FIX: update group.has_messages field weekly

app/models/group.rb

@@ -308,6 +308,7 @@ class Group < ActiveRecord::Base
   def self.ensure_consistency!
     reset_all_counters!
     refresh_automatic_groups!
+    refresh_has_messages!
   end
 
   def self.reset_all_counters!
@@ -331,6 +332,18 @@ class Group < ActiveRecord::Base
     args.each { |group| refresh_automatic_group!(group) }
   end
 
+  def self.refresh_has_messages!
+    exec_sql <<-SQL
+      UPDATE groups g SET has_messages = false
+      WHERE NOT EXISTS (SELECT tg.id
+                          FROM topic_allowed_groups tg
+                    INNER JOIN topics t ON t.id = tg.topic_id
+                         WHERE tg.group_id = g.id
+                           AND t.deleted_at IS NULL)
+      AND g.has_messages = true
+    SQL
+  end
+
   def self.ensure_automatic_groups!
     AUTO_GROUPS.each_key do |name|
       refresh_automatic_group!(name) unless lookup_group(name)

spec/models/group_spec.rb

@@ -577,4 +577,21 @@ describe Group do
       expect(group.group_users.map(&:user_id)).to contain_exactly(user.id, admin.id)
     end
   end
+
+  it "Correctly updates has_messages" do
+    group = Fabricate(:group, has_messages: true)
+    topic = Fabricate(:private_message_topic)
+
+    # when group message is not present
+    Group.refresh_has_messages!
+    group.reload
+    expect(group.has_messages?).to eq false
+
+    # when group message is present
+    group.update!(has_messages: true)
+    TopicAllowedGroup.create!(topic_id: topic.id, group_id: group.id)
+    Group.refresh_has_messages!
+    group.reload
+    expect(group.has_messages?).to eq true
+  end
 end