Unable to use deep update on nested collections

[vcantor]

Assemblies affected
Microsoft.AspNetCore.OData Version="8.0.11"
Microsoft.OData.Core" Version="7.12.5"
Microsoft.OData.Edm" Version="7.12.5"

Describe the bug
I am trying to implement a deep update according to Update Related Entities When Updating an Entity and I am receiving an error when patches on nested collections occur.

Reproduce steps
Make a patch request that is sending a delta update on a nested collection.

Data Model

public class OrderDTO
    {
        public string? Name { get; set; }
        public long Id { get; set; }
        public DateTime? Date { get; set; }
        public long? CustomerId { get; set; }
        public decimal? NetPrice { get; set; }
        public OrderItemDTO[] Items { get; set; }
    }

Controller:

 [ApiController]
    public class OrderController : ODataController
    {

        public OrderController(ILogger<OrderController> logger)
        {
            Logger = logger;
        }

        public ILogger<OrderController> Logger { get; }

        private static Task<IEnumerable<OrderDTO>> GetData()
        {
            return Task.FromResult(Enumerable.Range(1, 20).Select(id => new OrderDTO()
            {
                CustomerId = id,
                Id = id,
                Date = DateTime.UtcNow.AddDays(id),
                Name = "test",
                NetPrice = Convert.ToDecimal(Random.Shared.NextDouble()),
                Items = Enumerable.Range(1, 20).Select(itemId => new OrderItemDTO()
                {
                    Id = itemId,
                    OrderId = id,
                    Price = Convert.ToDecimal(Random.Shared.NextDouble())
                }).ToArray()
            }));
        }

        [HttpGet("v1/Orders")]
        [EnableQuery]
        public async Task<IEnumerable<OrderDTO>> GetAll()
        {
            return await GetData();
        }



        [HttpPatch("v1/Orders/{orderId}")]
        [EnableQuery]
        public async Task<IEnumerable<OrderDTO>> PatchOrder([FromRoute] long orderId, [FromBody] Delta<OrderDTO> patchedOrder)
        {
            Logger.LogInformation("Patched Instance for orderid {orderId} is {@patched}", orderId, JsonSerializer.Serialize(patchedOrder.GetInstance()));
            return await Task.FromResult(new List<OrderDTO>() { patchedOrder.GetInstance() });
        }


        [HttpPatch("v1/Orders/{orderId}/items")]
        [EnableQuery]
        public async void PatchOrderItems([FromRoute] long orderId, [FromBody] DeltaSet<OrderItemDTO> patchedOrder)
        {
            foreach (var item in patchedOrder)
            {
                if (item.Kind == DeltaItemKind.DeletedResource && item is DeltaDeletedResource<OrderItemDTO> deletedItem)
                {
                    Logger.LogInformation("Deleted Instance for orderid {orderId} is {@patched}", orderId, JsonSerializer.Serialize(deletedItem.GetInstance()));
                }
                else if (item.Kind == DeltaItemKind.Resource && item is Delta<OrderItemDTO> upsert)
                {
                    Logger.LogInformation("Patched Instance for orderid {orderId} is {@patched}", orderId, JsonSerializer.Serialize(upsert.GetInstance()));
                }
            }

        }
    }

EDM (CSDL) Model

<?xml version="1.0" encoding="utf-8"?>
  <edmx:Edmx Version="4.0" xmlns:edmx="http://docs.oasis-open.org/odata/ns/edmx">
    <edmx:DataServices>
      <Schema Namespace="Demo" xmlns="http://docs.oasis-open.org/odata/ns/edm">
        <EntityType Name="OrderDTO">
          <Key>
            <PropertyRef Name="id" />
          </Key>
          <Property Name="id" Type="Edm.Int64" Nullable="false" />
          <Property Name="name" Type="Edm.String" />
          <Property Name="date" Type="Edm.DateTimeOffset" />
          <Property Name="customerId" Type="Edm.Int64" />
          <Property Name="netPrice" Type="Edm.Decimal" Scale="Variable" />
          <NavigationProperty Name="items" Type="Collection(Demo.OrderItemDTO)" />
        </EntityType>
        <EntityType Name="OrderItemDTO">
          <Key>
            <PropertyRef Name="id" />
            <PropertyRef Name="orderId" />
          </Key>
          <Property Name="orderId" Type="Edm.Int64" Nullable="false" />
          <Property Name="id" Type="Edm.Int32" Nullable="false" />
          <Property Name="price" Type="Edm.Decimal" Scale="Variable" />
        </EntityType>
        <EntityContainer Name="ODataDemo">
          <EntitySet Name="Orders" EntityType="Demo.OrderDTO">
            <NavigationPropertyBinding Path="items" Target="OrderItems" />
          </EntitySet>
          <EntitySet Name="OrderItems" EntityType="Demo.OrderItemDTO" />
        </EntityContainer>
        <Annotations Target="Demo.OrderItemDTO">
          <Annotation Term="Org.OData.Capabilities.V1.UpdateRestrictions">
            <Record>
              <PropertyValue Property="Updatable" Bool="true" />
              <PropertyValue Property="DeltaUpdateSupported" Bool="true" />
            </Record>
          </Annotation>
        </Annotations>
        <Annotations Target="Demo.ODataDemo/Orders">
          <Annotation Term="Org.OData.Capabilities.V1.DeepUpdateSupport">
            <Record>
              <PropertyValue Property="Supported" Bool="true" />
            </Record>
          </Annotation>
          <Annotation Term="Org.OData.Capabilities.V1.UpdateRestrictions">
            <Record>
              <PropertyValue Property="DeltaUpdateSupported" Bool="true" />
            </Record>
          </Annotation>
        </Annotations>
      </Schema>
    </edmx:DataServices>
  </edmx:Edmx>

