Unexpected error when using the $lookup function

[PhoeniXPlayDEV]

Sample code for reproducing the error:

package com.example;

import com.api.jsonata4java.expressions.EvaluateException;
import com.api.jsonata4java.expressions.Expressions;
import com.api.jsonata4java.expressions.ParseException;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;

public class JSONataExample {
    public static void main(String[] args) {
        String json = """
        {
          "company": {
            "name": "TechCorp",
            "departments": {
              "IT": { "employees": 50 },
              "HR": { "employees": 10 }
            }
          }
        }
        """;

        final var expression = """
            $map($keys($.company.departments), function($k) {
                  [ $.company.name, $k, $lookup($.company.departments, $k).employees ]
                })
            """;

        final var mapper = new ObjectMapper();
        try {
            final var input = mapper.readTree(json);
            var expr = Expressions.parse(expression);
            try {
                final var result = expr.evaluate(input);
                System.out.println("JSONata result: " + result);
            } catch (EvaluateException e) {
                System.err.println(e.getLocalizedMessage());
            }
        } catch (IOException | ParseException  e) {
            e.printStackTrace();
        }
    }
}

Output:

Argument 2 of function $lookup does not match function signature

[hanfengcan]

try （$lookup($.company.departments, $k).

[Azbesciak]

Guys, any idea? I see setting ($lookup(field, key)) works but that is highly... unexpected. And a clear bug.

[wnm3]

Thank you for reporting this bug. The problem was thinking we needed to reference the context as an additional parameter because it misinterpreted $lookup... I added a check that the first child of the parent context is not a Function_callContext to not add an additional parameter and it seemed to work as expected.

I added dataobject_q.json with your object and ran some tests using the Tester utility. If you believe the problem is resolved, please close this issue:

Attempting to load JSON from file: testfiles/dataobject_q.json
Using json:
{
  "company" : {
    "name" : "TechCorp",
    "departments" : {
      "IT" : {
        "employees" : 50
      },
      "HR" : {
        "employees" : 10
      }
    }
  }
}
Enter jsonata expression (or q to quit):
$lookup($.company.departments, "IT").employees
50
Enter jsonata expression (or q to quit):
$map($keys($.company.departments), function($k) {[ $.company.name, $k, $lookup($.company.departments, $k).employees ]})
[ [ "TechCorp", "IT", 50 ], [ "TechCorp", "HR", 10 ] ]
Enter jsonata expression (or q to quit):
q
Goodbye