LUCENE-3351: DirectSpellChecker throws NPE if field doesn't exist

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1152669 13f79535-47bb-0310-9956-ffa450edef68

modules/suggest/src/java/org/apache/lucene/search/spell/DirectSpellChecker.java

@@ -28,6 +28,7 @@ import java.util.PriorityQueue;
 import org.apache.lucene.index.IndexReader;
 import org.apache.lucene.index.MultiFields;
 import org.apache.lucene.index.Term;
+import org.apache.lucene.index.Terms;
 import org.apache.lucene.search.FuzzyTermsEnum;
 import org.apache.lucene.search.BoostAttribute;
 import org.apache.lucene.search.MaxNonCompetitiveBoostAttribute;
@@ -395,7 +396,11 @@ public class DirectSpellChecker {
     AttributeSource atts = new AttributeSource();
     MaxNonCompetitiveBoostAttribute maxBoostAtt =
       atts.addAttribute(MaxNonCompetitiveBoostAttribute.class);
-    FuzzyTermsEnum e = new FuzzyTermsEnum(MultiFields.getTerms(ir, term.field()).iterator(), atts, term, editDistance, Math.max(minPrefix, editDistance-1));
+    Terms terms = MultiFields.getTerms(ir, term.field());
+    if (terms == null) {
+      return Collections.emptyList();
+    }
+    FuzzyTermsEnum e = new FuzzyTermsEnum(terms.iterator(), atts, term, editDistance, Math.max(minPrefix, editDistance-1));
     final PriorityQueue<ScoreTerm> stQueue = new PriorityQueue<ScoreTerm>();
     
     BytesRef queryTerm = new BytesRef(term.text());

modules/suggest/src/test/org/apache/lucene/search/spell/TestDirectSpellChecker.java

@@ -141,4 +141,25 @@ public class TestDirectSpellChecker extends LuceneTestCase {
     writer.close();
     dir.close();
   }
+  
+  public void testBogusField() throws Exception {
+    DirectSpellChecker spellChecker = new DirectSpellChecker();
+    Directory dir = newDirectory();
+    RandomIndexWriter writer = new RandomIndexWriter(random, dir, 
+        new MockAnalyzer(random, MockTokenizer.SIMPLE, true));
+
+    for (int i = 0; i < 20; i++) {
+      Document doc = new Document();
+      doc.add(newField("numbers", English.intToEnglish(i), Field.Store.NO, Field.Index.ANALYZED));
+      writer.addDocument(doc);
+    }
+
+    IndexReader ir = writer.getReader();
+
+    SuggestWord[] similar = spellChecker.suggestSimilar(new Term("bogusFieldBogusField", "fvie"), 2, ir, false);
+    assertEquals(0, similar.length);
+    ir.close();
+    writer.close();
+    dir.close();
+  }
 }

modules/suggest/src/test/org/apache/lucene/search/spell/TestSpellChecker.java

@@ -137,6 +137,20 @@ public class TestSpellChecker extends LuceneTestCase {
     compIdx.close();
   }
   
+  public void testBogusField() throws Exception {
+    IndexReader r = IndexReader.open(userindex, true);
+    Directory compIdx = newDirectory();
+    SpellChecker compareSP = new SpellCheckerMock(compIdx, new LevensteinDistance(), new SuggestWordFrequencyComparator());
+    addwords(r, compareSP, "field3");
+
+    String[] similar = compareSP.suggestSimilar("fvie", 2, r, "bogusFieldBogusField", false);
+    assertEquals(0, similar.length);
+    r.close();
+    if (!compareSP.isClosed())
+      compareSP.close();
+    compIdx.close();
+  }
+
   private void checkCommonSuggestions(IndexReader r) throws IOException {
     String[] similar = spellChecker.suggestSimilar("fvie", 2);
     assertTrue(similar.length > 0);