Problem with $expand when the Model have loops between object types

[legacy-carlostorrao]

Hi, first of all, thank you a lot for this great toolkit.

Right now, i'm having a trouble using $expand property from the OData protocol when using an expand in a Object which have other property object which have a List<> of the first Object (loop of object references).

My model is something like:

public class Content
{
public string Id { get; set; }
public string Title { get; set; }
public Channel Channel { get; set; }
}

public class Channel
{
    public string Id { get; set; }
    public string Name { get; set; }
    public IList<Content> Contents { get; set; }
}

And i invoke something like: "http://localhost/OData.svc/Contents?$expand=Channel&$select=Id,Channel"

I already identified the problem in the "Microsoft.Data.Services.Toolkit.QueryModel.TypeExtensions" class, and made the following changes.

public static IDictionary GetPropertyDetails(this IEnumerable properties, Type type) { var projectedProperties = new Dictionary(); var projectedTypes = new List() { type }; Action, Func> processProperties = null; processProperties = delegate(IEnumerable propertyList, Func accessor) { if (accessor == null) accessor = o => o;

            foreach (var property in propertyList)
            {
                var local = property;
                if (property.PropertyType.IsValueType || property.PropertyType == typeof(string))
                {
                    var propertyDetails = new PropertyDetails
                                              {
                                                  PropertyInfo = local,
                                                  PropertySetter = (target, value) => local.SetValue(accessor(target), Convert.ChangeType(value, local.PropertyType.TypeOrElementType()), null)
                                              };

                    projectedProperties.Add(local.GetUnderlyingColumnName(), propertyDetails);
                }
                else if (property.PropertyType.IsArray)
                {
                    var propertyDetails = new PropertyDetails
                    {
                        PropertyInfo = local,
                        PropertySetter = (target, value) => local.SetValue(accessor(target), value, null)
                    };

                    projectedProperties.Add(local.GetUnderlyingColumnName(), propertyDetails);
                }
                else
                {
                    if (!projectedTypes.Contains(local.PropertyType))
                    {
                        projectedTypes.Add(local.PropertyType);
                        processProperties(local.PropertyType.GetProperties(BindingFlags.Public | BindingFlags.Instance), o => local.GetValue(accessor(o), null));
                    }
                }
            }
        };

        processProperties(properties, null);
        return projectedProperties;
    }

Basically I added a list of types already iterated to avoid a loop in recursion of the processProperties(...) method! That way, it works just fine. Otherwise, it occurs an Exception in the Dictionary repeated key, and if you do an if before to check if it contains that key, occurs a StackOverflow because of the loop recursion problem.

Do you confirm that this is a bug, or am I doing something wrong?

[oising]

Sounds like a bug to me - I'll try to repro. Thanks!