Conditionally overriding an active model serializer association method

Question

I’m writing a serializer that includes has_one :source. source can be a number of different types. I’m trying to make the JSON smaller when source is a Foo by overriding the association methods. I tried this:

def source
  return super unless source_type == 'Foo'
  render json: source, serializer: LimitedFooSerializer
end

But then I get ​no superclass method `source’.

Then I tried:

def source
  render json: source unless source_type == 'Foo'
  render json: source, serializer: LimitedFooSerializer
end

But that errors ​stack level too deep​; presumably it’s an infinite recursion.

How can I conditionally override the association method?

Answer 1

Calling the serializer directly worked:

def source
  if source_type == 'Foo'
    FooSerializer::LimitedFooSerializer.new(object.source)
  else
    object.source
  end
end

I had to use object.source instead of source to avoid the recursion.