chore: Fix sentry errors in email processing for bounce notifications (#8677)

This case occurs for bounce notification emails where the from address is From: "" (Mail Delivery System) . We will be discarding these emails for now.

Fixes: https://linear.app/chatwoot/issue/CW-2793/activerecordrecordinvalid-validation-failed-email-invalid-email

app/mailboxes/support_mailbox.rb

@@ -7,11 +7,19 @@ class SupportMailbox < ApplicationMailbox
                     :decorate_mail
 
   def process
+    Rails.logger.info "Processing email #{mail.message_id} from #{original_sender_email} to #{mail.to} with subject #{mail.subject}"
+
     # to turn off spam conversation creation
     return unless @account.active?
     # prevent loop from chatwoot notification emails
     return if notification_email_from_chatwoot?
 
+    # return if email doesn't have a valid sender
+    # This can happen in cases like bounce emails for invalid contact email address
+    # TODO: Handle the bounce seperately and mark the contact as invalid
+    # we are checking for @ since the returned value could be "\"\"" for some email clients
+    return unless original_sender_email.include?('@')
+
     ActiveRecord::Base.transaction do
       find_or_create_contact
       find_or_create_conversation
@@ -56,6 +64,10 @@ class SupportMailbox < ApplicationMailbox
     mail['In-Reply-To'].try(:value)
   end
 
+  def original_sender_email
+    @processed_mail.original_sender&.downcase
+  end
+
   def find_or_create_conversation
     @conversation = find_conversation_by_in_reply_to || ::Conversation.create!({
                                                                                  account_id: @account.id,
@@ -74,7 +86,7 @@ class SupportMailbox < ApplicationMailbox
   end
 
   def find_or_create_contact
-    @contact = @inbox.contacts.find_by(email: @processed_mail.original_sender&.downcase)
+    @contact = @inbox.contacts.find_by(email: original_sender_email)
     if @contact.present?
       @contact_inbox = ContactInbox.find_by(inbox: @inbox, contact: @contact)
     else

