generate ApplicationJob if it does not already exist

ActiveJob jobs now inherit from ApplicationJob by default.
However, when updating to Rails 5 from the old Rails,
since there is a possibility that ApplicationJob does not exist.

2 files changed, 19 insertions, 0 deletions

diff --git a/activejob/lib/rails/generators/job/job_generator.rb b/activejob/lib/rails/generators/job/job_generator.rb
index 2115fb9f71..6e43e4a269 100644
--- a/activejob/lib/rails/generators/job/job_generator.rb
+++ b/activejob/lib/rails/generators/job/job_generator.rb
@@ -17,7 +17,22 @@ module Rails # :nodoc:
 
       def create_job_file
         template 'job.rb', File.join('app/jobs', class_path, "#{file_name}_job.rb")
+
+        in_root do
+          if self.behavior == :invoke && !File.exist?(application_job_file_name)
+            template 'application_job.rb', application_job_file_name
+          end
+        end
       end
+
+      private
+        def application_job_file_name
+           @application_job_file_name ||= if mountable_engine?
+             "app/jobs/#{namespaced_path}/application_job.rb"
+           else
+             'app/jobs/application_job.rb'
+           end
+        end
     end
   end
 end
diff --git a/activejob/lib/rails/generators/job/templates/application_job.rb b/activejob/lib/rails/generators/job/templates/application_job.rb
new file mode 100644
index 0000000000..0b113b950e
--- /dev/null
+++ b/activejob/lib/rails/generators/job/templates/application_job.rb
@@ -0,0 +1,4 @@
+<% module_namespacing do -%>
+class ApplicationJob < ActiveJob::Base
+end
+<% end -%>