Revert "Don't guard against `touch: []`."

`timestamp_attributes_for_updates_in_model` returns an empty
array when a model has no `updated_at` or `updated_on`.

So my previously thought uncommon case is a lot more likely
now.

This reverts commit a0a1ede8c2eb6436571eae8778033162d1f9dcc3.

1 files changed, 2 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index 93b9371206..cbd71a3779 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -105,7 +105,8 @@ module ActiveRecord
         end
 
         if touch
-          updates << sanitize_sql_for_assignment(touch_updates(touch))
+          touch_updates = touch_updates(touch)
+          updates << sanitize_sql_for_assignment(touch_updates) unless touch_updates.empty?
         end
 
         unscoped.where(primary_key => id).update_all updates.join(", ")