FIX: Make sure CC addresses for forwarded emails are used

When forwarding emails into the group inbox we are currently
ignoring the original CC addresses on the forwarded email. This
commit makes sure we record those CC addresses on the incoming
email record for the topic, as well as inviting those CC addresses
as staged users on the topic when it is created.

lib/email/receiver.rb

@@ -143,13 +143,17 @@ module Email
     end
 
     def create_incoming_email
+      cc_addresses = Array.wrap(@mail.cc)
+      if embedded_email&.cc
+        cc_addresses.concat(embedded_email.cc)
+      end
       IncomingEmail.create(
         message_id: @message_id,
         raw: Email::Cleaner.new(@raw_email).execute,
         subject: subject,
         from_address: @from_email,
         to_addresses: @mail.to,
-        cc_addresses: @mail.cc,
+        cc_addresses: cc_addresses,
         imap_uid_validity: @opts[:imap_uid_validity],
         imap_uid: @opts[:imap_uid],
         imap_group_id: @opts[:imap_group_id],
@@ -959,7 +963,7 @@ module Email
       email, display_name = parse_from_field(embedded)
 
       if @forwarded_by_address && @forwarded_by_name
-        forwarded_by_user = stage_sender_user(@forwarded_by_address, @forwarded_by_name)
+        @forwarded_by_user = stage_sender_user(@forwarded_by_address, @forwarded_by_name)
       end
 
       return false if email.blank? || !email["@"]
@@ -988,10 +992,10 @@ module Email
                        post_type: post_type,
                        skip_validations: user.staged?)
         else
-          if forwarded_by_user
-            post.topic.topic_allowed_users.find_or_create_by!(user_id: forwarded_by_user.id)
+          if @forwarded_by_user
+            post.topic.topic_allowed_users.find_or_create_by!(user_id: @forwarded_by_user.id)
           end
-          post.topic.add_small_action(forwarded_by_user || user, "forwarded")
+          post.topic.add_small_action(@forwarded_by_user || user, "forwarded")
         end
       end
 
@@ -1315,7 +1319,11 @@ module Email
       if result.post
         @incoming_email.update_columns(topic_id: result.post.topic_id, post_id: result.post.id)
         if result.post.topic&.private_message? && !is_bounce?
-          add_other_addresses(result.post, user)
+          add_other_addresses(result.post, user, @mail)
+
+          if has_been_forwarded?
+            add_other_addresses(result.post, @forwarded_by_user || user, embedded_email)
+          end
         end
 
         # Alert the people involved in the topic now that the incoming email
@@ -1337,11 +1345,11 @@ module Email
       html
     end
 
-    def add_other_addresses(post, sender)
+    def add_other_addresses(post, sender, mail_object)
       %i(to cc bcc).each do |d|
-        next if @mail[d].blank?
+        next if mail_object[d].blank?
 
-        @mail[d].each do |address_field|
+        mail_object[d].each do |address_field|
           begin
             address_field.decoded
             email = address_field.address.downcase

spec/components/email/receiver_spec.rb

@@ -1064,13 +1064,24 @@ describe Email::Receiver do
         end
 
         it "does not say the email was forwarded by the original sender, it says the email is forwarded by the group" do
-          expect { process(:forwarded_by_group_to_group) }.to change { User.where(staged: true).count }.by(2)
+          expect { process(:forwarded_by_group_to_group) }.to change { User.where(staged: true).count }.by(4)
           topic = Topic.last
           forwarded_small_post = topic.ordered_posts.last
           expect(forwarded_small_post.action_code).to eq("forwarded")
           expect(forwarded_small_post.user).to eq(User.find_by_email("team@somesmtpaddress.com"))
         end
 
+        it "keeps the CC addresses from the forwarded email" do
+          expect { process(:forwarded_by_group_to_group) }.to change { User.where(staged: true).count }.by(4)
+          topic = Topic.last
+          cc_user1 = User.find_by_email("terry@ccland.com")
+          cc_user2 = User.find_by_email("don@mmtest.com")
+          expect(cc_user1).not_to eq(nil)
+          expect(cc_user2).not_to eq(nil)
+          expect(topic.topic_allowed_users.pluck(:user_id)).to include(cc_user1.id)
+          expect(topic.incoming_email.first.cc_addresses).to eq("terry@ccland.com;don@mmtest.com")
+        end
+
         context "when staged user for the team email already exists" do
           let!(:staged_team_user) do
             User.create!(
@@ -1082,7 +1093,7 @@ describe Email::Receiver do
           end
 
           it "uses that and does not create another staged user" do
-            expect { process(:forwarded_by_group_to_group) }.to change { User.where(staged: true).count }.by(1)
+            expect { process(:forwarded_by_group_to_group) }.to change { User.where(staged: true).count }.by(3)
             topic = Topic.last
             forwarded_small_post = topic.ordered_posts.last
             expect(forwarded_small_post.action_code).to eq("forwarded")

spec/fixtures/emails/forwarded_by_group_to_group.eml

@@ -17,6 +17,7 @@ From: Fred Flintstone <fred@bedrock.com>
 Date: Mon, 1 Dec 2016 13:37:42 +0100
 Subject: Re: Login problems
 To: Discourse Team <team@somesmtpaddress.com>
+CC: Terry Jones <terry@ccland.com>, don@mmtest.com
 
 Hello I am having some issues with my forum.