Avoid a subquery in updating counter cache

Since UPDATE with a subquery doesn't work on MySQL.

2 files changed, 8 insertions, 7 deletions

diff --git a/activerecord/lib/active_record/associations/builder/belongs_to.rb b/activerecord/lib/active_record/associations/builder/belongs_to.rb
index 852a858d9b..1dd6e5bed8 100644
--- a/activerecord/lib/active_record/associations/builder/belongs_to.rb
+++ b/activerecord/lib/active_record/associations/builder/belongs_to.rb
@@ -63,12 +63,7 @@ module ActiveRecord::Associations::Builder # :nodoc:
         private
           def counter_cache_target(reflection, model, foreign_key)
             primary_key = reflection.association_primary_key(model)
-
-            if primary_key == model.primary_key
-              foreign_key
-            else
-              model.unscoped.where!(primary_key => foreign_key)
-            end
+            model.unscoped.where!(primary_key => foreign_key)
           end
       end
     end
diff --git a/activerecord/lib/active_record/counter_cache.rb b/activerecord/lib/active_record/counter_cache.rb
index ee4f818cbf..faaedf1d4a 100644
--- a/activerecord/lib/active_record/counter_cache.rb
+++ b/activerecord/lib/active_record/counter_cache.rb
@@ -111,7 +111,13 @@ module ActiveRecord
           updates << sanitize_sql_for_assignment(touch_updates) unless touch_updates.empty?
         end
 
-        unscoped.where(primary_key => id).update_all updates.join(", ")
+        if id.is_a?(Relation) && self == id.klass
+          relation = id
+        else
+          relation = unscoped.where!(primary_key => id)
+        end
+
+        relation.update_all updates.join(", ")
       end
 
       # Increment a numeric field by one, via a direct SQL update.