Clean up unused application records (#24871)

app/lib/application_extension.rb

@@ -4,6 +4,8 @@ module ApplicationExtension
   extend ActiveSupport::Concern
 
   included do
+    has_many :created_users, class_name: 'User', foreign_key: 'created_by_application_id', inverse_of: :created_by_application
+
     validates :name, length: { maximum: 60 }
     validates :website, url: true, length: { maximum: 2_000 }, if: :website?
     validates :redirect_uri, length: { maximum: 2_000 }

app/lib/vacuum/applications_vacuum.rb

@@ -0,0 +1,10 @@
+# frozen_string_literal: true
+
+class Vacuum::ApplicationsVacuum
+  def perform
+    Doorkeeper::Application.where(owner_id: nil)
+                           .where.missing(:created_users, :access_tokens, :access_grants)
+                           .where(created_at: ...1.day.ago)
+                           .in_batches.delete_all
+  end
+end

app/workers/scheduler/vacuum_scheduler.rb

@@ -22,6 +22,7 @@ class Scheduler::VacuumScheduler
       preview_cards_vacuum,
       backups_vacuum,
       access_tokens_vacuum,
+      applications_vacuum,
       feeds_vacuum,
       imports_vacuum,
     ]
@@ -55,6 +56,10 @@ class Scheduler::VacuumScheduler
     Vacuum::ImportsVacuum.new
   end
 
+  def applications_vacuum
+    Vacuum::ApplicationsVacuum.new
+  end
+
   def content_retention_policy
     ContentRetentionPolicy.current
   end