Fix deprecated DeliveryJob message

Notifications generate this deprecation error:

```
DEPRECATION WARNING: Sending mail with DeliveryJob and
Parameterized::DeliveryJob is deprecated and will be removed in Rails
6.1. Please use MailDeliveryJob instead. (called from new_project_member
at /builds/gitlab-org/gitlab/app/services/notification_service.rb:360)
```

This was introduced in Rails: https://github.com/rails/rails/pull/34591.

To migrate, we simply need to set the Rails configuration to use
`MailDeliveryJob` instead of `DeliveryJob` and update the code to
reflect that.

Closes https://gitlab.com/gitlab-org/gitlab/-/issues/208305

config/application.rb

@@ -158,6 +158,8 @@ class Application < Rails::Application
     # Webpack dev server configuration is handled in initializers/static_files.rb
     config.webpack.dev_server.enabled = false
 
+    config.action_mailer.delivery_job = "ActionMailer::MailDeliveryJob"
+
     # Enable the asset pipeline
     config.assets.enabled = true
 

doc/administration/troubleshooting/navigating_gitlab_via_rails_console.md

@@ -186,7 +186,7 @@ user.save
 Which would return:
 
 ```ruby
-Enqueued ActionMailer::DeliveryJob (Job ID: 05915c4e-c849-4e14-80bb-696d5ae22065) to Sidekiq(mailers) with arguments: "DeviseMailer", "password_change", "deliver_now", #<GlobalID:0x00007f42d8ccebe8 @uri=#<URI::GID gid://gitlab/User/1>>
+Enqueued ActionMailer::MailDeliveryJob (Job ID: 05915c4e-c849-4e14-80bb-696d5ae22065) to Sidekiq(mailers) with arguments: "DeviseMailer", "password_change", "deliver_now", #<GlobalID:0x00007f42d8ccebe8 @uri=#<URI::GID gid://gitlab/User/1>>
 => true
 ```
 

doc/administration/troubleshooting/sidekiq.md

@@ -38,7 +38,7 @@ Example log output:
 
 ```json
 {"severity":"INFO","time":"2020-06-08T14:37:37.892Z","class":"AdminEmailsWorker","args":["[FILTERED]","[FILTERED]","[FILTERED]"],"retry":3,"queue":"admin_emails","backtrace":true,"jid":"9e35e2674ac7b12d123e13cc","created_at":"2020-06-08T14:37:37.373Z","meta.user":"root","meta.caller_id":"Admin::EmailsController#create","correlation_id":"37D3lArJmT1","uber-trace-id":"2d942cc98cc1b561:6dc94409cfdd4d77:9fbe19bdee865293:1","enqueued_at":"2020-06-08T14:37:37.410Z","pid":65011,"message":"AdminEmailsWorker JID-9e35e2674ac7b12d123e13cc: done: 0.48085 sec","job_status":"done","scheduling_latency_s":0.001012,"redis_calls":9,"redis_duration_s":0.004608,"redis_read_bytes":696,"redis_write_bytes":6141,"duration_s":0.48085,"cpu_s":0.308849,"completed_at":"2020-06-08T14:37:37.892Z","db_duration_s":0.010742}
-{"severity":"INFO","time":"2020-06-08T14:37:37.894Z","class":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper","wrapped":"ActionMailer::DeliveryJob","queue":"mailers","args":["[FILTERED]"],"retry":3,"backtrace":true,"jid":"e47a4f6793d475378432e3c8","created_at":"2020-06-08T14:37:37.884Z","meta.user":"root","meta.caller_id":"AdminEmailsWorker","correlation_id":"37D3lArJmT1","uber-trace-id":"2d942cc98cc1b561:29344de0f966446d:5c3b0e0e1bef987b:1","enqueued_at":"2020-06-08T14:37:37.885Z","pid":65011,"message":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper JID-e47a4f6793d475378432e3c8: start","job_status":"start","scheduling_latency_s":0.009473}
+{"severity":"INFO","time":"2020-06-08T14:37:37.894Z","class":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper","wrapped":"ActionMailer::MailDeliveryJob","queue":"mailers","args":["[FILTERED]"],"retry":3,"backtrace":true,"jid":"e47a4f6793d475378432e3c8","created_at":"2020-06-08T14:37:37.884Z","meta.user":"root","meta.caller_id":"AdminEmailsWorker","correlation_id":"37D3lArJmT1","uber-trace-id":"2d942cc98cc1b561:29344de0f966446d:5c3b0e0e1bef987b:1","enqueued_at":"2020-06-08T14:37:37.885Z","pid":65011,"message":"ActiveJob::QueueAdapters::SidekiqAdapter::JobWrapper JID-e47a4f6793d475378432e3c8: start","job_status":"start","scheduling_latency_s":0.009473}
 {"severity":"INFO","time":"2020-06-08T14:39:50.648Z","class":"NewIssueWorker","args":["455","1"],"retry":3,"queue":"new_issue","backtrace":true,"jid":"a24af71f96fd129ec47f5d1e","created_at":"2020-06-08T14:39:50.643Z","meta.user":"root","meta.project":"h5bp/html5-boilerplate","meta.root_namespace":"h5bp","meta.caller_id":"Projects::IssuesController#create","correlation_id":"f9UCZHqhuP7","uber-trace-id":"28f65730f99f55a3:a5d2b62dec38dffc:48ddd092707fa1b7:1","enqueued_at":"2020-06-08T14:39:50.646Z","pid":65011,"message":"NewIssueWorker JID-a24af71f96fd129ec47f5d1e: start","job_status":"start","scheduling_latency_s":0.001144}
 ```
 

