domysee / pather.csharp Goto Github PK

NullReferenceException happens if you try to Resolve a indexer path on an object which does not implement IEnumerable

Test code:

    public class IndexerClassNoIEnumerable
    {
        private readonly string value;

        public IndexerClassNoIEnumerable(string value)
        {
            this.value = value;
        }

        public string this[int index] => value + index;
    }

    [TestMethod]
    public void Resolver_IndexerClassNoIEnumerable_ThrowsException()
    {
        var target = new IndexerClassNoIEnumerable("Test");
        var resolver = new Resolver();
        var path = "[123456]";

        var res = resolver.Resolve(target, path);
        // throws 
        // System.NullReferenceException: Object reference not set to an instance of an object.
        // at Pather.CSharp.PathElements.EnumerableAccess.Apply(Object target)
        // at Pather.CSharp.Resolver.Resolve(Object target, IList`1 pathElements)
        // at Pather.CSharp.Resolver.Resolve(Object target, String path)

        res.Should().Be("Test123456");
    }

This is a feature recommendation: supporting Environment Variable resolution. This could search for a match in the natural progression from process => user => computer level environment settings.

Is there any way to get the property's Sum or the Count of the List ?

For example:

users.Select(user=>user. Orders).SelectMany(order=>order. Prices).Sum(price=>price.AnyProperty);

Inevitably, when using the path through an object, you come across the case where an object in the path is null. As expected this causes an exception. Is there any way to deal with this in a similar way to the c#6 syntax e.g. myproperty?.mySubproperty

Really handy little library by the way :)

I like your work.
One thing I noticed is the dependency to the .Net Standard Library.
When I install the nuget package for Pather.CSharp I end up with over 2000 changed files.

Is the .Net Standard Library really required as a dependency?

Good library. Works great.

However, this is one small issue.
When I have a solution that targets .NET Standard 1.4 and I add your package, it adds a reference to System.Runtime.InteropServices version 4.3. When I compile I get the 'found conflicts between two different versions'. This is caused by your library combined with the the above reference.

If I change my target to .NET Standard 1.6, the warnings go away.

I think the issue is you have targeted .NET Standard 1.0, PLUS a package from .NET Standard 1.1. I think instead, you should simply target 1.1 and nothing else extra.

Thoughts?

if the current class has an abstract base class, the property does not get resolved:

File: Property.cs
Line of Code: PropertyInfo p = target.GetType().GetTypeInfo().GetDeclaredProperty(property);

It will get resolved with
PropertyInfo p = target.GetType().GetTypeInfo().GetProperty(property);