LUCENE-3919: fix czechstemmer aioobe on the empty term

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1305177 13f79535-47bb-0310-9956-ffa450edef68

modules/analysis/common/src/java/org/apache/lucene/analysis/cz/CzechStemmer.java

@@ -44,7 +44,9 @@ public class CzechStemmer {
   public int stem(char s[], int len) {
     len = removeCase(s, len);
     len = removePossessives(s, len);
-    len = normalize(s, len);
+    if (len > 0) {
+      len = normalize(s, len);
+    }
     return len;
   }
   

modules/analysis/common/src/test/org/apache/lucene/analysis/ar/TestArabicNormalizationFilter.java

@@ -18,9 +18,13 @@ package org.apache.lucene.analysis.ar;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test the Arabic Normalization Filter
@@ -89,4 +93,15 @@ public class TestArabicNormalizationFilter extends BaseTokenStreamTestCase {
     assertTokenStreamContents(filter, new String[]{expected});
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ArabicNormalizationFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/ar/TestArabicStemFilter.java

@@ -18,9 +18,13 @@ package org.apache.lucene.analysis.ar;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
 import org.apache.lucene.analysis.util.CharArraySet;
 
@@ -128,4 +132,15 @@ public class TestArabicStemFilter extends BaseTokenStreamTestCase {
     ArabicStemFilter filter = new ArabicStemFilter(tokenStream);
     assertTokenStreamContents(filter, new String[]{expected});
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ArabicStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/bg/TestBulgarianStemmer.java

@@ -18,10 +18,14 @@ package org.apache.lucene.analysis.bg;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
 import org.apache.lucene.analysis.util.CharArraySet;
 import org.apache.lucene.util.Version;
@@ -221,4 +225,15 @@ public class TestBulgarianStemmer extends BaseTokenStreamTestCase {
         new KeywordMarkerFilter(tokenStream, set));
     assertTokenStreamContents(filter, new String[] { "строй", "строеве" });
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new BulgarianStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/br/TestBrazilianStemmer.java

@@ -18,11 +18,13 @@ package org.apache.lucene.analysis.br;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
-import java.util.Collections;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.LowerCaseTokenizer;
 import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
 import org.apache.lucene.analysis.util.CharArraySet;
@@ -162,4 +164,15 @@ public class TestBrazilianStemmer extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, new BrazilianAnalyzer(TEST_VERSION_CURRENT), 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new BrazilianStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/cjk/TestCJKAnalyzer.java

@@ -23,13 +23,13 @@ import java.io.Reader;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.CharReader;
-import org.apache.lucene.analysis.CharStream;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.charfilter.MappingCharFilter;
 import org.apache.lucene.analysis.charfilter.NormalizeCharMap;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.StopFilter;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 import org.apache.lucene.analysis.tokenattributes.TypeAttribute;
@@ -277,4 +277,15 @@ public class TestCJKAnalyzer extends BaseTokenStreamTestCase {
   public void testRandomHugeStrings() throws Exception {
     checkRandomData(random, new CJKAnalyzer(TEST_VERSION_CURRENT), 200*RANDOM_MULTIPLIER, 8192);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new CJKBigramFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/cjk/TestCJKWidthFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Tests for {@link CJKWidthFilter}
@@ -64,4 +65,15 @@ public class TestCJKWidthFilter extends BaseTokenStreamTestCase {
   public void testRandomData() throws IOException {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new CJKWidthFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/compound/TestCompoundWordTokenFilter.java

