fix lookupWord false positive

lucene/analysis/common/src/java/org/apache/lucene/analysis/hunspell/WordStorage.java

@@ -191,7 +191,7 @@ class WordStorage {
         return i == 0;
       }
     }
-    return length == 0;
+    return length == 0 && dataPos == 0;
   }
 
   private void readForms(IntsRef forms, ByteArrayDataInput in, int length) {

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/TestDictionary.java

@@ -50,6 +50,10 @@ public class TestDictionary extends LuceneTestCase {
     assertNotNull(ordList);
     assertEquals(1, ordList.length);
     assertEquals('A', assertSingleFlag(dictionary, ordList));
+
+    assertNotNull(dictionary.lookupWord(new char[] {'a', 'b'}, 0, 2));
+    assertNotNull(dictionary.lookupWord(new char[] {'d', 'b'}, 0, 2));
+    assertNull(dictionary.lookupWord(new char[] {'b'}, 0, 1));
   }
 
   private static char assertSingleFlag(Dictionary dictionary, IntsRef ordList) {

lucene/analysis/common/src/test/org/apache/lucene/analysis/hunspell/simple.dic

@@ -8,3 +8,4 @@ lucene
 mahout/A
 moo/E
 olr/B
+db