Introduce setup hook for authorization/auditing adapters

app/controllers/rails_admin/application_controller.rb

@@ -56,10 +56,6 @@ def _audit!
       instance_eval(&RailsAdmin::Config.audit_with)
     end
 
-    def user_for_paper_trail
-      _current_user.try(:id) || _current_user
-    end
-
     rescue_from RailsAdmin::ObjectNotFound do
       flash[:error] = I18n.t('admin.flash.object_not_found', model: @model_name, id: params[:id])
       params[:action] = 'index'

lib/rails_admin/config.rb

@@ -110,8 +110,10 @@ def authenticate_with(&blk)
       def audit_with(*args, &block)
         extension = args.shift
         if extension
+          klass = RailsAdmin::AUDITING_ADAPTERS[extension]
+          klass.setup if klass.respond_to? :setup
           @audit = proc do
-            @auditing_adapter = RailsAdmin::AUDITING_ADAPTERS[extension].new(*([self] + args).compact)
+            @auditing_adapter = klass.new(*([self] + args).compact)
           end
         elsif block
           @audit = block
@@ -145,8 +147,10 @@ def audit_with(*args, &block)
       def authorize_with(*args, &block)
         extension = args.shift
         if extension
+          klass = RailsAdmin::AUTHORIZATION_ADAPTERS[extension]
+          klass.setup if klass.respond_to? :setup
           @authorize = proc do
-            @authorization_adapter = RailsAdmin::AUTHORIZATION_ADAPTERS[extension].new(*([self] + args).compact)
+            @authorization_adapter = klass.new(*([self] + args).compact)
           end
         elsif block
           @authorize = block

lib/rails_admin/extensions/paper_trail/auditing_adapter.rb

@@ -38,8 +38,16 @@ class AuditingAdapter
           message: :event,
         }.freeze
 
+        def self.setup
+          raise('PaperTrail not found') unless defined?(::PaperTrail)
+          RailsAdmin::ApplicationController.class_eval do
+            def user_for_paper_trail
+              _current_user.try(:id) || _current_user
+            end
+          end
+        end
+
         def initialize(controller, user_class = 'User', version_class = '::Version')
-          raise('PaperTrail not found') unless defined?(PaperTrail)
           @controller = controller
           @controller.send(:set_paper_trail_whodunnit) if @controller
           begin

lib/rails_admin/extensions/pundit/authorization_adapter.rb

@@ -5,6 +5,13 @@ module Pundit
       # You can create another adapter for different authorization behavior, just be certain it
       # responds to each of the public methods here.
       class AuthorizationAdapter
+        # This method is called first time only and used for setup
+        def self.setup
+          RailsAdmin::ApplicationController.class_eval do
+            include ::Pundit
+          end unless RailsAdmin::ApplicationController.ancestors.include? 'Pundit'
+        end
+
         # See the +authorize_with+ config method for where the initialization happens.
         def initialize(controller)
           @controller = controller

spec/integration/authorization/pundit_spec.rb

@@ -1,10 +1,6 @@
 require 'spec_helper'
 
 describe 'RailsAdmin Pundit Authorization', type: :request do
-  before(:all) do
-    ApplicationController.send :include, ::Pundit
-  end
-
   subject { page }
 
   before do
@@ -104,10 +100,12 @@
   context 'when ApplicationController already has pundit_user' do
     let(:admin) { FactoryGirl.create :user, roles: [:admin] }
     before do
+      RailsAdmin.config.parent_controller = 'ApplicationController'
       allow_any_instance_of(ApplicationController).to receive(:pundit_user).and_return(admin)
     end
 
     it 'uses original pundit_user' do
+      pending 'no way to dynamically change superclass'
       expect { visit dashboard_path }.not_to raise_error
     end
   end
@@ -137,6 +135,7 @@
           dashboard do
             authorization_key :dashboard?
           end
+          index
         end
       end
     end

spec/integration/history/rails_admin_paper_trail_spec.rb

@@ -8,6 +8,13 @@
     end
   end
 
+  after(:each) do
+    # if #user_for_paper_trail is left unused, PaperTrail complains about it
+    RailsAdmin::ApplicationController.class_eval do
+      undef user_for_paper_trail
+    end
+  end
+
   describe 'on object creation', type: :request do
     subject { page }
     before do

spec/rails_admin/config_spec.rb

@@ -263,7 +263,7 @@ class RecursivelyEmbedsMany
 
   describe '.parent_controller' do
     it 'uses default class' do
-      expect(RailsAdmin.config.parent_controller).to eq '::ApplicationController'
+      expect(RailsAdmin.config.parent_controller).to eq '::ActionController::Base'
     end
 
     it 'uses other class' do