Send notification for merge when pipeline succeeds

Filling up the code logic

Fix wrong arguments

Adding template and notification test cases

Add feature check and lint error fix

Add Documentation

Translation fix

Static analysis fix

Review comments addressed

Modify documentation

Make the action change

Making the method private and moving the feature check to child class

Add spec for feature check

Review comments

Moving back the notify

Review comments

Modifying the email template to provide pipeline information

Rubocop and test case fix

change build pipeline to create pipeline

Review comments addressed

Review comments on the notify

Change to small letter

Adding checks to present sending notification on update params

Fix the test case

Review comments

Change back to approval format

Fix translation and build

Fix static analysis

Lint fix

Lint fix

Changing the spec name

Review comments

Remove the feature from documentation

app/mailers/emails/merge_requests.rb

@@ -92,6 +92,13 @@ module Emails
       mail_answer_thread(@merge_request, merge_request_thread_options(resolved_by_user_id, recipient_id, reason))
     end
 
+    def merge_when_pipeline_succeeds_email(recipient_id, merge_request_id, mwps_set_by_user_id, reason = nil)
+      setup_merge_request_mail(merge_request_id, recipient_id)
+
+      @mwps_set_by = ::User.find(mwps_set_by_user_id)
+      mail_answer_thread(@merge_request, merge_request_thread_options(mwps_set_by_user_id, recipient_id, reason))
+    end
+
     private
 
     def setup_merge_request_mail(merge_request_id, recipient_id, present: false)

app/mailers/previews/notify_preview.rb

@@ -177,6 +177,10 @@ class NotifyPreview < ActionMailer::Preview
     Notify.service_desk_thank_you_email(issue.id).message
   end
 
+  def merge_when_pipeline_succeeds_email
+    Notify.merge_when_pipeline_succeeds_email(user.id, merge_request.id, user.id).message
+  end
+
   private
 
   def project

app/services/auto_merge/base_service.rb

@@ -11,7 +11,7 @@ module AutoMerge
         yield if block_given?
       end
 
-      # Notify the event that auto merge is enabled or merge param is updated
+      notify(merge_request)
       AutoMergeProcessWorker.perform_async(merge_request.id)
 
       strategy.to_sym
@@ -62,6 +62,10 @@ module AutoMerge
 
     private
 
+    # Overridden in child classes
+    def notify(merge_request)
+    end
+
     def strategy
       strong_memoize(:strategy) do
         self.class.name.demodulize.remove('Service').underscore

app/services/auto_merge/merge_when_pipeline_succeeds_service.rb

@@ -34,5 +34,13 @@ module AutoMerge
         merge_request.actual_head_pipeline&.active?
       end
     end
+
+    private
+
+    def notify(merge_request)
+      return unless Feature.enabled?(:mwps_notification, project)
+
+      notification_service.async.merge_when_pipeline_succeeds(merge_request, current_user) if merge_request.saved_change_to_auto_merge_enabled?
+    end
   end
 end

app/services/notification_service.rb

@@ -582,6 +582,14 @@ class NotificationService
     end
   end
 
+  def merge_when_pipeline_succeeds(merge_request, current_user)
+    recipients = ::NotificationRecipients::BuildService.build_recipients(merge_request, current_user, action: 'merge_when_pipeline_succeeds')
+
+    recipients.each do |recipient|
+      mailer.merge_when_pipeline_succeeds_email(recipient.user.id, merge_request.id, current_user.id).deliver_later
+    end
+  end
+
   protected
 
   def new_resource_email(target, method)

app/views/notify/merge_when_pipeline_succeeds_email.text.haml

+Merge Request #{@merge_request.to_reference} was scheduled to merge after pipeline succeeds by #{sanitize_name(@mwps_set_by.name)}
+
+Merge Request url: #{project_merge_request_url(@merge_request.target_project, @merge_request)}
+
+= merge_path_description(@merge_request, 'to')
+
+Author: #{sanitize_name(@merge_request.author_name)}
+= assignees_label(@merge_request)

locale/gitlab.pot

@@ -14546,6 +14546,9 @@ msgstr ""
 msgid "Merge request dependencies"
 msgstr ""
 
