Conditionally preload data for optional fields

[juanca]

At the moment, I cannot figure out if there is a way to conditionally preload an association given a certain request. At the moment, custom_preload is invoked with the models and the requests associations.

I think it would be beneficial to also have access to the optional fields (are there other possibilities of bottlenecks?) in the custom_preload method to allow custom preloading. At the moment, I am preloading optional fields on every request which has an impact on memory used -- even when it is not necessary for a subset of requests.

Or better yet: a field and an association should provide a preload interface that can be automatically pooled to maximize usage of the preloader and minimize unnecessary memory usage.

[juanca]

Here is an example of declaring an optional field with a preload interface:

field :color_name, :string, 
  optional: true, 
  preload: :account_color, 
  dynamic: lambda { |workspace| workspace.account_color&.color&.name }