@@ -32,6 +32,7 @@ import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.charfilter.MappingCharFilter;
 import org.apache.lucene.analysis.charfilter.NormalizeCharMap;
 import org.apache.lucene.analysis.compound.hyphenation.HyphenationTree;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.analysis.util.CharArraySet;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
@@ -361,4 +362,30 @@ public class TestCompoundWordTokenFilter extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, b, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws Exception {
+    final CharArraySet dict = makeDictionary("a", "e", "i", "o", "u", "y", "bc", "def");
+    Analyzer a = new Analyzer() {
+
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new DictionaryCompoundWordTokenFilter(TEST_VERSION_CURRENT, tokenizer, dict));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+    
+    InputSource is = new InputSource(getClass().getResource("da_UTF8.xml").toExternalForm());
+    final HyphenationTree hyphenator = HyphenationCompoundWordTokenFilter.getHyphenationTree(is);
+    Analyzer b = new Analyzer() {
+
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        TokenFilter filter = new HyphenationCompoundWordTokenFilter(TEST_VERSION_CURRENT, tokenizer, hyphenator);
+        return new TokenStreamComponents(tokenizer, filter);
+      }
+    };
+    checkOneTermReuse(b, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/cz/TestCzechStemmer.java

@@ -18,10 +18,14 @@ package org.apache.lucene.analysis.cz;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
 import org.apache.lucene.analysis.util.CharArraySet;
 
@@ -282,4 +286,15 @@ public class TestCzechStemmer extends BaseTokenStreamTestCase {
     assertTokenStreamContents(filter, new String[] { "hole", "desk" });
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new CzechStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+  
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/de/TestGermanLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -49,4 +50,15 @@ public class TestGermanLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GermanLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/de/TestGermanMinimalStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -61,4 +62,15 @@ public class TestGermanMinimalStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GermanMinimalStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/de/TestGermanNormalizationFilter.java

@@ -25,6 +25,7 @@ import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Tests {@link GermanNormalizationFilter}
@@ -65,4 +66,15 @@ public class TestGermanNormalizationFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GermanNormalizationFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/de/TestGermanStemFilter.java

@@ -17,6 +17,7 @@ package org.apache.lucene.analysis.de;
  * limitations under the License.
  */
 
+import java.io.IOException;
 import java.io.InputStream;
 import java.io.Reader;
 
@@ -61,4 +62,15 @@ public class TestGermanStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GermanStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/el/TestGreekStemmer.java

@@ -17,8 +17,13 @@ package org.apache.lucene.analysis.el;
  * limitations under the License.
  */
 
+import java.io.IOException;
+import java.io.Reader;
+
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 public class TestGreekStemmer extends BaseTokenStreamTestCase {
   Analyzer a = new GreekAnalyzer(TEST_VERSION_CURRENT);
@@ -522,4 +527,15 @@ public class TestGreekStemmer extends BaseTokenStreamTestCase {
     checkOneTerm(a, "αρχοντασ", "αρχοντ");
     checkOneTerm(a, "αρχοντων", "αρχοντ");
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GreekStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/en/TestEnglishMinimalStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Simple tests for {@link EnglishMinimalStemFilter}
@@ -55,4 +56,15 @@ public class TestEnglishMinimalStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new EnglishMinimalStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/en/TestKStemmer.java

@@ -19,12 +19,14 @@ package org.apache.lucene.analysis.en;
 
 import static org.apache.lucene.analysis.VocabularyAssert.assertVocabulary;
 
+import java.io.IOException;
 import java.io.Reader;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Tests for {@link KStemmer}
@@ -52,6 +54,17 @@ public class TestKStemmer extends BaseTokenStreamTestCase {
     assertVocabulary(a, getDataFile("kstemTestData.zip"), "kstem_examples.txt");
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new KStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
   /****** requires original java kstem source code to create map
   public void testCreateMap() throws Exception {
     String input = getBigDoc();

modules/analysis/common/src/test/org/apache/lucene/analysis/en/TestPorterStemFilter.java

@@ -22,6 +22,7 @@ import java.io.Reader;
 import java.io.StringReader;
 
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
 import org.apache.lucene.analysis.util.CharArraySet;
 import org.apache.lucene.analysis.Analyzer;
@@ -64,4 +65,15 @@ public class TestPorterStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new PorterStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/es/TestSpanishLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -49,4 +50,15 @@ public class TestSpanishLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new SpanishLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/fa/TestPersianNormalizationFilter.java

