Returning a ComplexType with a NavigationProperty from a function

[jbzdarkid]

I'm trying to write an OData function which returns a ComplexType containing two lists of entities:

<Function Name="foo" IsBound="true">
  <Parameter Name="bindingParameter" Type="root" />
  <ReturnType Type="bar" />
</Function>

<ComplexType Name="bar">
  <NavigationProperty Name="list_one" Type="Collection(baz)" />
  <NavigationProperty Name="list_two" Type="Collection(baz)" />
</ComplexType>

<EntityType Name="baz">
  <Key>
    <PropertyRef Name="id" />
  </Key>
  <Property Name="id" Type="Edm.String" Nullable="false" />
  <Property Name="displayName" Type="Edm.String" Nullable="false" />
  <Property Name="createdDateTime" Type="Edm.DateTimeOffset" />
</EntityType>

However, this function does not return any data! Instead, all I get back is the @odata.context key/value, with no other information.

{
  "@odata.context": "http://localhost:26693/root/$metadata#foo"
}

Assemblies affected

Microsoft.OData.OData version 7.5.14 (and probably others, this is the one I'm using now)

Reproduce steps

1. Call the function with GET http://localhost:26693/root/foo()
2. Observe that there is no response data
3. Open new OData bug

Expected result

I would expect both of the lists to appear, even if they have no data:

{
  "list_one": [],
  "list_two": [],
}

or, if data was present, I would expect it to appear in the list:

{
  "list_one": [
  {
    "id": "1",
    "displayName": "Alice",
    "createdDateTime": null,
  }],
  "list_two": [],
}

Actual result

In actuality, neither list appears -- not even when I pass ?$expand=list_one,list_two.

Additional details

@xuzhg was able to help me out with a workaround, by providing a custom serializer. As such, I am not actually blocked by this bug.

Also, I should mention that this is affecting a feature which is not yet released -- as such, I have replaced the names (and thus this may not quite work as written). For a more accurate details, please see the internal stackoverflow question.

[gathogojr]

As stated in the StackOverflow question, support for returning a NavigationProperty from a function that returns a complex type is currently not in place. A workaround is possible for now but there's a need to address the feature gap.