FIX: Capture CC addresses for forwarded emails (#14254)

When forwarding emails into the group inbox, we now use the
original sender email as the from_address since
2ac9fd9dff. However, we have not
been saving the original CC addresses of the forwarded email,
which are needed to include those recipients in on the conversation
when replying via the group inbox.

This commit captures the CC addresses on the incoming email, and
makes sure the emails are created as staged users and added to the
list of topic allowed users so they are included on CC's sent by
the GroupSmtpEmail and other jobs.

lib/email/receiver.rb

@@ -143,13 +143,17 @@ module Email
     end
 
     def create_incoming_email
+      cc_addresses = Array.wrap(@mail.cc)
+      if has_been_forwarded? && 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],
@@ -956,7 +960,7 @@ 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["@"]
@@ -985,10 +989,10 @@ 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
 
@@ -1324,7 +1328,11 @@ 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
@@ -1346,11 +1354,11 @@ 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 +1064,40 @@ 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_inbox) }.to change { User.where(staged: true).count }.by(2)
+          expect { process(:forwarded_by_group_to_inbox) }.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 track of the cc addresses of the forwarded email and creates staged users for them" do
+          expect { process(:forwarded_by_group_to_inbox) }.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@ccland.com")
+          fred_user = User.find_by_email("fred@bedrock.com")
+          team_user = User.find_by_email("team@somesmtpaddress.com")
+          expect(topic.incoming_email.first.cc_addresses).to eq("terry@ccland.com;don@ccland.com")
+          expect(topic.topic_allowed_users.pluck(:user_id)).to match_array([
+            fred_user.id, team_user.id, cc_user1.id, cc_user2.id
+          ])
+        end
+
+        it "keeps track of the cc addresses of the final forwarded email as well" do
+          expect { process(:forwarded_by_group_to_inbox_double_cc) }.to change { User.where(staged: true).count }.by(5)
+          topic = Topic.last
+          cc_user1 = User.find_by_email("terry@ccland.com")
+          cc_user2 = User.find_by_email("don@ccland.com")
+          fred_user = User.find_by_email("fred@bedrock.com")
+          team_user = User.find_by_email("team@somesmtpaddress.com")
+          someother_user = User.find_by_email("someotherparty@test.com")
+          expect(topic.incoming_email.first.cc_addresses).to eq("someotherparty@test.com;terry@ccland.com;don@ccland.com")
+          expect(topic.topic_allowed_users.pluck(:user_id)).to match_array([
+            fred_user.id, team_user.id, someother_user.id, cc_user1.id, cc_user2.id
+          ])
+        end
+
         context "when staged user for the team email already exists" do
           let!(:staged_team_user) do
             User.create!(
@@ -1082,7 +1109,7 @@ describe Email::Receiver do
           end
 
           it "uses that and does not create another staged user" do
-            expect { process(:forwarded_by_group_to_inbox) }.to change { User.where(staged: true).count }.by(1)
+            expect { process(:forwarded_by_group_to_inbox) }.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_inbox.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@ccland.com
 
 Hello I am having some issues with my forum.
 

spec/fixtures/emails/forwarded_by_group_to_inbox_double_cc.eml

@@ -0,0 +1,36 @@
+Message-ID: <58@somesmtpaddress.mail>
+From: Discourse Team <team@somesmtpaddress.com>
+To: support+team@bar.com
+CC: someotherparty@test.com
+Date: Mon, 1 Dec 2016 13:37:42 +0100
+Subject: Fwd: Login problems
+Content-Type: multipart/related; boundary="00000000000072702105c89858de"
+
+--00000000000072702105c89858de
+Content-Type: multipart/alternative; boundary="00000000000072702005c89858dd"
+
+--00000000000072702005c89858dd
+Content-Type: text/plain; charset="UTF-8"
+Content-Transfer-Encoding: quoted-printable
+
+---------- Forwarded message ---------
+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@ccland.com
+
+Hello I am having some issues with my forum.
+
+Fred
+
+--00000000000072702005c89858dd
+Content-Type: text/html; charset="UTF-8"
+Content-Transfer-Encoding: quoted-printable
+
+<p>Hello I am having some issues with my forum.</p>
+
+<br>Fred<br>
+
+--00000000000072702005c89858dd--
+--00000000000072702105c89858de