Index: lucene/CHANGES.txt
===================================================================
--- lucene/CHANGES.txt	(revision 1133885)
+++ lucene/CHANGES.txt	(working copy)
@@ -468,6 +468,11 @@
 * LUCENE-3102: CachingCollector.replay was failing to call setScorer
   per-segment (Martijn van Groningen via Mike McCandless)
 
+* LUCENE-3183: Fix rare corner case where seeking to empty term
+  (field="", term="") with terms index interval 1 could hit
+  ArrayIndexOutOfBoundsException (selckin, Robert Muir, Mike
+  McCandless)
+
 New Features
 
 * LUCENE-3140: Added experimental FST implementation to Lucene.
Index: lucene/src/test/org/apache/lucene/index/TestIndexWriter.java
===================================================================
--- lucene/src/test/org/apache/lucene/index/TestIndexWriter.java	(revision 1133885)
+++ lucene/src/test/org/apache/lucene/index/TestIndexWriter.java	(working copy)
@@ -73,6 +73,7 @@
 import org.apache.lucene.util.ThreadInterruptedException;
 import org.apache.lucene.util.UnicodeUtil;
 import org.apache.lucene.util._TestUtil;
+import org.apache.lucene.index.codecs.preflexrw.PreFlexRWCodec;
 
 public class TestIndexWriter extends LuceneTestCase {
 
@@ -1763,4 +1764,19 @@
     reader.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);
+    iwc.setReaderTermsIndexDivisor(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/SegmentTermEnum.java
===================================================================
--- lucene/src/java/org/apache/lucene/index/codecs/preflex/SegmentTermEnum.java	(revision 1133885)
+++ lucene/src/java/org/apache/lucene/index/codecs/preflex/SegmentTermEnum.java	(working copy)
@@ -61,6 +61,7 @@
   int skipInterval;
   int newSuffixStart;
   int maxSkipLevels;
+  private boolean first = true;
 
   SegmentTermEnum(IndexInput i, FieldInfos fis, boolean isi)
           throws CorruptIndexException, IOException {
@@ -123,6 +124,7 @@
     prevBuffer.reset();
     //System.out.println("  ste doSeek prev=" + prevBuffer.toTerm() + " this=" + this);
     termInfo.set(ti);
+    first = p == -1;
   }
 
   /** Increments the enumeration to the next element.  True if one exists.*/
@@ -158,6 +160,13 @@
   final int scanTo(Term term) throws IOException {
     scanBuffer.set(term);
     int count = 0;
+    if (first) {
+      // Always force initial next() in case term is
+      // Term("", "")
+      next();
+      first = false;
+      count++;
+    }
     while (scanBuffer.compareTo(termBuffer) > 0 && next()) {
       count++;
     }