Location.Start.Column and JavaScriptStackTrace properties of the JavaScriptException class sometimes have different column values

[Taritsyn]

Hello!

In Jint version Beta 2039, the accuracy of determining the location of error has been improved. I have encountered only one case where the location of error was not determined accurately.

To reproduce this inaccuracy, I created a example:

using System;

using Jint;
using Jint.Runtime;

namespace TestJint
{
    class Program
    {
        static void Main(string[] args)
        {
            try
            {
                var engine = new Engine();
                engine.Execute(@"var $variable1 = 611;
var _variable2 = 711;
var variable3 = 678;

$variable1 + -variable2 - variable3;");
            }
            catch (JavaScriptException e)
            {
                Console.WriteLine("Location.Start.Line: {0}", e.Location.Start.Line);
                Console.WriteLine("Location.Start.Column: {0}", e.Location.Start.Column);
                Console.WriteLine("JavaScriptStackTrace: {0}", e.JavaScriptStackTrace);
            }
        }
    }
}

This example produces the following result:

Location.Start.Line: 5
Location.Start.Column: 0
JavaScriptStackTrace:    at <anonymous>:5:15

The value of the Location.Start.Column property is zero, but should be equal to 14. The most interesting thing is that the JavaScriptStackTrace property contains the accurate location.

[lahma]

Thanks for the report and repro, this is the minimal test case which is failing:

        [Fact]
        public void ShouldReportCorrectColumn()
        {
            var e = Assert.Throws<JavaScriptException>(() =>
            {
                var engine = new Engine();
                engine.Execute(@"var $variable1 = 611;
var _variable2 = 711;
var variable3 = 678;

$variable1 + -variable2 - variable3;");
            });

            Assert.Equal(5, e.Location.Start.Line);
            Assert.Equal(15, e.Location.Start.Column);
            Assert.Equal("   at <anonymous>:5:15", e.JavaScriptStackTrace);
        }

I'll try to look into this at some point unless @christianrondeau gets nerd-sniped by this as he's been working with exceptions and stack traces recently 😉

[Taritsyn]

            Assert.Equal(15, e.Location.Start.Column);

Only in this place it will not be 15, but 14, because the value of this property usually starts from zero.

[Taritsyn]

Thanks!

[lahma]

Thanks for reporting all the regressions you find, you have a great test suite! 👍🏻