spec/fixtures/files/bounced_with_no_from.eml

@@ -0,0 +1,102 @@
+X-Original-To: unique-id@reply.example.com
+Received: from gate.forward.smtp.example.com (mxd [192.0.2.1]) by mx.example.net with ESMTP id JANE3UihQWCm3SPLwYMiwA for <unique-id@reply.example.com>; Mon, 01 Jan 2024 08:27:12.905 +0000 (UTC)
+Return-Path: <>
+X-Virus-Scanned: OK
+Authentication-Results: smtp6.gate.example.com; iprev=pass policy.iprev="192.0.2.2"; spf=neutral smtp.mailfrom="" smtp.helo="backend.example.com"; dkim=none (message not signed) header.d=none
+X-Suspicious-Flag: NO
+X-Classification-ID: 9026a23e-a87f-11ee-b226-52540050e3e0-1-1
+Received: from [192.0.2.2] ([192.0.2.2:52052] helo=backend.example.com)
+    by smtp6.gate.example.com (envelope-from <>)
+    (ecelerity 4.2.38.62370 r(:)) with ESMTPS (cipher=DHE-RSA-AES256-GCM-SHA384) 
+    id 69/60-03303-06772956; Mon, 01 Jan 2024 03:27:12 -0500
+Received: by backend.example.com (Postfix, from userid 5000)
+    id BE58147CF5; Mon,  1 Jan 2024 03:27:12 -0500 (EST)
+X-Sieve: Pigeonhole Sieve 0.5.12 (f22f7ab3)
+X-Sieve-Redirected-From: support@example.com
+Delivered-To: support@example.com
+Delivered-To: support@example.com
+Received: from director.example.com ([192.0.2.3])
+    by backend.example.com with LMTP
+    id AB5kLWB3kmV0bgAAStNUoA
+    (envelope-from <>)
+    for <support@example.com>; Mon, 01 Jan 2024 03:27:12 -0500
+Received: from proxy.example.com ([192.0.2.3])
+    by director.example.com with LMTP
+    id 0BPqLGB3kmWXKQAAfY0hYg
+    (envelope-from <>)
+    for <support@example.com>; Mon, 01 Jan 2024 03:27:12 -0500
+Received: from smtp.example.com ([192.0.2.3])
+    (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
+    by proxy.example.com with LMTPS
+    id yGPPLGB3kmXQNwAAyH2SIw
+    (envelope-from <>)
+    for <support@example.com>; Mon, 01 Jan 2024 03:27:12 -0500
+X-Spam-Threshold: 95
+X-Spam-Score: 0
+X-Spam-Flag: NO
+X-Virus-Scanned: OK
+X-Orig-To: support@example.com
+X-Originating-Ip: [192.0.2.4]
+Received: from [192.0.2.4] ([192.0.2.4:47194] helo=smtp.example.com)
+    by smtp36.gate.example.com (envelope-from <>)
+    (ecelerity 4.2.38.62370 r(:)) with ESMTPS (cipher=DHE-RSA-AES256-GCM-SHA384) 
+    id 57/13-02844-06772956; Mon, 01 Jan 2024 03:27:12 -0500
+Received: by smtp5.relay.example.com (SMTP Server)
+    id 8D329A008A; Mon,  1 Jan 2024 03:27:12 -0500 (EST)
+Date: Mon,  1 Jan 2024 03:27:12 -0500 (EST)
+From: "" (Mail Delivery System)
+Subject: Undelivered Mail Returned to Sender
+To: support@example.com
+Auto-Submitted: auto-replied
+MIME-Version: 1.0
+Content-Type: multipart/report; report-type=delivery-status;
+    boundary="AE732A0081.1704097632/smtp5.relay.example.com"
+Message-Id: <20240101082712.8D329A008A@smtp5.relay.example.com>
+
+This is a MIME-encapsulated message.
+
+--AE732A0081.1704097632/smtp5.relay.example.com
+Content-Description: Notification
+Content-Type: text/plain; charset=us-ascii
+
+This is the mail system at host smtp5.relay.example.com.
+
+I'm sorry to have to inform you that your message could not
+be delivered to one or more recipients. It's attached below.
+
+For further assistance, please send mail to postmaster.
+
+If you do so, please include this problem report. You can
+delete your own text from the attached returned message.
+
+                   The mail system
+
+<noreply@example-service.com>: host
+    mx.example-service.com.cust.a.hostedemail.com[198.51.100.4] said: 554 5.7.1
+    <noreply@example-service.com>: Recipient address rejected: user
+    noreply@example-service.com does not exist (in reply to RCPT TO command)
+
+--AE732A0081.1704097632/smtp5.relay.example.com
+Content-Description: Delivery report
+Content-Type: message/delivery-status
+
+Reporting-MTA: dns; smtp5.relay.example.com
+X-SMTP-Server-Queue-ID: AE732A0081
+X-SMTP-Server-Sender: rfc822; support@example.com
+Arrival-Date: Mon,  1 Jan 2024 03:27:11 -0500 (EST)
+
+Final-Recipient: rfc822; noreply@example-service.com
+Original-Recipient: rfc822;noreply@example-service.com
+Action: failed
+Status: 5.7.1
+Remote-MTA: dns; mx.example-service.com.cust.a.hostedemail.com
+Diagnostic-Code: smtp; 554 5.7.1 <noreply@example-service.com>: Recipient
+    address rejected: user noreply@example-service.com does not exist
+
+--AE732A0081.1704097632/smtp5.relay.example.com
+Content-Description: Undelivered Message
+Content-Type: message/rfc822
+
+Return-Path: <support@example.com>
+X-Milter-Dummy:
+DKIM-Signature: v=1; a=rsa-sha256; c

spec/mailboxes/support_mailbox_spec.rb

@@ -16,6 +16,17 @@ RSpec.describe SupportMailbox do
     end
   end
 
+  describe 'when bounced email with out a sender is recieved' do
+    let(:account) { create(:account) }
+    let(:bounced_email) { create_inbound_email_from_fixture('bounced_with_no_from.eml') }
+    let(:described_subject) { described_class.receive bounced_email }
+
+    it 'shouldnt throw an error' do
+      create(:channel_email, email: 'support@example.com', account: account)
+      expect { described_subject }.not_to raise_error
+    end
+  end
+
   describe 'when an account is suspended' do
     let(:account) { create(:account, status: :suspended) }
     let(:agent) { create(:user, email: 'agent1@example.com', account: account) }