FEATURE: new 'auto_generated_whitelist' site setting

config/locales/server.en.yml

@@ -1169,6 +1169,7 @@ en:
     delete_email_logs_after_days: "Delete email logs after (N) days. 0 to keep indefinitely"
     max_emails_per_day_per_user: "Maximum number of emails to send users per day. 0 to disable the limit"
     enable_staged_users: "Automatically create staged users when processing incoming emails."
+    auto_generated_whitelist: "List of email addresses that won't be checked for auto-generated content."
 
     manual_polling_enabled: "Push emails using the API for email replies."
     pop3_polling_enabled: "Poll via POP3 for email replies."

config/site_settings.yml

@@ -565,6 +565,9 @@ email:
     min: 0
   max_emails_per_day_per_user: 100
   enable_staged_users: true
+  auto_generated_whitelist:
+    default: ''
+    type: list
 
 files:
   max_image_size_kb:

lib/email/receiver.rb

@@ -118,6 +118,7 @@ module Email
     end
 
     def is_auto_generated?
+      return false if SiteSetting.auto_generated_whitelist.split('|').include?(@from_email)
       @mail[:precedence].to_s[/list|junk|bulk|auto_reply/i] ||
       @mail[:from].to_s[/(mailer-?daemon|postmaster|noreply)@/i] ||
       @mail.header.to_s[/auto[\-_]?(response|submitted|replied|reply|generated|respond)|holidayreply|machinegenerated/i]

spec/components/email/receiver_spec.rb

@@ -142,6 +142,11 @@ describe Email::Receiver do
       expect(topic.posts.last.raw).to eq("This email was sent with an invalid from header field.")
     end
 
+    it "doesn't raise an AutoGeneratedEmailError when the mail is auto generated but is whitelisted" do
+      SiteSetting.auto_generated_whitelist = "foo@bar.com|discourse@bar.com"
+      expect { process(:auto_generated_whitelisted) }.not_to raise_error
+    end
+
     describe 'Unsubscribing via email' do
       let(:last_email) { ActionMailer::Base.deliveries.last }
 

spec/fixtures/emails/auto_generated_whitelisted.eml

@@ -0,0 +1,11 @@
+Return-Path: <discourse@bar.com>
+From: White List Ed <discourse@bar.com>
+To: reply+4f97315cc828096c9cb34c6f1a0d6fe8@bar.com
+Date: Fri, 15 Jan 2016 00:12:43 +0100
+Message-ID: <1@foo.bar.mail>
+Auto-Submitted: auto-generated
+Mime-Version: 1.0
+Content-Type: text/plain
+Content-Transfer-Encoding: 7bit
+
+Lorem ipsum dolor sit amet, consectetur adipiscing elit.