pull preloading behavior in to the collection renderer

actionview/lib/action_view/renderer/collection_renderer.rb

@@ -70,6 +70,24 @@ def each_with_info
       end
     end
 
+    class PreloadCollectionIterator < SameCollectionIterator # :nodoc:
+      def initialize(collection, path, variables, relation)
+        super(collection, path, variables)
+        relation.skip_preloading! unless relation.loaded?
+        @relation = relation
+      end
+
+      def from_collection(collection)
+        self.class.new(collection, @path, @variables, @relation)
+      end
+
+      def each_with_info
+        return super unless block_given?
+        @relation.preload_associations(@collection)
+        super
+      end
+    end
+
     class MixedCollectionIterator < CollectionIterator # :nodoc:
       def initialize(collection, paths)
         super(collection)
@@ -84,7 +102,13 @@ def each_with_info
 
     def render_collection_with_partial(collection, partial, context, block)
       iter_vars  = retrieve_variable(partial)
-      collection = SameCollectionIterator.new(collection, partial, iter_vars)
+
+      collection = if collection.respond_to?(:preload_associations)
+        PreloadCollectionIterator.new(collection, partial, iter_vars, collection)
+      else
+        SameCollectionIterator.new(collection, partial, iter_vars)
+      end
+
 
       template = find_template(partial, @locals.keys + iter_vars)
 

actionview/test/activerecord/multifetch_cache_test.rb

@@ -1,9 +1,6 @@
 # frozen_string_literal: true
 
 require "active_record_unit"
-require "active_record/railties/collection_cache_association_loading"
-
-ActionView::CollectionRenderer.prepend(ActiveRecord::Railties::CollectionCacheAssociationLoading)
 
 class MultifetchCacheTest < ActiveRecordTestCase
   fixtures :topics, :replies

activerecord/lib/active_record/railtie.rb

@@ -221,13 +221,6 @@ class Railtie < Rails::Railtie # :nodoc:
       end
     end
 
-    initializer "active_record.collection_cache_association_loading" do
-      require "active_record/railties/collection_cache_association_loading"
-      ActiveSupport.on_load(:action_view) do
-        ActionView::CollectionRenderer.prepend(ActiveRecord::Railties::CollectionCacheAssociationLoading)
-      end
-    end
-
     initializer "active_record.set_reloader_hooks" do
       ActiveSupport.on_load(:active_record) do
         ActiveSupport::Reloader.before_class_unload do