Add support for alternate keys on navigation properties

[andrueastman]

The learningContent has the alternate Key present in the metadata set as externalId,

However, the alternate key path is not generated in the collection path in the openApi document with the AlternateKey setting.

      <EntityType Name="learningContent" BaseType="graph.entity">
...
        <Annotation Term="Org.OData.Core.V1.AlternateKeys">
          <Collection>
            <Record Type="Org.OData.Core.V1.AlternateKey">
              <PropertyValue Property="Key">
                <Collection>
                  <Record Type="Org.OData.Core.V1.PropertyRef">
                    <PropertyValue Property="Alias" String="externalId" />
                    <PropertyValue Property="Name" PropertyPath="externalId" />
                  </Record>
                </Collection>
              </PropertyValue>
            </Record>
          </Collection>
        </Annotation>
      </EntityType>

From tentative investigations, it looks like the setting may only work on Entity sets and not other nav properties that return collections.

[baywet]

We received the same question on the internal stack overflow.

After digging further

Key	Entity	Present In OpenAPI	Has Entity Set
appId	application	Y	Y
appId	servicePrincipal	Y	Y
deviceId	device	Y	Y
roleTemplateId	directoryObjectPartnerReference	Y	Y
externalcourseActivityId	learningCourseActivity	N	N
externalId	learningContent	N	N

Both the entity types this workload defines with alternate keys are only exposed through navigation properties and do not have entity sets contrary to the ones exposed by the AAD workload. Which sounds a lot like a limitation of this conversion library.

Updated the title and the issue properties to reflect the work to be done: support alt keys on navigation properties.
The only challenge here is the odata spec is not explicit about navigation property support nor is the vocab definition

[baywet]

I got a confirmation this scenario is supported at the AGS level. from @syprieur
And I received confirmation this is intended to be supported even though the specification is not super clear on that from @mikepizzo
We're good to proceed.
https://issues.oasis-open.org/browse/ODATA-1590?jql=project%20%3D%20ODATA

[andrueastman]

Thanks @baywet

Adding this path as part of the success criteria for the issue is also missing due to the same issue.

GET https://graph.microsoft.com/v1.0/employeeExperience/learningProviders/01e8f81b-3060-4dec-acf0-0389665a0a38/learningCourseActivities(externalCourseActivityId=12a2228a-e020-11ec-9d64-0242ac120002)
https://learn.microsoft.com/en-us/graph/api/learningcourseactivity-get?view=graph-rest-1.0&tabs=http#example-2-get-a-learning-course-activity-based-on-the-externalcourseactivityid-of-the-learning-provider