FIX: Ignore DMARC for emails sent to mailing list mirror

lib/email/receiver.rb

@@ -199,7 +199,7 @@ module Email
       @hidden_reason_id ||=
         if is_spam?
           Post.hidden_reasons[:email_spam_header_found]
-        elsif auth_res_action == :hide
+        elsif !sent_to_mailinglist_mirror? && auth_res_action == :hide
           Post.hidden_reasons[:email_authentication_result_header]
         else
           nil

spec/components/email/receiver_spec.rb

@@ -1422,6 +1422,14 @@ describe Email::Receiver do
 
       expect { process("mailinglist_unsubscribe") }.to_not change { ActionMailer::Base.deliveries.count }
     end
+
+    it "ignores dmarc fails" do
+      expect { process("mailinglist_dmarc_fail") }.to change { Topic.count }
+
+      post = Topic.last.first_post
+      expect(post.hidden).to eq(false)
+      expect(post.hidden_reason_id).to be_nil
+    end
   end
 
   it "tries to fix unparsable email addresses in To and CC headers" do

spec/fixtures/emails/mailinglist_dmarc_fail.eml

@@ -0,0 +1,13 @@
+Authentication-Results: example.com; dmarc=fail
+From: alice@foo.com
+To: list@example.com
+Subject: mailinglist mirror
+Date: Mon, 16 Oct 2017 09:18:32 +0100
+Message-ID: <bddaa334ef93b5f3c7c3a42599330844@foo.com>
+Precedence: list
+List-Id: Example List <list@example.com>
+Content-Transfer-Encoding: 7bit
+Content-Type: text/plain; charset="us-ascii"
+Sender: list-bounces@example.com
+
+I love Discourse's mailinglist mirror feature.