Request/Response
Request Headers:

Connection: keep-alive
Accept: application/json;odata.metadata=minimal
Content-Type: application/json
OData-Version: 4.01
OData-MaxVersion: 4.01
Content-Length: 207
Host: localhost:5086
User-Agent: Apache-HttpClient/4.5.13 (Java/13.0.2)

Request Body:

PATCH http://localhost:5086/v1/orders/2

PATCH data:
{
	"name":"anothertest",
	"@id": "Order(2)",
	"items@delta":[
	{
		"@id": "OrderItems(2, 1)",
		"price":0
	},
	{
	"@removed":{
			"reason":"deleted"
			},
		"@id": "OrderItems(2, 2)"
		}
		]
}

[no cookies]

Response Headers:

HTTP/1.1 400 Bad Request
Content-Type: application/problem+json; charset=utf-8
Date: Wed, 16 Nov 2022 06:25:36 GMT
Server: Kestrel
Transfer-Encoding: chunked

Response Body:

{
  "type": "https://tools.ietf.org/html/rfc7231#section-6.5.1",
  "title": "One or more validation errors occurred.",
  "status": 400,
  "traceId": "00-e5e58a4c6478a3ed25f2de9eeb25ad4a-435d9e53608229b5-00",
  "errors": {
    "": ["The input was not valid."],
    "patchedOrder": ["The patchedOrder field is required."]
  }
}

Expected behavior
The updates on the OrderItems should be populated in the Delta when using nested delta updates.

Additional context
When I am using the endpoint v1/Orders/{orderId}/items the DeltaSet is populated correctly. Only when nested patches occur the delta is not working.

Exception message from OData:

The value "Microsoft.AspNetCore.OData.Deltas.Delta`1[ODataDemo.Controllers.OrderItemDTO]" is not of type "ODataDemo.Controllers.OrderItemDTO" and cannot be used in this generic collection. (Parameter 'value')

Stacktrace:

   at System.Collections.Generic.List`1.System.Collections.IList.Add(Object item)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.CollectionDeserializationHelpers.AddToCollectionCore(IEnumerable items, IEnumerable collection, Type elementType, IList list, MethodInfo addMethod, ODataDeserializerContext context)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.DeserializationHelpers.SetCollectionProperty(Object resource, String propertyName, IEdmCollectionTypeReference edmPropertyType, Object value, Boolean clearCollection, ODataDeserializerContext context)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.ODataResourceDeserializer.ApplyNestedDeltaResourceSet(IEdmProperty nestedProperty, Object resource, ODataDeltaResourceSetWrapper deltaResourceSetWrapper, ODataDeserializerContext readContext)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.ODataResourceDeserializer.ApplyNestedProperty(Object resource, ODataNestedResourceInfoWrapper resourceInfoWrapper, IEdmStructuredTypeReference structuredType, ODataDeserializerContext readContext)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.ODataResourceDeserializer.ApplyNestedProperties(Object resource, ODataResourceWrapper resourceWrapper, IEdmStructuredTypeReference structuredType, ODataDeserializerContext readContext)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.ODataResourceDeserializer.ReadResource(ODataResourceWrapper resourceWrapper, IEdmStructuredTypeReference structuredType, ODataDeserializerContext readContext)
   at Microsoft.AspNetCore.OData.Formatter.Deserialization.ODataResourceDeserializer.ReadAsync(ODataMessageReader messageReader, Type type, ODataDeserializerContext readContext)
   at Microsoft.AspNetCore.OData.Formatter.ODataInputFormatter.ReadFromStreamAsync(Type type, Object defaultValue, Uri baseAddress, ODataVersion version, HttpRequest request, IList`1 disposes)

[vcantor]

ODataDemo.zip
Added the project as an attachment.

[xuzhg]

@vcantor thanks for reporting this. I think it's a feature gap. OData team has the re-design of the Delta request and response, see details OData/WebApi#2656. At the beginning, I thought I can port the works/codes from 7.x to 8.x. However, that works is still in review. Let me take a look and see whether I can move it forward in 8.x. Of course, it's open for contribution.

[xuzhg]

@vcantor @julealgon Please review the PR #747 and share your comments.

With the PR changes and use the ODataDemo.zip

It works fine:

Delta nested collection:

normal nested collection:

[gathogojr]

@vcantor Did @xuzhg's response help resolve your issue?

[vcantor]

With the pull request that @xuzhg made the issue is fixed! Thank you @xuzhg! The DeltaSet for the nested property can be obtained using the TryGetPropertyValue method of DeltaOfT so for me the integration in the Patch is not required. Thank you for the quick fix! With this PR my issue is resolved.