Add support for eager loading all rich text associations at once (#39397)

* Add `with_all_rich_text` method to eager load all RichText models at once

* Update actiontext/test/test_helper.rb

Co-authored-by: Kasper Timm Hansen <kaspth@gmail.com>

* Update actiontext/lib/action_text/attribute.rb

Co-authored-by: Kasper Timm Hansen <kaspth@gmail.com>

Co-authored-by: Kasper Timm Hansen <kaspth@gmail.com>

actiontext/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Add `with_all_rich_text` method to eager load all rich text associations on a model at once
+
+    *Matt Swanson*, *DHH*
+
 ## Rails 6.1.0.rc1 (November 02, 2020) ##
 
 *   Declare `ActionText::FixtureSet.attachment` to generate an

actiontext/lib/action_text/attribute.rb

@@ -45,6 +45,16 @@ module ActionText
         scope :"with_rich_text_#{name}", -> { includes("rich_text_#{name}") }
         scope :"with_rich_text_#{name}_and_embeds", -> { includes("rich_text_#{name}": { embeds_attachments: :blob }) }
       end
+
+      # Eager load all dependent RichText models in bulk.
+      def with_all_rich_text
+        eager_load(rich_text_association_names)
+      end
+
+      private
+        def rich_text_association_names
+          reflect_on_all_associations(:has_one).collect(&:name).select { |n| n.start_with?("rich_text_") }
+        end
     end
   end
 end

actiontext/test/test_helper.rb

@@ -22,6 +22,23 @@ if ActiveSupport::TestCase.respond_to?(:fixture_path=)
 end
 
 class ActiveSupport::TestCase
+  def assert_queries(expected_count)
+    ActiveRecord::Base.connection.materialize_transactions
+
+    queries = []
+    ActiveSupport::Notifications.subscribe("sql.active_record") do |*, sql:, name:, **|
+      queries << sql unless %w[ SCHEMA TRANSACTION ].include?(name)
+    end
+
+    yield.tap do
+      assert_equal expected_count, queries.size, "#{queries.size} instead of #{expected_count} queries were executed. #{queries.inspect}"
+    end
+  end
+
+  def assert_no_queries(&block)
+    assert_queries(0, &block)
+  end
+
   private
     def create_file_blob(filename:, content_type:, metadata: nil)
       ActiveStorage::Blob.create_and_upload! io: file_fixture(filename).open, filename: filename, content_type: content_type, metadata: metadata

actiontext/test/unit/model_test.rb

@@ -86,4 +86,23 @@ class ActionText::ModelTest < ActiveSupport::TestCase
       assert_kind_of ActionText::RichText, message.content
     end
   end
+
+  test "eager loading" do
+    Message.create!(subject: "Subject", content: "<h1>Content</h1>")
+
+    message = assert_queries(2) { Message.with_rich_text_content.last }
+    assert_no_queries do
+      assert_equal "Content", message.content.to_plain_text
+    end
+  end
+
+  test "eager loading all rich text" do
+    Message.create!(subject: "Subject", content: "<h1>Content</h1>", body: "<h2>Body</h2>")
+
+    message = assert_queries(1) { Message.with_all_rich_text.last }
+    assert_no_queries do
+      assert_equal "Content", message.content.to_plain_text
+      assert_equal "Body", message.body.to_plain_text
+    end
+  end
 end