ConsString is not converted to Java String when nested JS execution

[821938089]

When nested JS execution, ScriptRuntime.hasTopCall(cx) is true and the ConsString returned by the else branch is not converted to a Java String.

rhino/rhino/src/main/java/org/mozilla/javascript/InterpretedFunction.java

Lines 91 to 107 in 3e899f6

	public Object exec(Context cx, Scriptable scope) {
	if (!isScript()) {
	// Can only be applied to scripts
	throw new IllegalStateException();
	}
	Object ret;
	if (!ScriptRuntime.hasTopCall(cx)) {
	// It will go through "call" path. but they are equivalent
	ret =
	ScriptRuntime.doTopCall(
	this, cx, scope, scope, ScriptRuntime.emptyArgs, idata.isStrict);
	} else {
	ret = Interpreter.interpret(this, cx, scope, scope, ScriptRuntime.emptyArgs);
	}
	cx.processMicrotasks();
	return ret;
	}

rhino/rhino/src/main/java/org/mozilla/javascript/ContextFactory.java

Lines 381 to 385 in 3e899f6

	protected Object doTopCall(
	Callable callable, Context cx, Scriptable scope, Scriptable thisObj, Object[] args) {
	Object result = callable.call(cx, scope, thisObj, args);
	return result instanceof ConsString ? result.toString() : result;
	}

Reproduce code:

public class Main {

  public static void main(String[] args) {
    var obj = new MyObject();

    obj.evalJS("myObj.method1()");
    System.out.println(obj.evalJS("var a = 'a'; a + 'b'").getClass().getName());

  }

}

public class MyObject {

  public void method1() {
    System.out.println(evalJS("var a = 'a'; a + 'b'").getClass().getName());
  }

  public Object evalJS(String jsStr) {
    try (var cx = Context.enter()) {
      cx.setOptimizationLevel(-1);
      var scope = cx.initStandardObjects();
      scope.put("myObj", scope, Context.javaToJS(this, scope));
      return cx.evaluateString(scope, jsStr, "unknown source", 0, null);
    }
  }

}

[p-bakker]

You should not expect calls from Java into JavaScript that return a JavaScript string to be a Java String.

Instead expect CharSequence

[p-bakker]

@gbrail @rbri agree this isn't a bug, but working as expected?

[p-bakker]

Also see #247