Index: lucene/src/test/org/apache/lucene/index/TestIndexWriter.java
===================================================================
--- lucene/src/test/org/apache/lucene/index/TestIndexWriter.java	(revision 1133616)
+++ lucene/src/test/org/apache/lucene/index/TestIndexWriter.java	(working copy)
@@ -49,6 +49,7 @@
 import org.apache.lucene.document.Field;
 import org.apache.lucene.document.Fieldable;
 import org.apache.lucene.index.IndexWriterConfig.OpenMode;
+import org.apache.lucene.index.codecs.preflexrw.PreFlexRWCodec;
 import org.apache.lucene.search.DocIdSetIterator;
 import org.apache.lucene.search.FieldCache;
 import org.apache.lucene.search.IndexSearcher;
@@ -856,6 +857,20 @@
     writer.close();
     dir.close();
   }
+  
+  // LUCENE-3183
+  public void testEmptyFieldNameTIIOne() throws IOException {
+    Directory dir = newDirectory();
+    IndexWriterConfig iwc = newIndexWriterConfig(TEST_VERSION_CURRENT, new MockAnalyzer(random))
+      .setCodecProvider(_TestUtil.alwaysCodec(new PreFlexRWCodec()));
+    iwc.setTermIndexInterval(1);
+    IndexWriter writer = new IndexWriter(dir, iwc);
+    Document doc = new Document();
+    doc.add(newField("", "a b c", Field.Store.NO, Field.Index.ANALYZED));
+    writer.addDocument(doc);
+    writer.close();
+    dir.close();
+  }
 
 
 
Index: lucene/src/java/org/apache/lucene/index/codecs/preflex/TermInfosReader.java
===================================================================
--- lucene/src/java/org/apache/lucene/index/codecs/preflex/TermInfosReader.java	(revision 1133599)
+++ lucene/src/java/org/apache/lucene/index/codecs/preflex/TermInfosReader.java	(working copy)
@@ -57,6 +57,7 @@
     final long termOrd;
     public TermInfoAndOrd(TermInfo ti, long termOrd) {
       super(ti);
+      assert termOrd >= 0L;
       this.termOrd = termOrd;
     }
   }
@@ -305,7 +306,7 @@
     if (enumerator.term() != null && term.compareToUTF16(enumerator.term()) == 0) {
       ti = enumerator.termInfo;
       if (tiOrd == null) {
-        if (useCache) {
+        if (useCache && enumerator.position >= 0L) {
           termsCache.put(new CloneableTerm(term), new TermInfoAndOrd(ti, enumerator.position));
         }
       } else {