Remove deprecated automatic counter caches on has_many :through

activerecord/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Remove deprecated automatic counter caches on `has_many :through`.
+
+    *Rafael Mendonça França*
+
 *   Change the way in which callback chains can be halted.
 
     The preferred method to halt a callback chain from now on is to explicitly

activerecord/lib/active_record/associations/has_many_through_association.rb

@@ -49,16 +49,7 @@ def insert_record(record, validate = true, raise = false)
         end
 
         save_through_record(record)
-        if has_cached_counter? && !through_reflection_updates_counter_cache?
-          ActiveSupport::Deprecation.warn(<<-MSG.squish)
-            Automatic updating of counter caches on through associations has been
-            deprecated, and will be removed in Rails 5. Instead, please set the
-            appropriate `counter_cache` options on the `has_many` and `belongs_to`
-            for your associations to #{through_reflection.name}.
-          MSG
 
-          update_counter_in_database(1)
-        end
         record
       end
 
@@ -211,11 +202,6 @@ def find_target
         def invertible_for?(record)
           false
         end
-
-        def through_reflection_updates_counter_cache?
-          counter_name = cached_counter_attribute_name
-          inverse_updates_counter_named?(counter_name, through_reflection)
-        end
     end
   end
 end

activerecord/test/cases/associations/deprecated_counter_cache_on_has_many_through_test.rb

@@ -1,26 +0,0 @@
-require "cases/helper"
-
-class DeprecatedCounterCacheOnHasManyThroughTest < ActiveRecord::TestCase
-  class Post < ActiveRecord::Base
-    has_many :taggings, as: :taggable
-    has_many :tags, through: :taggings
-  end
-
-  class Tagging < ActiveRecord::Base
-    belongs_to :taggable, polymorphic: true
-    belongs_to :tag
-  end
-
-  class Tag < ActiveRecord::Base
-  end
-
-  test "counter caches are updated in the database if the belongs_to association doesn't specify a counter cache" do
-    post = Post.create!(title: 'Hello', body: 'World!')
-    assert_deprecated { post.tags << Tag.create!(name: 'whatever') }
-
-    assert_equal 1, post.tags.size
-    assert_equal 1, post.tags_count
-    assert_equal 1, post.reload.tags.size
-    assert_equal 1, post.reload.tags_count
-  end
-end