Fix bugs with cached models

Author: artemlutsenko

lib/active_admin_import/dsl.rb

@@ -54,11 +54,14 @@ def active_admin_import(options = {}, &block)
       options.assert_valid_keys(*Options::VALID_OPTIONS)
 
       options = Options.options_for(config, options)
-      params_key = ActiveModel::Naming.param_key(options[:template_object])
 
       collection_action :import, method: :get do
         authorize!(ActiveAdminImport::Auth::IMPORT, active_admin_config.resource_class)
-        @active_admin_import_model = options[:template_object]
+        @active_admin_import_model = if options[:template_object].is_a?(Proc)
+                                       options[:template_object].call
+                                     else
+                                       options[:template_object]
+                                     end
         render template: options[:template]
       end
 
@@ -75,7 +78,12 @@ def active_admin_import(options = {}, &block)
         authorize!(ActiveAdminImport::Auth::IMPORT, active_admin_config.resource_class)
         _params = params.respond_to?(:to_unsafe_h) ? params.to_unsafe_h : params
         params = ActiveSupport::HashWithIndifferentAccess.new _params
-        @active_admin_import_model = options[:template_object]
+        @active_admin_import_model = if options[:template_object].is_a?(Proc)
+                                       options[:template_object].call
+                                     else
+                                       options[:template_object]
+                                     end
+        params_key = ActiveModel::Naming.param_key(@active_admin_import_model.class)
         @active_admin_import_model.assign_attributes(params[params_key].try(:deep_symbolize_keys) || {})
         # go back to form
         return render template: options[:template] unless @active_admin_import_model.valid?

lib/active_admin_import/options.rb

@@ -26,7 +26,7 @@ module Options
 
     def self.options_for(config, options = {})
       unless options.key? :template_object
-        options[:template_object] = ActiveAdminImport::Model.new
+        options[:template_object] = -> { ActiveAdminImport::Model.new }
       end
 
       {

spec/import_spec.rb

@@ -96,6 +96,38 @@ def upload_file!(name, ext = 'csv')
         end
         include_examples 'successful inserts for author'
       end
+
+      context 'when template object passed like proc' do
+        before do
+          add_post_resource(template_object: -> { ActiveAdminImport::Model.new(author_id: author.id) },
+                            validate: true,
+                            before_batch_import: lambda do |importer|
+                              importer.csv_lines.map! { |row| row << importer.model.author_id }
+                              importer.headers.merge!(:'Author Id' => :author_id)
+                            end
+          )
+
+          visit '/admin/posts/import'
+          upload_file!(:posts_for_author)
+        end
+
+        include_examples 'successful inserts for author'
+
+        context 'after successful import try without file' do
+          let(:after_successful_import_do!) do
+            # reload page
+            visit '/admin/posts/import'
+            # submit form without file
+            find_button('Import').click
+          end
+
+          it 'should render validation error' do
+            after_successful_import_do!
+
+            expect(page).to have_content I18n.t('active_admin_import.no_file_error')
+          end
+        end
+      end
     end
 
     context 'for csv with author name' do