FIX: Ensure calendar events are recreated when first post changes

lib/calendar.rb

@@ -22,17 +22,22 @@ module DiscourseCalendar
 
     def self.update(post)
       calendar = extract(post)
-
       return destroy(post) if calendar.size != 1
       calendar = calendar.first
 
       post.custom_fields[DiscourseCalendar::CALENDAR_CUSTOM_FIELD] = calendar.delete("type") || "dynamic"
       post.save_custom_fields
+
+      Post.where(topic_id: post.topic_id).each { |p| CalendarEvent.update(p) }
     end
 
     def self.destroy(post)
+      return if post.custom_fields[DiscourseCalendar::CALENDAR_CUSTOM_FIELD].blank?
+
       post.custom_fields.delete(DiscourseCalendar::CALENDAR_CUSTOM_FIELD)
       post.save_custom_fields
+
+      CalendarEvent.where(topic_id: post.topic_id).destroy_all
     end
   end
 end

spec/models/calendar_event_spec.rb

@@ -74,6 +74,17 @@ describe CalendarEvent do
     expect(post.deleted_at).to eq(nil)
   end
 
+  it "recreates calendar event for all posts" do
+    post = create_post(raw: 'Rome [date="2018-06-05" time="10:20:00"]', topic: calendar_post.topic)
+    expect(CalendarEvent.count).to eq(1)
+
+    PostDestroyer.new(Discourse.system_user, calendar_post.reload).destroy
+    expect(CalendarEvent.count).to eq(0)
+
+    PostDestroyer.new(Discourse.system_user, calendar_post.reload).recover
+    expect(CalendarEvent.count).to eq(1)
+  end
+
   describe "all day event site settings" do
     before do
       SiteSetting.all_day_event_start_time = "06:30"