ignore emails that are from the reply by email addresses (#5843)

lib/email/processor.rb

@@ -36,6 +36,7 @@ module Email
     def handle_failure(mail_string, e)
       message_template = case e
                          when Email::Receiver::NoSenderDetectedError       then return nil
+                         when Email::Receiver::FromReplyByAddressError     then return nil
                          when Email::Receiver::EmptyEmailError             then :email_reject_empty
                          when Email::Receiver::NoBodyDetectedError         then :email_reject_empty
                          when Email::Receiver::UserNotFoundError           then :email_reject_user_not_found

lib/email/receiver.rb

@@ -21,6 +21,7 @@ module Email
     class BouncedEmailError            < ProcessingError; end
     class NoBodyDetectedError          < ProcessingError; end
     class NoSenderDetectedError        < ProcessingError; end
+    class FromReplyByAddressError      < ProcessingError; end
     class InactiveUserError            < ProcessingError; end
     class SilencedUserError            < ProcessingError; end
     class BadDestinationAddress        < ProcessingError; end
@@ -107,6 +108,7 @@ module Email
     def process_internal
       raise BouncedEmailError  if is_bounce?
       raise NoSenderDetectedError if @from_email.blank?
+      raise FromReplyByAddressError if is_from_reply_by_email_address?
       raise ScreenedEmailError if ScreenedEmail.should_block?(@from_email)
 
       user = find_user(@from_email)
@@ -203,6 +205,10 @@ module Email
       true
     end
 
+    def is_from_reply_by_email_address?
+      Email::Receiver.reply_by_email_address_regex.match(@from_email)
+    end
+
     def verp
       @verp ||= all_destinations.select { |to| to[/\+verp-\h{32}@/] }.first
     end
@@ -723,9 +729,13 @@ module Email
       reply_addresses.flatten!
       reply_addresses.select!(&:present?)
       reply_addresses.map! { |a| Regexp.escape(a) }
-      reply_addresses.map! { |a| a.gsub(Regexp.escape("%{reply_key}"), "(\\h{32})") }
-
-      /#{reply_addresses.join("|")}/
+      reply_addresses.map! { |a| a.gsub("\+", "\+?") }
+      reply_addresses.map! { |a| a.gsub(Regexp.escape("%{reply_key}"), "(\\h{32})?") }
+      if reply_addresses.empty?
+        /$a/ # a regex that can never match
+      else
+        /#{reply_addresses.join("|")}/
+      end
     end
 
     def group_incoming_emails_regex