From 75ef18c67c29b1b51314b6c8a963cee53394080b Mon Sep 17 00:00:00 2001 From: Dana Sherson Date: Fri, 20 Apr 2018 10:56:49 +1000 Subject: Can preload associations through polymorphic associations --- activerecord/CHANGELOG.md | 4 +++ .../lib/active_record/associations/preloader.rb | 25 +++++++++++-------- activerecord/test/cases/associations/eager_test.rb | 29 ++++++++++++++++++++++ activerecord/test/fixtures/sponsors.yml | 3 +++ 4 files changed, 51 insertions(+), 10 deletions(-) diff --git a/activerecord/CHANGELOG.md b/activerecord/CHANGELOG.md index c4a4e767cd..0d8fa48235 100644 --- a/activerecord/CHANGELOG.md +++ b/activerecord/CHANGELOG.md @@ -1,3 +1,7 @@ +* Add support to preload associations of polymorphic associations when not all the records have the requested associations. + + *Dana Sherson* + * Add `touch_all` method to `ActiveRecord::Relation`. Example: diff --git a/activerecord/lib/active_record/associations/preloader.rb b/activerecord/lib/active_record/associations/preloader.rb index 1ea0aeac3a..5c2ac5b374 100644 --- a/activerecord/lib/active_record/associations/preloader.rb +++ b/activerecord/lib/active_record/associations/preloader.rb @@ -98,26 +98,30 @@ module ActiveRecord private # Loads all the given data into +records+ for the +association+. - def preloaders_on(association, records, scope) + def preloaders_on(association, records, scope, polymorphic_parent = false) case association when Hash - preloaders_for_hash(association, records, scope) + preloaders_for_hash(association, records, scope, polymorphic_parent) when Symbol - preloaders_for_one(association, records, scope) + preloaders_for_one(association, records, scope, polymorphic_parent) when String - preloaders_for_one(association.to_sym, records, scope) + preloaders_for_one(association.to_sym, records, scope, polymorphic_parent) else raise ArgumentError, "#{association.inspect} was not recognized for preload" end end - def preloaders_for_hash(association, records, scope) + def preloaders_for_hash(association, records, scope, polymorphic_parent) association.flat_map { |parent, child| - loaders = preloaders_for_one parent, records, scope + loaders = preloaders_for_one parent, records, scope, polymorphic_parent recs = loaders.flat_map(&:preloaded_records).uniq + + reflection = records.first.class._reflect_on_association(parent) + polymorphic_parent = reflection && reflection.options[:polymorphic] + loaders.concat Array.wrap(child).flat_map { |assoc| - preloaders_on assoc, recs, scope + preloaders_on assoc, recs, scope, polymorphic_parent } loaders } @@ -135,8 +139,8 @@ module ActiveRecord # Additionally, polymorphic belongs_to associations can have multiple associated # classes, depending on the polymorphic_type field. So we group by the classes as # well. - def preloaders_for_one(association, records, scope) - grouped_records(association, records).flat_map do |reflection, klasses| + def preloaders_for_one(association, records, scope, polymorphic_parent) + grouped_records(association, records, polymorphic_parent).flat_map do |reflection, klasses| klasses.map do |rhs_klass, rs| loader = preloader_for(reflection, rs).new(rhs_klass, rs, reflection, scope) loader.run self @@ -145,10 +149,11 @@ module ActiveRecord end end - def grouped_records(association, records) + def grouped_records(association, records, polymorphic_parent) h = {} records.each do |record| next unless record + next if polymorphic_parent && !record.class._reflect_on_association(association) assoc = record.association(association) next unless assoc.klass klasses = h[assoc.reflection] ||= {} diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb index 6e0cf30092..f46be8734b 100644 --- a/activerecord/test/cases/associations/eager_test.rb +++ b/activerecord/test/cases/associations/eager_test.rb @@ -1515,6 +1515,35 @@ class EagerAssociationTest < ActiveRecord::TestCase Author.preload(:readonly_comments).first! end + test "preloading through a polymorphic association doesn't require the association to exist" do + sponsors = [] + assert_queries 5 do + sponsors = Sponsor.where(sponsorable_id: 1).preload(sponsorable: [:post, :membership]).to_a + end + # check the preload worked + assert_queries 0 do + sponsors.map(&:sponsorable).map { |s| s.respond_to?(:posts) ? s.post.author : s.membership } + end + end + + test "preloading a regular association through a polymorphic association doesn't require the association to exist on all types" do + sponsors = [] + assert_queries 6 do + sponsors = Sponsor.where(sponsorable_id: 1).preload(sponsorable: [{ post: :first_comment }, :membership]).to_a + end + # check the preload worked + assert_queries 0 do + sponsors.map(&:sponsorable).map { |s| s.respond_to?(:posts) ? s.post.author : s.membership } + end + end + + test "preloading a regular association with a typo through a polymorphic association still raises" do + # this test contains an intentional typo of first -> fist + assert_raises(ActiveRecord::AssociationNotFoundError) do + Sponsor.where(sponsorable_id: 1).preload(sponsorable: [{ post: :fist_comment }, :membership]).to_a + end + end + private def find_all_ordered(klass, include = nil) klass.order("#{klass.table_name}.#{klass.primary_key}").includes(include).to_a diff --git a/activerecord/test/fixtures/sponsors.yml b/activerecord/test/fixtures/sponsors.yml index 2da541c539..02ddb8dd38 100644 --- a/activerecord/test/fixtures/sponsors.yml +++ b/activerecord/test/fixtures/sponsors.yml @@ -10,3 +10,6 @@ crazy_club_sponsor_for_groucho: sponsor_club: crazy_club sponsorable_id: 3 sponsorable_type: Member +sponsor_for_author_david: + sponsorable_id: 1 + sponsorable_type: Author -- cgit v1.2.3