FIX: auto-closing attribution when a TL4 user auto-closes a topic

app/models/topic.rb

@@ -797,10 +797,10 @@ class Topic < ActiveRecord::Base
       else
         self.auto_close_started_at ||= Time.zone.now
       end
-      if by_user.try(:staff?)
+      if by_user.try(:staff?) || by_user.try(:trust_level) == TrustLevel[4]
         self.auto_close_user = by_user
       else
-        self.auto_close_user ||= (self.user.staff? ? self.user : Discourse.system_user)
+        self.auto_close_user ||= (self.user.staff? || self.user.trust_level == TrustLevel[4] ? self.user : Discourse.system_user)
       end
     end
 

spec/models/topic_spec.rb

@@ -1078,6 +1078,7 @@ describe Topic do
     let(:topic)         { Fabricate.build(:topic) }
     let(:closing_topic) { Fabricate.build(:topic, auto_close_hours: 5, auto_close_at: 5.hours.from_now, auto_close_started_at: 5.hours.from_now) }
     let(:admin)         { Fabricate.build(:user, id: 123) }
+    let(:trust_level_4) { Fabricate.build(:trust_level_4) }
 
     before { Discourse.stubs(:system_user).returns(admin) }
 
@@ -1131,17 +1132,22 @@ describe Topic do
       end
     end
 
-    it 'sets auto_close_user to given user if it is a staff user' do
+    it 'sets auto_close_user to given user if it is a staff or TL4 user' do
       topic.set_auto_close(3, admin)
       expect(topic.auto_close_user_id).to eq(admin.id)
     end
 
-    it 'sets auto_close_user to system user if given user is not staff' do
+    it 'sets auto_close_user to given user if it is a TL4 user' do
+      topic.set_auto_close(3, trust_level_4)
+      expect(topic.auto_close_user_id).to eq(trust_level_4.id)
+    end
+
+    it 'sets auto_close_user to system user if given user is not staff or a TL4 user' do
       topic.set_auto_close(3, Fabricate.build(:user, id: 444))
       expect(topic.auto_close_user_id).to eq(admin.id)
     end
 
-    it 'sets auto_close_user to system_user if user is not given and topic creator is not staff' do
+    it 'sets auto_close_user to system user if user is not given and topic creator is not staff nor TL4 user' do
       topic.set_auto_close(3)
       expect(topic.auto_close_user_id).to eq(admin.id)
     end
@@ -1152,6 +1158,12 @@ describe Topic do
       expect(staff_topic.auto_close_user_id).to eq(999)
     end
 
+    it 'sets auto_close_user to topic creator if it is a TL4 user' do
+      tl4_topic = Fabricate.build(:topic, user: Fabricate.build(:trust_level_4, id: 998))
+      tl4_topic.set_auto_close(3)
+      expect(tl4_topic.auto_close_user_id).to eq(998)
+    end
+
     it 'clears auto_close_at if arg is nil' do
       closing_topic.set_auto_close(nil)
       expect(closing_topic.auto_close_at).to be_nil