Add MailDeliveryJob for unified mail delivery

Add `MailDeliveryJob` for delivering both regular and parameterized mail.
Deprecate using `DeliveryJob` and `Parameterized::DeliveryJob`.

7 files changed, 77 insertions, 9 deletions

diff --git a/actionmailer/lib/action_mailer.rb b/actionmailer/lib/action_mailer.rb
index 69eae65d60..48f16180be 100644
--- a/actionmailer/lib/action_mailer.rb
+++ b/actionmailer/lib/action_mailer.rb
@@ -52,6 +52,7 @@ module ActionMailer
   autoload :TestHelper
   autoload :MessageDelivery
   autoload :DeliveryJob
+  autoload :MailDeliveryJob
 
   def self.eager_load!
     super
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 5d41e5ff2a..8ddc90b9df 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -461,7 +461,7 @@ module ActionMailer
 
     helper ActionMailer::MailHelper
 
-    class_attribute :delivery_job, default: ::ActionMailer::DeliveryJob
+    class_attribute :delivery_job, default: ::ActionMailer::MailDeliveryJob
     class_attribute :default_params, default: {
       mime_version: "1.0",
       charset:      "UTF-8",
diff --git a/actionmailer/lib/action_mailer/delivery_job.rb b/actionmailer/lib/action_mailer/delivery_job.rb
index 8af2097819..f228006920 100644
--- a/actionmailer/lib/action_mailer/delivery_job.rb
+++ b/actionmailer/lib/action_mailer/delivery_job.rb
@@ -12,9 +12,16 @@ module ActionMailer
 
     rescue_from StandardError, with: :handle_exception_with_mailer_class
 
-    def perform(mailer, mail_method, delivery_method, params, *args) #:nodoc:
-      mailer_class = params ? mailer.constantize.with(params) : mailer.constantize
-      mailer_class.public_send(mail_method, *args).send(delivery_method)
+    before_perform do
+      ActiveSupport::Deprecation.warn <<~MSG.squish
+        Sending mail with DeliveryJob and Parameterized::DeliveryJob
+        is deprecated and will be removed in Rails 6.1.
+        Please use MailDeliveryJob instead.
+      MSG
+    end
+
+    def perform(mailer, mail_method, delivery_method, *args) #:nodoc:
+      mailer.constantize.public_send(mail_method, *args).send(delivery_method)
     end
 
     private
diff --git a/actionmailer/lib/action_mailer/mail_delivery_job.rb b/actionmailer/lib/action_mailer/mail_delivery_job.rb
new file mode 100644
index 0000000000..93778edfce
--- /dev/null
+++ b/actionmailer/lib/action_mailer/mail_delivery_job.rb
@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require "active_job"
+
+module ActionMailer
+  # The <tt>ActionMailer::NewDeliveryJob</tt> class is used when you
+  # want to send emails outside of the request-response cycle. It supports
+  # sending either parameterized or normal mail.
+  #
+  # Exceptions are rescued and handled by the mailer class.
+  class MailDeliveryJob < ActiveJob::Base # :nodoc:
+    queue_as { ActionMailer::Base.deliver_later_queue_name }
+
+    rescue_from StandardError, with: :handle_exception_with_mailer_class
+
+    def perform(mailer, mail_method, delivery_method, args:, params: nil) #:nodoc:
+      mailer_class = params ? mailer.constantize.with(params) : mailer.constantize
+      mailer_class.public_send(mail_method, *args).send(delivery_method)
+    end
+
+    private
+      # "Deserialize" the mailer class name by hand in case another argument
+      # (like a Global ID reference) raised DeserializationError.
+      def mailer_class
+        if mailer = Array(@serialized_arguments).first || Array(arguments).first
+          mailer.constantize
+        end
+      end
+
+      def handle_exception_with_mailer_class(exception)
+        if klass = mailer_class
+          klass.handle_exception exception
+        else
+          raise exception
+        end
+      end
+  end
+end
diff --git a/actionmailer/lib/action_mailer/message_delivery.rb b/actionmailer/lib/action_mailer/message_delivery.rb
index 6b02076422..1e5cab6d47 100644
--- a/actionmailer/lib/action_mailer/message_delivery.rb
+++ b/actionmailer/lib/action_mailer/message_delivery.rb
@@ -135,10 +135,18 @@ module ActionMailer
             "#deliver_later, 2. only touch the message *within your mailer " \
             "method*, or 3. use a custom Active Job instead of #deliver_later."
         else
-          args = @mailer_class.name, @action.to_s, delivery_method.to_s, nil, *@args
           job = @mailer_class.delivery_job
+          args = arguments_for(job, delivery_method)
           job.set(options).perform_later(*args)
         end
       end
+
+      def arguments_for(delivery_job, delivery_method)
+        if delivery_job <= MailDeliveryJob
+          [@mailer_class.name, @action.to_s, delivery_method.to_s, args: @args]
+        else
+          [@mailer_class.name, @action.to_s, delivery_method.to_s, *@args]
+        end
+      end
   end
 end
diff --git a/actionmailer/lib/action_mailer/parameterized.rb b/actionmailer/lib/action_mailer/parameterized.rb
index 0b0afd6ad4..999435919e 100644
--- a/actionmailer/lib/action_mailer/parameterized.rb
+++ b/actionmailer/lib/action_mailer/parameterized.rb
@@ -121,6 +121,12 @@ module ActionMailer
         end
     end
 
+    class DeliveryJob < ActionMailer::DeliveryJob # :nodoc:
+      def perform(mailer, mail_method, delivery_method, params, *args)
+        mailer.constantize.with(params).public_send(mail_method, *args).send(delivery_method)
+      end
+    end
+
     class MessageDelivery < ActionMailer::MessageDelivery # :nodoc:
       def initialize(mailer_class, action, params, *args)
         super(mailer_class, action, *args)
@@ -139,11 +145,19 @@ module ActionMailer
           if processed?
             super
           else
-            args = @mailer_class.name, @action.to_s, delivery_method.to_s, @params, *@args
-            job = @mailer_class.delivery_job
+            job  = @mailer_class.delivery_job
+            args = arguments_for(job, delivery_method)
             job.set(options).perform_later(*args)
           end
         end
+
+        def arguments_for(delivery_job, delivery_method)
+          if delivery_job <= MailDeliveryJob
+            [@mailer_class.name, @action.to_s, delivery_method.to_s, params: @params, args: @args]
+          else
+            [@mailer_class.name, @action.to_s, delivery_method.to_s, @params, *@args]
+          end
+        end
     end
   end
 end
diff --git a/actionmailer/lib/action_mailer/test_helper.rb b/actionmailer/lib/action_mailer/test_helper.rb
index 3eb61c2363..e222301dff 100644
--- a/actionmailer/lib/action_mailer/test_helper.rb
+++ b/actionmailer/lib/action_mailer/test_helper.rb
@@ -125,9 +125,9 @@ module ActionMailer
     #   end
     def assert_enqueued_email_with(mailer, method, args: nil, queue: "mailers", &block)
       args = if args.is_a?(Hash)
-        [mailer.to_s, method.to_s, "deliver_now", args]
+        [mailer.to_s, method.to_s, "deliver_now", params: args, args: []]
       else
-        [mailer.to_s, method.to_s, "deliver_now", nil, *args]
+        [mailer.to_s, method.to_s, "deliver_now", args: Array(args)]
       end
       assert_enqueued_with(job: mailer.delivery_job, args: args, queue: queue, &block)
     end