@@ -18,10 +18,14 @@ package org.apache.lucene.analysis.fa;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
+import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.analysis.ar.ArabicLetterTokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test the Persian Normalization Filter
@@ -61,4 +65,15 @@ public class TestPersianNormalizationFilter extends BaseTokenStreamTestCase {
     assertTokenStreamContents(filter, new String[]{expected});
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new PersianNormalizationFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/fi/TestFinnishLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -49,4 +50,15 @@ public class TestFinnishLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new FinnishLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/fr/TestElision.java

@@ -18,13 +18,16 @@ package org.apache.lucene.analysis.fr;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.analysis.util.CharArraySet;
@@ -54,4 +57,15 @@ public class TestElision extends BaseTokenStreamTestCase {
     return tas;
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ElisionFilter(TEST_VERSION_CURRENT, tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/fr/TestFrenchLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -163,4 +164,15 @@ public class TestFrenchLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new FrenchLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/fr/TestFrenchMinimalStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -63,4 +64,15 @@ public class TestFrenchMinimalStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new FrenchMinimalStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/ga/TestIrishLowerCaseFilter.java

@@ -17,11 +17,16 @@ package org.apache.lucene.analysis.ga;
  * limitations under the License.
  */
 
+import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test the Irish lowercase filter.
@@ -38,4 +43,15 @@ public class TestIrishLowerCaseFilter extends BaseTokenStreamTestCase {
     assertTokenStreamContents(filter, new String[] {"n-athair", "t-uisce",
         "hard",});
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new IrishLowerCaseFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/gl/TestGalicianMinimalStemFilter.java

@@ -17,12 +17,14 @@ package org.apache.lucene.analysis.gl;
  * limitations under the License.
  */
 
+import java.io.IOException;
 import java.io.Reader;
 
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Simple tests for {@link GalicianMinimalStemmer}
@@ -52,4 +54,15 @@ public class TestGalicianMinimalStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GalicianMinimalStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/gl/TestGalicianStemFilter.java

@@ -26,6 +26,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.LowerCaseFilter;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 
@@ -48,4 +49,15 @@ public class TestGalicianStemFilter extends BaseTokenStreamTestCase {
   public void testVocabulary() throws IOException {
     assertVocabulary(analyzer, getDataFile("gltestdata.zip"), "gl.txt");
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new GalicianStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/hi/TestHindiNormalizer.java

@@ -18,12 +18,15 @@ package org.apache.lucene.analysis.hi;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test HindiNormalizer
@@ -63,4 +66,15 @@ public class TestHindiNormalizer extends BaseTokenStreamTestCase {
     TokenFilter tf = new HindiNormalizationFilter(tokenizer);
     assertTokenStreamContents(tf, new String[] { output });
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new HindiNormalizationFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/hi/TestHindiStemmer.java

@@ -18,12 +18,15 @@ package org.apache.lucene.analysis.hi;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test HindiStemmer
@@ -85,4 +88,15 @@ public class TestHindiStemmer extends BaseTokenStreamTestCase {
     TokenFilter tf = new HindiStemFilter(tokenizer);
     assertTokenStreamContents(tf, new String[] { output });
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new HindiStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/hu/TestHungarianLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -44,4 +45,15 @@ public class TestHungarianLightStemFilter extends BaseTokenStreamTestCase {
   public void testVocabulary() throws IOException {
     assertVocabulary(analyzer, getDataFile("hulighttestdata.zip"), "hulight.txt");
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new HungarianLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/hunspell/HunspellStemFilterTest.java

@@ -27,6 +27,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.miscellaneous.KeywordMarkerFilter;
 import org.apache.lucene.analysis.util.CharArraySet;
 import org.junit.BeforeClass;
@@ -73,4 +74,15 @@ public class HunspellStemFilterTest  extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new HunspellStemFilter(tokenizer, DICTIONARY));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/id/TestIndonesianStemmer.java

@@ -132,4 +132,15 @@ public class TestIndonesianStemmer extends BaseTokenStreamTestCase {
     checkOneTermReuse(a, "bukukah", "buku");
     checkOneTermReuse(a, "gigi", "gigi");
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new IndonesianStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/in/TestIndicNormalizer.java

