Fixes #9167: Fix chained scopes when using scoped_search in API

Scoped search claims to support being applied to a set of scopes via
scopes.search_for. However, when multiple joins are used within the 'scopes'
the last join wins in the prior format. To combat this, we apply the
search_for first, which is itself a scope, and merge the scopes into
that result.

app/controllers/katello/api/v2/api_controller.rb

@@ -45,6 +45,12 @@ class Api::V2::ApiController < ::Api::V2::BaseController
     param :object_root, String, :desc => N_("root-node of single-resource responses (optional)")
     param :root_name, String, :desc => N_("root-node of collection contained in responses (default: 'results')")
 
+    def resource_class
+      @resource_class ||= resource_name.classify.constantize
+    rescue NameError
+      @resource_class ||= "Katello::#{resource_name.classify}".constantize
+    end
+
     def item_search(item_class, param_hash, options)
       fail "@search_service search not defined" if @search_service.nil?
       if param_hash[:order]
@@ -79,10 +85,10 @@ def item_search(item_class, param_hash, options)
       }
     end
 
-    def scoped_search(query, default_sort_by, default_sort_order)
+    def scoped_search(query, default_sort_by, default_sort_order, resource = resource_class)
       total = query.count
-      sub_total = query.search_for(*search_options).count
-      query = query.search_for(*search_options)
+      sub_total = resource.search_for(*search_options).merge(query).count
+      query = resource.search_for(*search_options).merge(query)
       sort_attr = params[:sort_by] || default_sort_by
       sort_attr = "#{query.table_name}.#{sort_attr}" unless sort_attr.to_s.include?('.')
 

app/controllers/katello/api/v2/content_view_filters_controller.rb

@@ -98,7 +98,7 @@ def available_errata
       scoped = scoped.of_type(params[:types]) if params[:types]
 
       respond_for_index :template => '../errata/index',
-                        :collection => scoped_search(scoped, 'issued', 'desc')
+                        :collection => scoped_search(scoped, 'issued', 'desc', Erratum)
     end
 
     api :GET, "/content_views/:content_view_id/filters/:id/available_package_groups",