[LUCENE-2365] Finding Newest Segment In Empty Index

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.0.1
• Fix Version/s: 2.9.4, 3.0.3, 3.1, 4.0-ALPHA
• Component/s: core/index
• Labels: index writer
• Lucene Fields: New, Patch Available
• Assignee: Michael McCandless
• Reporter: Karthick Sankarachary
• Created: 05/Apr/10 03:44
• Updated: 28/Aug/22 12:23
• Resolved: 30/Oct/10 10:53

Description

While extending the index writer, I discovered that its newestSegment method does not check to see if there are any segments before accessing the segment infos vector. Specifically, if you call the IndexWriter#newestSegment method on a brand-new index which is essentially empty, then it throws an java.lang.ArrayIndexOutOfBoundsException exception.

The proposed fix is to return null if no segments exist, as shown below:

— lucene/src/java/org/apache/lucene/index/IndexWriter.java (revision 930788)
+++ lucene/src/java/org/apache/lucene/index/IndexWriter.java (working copy)
@@ -4587,7 +4587,7 @@

// utility routines for tests
SegmentInfo newestSegment()

{ - return segmentInfos.info(segmentInfos.size()-1); + return segmentInfos.size() > 0 ? segmentInfos.info(segmentInfos.size()-1) : null; }