@@ -18,12 +18,15 @@ package org.apache.lucene.analysis.in;
  */
 
 import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test IndicNormalizer
@@ -48,4 +51,15 @@ public class TestIndicNormalizer extends BaseTokenStreamTestCase {
     TokenFilter tf = new IndicNormalizationFilter(tokenizer);
     assertTokenStreamContents(tf, new String[] { output });
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new IndicNormalizationFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/it/TestItalianLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -49,4 +50,15 @@ public class TestItalianLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ItalianLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/lv/TestLatvianStemmer.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Basic tests for {@link LatvianStemmer}
@@ -268,4 +269,15 @@ public class TestLatvianStemmer extends BaseTokenStreamTestCase {
     checkOneTerm(a, "usa", "usa"); // length
     checkOneTerm(a, "60ms", "60ms"); // vowel count
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new LatvianStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestASCIIFoldingFilter.java

@@ -22,8 +22,10 @@ import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 import java.util.List;
@@ -1923,4 +1925,15 @@ public class TestASCIIFoldingFilter extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ASCIIFoldingFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestCapitalizationFilter.java

@@ -29,6 +29,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.util.CharArraySet;
 
 import static org.apache.lucene.analysis.miscellaneous.CapitalizationFilter.*;
@@ -133,4 +134,15 @@ public class TestCapitalizationFilter extends BaseTokenStreamTestCase {
     
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new CapitalizationFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestHyphenatedWordsFilter.java

@@ -17,6 +17,7 @@
 
 package org.apache.lucene.analysis.miscellaneous;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 
@@ -25,6 +26,7 @@ import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * HyphenatedWordsFilter test
@@ -74,4 +76,15 @@ public class TestHyphenatedWordsFilter extends BaseTokenStreamTestCase {
     
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new HyphenatedWordsFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestLengthFilter.java

@@ -18,6 +18,10 @@ package org.apache.lucene.analysis.miscellaneous;
  */
 
 import org.apache.lucene.analysis.*;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
+
+import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
 public class TestLengthFilter extends BaseTokenStreamTestCase {
@@ -42,4 +46,15 @@ public class TestLengthFilter extends BaseTokenStreamTestCase {
     );
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new LengthFilter(true, tokenizer, 0, 5));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestRemoveDuplicatesTokenFilter.java

@@ -23,6 +23,7 @@ import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Token;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.synonym.SynonymFilter;
 import org.apache.lucene.analysis.synonym.SynonymMap;
 import org.apache.lucene.analysis.tokenattributes.OffsetAttribute;
@@ -31,6 +32,7 @@ import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.util.CharsRef;
 import org.apache.lucene.util._TestUtil;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.util.Iterator;
 import java.util.Arrays;
@@ -165,4 +167,15 @@ public class TestRemoveDuplicatesTokenFilter extends BaseTokenStreamTestCase {
     }
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new RemoveDuplicatesTokenFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestTrimFilter.java

@@ -27,6 +27,7 @@ import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Token;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.tokenattributes.*;
 
 /**
@@ -130,4 +131,15 @@ public class TestTrimFilter extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, b, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new TrimFilter(tokenizer, random.nextBoolean()));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/miscellaneous/TestWordDelimiterFilter.java

@@ -18,7 +18,10 @@
 package org.apache.lucene.analysis.miscellaneous;
 