lib/gitlab/marginalia/comment.rb

@@ -26,9 +26,9 @@ def bg_job
         job = ::Marginalia::Comment.marginalia_job
 
         # We are using 'Marginalia::SidekiqInstrumentation' which does not support 'ActiveJob::Base'.
-        # Gitlab also uses 'ActionMailer::DeliveryJob' which inherits from ActiveJob::Base.
+        # Gitlab also uses 'ActionMailer::MailDeliveryJob' which inherits from ActiveJob::Base.
         # So below condition is used to return metadata for such jobs.
-        if job && job.is_a?(ActionMailer::DeliveryJob)
+        if job.is_a?(ActionMailer::MailDeliveryJob) || job.is_a?(ActionMailer::DeliveryJob)
           {
             "class" => job.arguments.first,
             "jid"   => job.job_id

spec/support/helpers/notification_helpers.rb

@@ -38,26 +38,26 @@ def update_custom_notification(event, user, resource: nil, value: true)
   end
 
   def expect_delivery_jobs_count(count)
-    expect(ActionMailer::DeliveryJob).to have_been_enqueued.exactly(count).times
+    expect(ActionMailer::MailDeliveryJob).to have_been_enqueued.exactly(count).times
   end
 
   def expect_no_delivery_jobs
-    expect(ActionMailer::DeliveryJob).not_to have_been_enqueued
+    expect(ActionMailer::MailDeliveryJob).not_to have_been_enqueued
   end
 
   def expect_any_delivery_jobs
-    expect(ActionMailer::DeliveryJob).to have_been_enqueued.at_least(:once)
+    expect(ActionMailer::MailDeliveryJob).to have_been_enqueued.at_least(:once)
   end
 
   def have_enqueued_email(*args, mailer: "Notify", mail: "", delivery: "deliver_now")
-    have_enqueued_job(ActionMailer::DeliveryJob).with(mailer, mail, delivery, *args)
+    have_enqueued_job(ActionMailer::MailDeliveryJob).with(mailer, mail, delivery, args: args)
   end
 
   def expect_enqueud_email(*args, mailer: "Notify", mail: "", delivery: "deliver_now")
-    expect(ActionMailer::DeliveryJob).to have_been_enqueued.with(mailer, mail, delivery, *args)
+    expect(ActionMailer::MailDeliveryJob).to have_been_enqueued.with(mailer, mail, delivery, args: args)
   end
 
   def expect_not_enqueud_email(*args, mailer: "Notify", mail: "")
-    expect(ActionMailer::DeliveryJob).not_to have_been_enqueued.with(mailer, mail, *args, any_args)
+    expect(ActionMailer::MailDeliveryJob).not_to have_been_enqueued.with(mailer, mail, args: any_args)
   end
 end

spec/workers/every_sidekiq_worker_spec.rb

@@ -19,7 +19,7 @@
     file_worker_queues = Gitlab::SidekiqConfig.worker_queues.to_set
 
     worker_queues = Gitlab::SidekiqConfig.workers.map(&:queue).to_set
-    worker_queues << ActionMailer::DeliveryJob.new.queue_name
+    worker_queues << ActionMailer::MailDeliveryJob.new.queue_name
     worker_queues << 'default'
 
     missing_from_file = worker_queues - file_worker_queues