Embedded $expand not returning the Navigation property in certain scenarios

[saidinarts]

In a specific scenario, where a [Contained] houses a EntitySet, an embedded navigational property two levels deep within said EntitySet will not be returned.

Assemblies affected

Microsoft.AspNet.OData lib 7.6.0

Reproduce steps

The following entities are defined:

    public class Customer 
    {
        [Key]
        public int ID { get; set; }
        
        [Contained]
        public ICollection<CustomerReferral> CustomerReferrals { get; set; }

        [Contained]
        public ICollection<CustomerPhone> Phones { get; set; }
    }

    public class CustomerReferral
    {
        [Key]
        public int ID { get; set; }

        public int CustomerID { get; set; }

        public int ReferredCustomerID { get; set; }

        [Required]
        [ForeignKey(nameof(CustomerID))]
        public Customer Customer { get; set; }

        [Required]
        [ForeignKey(nameof(ReferredCustomerID))]
        public Customer ReferredCustomer { get; set; }
    }

    public class CustomerPhone
    {
        [Key]
        public int ID { get; set; }

        [Editable(false)]
        public int CustomerID { get; set; }

        [Contained]
        public CustomerPhoneNumberFormatted Formatted { get; set; }
    }

    public class CustomerPhoneNumberFormatted
    {
        [Key]
        public int CustomerPhoneNumberID { get; set; }

        public string FormattedNumber { get; set; }
    }

The DbContext model builder has the following:

            modelBuilder.Entity<CustomerPhone>().HasOptional(a => a.Formatted).WithRequired();
            modelBuilder.Entity<Customer>()
                .HasMany(c => c.CustomerReferrals)
                .WithRequired(c => c.Customer)
                .HasForeignKey(c => c.CustomerID);

The OData model builder is as follows:

ODataModelBuilder builder = new ODataConventionModelBuilder();
builder.EntitySet<Customer>("Customers");

A defined route is established for CustomerReferrals from a Customer, and the following query is applied:

salesinventory/Customers(486)/CustomerReferrals?$expand=ReferredCustomer($expand=Phones($expand=Formatted))

Expected result

The Formatted entity is returned in the results.

Actual result

The Formatted entity is not returned. Everything is returned except the Formatted entity.

Additional detail

The breakdown seems to happen during the serialization of the OData resource. The actual underlining SQL call and the entities returned to the ODataResourceSerializer have the Formatted class, but it is dropped. This seems to be as the NavigationSource is null on the given ResourceContext for CustomerPhone.

[isabekyan]

Had the same issue with implicit containment - no attribute, no entity set declaration.
Our workaround is currently having no containment and declare fake entity set for every contained entity type.

[xuzhg]

@saidinarts @isabekyan
Thanks for reporting this. I dig a lot for this scenario, there are two places (wrong) that needs to fix:

1. at model side (you side), all non-containment navigation property should have a navigation property binding. Please refer Modify to fix issue for #2076, Containment expand problem #2083 sample codes about how to add the navigation property binding.
2. at ASP.NET Core OData side (our side), the ODataQueryOptionParser should instantiate with the Path, or at lease know the path. Otherwise, the Query option parser can't figure out the correct navigation source to use. The change is also include in Modify to fix issue for #2076, Containment expand problem #2083.

The PR #2083 itself includes the sample project change to use your sample codes. For example i change to use EF from EF Core. FYI. Thanks.

The response for your query (http://localhost:5000/odata/Customers(456)/CustomerReferrals?$expand=ReferredCustomer($expand=Phones($expand=Formatted))) looks like:

{
    "@odata.context": "http://localhost:5000/odata/$metadata#Customers(456)/CustomerReferrals(ReferredCustomer(Phones(Formatted())))",
    "value": [
        {
            "ID": 18,
            "CustomerID": 456,
            "ReferredCustomerID": 8,
            "ReferredCustomer": {
                "ID": 456,
                "Phones": [
                    {
                        "ID": 21,
                        "CustomerID": 456,
                        "Formatted": {
                            "CustomerPhoneNumberID": 17,
                            "FormattedNumber": "abc"
                        }
                    },
                    {
                        "ID": 22,
                        "CustomerID": 457,
                        "Formatted": {
                            "CustomerPhoneNumberID": 18,
                            "FormattedNumber": "abc"
                        }
                    }
                ]
            }
        },
        {
            "ID": 19,
            "CustomerID": 456,
            "ReferredCustomerID": 9,
            "ReferredCustomer": {
                "ID": 456,
                "Phones": [
                    {
                        "ID": 21,
                        "CustomerID": 456,
                        "Formatted": {
                            "CustomerPhoneNumberID": 17,
                            "FormattedNumber": "abc"
                        }
                    },
                    {
                        "ID": 22,
                        "CustomerID": 457,
                        "Formatted": {
                            "CustomerPhoneNumberID": 18,
                            "FormattedNumber": "abc"
                        }
                    }
                ]
            }
        }
    ]
}

@mikepizzo

[SireGoatMonkey]

Can I ask why the commit for this issue hasn't been merged yet? It looks like the fix was identified pretty quickly but this issue has been open for over a year. I still hit this fairly frequently and would love for the fix to be implemented. Thank you!!!