Endpoints API - protorpc validation error

Question

I'm getting some weird errors from protorpc when I use endpoints. In this code:

class Application(EndpointsModel):

    _message_fields_schema = ('id', 'name')

    created = ndb.DateTimeProperty(auto_now_add=True)
    name = ndb.StringProperty()
    roles = ndb.IntegerProperty(repeated=True)
    updated = ndb.DateTimeProperty(auto_now=True)
    owner = ndb.KeyProperty(kind='User')

@API.api_class(resource_name="application")
class ApplicationApi(protorpc.remote.Service):

    @Application.method(http_method="GET",
                        request_fields=('id',),
                        name="get",
                        path="applications/{id}")
    def ApplicationGet(self, instance):
        if not instance.from_datastore:
            raise endpoints.NotFoundException("Application not found.")
        return instance

    @Application.query_method(http_method="GET",
                              query_fields=('limit', 'order', 'pageToken'),
                              name="list",
                              path="applications")
    def ApplicationList(self, query):
        return query

when I call application.get() error is as follows: (full trace here):

TypeError: Can only copy from entities of the exact type Application. Received an instance of Application.

and for calling application.list() error is as follows: (full trace here):

ValidationError: Expected type <class '.Application'> for field items, found <Application name: u'test'> (type <class '.Application'>)

What could be causing this? My other models with pretty much the same code (just different properties) work fine.

Answer 1

Subclass class JsonModel(EndpointsModel) to make it start working again.