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Expression $[-1] throws ArrayIndexOutOfBoundsException on empty array input #106

@Arowa-Z

Description

@Arowa-Z

Title

$[-1] throws ArrayIndexOutOfBoundsException when evaluating against an empty array []


Description

The expression $[-1] (to get the last element of an array) throws an ArrayIndexOutOfBoundsException when evaluated against an empty array [], instead of returning no match/null as expected and as seen in the official JSONata online evaluator.


Steps to Reproduce

  1. Define the expression $[-1].
  2. Evaluate the expression against an empty array [].

Sample Code:

import com.dashjoin.jsonata.Jsonata;
import java.util.List;

public class UnitTest {
    public static void main(String[] args) {
        var jsonata = Jsonata.jsonata("$[-1]");
        System.out.println(jsonata.evaluate(List.of()));
    }
}

Expected Behavior

The expression should return null or no match (consistent with the behavior in the official JSONata Exerciser) without throwing an exception.

Image

Actual Behavior

The evaluation throws an ArrayIndexOutOfBoundsException:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 0
	at java.base/java.util.ImmutableCollections$ListN.get(ImmutableCollections.java:687)
	at com.dashjoin.jsonata.Jsonata.evaluateFilter(Jsonata.java:503)
	at com.dashjoin.jsonata.Jsonata._evaluate(Jsonata.java:212)
	at com.dashjoin.jsonata.Jsonata.evaluate(Jsonata.java:131)
	at com.dashjoin.jsonata.Jsonata.evaluate(Jsonata.java:2583)
	at com.dashjoin.jsonata.Jsonata.evaluate(Jsonata.java:2544)
	at com.example.demo.UnitTest.main(UnitTest.java:17)

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