[SOLR-13185] NPE in query parsing because of missing null check

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 9.0
• Component/s: query parsers
• Labels: diffblue newdev

Environment

Steps to reproduce

• Use a Linux machine.
• Build commit ea2c8ba of Solr as described in the section below.
• Build the films collection as described below.
• Start the server using the command ./bin/solr start -f -p 8983 -s /tmp/home
• Request the URL given in the bug description.

Compiling the server

git clone https://github.com/apache/lucene-solr
cd lucene-solr
git checkout ea2c8ba
ant compile
cd solr
ant server

Building the collection

We followed Exercise 2 from the Solr Tutorial. The attached file (home.zip) gives the contents of folder /tmp/home that you will obtain by following the steps below:

mkdir -p /tmp/home
echo '<?xml version="1.0" encoding="UTF-8" ?><solr></solr>' > /tmp/home/solr.xml

In one terminal start a Solr instance in foreground:

./bin/solr start -f -p 8983 -s /tmp/home

In another terminal, create a collection of movies, with no shards and no replication, and initialize it:

bin/solr create -c films
curl -X POST -H 'Content-type:application/json' --data-binary '{"add-field": {"name":"name", "type":"text_general", "multiValued":false, "stored":true}}' http://localhost:8983/solr/films/schema
curl -X POST -H 'Content-type:application/json' --data-binary '{"add-copy-field" : {"source":"*","dest":"_text_"}}' http://localhost:8983/solr/films/schema
./bin/post -c films example/films/films.json

• Assignee: Unassigned
• Reporter: Johannes Kloos
• Created: 29/Jan/19 17:05
• Updated: 08/Jun/19 15:02

Description

Requesting the following URL causes Solr to return an HTTP 500 error response:

http://localhost:8983/solr/films/select?defType=complexphrase&q.op=AND

The error response seems to be caused by the following uncaught exception:

java.lang.NullPointerException
at java.io.StringReader.<init>(StringReader.java:50)
at org.apache.lucene.queryparser.classic.QueryParserBase.parse(QueryParserBase.java:106)
at org.apache.lucene.queryparser.complexPhrase.ComplexPhraseQueryParser.parse(ComplexPhraseQueryParser.java:125)
at org.apache.solr.search.ComplexPhraseQParserPlugin$ComplexPhraseQParser.parse(ComplexPhraseQParserPlugin.java:164)
at org.apache.solr.search.QParser.getQuery(QParser.java:173)
at org.apache.solr.handler.component.QueryComponent.prepare(QueryComponent.java:158)
[...]

What happens here is that a querystring (qstr) is passed into a StringReader. Ultimately, this query string comes from the method o.a.s.h.c.QueryComponent, in method prepare (line 157), where it is extracted using rb.queryString() [rb is of type responseBuffer]. The query string stored in the response buffer was earlier on extracted from the request URL by looking for the "q" parameter; note that this parameter is absent in the example request, so qstr would be null. The extracted qstr is then passed to QParser.getParser, which expects a non-null query string.

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