Just to clarify for those that may encounter this in the wild, this means that all uses of the serialization methods in ActiveModel::Serialization, e.g. as_json, regardless of context (including in specs), will result in an error unless you pass the only option. See further
Well, it took 21 days, but I finally made sense of what you said here in your linked code, in at least one context, and hopefully the other one mentioned in the split topic mentioned above. That one seems harder (by my memory, anyway) since I don’t quite know just where the problem is.
Thanks for saving the day (or at least this day).
The other issue was that my server model included the user model and I needed to be calling the user serializer (or limiting fields) of the user model in my server serializer.
It turned out that I didn’t need any of the user model in my server model (user_id_was already there,and there’s a reasonable chance I don’t really even need that)