From 7c612dcb2d7ec18ac4e1bc13b50992cea9b43c94 Mon Sep 17 00:00:00 2001
From: Michael Busch <buschmi@apache.org>
Date: Thu, 12 Jul 2007 16:23:46 +0000
Subject: [PATCH] LUCENE-951: Fixed NullPointerException in
 MultiLevelSkipListReader that was thrown after a call of
 TermPositions.seek().

git-svn-id: https://svn.apache.org/repos/asf/lucene/java/trunk@555683 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  4 ++++
 .../index/MultiLevelSkipListReader.java       |  4 +++-
 .../lucene/index/TestMultiLevelSkipList.java  | 21 +++++++++++--------
 3 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index ef1fa8cbeef..0684926305f 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -23,6 +23,10 @@ Bug fixes
 
  2. LUCENE-955: Fixed SegmentTermPositions to work correctly with the
     first term in the dictionary. (Michael Busch)
+
+ 3. LUCENE-951: Fixed NullPointerException in MultiLevelSkipListReader
+    that was thrown after a call of TermPositions.seek(). 
+    (Rich Johnson via Michael Busch)
     
 New features
 
diff --git a/src/java/org/apache/lucene/index/MultiLevelSkipListReader.java b/src/java/org/apache/lucene/index/MultiLevelSkipListReader.java
index 73cb861ae9d..ede8e8f6231 100644
--- a/src/java/org/apache/lucene/index/MultiLevelSkipListReader.java
+++ b/src/java/org/apache/lucene/index/MultiLevelSkipListReader.java
@@ -172,9 +172,11 @@ abstract class MultiLevelSkipListReader {
     this.docCount = df;
     Arrays.fill(skipDoc, 0);
     Arrays.fill(numSkipped, 0);
+    Arrays.fill(childPointer, 0);
+    
     haveSkipped = false;
     for (int i = 1; i < numberOfSkipLevels; i++) {
-      skipStream[0] = null;
+      skipStream[i] = null;
     }
   }
   
diff --git a/src/test/org/apache/lucene/index/TestMultiLevelSkipList.java b/src/test/org/apache/lucene/index/TestMultiLevelSkipList.java
index 7511ff14644..bee96d5c595 100644
--- a/src/test/org/apache/lucene/index/TestMultiLevelSkipList.java
+++ b/src/test/org/apache/lucene/index/TestMultiLevelSkipList.java
@@ -57,18 +57,21 @@ public class TestMultiLevelSkipList extends TestCase {
     writer.close();
 
     IndexReader reader = IndexReader.open(dir);
-    SegmentTermPositions tp = (SegmentTermPositions) reader.termPositions(term);
+    SegmentTermPositions tp = (SegmentTermPositions) reader.termPositions();
     tp.freqStream = new CountingStream(tp.freqStream);
-    
-    tp.next();
 
-    checkSkipTo(tp, 14, 185); // no skips
-    checkSkipTo(tp, 17, 190); // one skip on level 0
-    checkSkipTo(tp, 287, 200); // one skip on level 1, two on level 0
+    for (int i = 0; i < 2; i++) {
+      counter = 0;
+      tp.seek(term);
+
+      checkSkipTo(tp, 14, 185); // no skips
+      checkSkipTo(tp, 17, 190); // one skip on level 0
+      checkSkipTo(tp, 287, 200); // one skip on level 1, two on level 0
     
-    // this test would fail if we had only one skip level,
-    // because than more bytes would be read from the freqStream
-    checkSkipTo(tp, 4800, 250);// one skip on level 2
+      // this test would fail if we had only one skip level,
+      // because than more bytes would be read from the freqStream
+      checkSkipTo(tp, 4800, 250);// one skip on level 2
+    }
   }
 
   public void checkSkipTo(TermPositions tp, int target, int maxCounter) throws IOException {