FEATURE: allow logging of raw body of all unprocessable email

set log_mail_processing_failures to true to enable

app/jobs/scheduled/poll_mailbox.rb

@@ -31,6 +31,9 @@ module Jobs
     end
 
     def handle_failure(mail_string, e)
+
+      Rails.logger.warn("Email can not be processed: #{e}\n\n#{mail_string}") if SiteSetting.log_mail_processing_failures
+
       template_args = {}
       case e
         when Email::Receiver::UserNotSufficientTrustLevelError

config/locales/server.en.yml

@@ -1093,6 +1093,7 @@ en:
     pop3_polling_host: "The host to poll for email via POP3."
     pop3_polling_username: "The username for the POP3 account to poll for email."
     pop3_polling_password: "The password for the POP3 account to poll for email."
+    log_mail_processing_failures: "Log all email processing failures to http://yoursitename.com/logs"
     email_in: "Allow users to post new topics via email (requires pop3 polling). Configure the addresses in the \"Settings\" tab of each category."
     email_in_min_trust: "The minimum trust level a user needs to have to be allowed to post new topics via email."
     email_prefix: "The [label] used in the subject of emails. It will default to 'title' if not set."

config/site_settings.yml

@@ -491,6 +491,7 @@ email:
   pop3_polling_port: 995
   pop3_polling_username: ''
   pop3_polling_password: ''
+  log_mail_processing_failures: false
   email_in:
     default: false
     client: true