incorrect eval with deep (ThreadLocal context)

[sergeevik]

example input

{
  "funcs": {
    "func": "$.a + $.b"
  },
  "a": 3,
  "b": 4
}

query $eval($.funcs.func)

expected result: 7
in jsonata online https://try.jsonata.org/fU8Heq6ee work correct

simple code in test jsonata-java

  @Test
  public void testEvalDeep() {
    Object input = Json.parseJson("{" +
            "  \"funcs\": {" +
            "    \"func\": \"$.a + $.b\"" +
            "  }," +
            "  \"a\": 3," +
            "  \"b\": 4" +
            "}");
    var expression = Jsonata.jsonata("$eval($.funcs.func)");
    Object evaluate = expression.evaluate(input);
    Assertions.assertEquals(7, evaluate);
  }

result:

org.opentest4j.AssertionFailedError: 
Expected :7
Actual   :null

While debugging, I discovered that the input data is stored in a threadLocal.
When evaluatePath executes along a path, each new step stores a new input in the threadLocal. When the evaluatePath completes, the previous operation returns, and the input data remains from the evaluatePath operation.