 import org.apache.lucene.analysis.*;
+import org.apache.lucene.analysis.Analyzer.TokenStreamComponents;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.StopFilter;
+import org.apache.lucene.analysis.cz.CzechStemFilter;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.analysis.tokenattributes.PositionIncrementAttribute;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
@@ -322,4 +325,26 @@ public class TestWordDelimiterFilter extends BaseTokenStreamTestCase {
       checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
     }
   }
+  
+  public void testEmptyTerm() throws IOException {
+    for (int i = 0; i < 512; i++) {
+      final int flags = i;
+      final CharArraySet protectedWords;
+      if (random.nextBoolean()) {
+        protectedWords = new CharArraySet(TEST_VERSION_CURRENT, new HashSet<String>(Arrays.asList("a", "b", "cd")), false);
+      } else {
+        protectedWords = null;
+      }
+    
+      Analyzer a = new Analyzer() { 
+        @Override
+        protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+          Tokenizer tokenizer = new KeywordTokenizer(reader);
+          return new TokenStreamComponents(tokenizer, new WordDelimiterFilter(tokenizer, flags, protectedWords));
+        }
+      };
+      // depending upon options, this thing may or may not preserve the empty term
+      checkAnalysisConsistency(random, a, random.nextBoolean(), "");
+    }
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/ngram/EdgeNGramTokenFilterTest.java

@@ -23,6 +23,7 @@ import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
 
@@ -152,4 +153,26 @@ public class EdgeNGramTokenFilterTest extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, b, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws Exception {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, 
+            new EdgeNGramTokenFilter(tokenizer, EdgeNGramTokenFilter.Side.FRONT, 2, 15));
+      }    
+    };
+    checkAnalysisConsistency(random, a, random.nextBoolean(), "");
+    
+    Analyzer b = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, 
+            new EdgeNGramTokenFilter(tokenizer, EdgeNGramTokenFilter.Side.BACK, 2, 15));
+      }    
+    };
+    checkAnalysisConsistency(random, b, random.nextBoolean(), "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/ngram/NGramTokenFilterTest.java

@@ -23,7 +23,7 @@ import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Tokenizer;
-import org.apache.lucene.analysis.Analyzer.TokenStreamComponents;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
 
@@ -132,4 +132,16 @@ public class NGramTokenFilterTest extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws Exception {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, 
+            new NGramTokenFilter(tokenizer, 2, 15));
+      }    
+    };
+    checkAnalysisConsistency(random, a, random.nextBoolean(), "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/no/TestNorwegianLightStemFilter.java

@@ -25,6 +25,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -50,4 +51,15 @@ public class TestNorwegianLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new NorwegianLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/no/TestNorwegianMinimalStemFilter.java

@@ -25,6 +25,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -50,4 +51,15 @@ public class TestNorwegianMinimalStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new NorwegianMinimalStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/pattern/TestPatternReplaceFilter.java

@@ -22,7 +22,9 @@ import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 import java.util.regex.Pattern;
@@ -104,4 +106,15 @@ public class TestPatternReplaceFilter extends BaseTokenStreamTestCase {
     checkRandomData(random, b, 10000*RANDOM_MULTIPLIER);
   }
   
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer,  new PatternReplaceFilter(tokenizer, Pattern.compile("a"), "b", true));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
+
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/pt/TestPortugueseLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.LowerCaseFilter;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 
@@ -96,4 +97,15 @@ public class TestPortugueseLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new PortugueseLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/pt/TestPortugueseMinimalStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.LowerCaseFilter;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 
@@ -70,4 +71,15 @@ public class TestPortugueseMinimalStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new PortugueseMinimalStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/pt/TestPortugueseStemFilter.java

@@ -26,6 +26,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.LowerCaseFilter;
 import org.apache.lucene.analysis.standard.StandardTokenizer;
 
@@ -70,4 +71,15 @@ public class TestPortugueseStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new PortugueseStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/reverse/TestReverseStringFilter.java

@@ -17,6 +17,7 @@
 
 package org.apache.lucene.analysis.reverse;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 
@@ -25,6 +26,7 @@ import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.util.Version;
 
 public class TestReverseStringFilter extends BaseTokenStreamTestCase {
@@ -111,4 +113,15 @@ public class TestReverseStringFilter extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ReverseStringFilter(TEST_VERSION_CURRENT, tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/ru/TestRussianLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -49,4 +50,15 @@ public class TestRussianLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new RussianLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/shingle/ShingleFilterTest.java

@@ -27,6 +27,7 @@ import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Token;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.analysis.tokenattributes.*;
 
