtt.getBytesRef();
 
-    if (numTokens == 0)
+    if (numTokens == 0) {
       return null;
-    else if (numTokens == 1) {
+    } else if (numTokens == 1) {
       try {
         boolean hasNext = buffer.incrementToken();
         assert hasNext == true;

lucene/core/src/test/org/apache/lucene/util/TestQueryBuilder.java

@@ -19,6 +19,7 @@ package org.apache.lucene.util;
 
 import java.io.IOException;
 import java.io.Reader;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.MockAnalyzer;
@@ -355,4 +356,32 @@ public class TestQueryBuilder extends LuceneTestCase {
     expected.setSlop(3);
     assertEquals(expected, builder.createPhraseQuery("field", "中国", 3));
   }
+
+  public void testNoTermAttribute() {
+    //Can't use MockTokenizer because it adds TermAttribute and we don't want that
+    Analyzer analyzer = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName) {
+        return new TokenStreamComponents(
+            new Tokenizer() {
+              boolean wasReset = false;
+              @Override
+              public void reset() throws IOException {
+                super.reset();
+                assertFalse(wasReset);
+                wasReset = true;
+              }
+
+              @Override
+              public boolean incrementToken() throws IOException {
+                assertTrue(wasReset);
+                return false;
+              }
+            }
+        );
+      }
+    };
+    QueryBuilder builder = new QueryBuilder(analyzer);
+    assertNull(builder.createBooleanQuery("field", "whatever"));
+  }
 }