Don't send rejection mails for all auto-generated mails

Also make it easier to have mailer helper

app/workers/email_receiver_worker.rb

@@ -31,8 +31,6 @@ class EmailReceiverWorker
       when Gitlab::Email::EmptyEmailError
         can_retry = true
         "It appears that the email is blank. Make sure your reply is at the top of the email, we can't process inline replies."
-      when Gitlab::Email::AutoGeneratedEmailError
-        "The email was marked as 'auto generated', which we can't accept. Please create your comment through the web interface."
       when Gitlab::Email::UserNotFoundError
         "We couldn't figure out what user corresponds to the email. Please create your comment through the web interface."
       when Gitlab::Email::UserBlockedError

changelogs/unreleased/28472-ignore-auto-generated-mails.yml

+---
+title: Don't send rejection mails for all auto-generated mails
+merge_request: 13254
+author:

lib/gitlab/email/handler/create_note_handler.rb

@@ -15,7 +15,6 @@ module Gitlab
         def execute
           raise SentNotificationNotFoundError unless sent_notification
-          raise AutoGeneratedEmailError if mail.header.to_s =~ /auto-(generated|replied)/
           validate_permission!(:create_note)

lib/gitlab/email/receiver.rb

@@ -26,6 +26,10 @@ module Gitlab
         raise EmptyEmailError if @raw.blank?
         mail = build_mail
+
+        raise AutoGeneratedEmailError if
+          mail.header.to_s =~ /auto-(generated|replied)/
+
         mail_key = extract_mail_key(mail)
         handler = Handler.for(mail, mail_key)

spec/lib/gitlab/email/handler/create_note_handler_spec.rb

@@ -36,15 +36,6 @@ describe Gitlab::Email::Handler::CreateNoteHandler do
     end
   end
-  context "when the email was auto generated" do
-    let!(:mail_key)  { '636ca428858779856c226bb145ef4fad' }
-    let!(:email_raw) { fixture_file("emails/auto_reply.eml") }
-
-    it "raises an AutoGeneratedEmailError" do
-      expect { receiver.execute }.to raise_error(Gitlab::Email::AutoGeneratedEmailError)
-    end
-  end
-
   context "when the noteable could not be found" do
     before do
       noteable.destroy

spec/lib/gitlab/email/receiver_spec.rb

@@ -28,14 +28,6 @@ describe Gitlab::Email::Receiver do
     it "raises an UnknownIncomingEmail error" do
       expect { receiver.execute }.to raise_error(Gitlab::Email::UnknownIncomingEmail)
     end
-
-    context "and the email contains no references header" do
-      let(:email_raw) { fixture_file("emails/auto_reply.eml").gsub(mail_key, "!!!") }
-
-      it "raises an UnknownIncomingEmail error" do
-        expect { receiver.execute }.to raise_error(Gitlab::Email::UnknownIncomingEmail)
-      end
-    end
   end
   context "when the email is blank" do
@@ -45,4 +37,12 @@ describe Gitlab::Email::Receiver do
       expect { receiver.execute }.to raise_error(Gitlab::Email::EmptyEmailError)
     end
   end
+
+  context "when the email was auto generated" do
+    let(:email_raw) { fixture_file("emails/auto_reply.eml") }
+
+    it "raises an AutoGeneratedEmailError" do
+      expect { receiver.execute }.to raise_error(Gitlab::Email::AutoGeneratedEmailError)
+    end
+  end
 end

spec/spec_helper.rb

@@ -49,7 +49,7 @@ RSpec.configure do |config|
   config.include SearchHelpers, type: :feature
   config.include WaitForRequests, :js
   config.include StubConfiguration
-  config.include EmailHelpers, type: :mailer
+  config.include EmailHelpers, :mailer, type: :mailer
   config.include TestEnv
   config.include ActiveJob::TestHelper
   config.include ActiveSupport::Testing::TimeHelpers
@@ -93,6 +93,10 @@ RSpec.configure do |config|
     RequestStore.clear!
   end
+  config.before(:example, :mailer) do
+    reset_delivered_emails!
+  end
+
   if ENV['CI']
     config.around(:each) do |ex|
       ex.run_with_retry retry: 2

spec/workers/email_receiver_worker_spec.rb

 require "spec_helper"
-describe EmailReceiverWorker do
+describe EmailReceiverWorker, :mailer do
   let(:raw_message) { fixture_file('emails/valid_reply.eml') }
   context "when reply by email is enabled" do
@@ -17,12 +17,16 @@ describe EmailReceiverWorker do
     context "when an error occurs" do
       before do
-        allow_any_instance_of(Gitlab::Email::Receiver).to receive(:execute).and_raise(Gitlab::Email::EmptyEmailError)
+        allow_any_instance_of(Gitlab::Email::Receiver).to receive(:execute).and_raise(error)
       end
-      it "sends out a rejection email" do
-        perform_enqueued_jobs do
-          described_class.new.perform(raw_message)
+      context 'when the error is Gitlab::Email::EmptyEmailError' do
+        let(:error) { Gitlab::Email::EmptyEmailError }
+
+        it 'sends out a rejection email' do
+          perform_enqueued_jobs do
+            described_class.new.perform(raw_message)
+          end
           email = ActionMailer::Base.deliveries.last
           expect(email).not_to be_nil
@@ -30,6 +34,18 @@ describe EmailReceiverWorker do
           expect(email.subject).to include("Rejected")
         end
       end
+
+      context 'when the error is Gitlab::Email::AutoGeneratedEmailError' do
+        let(:error) { Gitlab::Email::AutoGeneratedEmailError }
+
+        it 'does not send out any rejection email' do
+          perform_enqueued_jobs do
+            described_class.new.perform(raw_message)
+          end
+
+          should_not_email_anyone
+        end
+      end
     end
   end