@@ -1156,4 +1157,15 @@ public class ShingleFilterTest extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, a, 200*RANDOM_MULTIPLIER, 8192);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ShingleFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/snowball/TestSnowball.java

@@ -17,10 +17,15 @@ package org.apache.lucene.analysis.snowball;
  * limitations under the License.
  */
 
+import java.io.IOException;
+import java.io.Reader;
+
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Analyzer;
+import org.apache.lucene.analysis.Tokenizer;
 import org.apache.lucene.index.Payload;
 import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.standard.StandardAnalyzer;
 import org.apache.lucene.analysis.tokenattributes.CharTermAttribute;
 import org.apache.lucene.analysis.tokenattributes.FlagsAttribute;
@@ -136,4 +141,23 @@ public class TestSnowball extends BaseTokenStreamTestCase {
       return true;
     }
   }
+  
+  public void testEmptyTerm() throws IOException {
+    String langs[] = { 
+        "Armenian", "Basque", "Catalan", "Danish", "Dutch", "English",
+        "Finnish", "French", "German2", "German", "Hungarian", "Irish",
+        "Italian", "Kp", "Lovins", "Norwegian", "Porter", "Portuguese",
+        "Romanian", "Russian", "Spanish", "Swedish", "Turkish"
+    };
+    for (final String lang : langs) {
+      Analyzer a = new Analyzer() {
+        @Override
+        protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+          Tokenizer tokenizer = new KeywordTokenizer(reader);
+          return new TokenStreamComponents(tokenizer, new SnowballFilter(tokenizer, lang));
+        }
+      };
+      checkOneTermReuse(a, "", "");
+    }
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/sv/TestSwedishLightStemFilter.java

@@ -24,6 +24,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import static org.apache.lucene.analysis.VocabularyAssert.*;
 
@@ -49,4 +50,15 @@ public class TestSwedishLightStemFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new SwedishLightStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/synonym/TestSynonymMapFilter.java

@@ -17,6 +17,7 @@
 
 package org.apache.lucene.analysis.synonym;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 import java.util.ArrayList;
@@ -32,6 +33,7 @@ import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockAnalyzer;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.tokenattributes.*;
 import org.apache.lucene.util.CharsRef;
 import org.apache.lucene.util._TestUtil;
@@ -428,6 +430,29 @@ public class TestSynonymMapFilter extends BaseTokenStreamTestCase {
     }
   }
   
+  public void testEmptyTerm() throws IOException {
+    final int numIters = atLeast(10);
+    for (int i = 0; i < numIters; i++) {
+      b = new SynonymMap.Builder(random.nextBoolean());
+      final int numEntries = atLeast(10);
+      for (int j = 0; j < numEntries; j++) {
+        add(randomNonEmptyString(), randomNonEmptyString(), random.nextBoolean());
+      }
+      final SynonymMap map = b.build();
+      final boolean ignoreCase = random.nextBoolean();
+      
+      final Analyzer analyzer = new Analyzer() {
+        @Override
+        protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+          Tokenizer tokenizer = new KeywordTokenizer(reader);
+          return new TokenStreamComponents(tokenizer, new SynonymFilter(tokenizer, map, ignoreCase));
+        }
+      };
+
+      checkAnalysisConsistency(random, analyzer, random.nextBoolean(), "");
+    }
+  }
+  
   /** simple random test like testRandom2, but for large docs
    */
   public void testRandomHuge() throws Exception {

modules/analysis/common/src/test/org/apache/lucene/analysis/th/TestThaiAnalyzer.java

@@ -17,10 +17,15 @@ package org.apache.lucene.analysis.th;
  * limitations under the License.
  */
 
+import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.StopAnalyzer;
 import org.apache.lucene.analysis.tokenattributes.FlagsAttribute;
 import org.apache.lucene.analysis.util.CharArraySet;
@@ -183,4 +188,15 @@ public class TestThaiAnalyzer extends BaseTokenStreamTestCase {
     ts.addAttribute(FlagsAttribute.class);
     assertTokenStreamContents(ts, new String[] { "ภาษา", "ไทย" });
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ThaiWordFilter(TEST_VERSION_CURRENT, tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/common/src/test/org/apache/lucene/analysis/tr/TestTurkishLowerCaseFilter.java

