Add custom additonal email text to all emails

app/views/email_rejection_mailer/rejection.text.haml

 Unfortunately, your email message to GitLab could not be processed.
-
-
+\
 = @reason

doc/administration/index.md

@@ -85,7 +85,6 @@ created in snippets, wikis, and repos.
   - [Postfix for incoming email](reply_by_email_postfix_setup.md): Set up a
   basic Postfix mail server with IMAP authentication on Ubuntu for incoming
   emails.
-server with IMAP authentication on Ubuntu, to be used with Reply by email.
 - [User Cohorts](../user/admin_area/user_cohorts.md): Display the monthly cohorts of new users and their activities over time.
 
 [reply by email]: reply_by_email.md

doc/user/admin_area/settings/email.md

+# Email
+
+## Custom logo
+
+The logo in the header of some emails can be customized, see the [logo customization section](../../../customization/branded_page_and_email_header.md).

lib/gitlab/git/hook.rb

@@ -95,13 +95,13 @@ module Gitlab
         args = [ref, oldrev, newrev]
 
         stdout, stderr, status = Open3.capture3(env, path, *args, options)
-        [status.success?, (stderr.presence || stdout).gsub(/\R/, "<br>").html_safe]
+        [status.success?, Gitlab::Utils.nlbr(stderr.presence || stdout)]
       end
 
       def retrieve_error_message(stderr, stdout)
         err_message = stderr.read
         err_message = err_message.blank? ? stdout.read : err_message
-        err_message.gsub(/\R/, "<br>").html_safe
+        Gitlab::Utils.nlbr(err_message)
       end
     end
   end

lib/gitlab/utils.rb

@@ -27,6 +27,11 @@ module Gitlab
         .gsub(/(\A-+|-+\z)/, '')
     end
 
+    # Converts newlines into HTML line break elements
+    def nlbr(str)
+      ActionView::Base.full_sanitizer.sanitize(str, tags: []).gsub(/\r?\n/, '<br>').html_safe
+    end
+
     def remove_line_breaks(str)
       str.gsub(/\r?\n/, '')
     end

spec/mailers/previews/email_rejection_mailer_preview.rb

+class EmailRejectionMailerPreview < ActionMailer::Preview
+  def rejection
+    EmailRejectionMailer.rejection("some rejection reason", "From: someone@example.com\nraw email here").message
+  end
+end

spec/mailers/previews/notify_preview.rb

@@ -58,16 +58,89 @@ class NotifyPreview < ActionMailer::Preview
     end
   end
 
+  def closed_issue_email
+    Notify.closed_issue_email(user.id, issue.id, user.id).message
+  end
+
+  def issue_status_changed_email
+    Notify.issue_status_changed_email(user.id, issue.id, 'closed', user.id).message
+  end
+
+  def closed_merge_request_email
+    Notify.closed_merge_request_email(user.id, issue.id, user.id).message
+  end
+
+  def merge_request_status_email
+    Notify.merge_request_status_email(user.id, merge_request.id, 'closed', user.id).message
+  end
+
+  def merged_merge_request_email
+    Notify.merged_merge_request_email(user.id, merge_request.id, user.id).message
+  end
+
+  def member_access_denied_email
+    Notify.member_access_denied_email('project', project.id, user.id).message
+  end
+
+  def member_access_granted_email
+    Notify.member_access_granted_email('project', user.id).message
+  end
+
+  def member_access_requested_email
+    Notify.member_access_requested_email('group', user.id, 'some@example.com').message
+  end
+
+  def member_invite_accepted_email
+    Notify.member_invite_accepted_email('project', user.id).message
+  end
+
+  def member_invite_declined_email
+    Notify.member_invite_declined_email(
+      'project',
+      project.id,
+      'invite@example.com',
+      user.id
+    ).message
+  end
+
+  def member_invited_email
+    Notify.member_invited_email('project', user.id, '1234').message
+  end
+
+  def pages_domain_enabled_email
+    cleanup do
+      pages_domain = PagesDomain.new(domain: 'my.example.com', project: project, verified_at: Time.now, enabled_until: 1.week.from_now)
+
+      Notify.pages_domain_enabled_email(pages_domain, user).message
+    end
+  end
+
+  def pipeline_success_email
+    Notify.pipeline_success_email(pipeline, pipeline.user.try(:email))
+  end
+
+  def pipeline_failed_email
+    Notify.pipeline_failed_email(pipeline, pipeline.user.try(:email))
+  end
+
   private
 
   def project
     @project ||= Project.find_by_full_path('gitlab-org/gitlab-test')
   end
 
+  def issue
+    @merge_request ||= project.issues.first
+  end
+
   def merge_request
     @merge_request ||= project.merge_requests.first
   end
 
+  def pipeline
+    @pipeline = Ci::Pipeline.last
+  end
+
   def user
     @user ||= User.last
   end
@@ -94,14 +167,4 @@ class NotifyPreview < ActionMailer::Preview
 
     email
   end
-
-  def pipeline_success_email
-    pipeline = Ci::Pipeline.last
-    Notify.pipeline_success_email(pipeline, pipeline.user.try(:email))
-  end
-
-  def pipeline_failed_email
-    pipeline = Ci::Pipeline.last
-    Notify.pipeline_failed_email(pipeline, pipeline.user.try(:email))
-  end
 end

spec/mailers/previews/repository_check_mailer_preview.rb

+class RepositoryCheckMailerPreview < ActionMailer::Preview
+  def notify
+    RepositoryCheckMailer.notify(3).message
+  end
+end