1 files changed, 30 insertions, 11 deletions

diff --git a/actionmailer/lib/action_mailer/railtie.rb b/actionmailer/lib/action_mailer/railtie.rb
index a727ed38e9..893a4a25b1 100644
--- a/actionmailer/lib/action_mailer/railtie.rb
+++ b/actionmailer/lib/action_mailer/railtie.rb
@@ -1,4 +1,6 @@
-require 'active_job/railtie'
+# frozen_string_literal: true
+
+require "active_job/railtie"
 require "action_mailer"
 require "rails"
 require "abstract_controller/railties/routes_helpers"
@@ -18,7 +20,7 @@ module ActionMailer
 
       if app.config.force_ssl
         options.default_url_options ||= {}
-        options.default_url_options[:protocol] ||= 'https'
+        options.default_url_options[:protocol] ||= "https"
       end
 
       options.assets_dir      ||= paths["public"].first
@@ -28,7 +30,7 @@ module ActionMailer
       options.cache_store ||= Rails.cache
 
       if options.show_previews
-        options.preview_path  ||= defined?(Rails.root) ? "#{Rails.root}/test/mailers/previews" : nil
+        options.preview_path ||= defined?(Rails.root) ? "#{Rails.root}/test/mailers/previews" : nil
       end
 
       # make sure readers methods get compiled
@@ -44,10 +46,25 @@ module ActionMailer
         register_preview_interceptors(options.delete(:preview_interceptors))
         register_observers(options.delete(:observers))
 
-        options.each { |k,v| send("#{k}=", v) }
+        if delivery_job = options.delete(:delivery_job)
+          self.delivery_job = delivery_job.constantize
+        end
+
+        options.each { |k, v| send("#{k}=", v) }
       end
 
-      ActiveSupport.on_load(:action_dispatch_integration_test) { include ActionMailer::TestCase::ClearTestDeliveries }
+      ActiveSupport.on_load(:action_dispatch_integration_test) do
+        include ActionMailer::TestHelper
+        include ActionMailer::TestCase::ClearTestDeliveries
+      end
+    end
+
+    initializer "action_mailer.set_autoload_paths" do |app|
+      options = app.config.action_mailer
+
+      if options.show_previews && options.preview_path
+        ActiveSupport::Dependencies.autoload_paths << options.preview_path
+      end
     end
 
     initializer "action_mailer.compile_config_methods" do
@@ -56,17 +73,19 @@ module ActionMailer
       end
     end
 
+    initializer "action_mailer.eager_load_actions" do
+      ActiveSupport.on_load(:after_initialize) do
+        ActionMailer::Base.descendants.each(&:action_methods) if config.eager_load
+      end
+    end
+
     config.after_initialize do |app|
       options = app.config.action_mailer
 
       if options.show_previews
         app.routes.prepend do
-          get '/rails/mailers'         => "rails/mailers#index", internal: true
-          get '/rails/mailers/*path'   => "rails/mailers#preview", internal: true
-        end
-
-        if options.preview_path
-          ActiveSupport::Dependencies.autoload_paths << options.preview_path
+          get "/rails/mailers"       => "rails/mailers#index", internal: true
+          get "/rails/mailers/*path" => "rails/mailers#preview", internal: true
         end
       end
     end