FEATURE: automatic PM when a user's email is revoked

config/locales/server.en.yml

@@ -2593,6 +2593,15 @@ en:
         Please make sure you have properly configured the POP credentials in [the site settings](%{base_url}/admin/site_settings/category/email).
 
         If there is a web UI for the POP email account, you may need to log in on the web and check your settings there.
+
+    email_revoked:
+      title: "Email Revoked"
+      subject_template: "[%{email_prefix}] Is your email address correct?"
+      text_body_template: |
+        We're sorry, but we're having trouble reaching you via email.
+
+        Can you make sure [your email address](%{base_url}/my/preferences/email) is a valid and working email address?
+
     too_many_spam_flags:
       title: "Too Many Spam Flags"
       subject_template: "New account on hold"

lib/email/receiver.rb

@@ -232,9 +232,12 @@ module Email
           reason = I18n.t("user.deactivated", email: user.email)
           StaffActionLogger.new(Discourse.system_user).log_user_deactivate(user, reason)
         elsif range === SiteSetting.bounce_score_threshold
-          # NOTE: we check bounce_score before sending emails, nothing to do here other than log it happened.
+          # NOTE: we check bounce_score before sending emails
+          # So log we revoked the email...
           reason = I18n.t("user.email.revoked", email: user.email, date: user.user_stat.reset_bounce_score_after)
           StaffActionLogger.new(Discourse.system_user).log_revoke_email(user, reason)
+          # ... and PM the user
+          SystemMessage.create_from_system_user(user, :email_revoked)
         end
       end
     end

spec/components/email/receiver_spec.rb

@@ -129,6 +129,17 @@ describe Email::Receiver do
       expect(email_log_2.bounced).to eq(true)
     end
 
+    it "sends a system message once they reach the 'bounce_score_threshold'" do
+      expect(user.active).to eq(true)
+
+      user.user_stat.bounce_score = SiteSetting.bounce_score_threshold - 1
+      user.user_stat.save!
+
+      SystemMessage.expects(:create_from_system_user).with(user, :email_revoked)
+
+      expect { process(:hard_bounce_via_verp) }.to raise_error(Email::Receiver::BouncedEmailError)
+    end
+
     it "automatically deactive users once they reach the 'bounce_score_threshold_deactivate' threshold" do
       expect(user.active).to eq(true)