FIX: Can't update status_type of topic timers.

https://meta.discourse.org/t/topic-timers-internal-error-500/64805

app/models/topic.rb

@@ -988,9 +988,10 @@ SQL
   #  * based_on_last_post: True if time should be based on timestamp of the last post.
   #  * category_id: Category that the update will apply to.
   def set_or_create_timer(status_type, time, by_user: nil, timezone_offset: 0, based_on_last_post: false, category_id: SiteSetting.uncategorized_category_id)
-    topic_timer_options = { status_type: status_type, topic: self }
+    topic_timer_options = { topic: self }
     topic_timer_options.merge!(user: by_user) unless TopicTimer.public_types[status_type]
     topic_timer = TopicTimer.find_or_initialize_by(topic_timer_options)
+    topic_timer.status_type = status_type
 
     if time.blank?
       topic_timer.trash!(trashed_by: by_user || Discourse.system_user)

spec/models/topic_spec.rb

@@ -1267,6 +1267,16 @@ describe Topic do
       end
     end
 
+    it 'should allow status_type to be updated' do
+      Timecop.freeze do
+        topic_timer = closing_topic.set_or_create_timer(
+          TopicTimer.types[:publish_to_category], 72, by_user: admin
+        )
+
+        expect(topic_timer.execute_at).to eq(3.days.from_now)
+      end
+    end
+
     it "does not update topic's topic status created_at it was already set to close" do
       expect{
         closing_topic.set_or_create_timer(TopicTimer.types[:close], 14)

spec/models/topic_timer_spec.rb

@@ -260,7 +260,8 @@ RSpec.describe TopicTimer, type: :model do
       open_topic_timer = Fabricate(:topic_timer,
         status_type: described_class.types[:open],
         execute_at: Time.zone.now - 1.hour,
-        created_at: Time.zone.now - 2.hour
+        created_at: Time.zone.now - 2.hour,
+        topic: Fabricate(:topic, closed: true)
       )
 
       Fabricate(:topic_timer)