ODL Client 8.2.3 Breaks SaveChanges with BatchWithSingleChangeset

[uffelauesen]

Regression. ODL Client 8.2.3 fails to generate batch request.

Assemblies affected

OData .Net Client lib 8.2.3

Reproduce steps

Adding a new entity object to an existing tracked object's collection navigation properties and calling SaveChanges with BatchWithSingleChangeset now fails where as it used to (in ODL 8.2.2 and earlier) to correctly construct the $batch request with the one single change in it.

Despite the fact that the "reference" Trip/Pin service is buggy (and fails for the batch request on 8.2.2), you can use the following code to reproduce the issue...

            var q = from p in ctx.People.Take(1)
                          select p;

            var people = new DataServiceCollection<Person>(q);

            var aFriend = new Person();
            people.First().Friends.Add(aFriend);
            aFriend.UserName = Guid.NewGuid().ToString();
            aFriend.FirstName = "Test Friend";
            aFriend.LastName = "Test Friend";

            ctx.SaveChanges(SaveChangesOptions.BatchWithSingleChangeset | SaveChangesOptions.PostOnlySetProperties);

Expected result

You get the $batch request generated and sent to the service like on ODL 8.2.2.

POST https://services.odata.org/TripPinRESTierService/(S(wb2pbbsx13f0npnrt4az5qwt))/$batch HTTP/1.1
Host: services.odata.org
OData-Version: 4.0
OData-MaxVersion: 4.0
Accept: multipart/mixed
Accept-Charset: UTF-8
User-Agent: Microsoft.OData.Client/8.2.2
Content-Type: multipart/mixed; boundary=batch_f0378b81-a652-420a-a1b4-34e4a523390a
Content-Length: 845

--batch_f0378b81-a652-420a-a1b4-34e4a523390a
Content-Type: multipart/mixed; boundary=changeset_6e82e35f-f898-42ed-8031-fc0bc575b6b6

--changeset_6e82e35f-f898-42ed-8031-fc0bc575b6b6
Content-Type: application/http
Content-Transfer-Encoding: binary
Content-ID: 3

POST https://services.odata.org/TripPinRESTierService/(S(wb2pbbsx13f0npnrt4az5qwt))/People('angelhuffman')/Friends HTTP/1.1
OData-Version: 4.0
OData-MaxVersion: 4.0
Content-Type: application/json;odata.metadata=minimal
Accept: application/json;odata.metadata=minimal
Accept-Charset: UTF-8
User-Agent: Microsoft.OData.Client/8.2.2

{"@odata.type":"#Trippin.Person","FirstName":"Test Friend","LastName":"Test Friend","UserName":"b8afa014-5dc9-491f-847d-9d663be87e2a"}
--changeset_6e82e35f-f898-42ed-8031-fc0bc575b6b6--
--batch_f0378b81-a652-420a-a1b4-34e4a523390a--

Actual result

You get an exception on ODL 8.2.3:

Unhandled exception. Microsoft.OData.ODataException: The dependsOn Id: [1] in request [3] is not matching any of the request Id and atomic group Id seen so far. Forward reference is not allowed.
at Microsoft.OData.MultipartMixed.ODataMultipartMixedBatchWriter.ValidateDependsOnIds(String contentId, IEnumerable1 dependsOnIds) at Microsoft.OData.ODataBatchWriter.BuildOperationRequestMessage(Stream outputStream, String method, Uri uri, String contentId, String groupId, IEnumerable1 dependsOnIds)
at Microsoft.OData.MultipartMixed.ODataMultipartMixedBatchWriter.CreateOperationRequestMessageImplementation(String method, Uri uri, String contentId, BatchPayloadUriOption payloadUriOption, IEnumerable1 dependsOnIds) at Microsoft.OData.ODataBatchWriter.CreateOperationRequestMessageInternal(String method, Uri uri, String contentId, BatchPayloadUriOption payloadUriOption, IEnumerable1 dependsOnIds)
at Microsoft.OData.ODataBatchWriter.CreateOperationRequestMessage(String method, Uri uri, String contentId, BatchPayloadUriOption payloadUriOption, IEnumerable`1 dependsOnIds)
at Microsoft.OData.Client.ODataRequestMessageWrapper.CreateBatchPartRequestMessage(ODataBatchWriter batchWriter, BuildingRequestEventArgs requestMessageArgs, RequestInfo requestInfo, String contentId, Boolean isRelativeUri)
at Microsoft.OData.Client.BatchSaveResult.CreateRequestMessage(String method, Uri requestUri, HeaderCollection headers, HttpStack httpStack, Descriptor descriptor, String contentId)
at Microsoft.OData.Client.BaseSaveResult.CreateRequest(EntityDescriptor entityDescriptor)
at Microsoft.OData.Client.BatchSaveResult.GenerateBatchRequest()
at Microsoft.OData.Client.BatchSaveResult.BatchRequest()
at Microsoft.OData.Client.DataServiceContext.SaveChanges(SaveChangesOptions options)
at ReferenceService.Program.Main(String[] args) in C:\Users\Z6UFE\Source\Repos\ReferenceService\Program.cs:line 23

Additional detail

Optional, details of the root cause if known. Delete this section if you have no additional details to add.

[corranrogue9]

This may be related to @DButoyez recent change, we should investigate if that's the regression, and just investigate in general to address the issue.