@@ -17,11 +17,16 @@ package org.apache.lucene.analysis.tr;
  * limitations under the License.
  */
 
+import java.io.IOException;
+import java.io.Reader;
 import java.io.StringReader;
 
+import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
+import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Test the Turkish lowercase filter.
@@ -62,4 +67,15 @@ public class TestTurkishLowerCaseFilter extends BaseTokenStreamTestCase {
     assertTokenStreamContents(filter, new String[] {"i\u0316stanbul", "izmir",
         "\u0131\u0316sparta",});
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new TurkishLowerCaseFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/icu/src/test/org/apache/lucene/analysis/icu/TestICUFoldingFilter.java

@@ -21,6 +21,7 @@ import java.io.IOException;
 import java.io.Reader;
 
 import org.apache.lucene.analysis.*;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 /**
  * Tests ICUFoldingFilter
@@ -77,4 +78,15 @@ public class TestICUFoldingFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ICUFoldingFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/icu/src/test/org/apache/lucene/analysis/icu/TestICUNormalizer2Filter.java

@@ -21,6 +21,7 @@ import java.io.IOException;
 import java.io.Reader;
 
 import org.apache.lucene.analysis.*;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import com.ibm.icu.text.Normalizer2;
 
@@ -77,4 +78,15 @@ public class TestICUNormalizer2Filter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws Exception {
     checkRandomData(random, a, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ICUNormalizer2Filter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/icu/src/test/org/apache/lucene/analysis/icu/TestICUTransformFilter.java

@@ -100,4 +100,15 @@ public class TestICUTransformFilter extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, a, 1000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new ICUTransformFilter(tokenizer, Transliterator.getInstance("Any-Latin")));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/kuromoji/src/test/org/apache/lucene/analysis/kuromoji/TestKuromojiBaseFormFilter.java

@@ -23,6 +23,7 @@ import java.io.Reader;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 public class TestKuromojiBaseFormFilter extends BaseTokenStreamTestCase {
   private Analyzer analyzer = new Analyzer() {
@@ -47,4 +48,15 @@ public class TestKuromojiBaseFormFilter extends BaseTokenStreamTestCase {
   public void testRandomStrings() throws IOException {
     checkRandomData(random, analyzer, atLeast(10000));
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new KuromojiBaseFormFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/kuromoji/src/test/org/apache/lucene/analysis/kuromoji/TestKuromojiKatakanaStemFilter.java

@@ -21,6 +21,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import java.io.IOException;
 import java.io.Reader;
@@ -68,4 +69,15 @@ public class TestKuromojiKatakanaStemFilter extends BaseTokenStreamTestCase {
   public void testRandomData() throws IOException {
     checkRandomData(random, analyzer, 10000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new KuromojiKatakanaStemFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/kuromoji/src/test/org/apache/lucene/analysis/kuromoji/TestKuromojiReadingFormFilter.java

@@ -20,6 +20,7 @@ package org.apache.lucene.analysis.kuromoji;
 import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 
 import java.io.IOException;
 import java.io.Reader;
@@ -61,4 +62,15 @@ public class TestKuromojiReadingFormFilter extends BaseTokenStreamTestCase {
     checkRandomData(random, katakanaAnalyzer, 1000*RANDOM_MULTIPLIER);
     checkRandomData(random, romajiAnalyzer, 1000*RANDOM_MULTIPLIER);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new KuromojiReadingFormFilter(tokenizer));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/phonetic/src/test/org/apache/lucene/analysis/phonetic/DoubleMetaphoneFilterTest.java

@@ -16,6 +16,7 @@
  */
 package org.apache.lucene.analysis.phonetic;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 
@@ -24,7 +25,7 @@ import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
-import org.apache.lucene.analysis.Analyzer.TokenStreamComponents;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 import org.apache.lucene.util._TestUtil;
 
