Problem statement

While using DropkicK to manage the deployment of a C# project (.Net 4.5), we use Json files to describe deployment settings. Those are bound at run-time, by the Magnum library, against custom C# class files (extending dropkick.Configuration.Dsl.Deployment).

Unfortunately, JSON lists were bound to an empty List at runtime.

Magnum internal details

JsonValueProvider

Recursive calls in the JsonValueProvider, when reading the Json content, were wrongly linking each array item into a separate {key, value} pair within its internal dictionary.

ListBinder / EnumerableBinderBase

On the other end, the EnumerableBinderBase was binding an empty list to the custom c# deployment settings object, regardless of the context property value (that is, the list content).

Example

{
    BuildFolder: "..\\..\\build",
    ERPBinariesGroups: ["Binaries0","Binaries1","Binaries2","Binaries3"],
    IntegrationService: true,
    Debug: true
}

using dropkick.Configuration;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Deployment
{
    public class MyDeploymentSettings: DropkickConfiguration
    {
        public string BuildFolder { get; set; }

        public List<string> ERPBinariesGroups { get; set; }

        public bool IntegrationService { get; set; }

        public bool Debug { get; set; }
    }
}

Considering the JSON sample, the internal dictionary of JsonValueProvider would have the following wrong content:

[
{ "BuildFolder",  "..\\..\\build" }, 
{ "ERPBinariesGroups[0]", "Binaries0" },
{ "ERPBinariesGroups[1]", "Binaries1" },
{ "ERPBinariesGroups[2]", "Binaries2" },
{ "ERPBinariesGroups[3]", "Binaries3" },
{ "IntegrationService", true },
{ "Debug", true }
]

The correct content should be:

[
{ "BuildFolder",  "..\\..\\build" }, 
{ "ERPBinariesGroups", ["Binaries0", "Binaries1", "Binaries2", "Binaries3"] },
{ "IntegrationService", true },
{ "Debug", true }
]

Therefore, at binding time (InstanceBinderContext), the binder would look to match the C# property ERPBinariesGroups to a context unable to match its request as it only knows the properties ERPBinariesGroups[i].

Few comments

Took me a while to figure the whole thing out. I don't recommend using my commits "as is" to fix the issue as I have disabled the rake tests task and hardcoded the string type for the List being recursively constructed in the JsonParser.
I looked at making the whole thing generic and a bit cleaner but that's the best I can do for the time being without breaking half of the API.

Hope this helps,

Pierre.