[SOLR-40] getDocListAndSet w/o scores can result in NPE when writing output

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Component/s: search
• Assignee: Yonik Seeley
• Reporter: Greg Ludington
• Created: 26/Jul/06 07:39
• Updated: 23/Feb/12 09:11
• Resolved: 23/Feb/12 09:11

Description

From email regarding SOLR-39...

> I'm all in favor of the patch as commited, but the NPE still concerens me
> ... the OutputWriter should be able to cleanly deal with a DocList that
> doesn't contain scores right?
>
> Should we open a seperate issue to look into this? ... it seems like it
> must be a somewhat obscure code path since I've certainly used Solr
> without scores in the past.
>
> Greg: do you by any chance have a stacktrace so we can see exactly where
> the NPE was getting thrown from?

It may be a somewhat obscure pathway to produce this – I only came
across it when, in applying faceting, I was using getDocListAndSet to
return both the DocList for output and the DocSet for facet
calculations, without fetching documents in any other way. Scores are
set to null here – but, as you indicate, they are also set to null if
you getDocListNC, but that does not end up with an error. I agree
that the underlying issue should also be addressed, as well, but I
have not dug deeply enough into the internals to see the cause yet.

Here is the stack trace, when using a getDocListAndSet method without flags:

09> Started org.mortbay.jetty.Server@29ab3e
Jul 25, 2006 9:32:22 PM org.apache.solr.core.SolrCore execute
INFO:
rows=10&explainOther=&start=0&indent=on&q=dell&fl=&qt=dismax&stylesheet=&v
ersion=2.1 0 140
Jul 25, 2006 9:32:22 PM org.apache.solr.core.SolrException log
SEVERE: java.lang.NullPointerException
at org.apache.solr.search.DocSlice$1.score(DocSlice.java:116)
at org.apache.solr.request.XMLWriter.writeDocList(XMLWriter.java:346)
at org.apache.solr.request.XMLWriter.writeVal(XMLWriter.java:385)
at org.apache.solr.request.XMLWriter.writeResponse(XMLWriter.java:106)
at
org.apache.solr.request.XMLResponseWriter.write(XMLResponseWriter.jav
a:29)
at org.apache.solr.servlet.SolrServlet.doGet(SolrServlet.java:96)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:596)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at
org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:428
)

Issue Links

• is a clone of: SOLR-39 Searcher's getDocListAndSet methods do not accept flags, can cause NPE when writing output