@@ -95,4 +96,15 @@ public class DoubleMetaphoneFilterTest extends BaseTokenStreamTestCase {
     };
     checkRandomData(random, b, 1000 * RANDOM_MULTIPLIER); 
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new DoubleMetaphoneFilter(tokenizer, 8, random.nextBoolean()));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/phonetic/src/test/org/apache/lucene/analysis/phonetic/TestBeiderMorseFilter.java

@@ -17,6 +17,7 @@ package org.apache.lucene.analysis.phonetic;
  * limitations under the License.
  */
 
+import java.io.IOException;
 import java.io.Reader;
 import java.util.HashSet;
 
@@ -28,6 +29,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.junit.Ignore;
 
 /** Tests {@link BeiderMorseFilter} */
@@ -91,4 +93,15 @@ public class TestBeiderMorseFilter extends BaseTokenStreamTestCase {
   public void testRandom() throws Exception {
     checkRandomData(random, analyzer, 1000 * RANDOM_MULTIPLIER); 
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new BeiderMorseFilter(tokenizer, new PhoneticEngine(NameType.GENERIC, RuleType.EXACT, true)));
+      }
+    };
+    checkOneTermReuse(a, "", "");
+  }
 }

modules/analysis/phonetic/src/test/org/apache/lucene/analysis/phonetic/TestPhoneticFilter.java

@@ -31,6 +31,7 @@ import org.apache.lucene.analysis.Analyzer;
 import org.apache.lucene.analysis.BaseTokenStreamTestCase;
 import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.core.WhitespaceTokenizer;
 
 /**
@@ -103,4 +104,20 @@ public class TestPhoneticFilter extends BaseTokenStreamTestCase {
       checkRandomData(random, b, 1000*RANDOM_MULTIPLIER);
     }
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Encoder encoders[] = new Encoder[] {
+        new Metaphone(), new DoubleMetaphone(), new Soundex(), new RefinedSoundex(), new Caverphone()
+    };
+    for (final Encoder e : encoders) {
+      Analyzer a = new Analyzer() {
+        @Override
+        protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+          Tokenizer tokenizer = new KeywordTokenizer(reader);
+          return new TokenStreamComponents(tokenizer, new PhoneticFilter(tokenizer, e, random.nextBoolean()));
+        }
+      };
+      checkOneTermReuse(a, "", "");
+    }
+  }
 }

modules/analysis/smartcn/src/test/org/apache/lucene/analysis/cn/smart/TestSmartChineseAnalyzer.java

@@ -17,6 +17,7 @@
 
 package org.apache.lucene.analysis.cn.smart;
 
+import java.io.IOException;
 import java.io.Reader;
 import java.io.StringReader;
 
@@ -26,6 +27,7 @@ import org.apache.lucene.analysis.MockTokenizer;
 import org.apache.lucene.analysis.TokenFilter;
 import org.apache.lucene.analysis.TokenStream;
 import org.apache.lucene.analysis.Tokenizer;
+import org.apache.lucene.analysis.core.KeywordTokenizer;
 import org.apache.lucene.analysis.miscellaneous.ASCIIFoldingFilter;
 import org.apache.lucene.util.Version;
 
@@ -228,4 +230,15 @@ public class TestSmartChineseAnalyzer extends BaseTokenStreamTestCase {
   public void testRandomHugeStrings() throws Exception {
     checkRandomData(random, new SmartChineseAnalyzer(TEST_VERSION_CURRENT), 200*RANDOM_MULTIPLIER, 8192);
   }
+  
+  public void testEmptyTerm() throws IOException {
+    Analyzer a = new Analyzer() {
+      @Override
+      protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
+        Tokenizer tokenizer = new KeywordTokenizer(reader);
+        return new TokenStreamComponents(tokenizer, new WordTokenFilter(tokenizer));
+      }
+    };
+    checkAnalysisConsistency(random, a, random.nextBoolean(), "");
+  }
 }