Block blocked users from replying to threads by email.

app/workers/email_receiver_worker.rb

@@ -31,6 +31,8 @@ class EmailReceiverWorker
       reason = "The email was marked as 'auto generated', which we can't accept. Please create your comment through the web interface."
     when Gitlab::Email::Receiver::UserNotFoundError
       reason = "We couldn't figure out what user corresponds to the email. Please create your comment through the web interface."
+    when Gitlab::Email::Receiver::UserBlockedError
+      reason = "Your account has been blocked. If you believe this is in error, contact a staff member."
     when Gitlab::Email::Receiver::UserNotAuthorizedError
       reason = "You are not allowed to respond to the thread you are replying to. If you believe this is in error, contact a staff member."
     when Gitlab::Email::Receiver::NoteableNotFoundError

lib/gitlab/email/receiver.rb

@@ -8,6 +8,7 @@ module Gitlab
       class EmptyEmailError < ProcessingError; end
       class AutoGeneratedEmailError < ProcessingError; end
       class UserNotFoundError < ProcessingError; end
+      class UserBlockedError < ProcessingError; end
       class UserNotAuthorizedError < ProcessingError; end
       class NoteableNotFoundError < ProcessingError; end
       class InvalidNoteError < ProcessingError; end
@@ -27,6 +28,8 @@ module Gitlab
 
         raise UserNotFoundError unless author
 
+        raise UserBlockedError if author.blocked?
+
         project = sent_notification.project
 
         raise UserNotAuthorizedError unless project && author.can?(:create_note, project)

spec/lib/gitlab/email/receiver_spec.rb

@@ -58,6 +58,16 @@ describe Gitlab::Email::Receiver do
     end
   end
 
+  context "when the user has been blocked" do
+    before do
+      user.block
+    end
+
+    it "raises a UserBlockedError" do
+      expect { receiver.execute }.to raise_error(Gitlab::Email::Receiver::UserBlockedError)
+    end
+  end
+
   context "when the user is not authorized to create a note" do
     before do
       project.update_attribute(:visibility_level, Project::PRIVATE)