Mediamanager Item within a RichText field is not working in retrofit mode.

[justsayantan]

Mediamanager Item within a RichText field is not working while using retrofit mode. It is always getting failed to map the mediamanager item.
Error Details -

Sdl.Web.Common.DxaException: Unable to map field 'Content' to property of type 'Sdl.Web.Common.Models.RichText'. ---> Sdl.Web.Common.DxaException: No semantic mapping found between Schema 33274 (uuid:9389a8ce-0f19-44ee-9eb6-2d04d0c02c25:ExternalContentLibraryStubSchemamm) and model type 'Sdl.Web.Common.Models.MediaItem'
   at Sdl.Web.Common.Mapping.SemanticSchema.GetModelTypeFromSemanticMapping(Type baseModelType)

As a workaround we have created a subclass and extended the default MediaManagerDistribution model. But need proper fix for that.

[rpannekoek]

Indeed, the MediaManagerDistribution View Model currently doesn't work properly in conjunction with retrofit mode. The problem is that it only has a SemanticEntity annotation for the Core Vocabulary, but in retrofit mode, each CM Schema has its own Vocabulary (named after the Schema's namespace URI). So: an additional SemanticEntity annotation is needed for the MM Stub Schema. Indeed, a work-around for this issue it to create abd register your own subclass which does have the appropriate SemanticEntity annotation.

[rpannekoek]

Internal Issue ID (for tracking purposes): CRQ-13306