Creating an activeadmin filter on a scope in ransackable_scopes

I'd like to create an activeadmin filter on a page for a model that has an association with the User model. I'd like to use the custom scope matches_name, which combines the first_name and last_name fields. I've added that scope to the model's ransackable_scopes method, and I am able to query it in the rails console.

I've specified the filter like so:

filter :user_matches_name, as: :string, label: "User"

However, when I load the page, it errors out with this message:

undefined method `user_matches_name_contains' for Ransack::Search<class: MyModel, base: Grouping <combinator: and>>:Ransack::Search

I've been able to create a filter on the user activeadmin page without a similar error:

filter :matches_name, as: :string, label: "User"

Is there a way to prevent either ransack or activeadmin from appending the extra _contains on the end of the filter?

You can use ransacker to combine first_name and last_name (full_name for example) for the User class and then from ActiveAdmin resource file that has an association with the User model use this filter: filter :user_full_name, as: :string, label: 'User'

registration of my model resource

ActiveAdmin.register MyModel do
  actions :index

  filter :user_full_name, as: :string, label: 'User'
end

registration of User resource

ActiveAdmin.register User do
  actions :index
end

User and MyModel models

class MyModel < ApplicationRecord
  belongs_to :user

  def self.ransackable_associations(auth_object = nil)
    %w[user]
  end

  def self.ransackable_attributes(auth_object = nil)
    %w[created_at id id_value updated_at user_id]
  end
end

class User < ApplicationRecord
  ransacker :full_name do |parent|
    Arel::Nodes::InfixOperation.new('||', parent.table[:first_name], parent.table[:last_name])
  end

  def self.ransackable_attributes(auth_object = nil)
    %w[created_at first_name full_name id id_value last_name updated_at]
  end
end

this code should work properly with both 3.x.x and 2.x.x versions of ActiveAdmin gem