SOLR-16483: Fix IndexOutOfBounds in RecursiveNumericEvaluator

[acsbendi]

https://issues.apache.org/jira/browse/SOLR-16483

Description

This change fixes the following exception:

2022-10-04 12:21:26.033 ERROR (...) [...] o.a.s.c.s.i.s.ExceptionStream java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0 => java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
        at java.base/jdk.internal.util.Preconditions.outOfBounds(Unknown Source)
java.lang.IndexOutOfBoundsException: Index 0 out of bounds for length 0
        at jdk.internal.util.Preconditions.outOfBounds(Unknown Source) ~[?:?]
        at jdk.internal.util.Preconditions.outOfBoundsCheckIndex(Unknown Source) ~[?:?]
        at jdk.internal.util.Preconditions.checkIndex(Unknown Source) ~[?:?]
        at java.util.Objects.checkIndex(Unknown Source) ~[?:?]
        at java.util.ArrayList.get(Unknown Source) ~[?:?]
        at [org.apache.solr.client.solrj.io](http://org.apache.solr.client.solrj.io/).eval.RecursiveNumericEvaluator.normalizeInputType(RecursiveNumericEvaluator.java:55) ~[?:?]
        at [org.apache.solr.client.solrj.io](http://org.apache.solr.client.solrj.io/).eval.RecursiveEvaluator.recursivelyEvaluate(RecursiveEvaluator.java:214) ~[?:?]
        at [org.apache.solr.client.solrj.io](http://org.apache.solr.client.solrj.io/).eval.RecursiveEvaluator.evaluate(RecursiveEvaluator.java:202) ~[?:?]
        at [org.apache.solr.client.solrj.io](http://org.apache.solr.client.solrj.io/).stream.LetStream.open(LetStream.java:195) ~[?:?]
        at [org.apache.solr.client.solrj.io](http://org.apache.solr.client.solrj.io/).stream.ExceptionStream.open(ExceptionStream.java:49) ~[?:?]
        at org.apache.solr.handler.StreamHandler$TimerStream.open(StreamHandler.java:486) ~[?:?]
        at [org.apache.solr.client.solrj.io](http://org.apache.solr.client.solrj.io/).stream.TupleStream.writeMap(TupleStream.java:77) ~[?:?]
        at org.apache.solr.common.util.JsonTextWriter.writeMap(JsonTextWriter.java:168) ~[?:?]
        at org.apache.solr.common.util.TextWriter.writeMap(TextWriter.java:241) ~[?:?]
        at org.apache.solr.common.util.TextWriter.writeVal(TextWriter.java:85) ~[?:?]
        at org.apache.solr.response.TextResponseWriter.writeVal(TextResponseWriter.java:205) ~[?:?]
        at org.apache.solr.common.util.TextWriter.writeVal(TextWriter.java:45) ~[?:?]
        at org.apache.solr.common.util.JsonTextWriter.writeNamedListAsMapWithDups(JsonTextWriter.java:387) ~[?:?]
        at org.apache.solr.common.util.JsonTextWriter.writeNamedList(JsonTextWriter.java:295) ~[?:?]
        at org.apache.solr.response.JSONWriter.writeResponse(JSONWriter.java:77) ~[?:?]
        at org.apache.solr.response.JSONResponseWriter.write(JSONResponseWriter.java:63) ~[?:?]
        at org.apache.solr.response.QueryResponseWriterUtil.writeQueryResponse(QueryResponseWriterUtil.java:71) ~[?:?]
        at org.apache.solr.servlet.HttpSolrCall.writeResponse(HttpSolrCall.java:999) ~[?:?]
        at org.apache.solr.servlet.HttpSolrCall.call(HttpSolrCall.java:631) ~[?:?]
        at org.apache.solr.servlet.SolrDispatchFilter.dispatch(SolrDispatchFilter.java:239) ~[?:?]
        at org.apache.solr.servlet.SolrDispatchFilter.lambda$doFilter$0(SolrDispatchFilter.java:207) ~[?:?]
        at org.apache.solr.servlet.ServletUtils.traceHttpRequestExecution2(ServletUtils.java:257) ~[?:?]
        at org.apache.solr.servlet.ServletUtils.rateLimitRequest(ServletUtils.java:227) ~[?:?]
        at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:202) ~[?:?]

Solution

I check if the list if empty before accessing its first item.

Tests

Checklist

Please review the following and check all that apply:

• I have reviewed the guidelines for How to Contribute and my code conforms to the standards described there to the best of my ability.
• I have created a Jira issue and added the issue ID to my pull request title.
• I have given Solr maintainers access to contribute to my PR branch. (optional but recommended)
• I have developed this patch against the main branch.
• I have run ./gradlew check.
• I have added tests for my changes.
• I have added documentation for the Reference Guide

[sonatype-lift]

⚠️ 314 God Classes were detected by Lift in this project. Visit the Lift web console for more details.

[risdenk]

@acsbendi can you add a test case for this? looks like its a streaming expression potentially?

[acsbendi]

@risdenk Sure, where should I add one? Yes, this happened in a streaming expression, should I add a test for that streaming expression?

[risdenk]

@acsbendi https://github.com/apache/solr/blob/main/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/StreamExpressionTest.java potentially or one of the other existing classes under https://github.com/apache/solr/tree/main/solr/solrj/src/test/org/apache/solr/client/solrj/io

[risdenk]

I do see a https://github.com/apache/solr/blob/main/solr/solrj/src/test/org/apache/solr/client/solrj/io/stream/eval/RecursiveEvaluatorTest.java, but no RecursiveNumericEvaluatorTest so take a look and see where your test case might go.

[acsbendi]

@risdenk I've added a test for it, and checked that it fails without my fix:)

[risdenk]

Thanks @acsbendi - running ./gradlew check -x test would surface a few errors.

• Assert.... shouldn't be needed. just use assertEquals
• Add license header that matches other tests

[acsbendi]

My pleasure:) The problems are fixed now

[risdenk]

./gradlew tidy should fix up any formatting stuff that was found.

[risdenk]

@acsbendi this looks good. I'm going to create a jira ticket and make a minor change (add solr/CHANGES.txt entry)

[risdenk]

Thanks @acsbendi

[acsbendi]

@risdenk You're welcome, glad to be able to contribute!