merge multiple nested associations

.gitignore

@@ -17,3 +17,4 @@ test/version_tmp
 tmp
 *.swp
 .ruby-version
+vendor/bundle

.travis.yml

@@ -11,17 +11,18 @@ rvm:
 
 sudo: false
 
-install:
-  - bundle install --retry=3
+install: bundle install --path=vendor/bundle --retry=3 --jobs=3
+cache:
+  directories:
+    - vendor/bundle
 
 env:
-  - "RAILS_VERSION=3.2.17"
-  - "RAILS_VERSION=4.0.3"
-  - "RAILS_VERSION=4.1.0"
+  - "RAILS_VERSION=4.0"
+  - "RAILS_VERSION=4.1"
+  - "RAILS_VERSION=4.2"
   - "RAILS_VERSION=master"
 
 matrix:
   allow_failures:
     - rvm: ruby-head
     - env: "RAILS_VERSION=master"
-

Gemfile

@@ -2,25 +2,47 @@ source 'https://rubygems.org'
 
 gemspec
 
-platforms :ruby do
-  # sqlite3 1.3.9 does not work with rubinius 2.2.5:
-  # https://github.com/sparklemotion/sqlite3-ruby/issues/122
-  gem 'sqlite3', '1.3.8'
+version = ENV["RAILS_VERSION"] || "4.2"
+
+if version == 'master'
+  gem 'rack', github: 'rack/rack'
+  git 'https://github.com/rails/rails.git' do
+    gem 'railties'
+    gem 'activesupport'
+    gem 'activemodel'
+    gem 'actionpack'
+    # Rails 5
+    gem 'actionview'
+  end
+  # Rails 5
+  gem 'rails-controller-testing', github: 'rails/rails-controller-testing'
+else
+  gem_version = "~> #{version}.0"
+  gem 'railties', gem_version
+  gem 'activesupport', gem_version
+  gem 'activemodel', gem_version
+  gem 'actionpack', gem_version
 end
 
-platforms :jruby do
-  gem 'activerecord-jdbcsqlite3-adapter'
+if RUBY_VERSION < '2'
+  gem 'mime-types', [ '>= 2.6.2', '< 3' ]
 end
 
-version = ENV["RAILS_VERSION"] || "4.0.2"
-rails = case version
-        when "master"
-          {:github => "rails/rails"}
-        else
-          "~> #{version}"
-        end
-gem "rails", rails
+# https://github.com/bundler/bundler/blob/89a8778c19269561926cea172acdcda241d26d23/lib/bundler/dependency.rb#L30-L54
+@windows_platforms = [:mswin, :mingw, :x64_mingw]
 
-if version < "4"
-  gem "minitest", "~> 4.7.5"
+# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
+gem 'tzinfo-data', platforms: (@windows_platforms + [:jruby])
+
+group :test do
+  gem 'activerecord'
+  gem 'sqlite3',                          platform: (@windows_platforms + [:ruby])
+  gem 'activerecord-jdbcsqlite3-adapter', platform: :jruby
+
+  gem 'codeclimate-test-reporter', require: false
+  gem 'simplecov', '~> 0.10', require: false, group: :development
+end
+
+group :development, :test do
+  gem 'rubocop', '~> 0.34.0', require: false
 end

appveyor.yml

@@ -0,0 +1,27 @@
+version: '{build}'
+
+skip_tags: true
+
+environment:
+  matrix:
+    - ruby_version: "200"
+    - ruby_version: "200-x64"
+    - ruby_version: "21"
+    - ruby_version: "21-x64"
+
+cache:
+  - vendor/bundle
+
+install:
+  - SET PATH=C:\Ruby%ruby_version%\bin;%PATH%
+  - ruby --version
+  - gem --version
+  - gem install bundler
+  - bundler --version
+  - bundle platform
+  - bundle install --path=vendor/bundle --retry=3 --jobs=3
+
+test_script:
+  - bundle exec rake test
+
+build: off

lib/active_model/serializer.rb

@@ -205,7 +205,11 @@ end
           # we must do this always because even if the current association is not
           # embeded in root, it might have its own associations that are embeded in root
           hash.merge!(association_serializer.embedded_in_root_associations) do |key, oldval, newval|
-            oldval.merge(newval) { |_, oldval, newval| [oldval, newval].flatten.uniq }
+            if oldval.respond_to?(:to_ary)
+              [oldval, newval].flatten.uniq
+            else
+              oldval.merge(newval) { |_, oldval, newval| [oldval, newval].flatten.uniq }
+            end
           end
 
           if association.embed_in_root?

test/fixtures/poro.rb

@@ -53,6 +53,26 @@ class SpecialPost < Post
   end
 end
 
+class Type < Model
+end
+
+class SelfReferencingUser < Model
+  def type
+    @type ||= Type.new(name: 'N1')
+  end
+  def parent
+    @parent ||= SelfReferencingUserParent.new(name: 'N1')
+  end
+end
+
+class SelfReferencingUserParent < Model
+  def type
+    @type ||= Type.new(name: 'N2')
+  end
+  def parent
+  end
+end
+
 class Comment < Model
 end
 
@@ -87,6 +107,22 @@ class UserSerializer < ActiveModel::Serializer
   has_one :profile
 end
 
+class TypeSerializer < ActiveModel::Serializer
+  attributes :name
+end
+
+class SelfReferencingUserParentSerializer < ActiveModel::Serializer
+  attributes :name
+  has_one :type, serializer: TypeSerializer, embed: :ids, include: true
+end
+
+class SelfReferencingUserSerializer < ActiveModel::Serializer
+  attributes :name
+
+  has_one :type, serializer: TypeSerializer, embed: :ids, include: true
+  has_one :parent, serializer: SelfReferencingUserSerializer, embed: :ids, include: true
+end
+
 class UserInfoSerializer < ActiveModel::Serializer
   has_one :user, serializer: UserSerializer
 end
@@ -176,7 +212,7 @@ end
 
 class NameKeyPostSerializer < ActiveModel::Serializer
   attributes :title, :body
-  
+
   has_many :comments
 end
 

test/unit/active_model/serializer/associations_test.rb

@@ -14,6 +14,36 @@ module ActiveModel
         assert_equal([:comments],
                      another_inherited_serializer_klass._associations.keys)
       end
+      def test_multiple_nested_associations
+        parent = SelfReferencingUserParent.new(name: "The Parent")
+        child = SelfReferencingUser.new(name: "The child", parent: parent)
+        self_referencing_user_serializer = SelfReferencingUserSerializer.new(child)
+        result = self_referencing_user_serializer.as_json
+        expected_result = {
+          "self_referencing_user"=>{
+            :name=>"The child",
+            "type_id"=>child.type.object_id,
+            "parent_id"=>child.parent.object_id
+
+          },
+          "types"=>[
+            {
+              :name=>"N1",
+            },
+            {
+              :name=>"N2",
+            }
+          ],
+          "parents"=>[
+            {
+              :name=>"N1",
+              "type_id"=>child.parent.type.object_id,
+              "parent_id"=>nil
+            }
+          ]
+        }
+        assert_equal(expected_result, result)
+      end
     end
   end
 end