FEATURE: automatically archive welcome messages for site_contact_user

This de-clutters the sent messages box for site_contact_user, making it again usable

db/migrate/20160110053003_archive_system_messages_with_no_replies.rb

@@ -0,0 +1,24 @@
+class ArchiveSystemMessagesWithNoReplies < ActiveRecord::Migration
+  def up
+    # backdate archival of system messages send on behalf of site_contact_user
+    execute <<SQL
+
+    INSERT INTO user_archived_messages (user_id, topic_id, created_at, updated_at)
+    SELECT p.user_id, p.topic_id, p.created_at, p.updated_at
+    FROM posts p
+    JOIN topics t ON t.id = p.topic_id
+    LEFT JOIN user_archived_messages um ON um.user_id = p.user_id AND um.topic_id = p.topic_id
+    WHERE t.subtype = 'system_message' AND
+          t.posts_count = 1 AND
+          t.archetype = 'private_message' AND
+          um.id IS NULL AND
+          p.user_id IS NOT NULL AND
+          p.topic_id IS NOT NULL AND
+          p.post_number = 1
+SQL
+
+  end
+
+  def down
+  end
+end

lib/system_message.rb

@@ -23,12 +23,17 @@ class SystemMessage
     title = I18n.t("system_messages.#{type}.subject_template", params)
     raw = I18n.t("system_messages.#{type}.text_body_template", params)
 
-    PostCreator.create(Discourse.site_contact_user,
+    post = PostCreator.create(Discourse.site_contact_user,
                        title: title,
                        raw: raw,
                        archetype: Archetype.private_message,
                        target_usernames: @recipient.username,
                        subtype: TopicSubtype.system_message)
+
+
+    UserArchivedMessage.create!(user: Discourse.site_contact_user, topic: post.topic)
+
+    post
   end
 
   def create_from_system_user(type, params = {})

spec/components/system_message_spec.rb

@@ -4,22 +4,27 @@ require 'topic_subtype'
 
 describe SystemMessage do
 
-  let!(:admin) { Fabricate(:admin) }
 
   context 'send' do
 
-    let(:user) { Fabricate(:user) }
-    let(:system_message) { SystemMessage.new(user) }
-    let(:post) { system_message.create(:welcome_invite) }
-    let(:topic) { post.topic }
-
     it 'should create a post correctly' do
+
+      admin = Fabricate(:admin)
+      user = Fabricate(:user)
+      SiteSetting.site_contact_username = admin.username
+      system_message = SystemMessage.new(user)
+      post = system_message.create(:welcome_invite)
+      topic = post.topic
+
       expect(post).to be_present
       expect(post).to be_valid
       expect(topic).to be_private_message
       expect(topic).to be_valid
       expect(topic.subtype).to eq(TopicSubtype.system_message)
       expect(topic.allowed_users.include?(user)).to eq(true)
+      expect(topic.allowed_users.include?(admin)).to eq(true)
+
+      expect(UserArchivedMessage.where(user_id: admin.id, topic_id: topic.id).length).to eq(1)
     end
   end