[LUCENE-3567] NPE from SegmentTermDocs.<init> from SegmentReader.termDocs

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 3.0.3
• Component/s: core/index

Environment

various OS and JRE combos: http://statistics.netbeans.org/exceptions/detail.do?id=180686

• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Jesse Glick
• Created: 07/Nov/11 17:52
• Updated: 28/Aug/22 13:01

Description

Occasionally NetBeans IDE users receive an NPE from Lucene 3.0.3 inside Maven Indexer (currently 4.1.2) code:

java.lang.NullPointerException
	at org.apache.lucene.index.SegmentTermDocs.<init>(SegmentTermDocs.java:52)
	at org.apache.lucene.index.SegmentReader.termDocs(SegmentReader.java:963)
	at org.apache.lucene.index.IndexReader.termDocs(IndexReader.java:813)
	at org.apache.lucene.index.SegmentReader.termDocs(SegmentReader.java:956)
	at org.apache.lucene.search.TermQuery$TermWeight.scorer(TermQuery.java:74)
	at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:210)
	at org.apache.lucene.search.IndexSearcher.search(IndexSearcher.java:170)
	at org.apache.lucene.search.Searcher.search(Searcher.java:98)
	at org.apache.lucene.search.Searcher.search(Searcher.java:108)
	at org.apache.maven.index.DefaultIndexerEngine.getOldDocument(DefaultIndexerEngine.java:158)
        ....

Working backwards, parent.core.getTermsReader() is null, which means SegmentReaders.CoreReaders.decRef was called, which means SegmentReader.doClose was called, which means IndexReader.doClose was called, which I suppose means something called IndexReader.decRef prematurely. But plenty of things can call IndexReader.decRef and it is not clear how to track down the root cause.

Note that SegmentReader.termDocs first calls ensureOpen(), which is presumably supposed to ensure that decRef had not been called too many times; perhaps this assertion did not work?

Downstream bug, for reference: https://netbeans.org/bugzilla/show_bug.cgi?id=201057