+msgid "Merge request was scheduled to merge after pipeline succeeds"
+msgstr ""
+
 msgid "Merge requests"
 msgstr ""
 
@@ -28914,6 +28917,9 @@ msgstr ""
 msgid "vulnerability|dismissed"
 msgstr ""
 
+msgid "was scheduled to merge after pipeline succeeds by"
+msgstr ""
+
 msgid "wiki page"
 msgstr ""
 

spec/mailers/emails/merge_requests_spec.rb

@@ -17,4 +17,20 @@ RSpec.describe Emails::MergeRequests do
       expect(subject).to have_body_text current_user.name
     end
   end
+
+  describe "#merge_when_pipeline_succeeds_email" do
+    let(:user) { create(:user) }
+    let(:merge_request) { create(:merge_request) }
+    let(:current_user) { create(:user) }
+    let(:project) { create(:project, :repository) }
+    let(:title) { "Merge request #{merge_request.to_reference} was scheduled to merge after pipeline succeeds by #{current_user.name}" }
+
+    subject { Notify.merge_when_pipeline_succeeds_email(user.id, merge_request.id, current_user.id) }
+
+    it "has required details" do
+      expect(subject).to have_content title
+      expect(subject).to have_content merge_request.to_reference
+      expect(subject).to have_content current_user.name
+    end
+  end
 end

spec/services/auto_merge/merge_when_pipeline_succeeds_service_spec.rb

@@ -69,6 +69,7 @@ RSpec.describe AutoMerge::MergeWhenPipelineSucceedsService do
       before do
         allow(merge_request)
           .to receive_messages(head_pipeline: pipeline, actual_head_pipeline: pipeline)
+        expect(MailScheduler::NotificationServiceWorker).to receive(:perform_async).with('merge_when_pipeline_succeeds', merge_request, user).once
 
         service.execute(merge_request)
       end
@@ -90,6 +91,18 @@ RSpec.describe AutoMerge::MergeWhenPipelineSucceedsService do
       end
     end
 
+    context 'without feature enabled' do
+      it 'does not send notification' do
+        stub_feature_flags(mwps_notification: false)
+
+        allow(merge_request)
+          .to receive_messages(head_pipeline: pipeline, actual_head_pipeline: pipeline)
+        expect(MailScheduler::NotificationServiceWorker).not_to receive(:perform_async)
+
+        service.execute(merge_request)
+      end
+    end
+
     context 'already approved' do
       let(:service) { described_class.new(project, user, should_remove_source_branch: true) }
       let(:build)   { create(:ci_build, ref: mr_merge_if_green_enabled.source_branch) }
@@ -106,6 +119,7 @@ RSpec.describe AutoMerge::MergeWhenPipelineSucceedsService do
 
       it 'updates the merge params' do
         expect(SystemNoteService).not_to receive(:merge_when_pipeline_succeeds)
+        expect(MailScheduler::NotificationServiceWorker).not_to receive(:perform_async).with('merge_when_pipeline_succeeds', any_args)
 
         service.execute(mr_merge_if_green_enabled)
         expect(mr_merge_if_green_enabled.merge_params).to have_key('should_remove_source_branch')

spec/services/notification_service_spec.rb

@@ -2023,6 +2023,26 @@ RSpec.describe NotificationService, :mailer do
         let(:notification_trigger) { notification.resolve_all_discussions(merge_request, @u_disabled) }
       end
     end
+
+    describe '#merge_when_pipeline_succeeds' do
+      it 'send notification that merge will happen when pipeline succeeds' do
+        notification.merge_when_pipeline_succeeds(merge_request, assignee)
+        should_email(merge_request.author)
+        should_email(@u_watcher)
+        should_email(@subscriber)
+      end
+
+      it_behaves_like 'participating notifications' do
+        let(:participant) { create(:user, username: 'user-participant') }
+        let(:issuable) { merge_request }
+        let(:notification_trigger) { notification.merge_when_pipeline_succeeds(merge_request, @u_disabled) }
+      end
+
+      it_behaves_like 'project emails are disabled' do
+        let(:notification_target)  { merge_request }
+        let(:notification_trigger) { notification.merge_when_pipeline_succeeds(merge_request, @u_disabled) }
+      end
+    end
   end
 
   describe 'Projects', :deliver_mails_inline do