Bugfix/redefine associations on inherited serializers

lib/active_model/serializer/associations.rb

@@ -13,7 +13,7 @@ module Associations
       included do
         with_options instance_writer: false, instance_reader: true do |serializer|
           serializer.class_attribute :_reflections
-          self._reflections ||= []
+          self._reflections ||= {}
         end
 
         extend ActiveSupport::Autoload
@@ -74,7 +74,8 @@ def has_one(name, options = {}, &block) # rubocop:disable Style/PredicateName
         # @api private
         #
         def associate(reflection)
-          self._reflections << reflection
+          key = reflection.options[:key]
+          key ? self._reflections[key] = reflection : self._reflections[reflection.name] = reflection
         end
       end
 
@@ -86,7 +87,7 @@ def associations(include_directive = ActiveModelSerializers.default_include_dire
         return unless object
 
         Enumerator.new do |y|
-          self.class._reflections.each do |reflection|
+          self.class._reflections.values.each do |reflection|
             next if reflection.excluded?(self)
             key = reflection.options.fetch(:key, reflection.name)
             next unless include_directive.key?(key)

test/serializers/association_macros_test.rb

@@ -11,7 +11,7 @@ class AssociationsTestSerializer < Serializer
       end
 
       def before_setup
-        @reflections = AssociationsTestSerializer._reflections
+        @reflections = AssociationsTestSerializer._reflections.values
       end
 
       def test_has_one_defines_reflection

test/serializers/associations_test.rb

@@ -1,5 +1,5 @@
 require 'test_helper'
-
+require 'pry'
 module ActiveModel
   class Serializer
     class AssociationsTest < ActiveSupport::TestCase
@@ -104,13 +104,13 @@ def test_associations_inheritance_with_new_association
         end
 
         assert(
-          PostSerializer._reflections.all? do |reflection|
-            inherited_klass._reflections.include?(reflection)
+          PostSerializer._reflections.values.all? do |reflection|
+            inherited_klass._reflections.values.include?(reflection)
           end
         )
 
         assert(
-          inherited_klass._reflections.any? do |reflection|
+          inherited_klass._reflections.values.any? do |reflection|
             reflection.name == :top_comments
           end
         )
@@ -290,6 +290,48 @@ def test_illegal_conditional_associations
           assert_match(/:if should be a Symbol, String or Proc/, exception.message)
         end
       end
+
+      class InheritedSerializerTest < ActiveSupport::TestCase
+        InheritedPostSerializer = Class.new(PostSerializer) do
+          belongs_to :author, polymorphic: true
+          has_many :comments, key: :reviews
+        end
+
+        InheritedAuthorSerializer = Class.new(AuthorSerializer) do
+          has_many :posts, polymorphic: true
+          has_one :roles, key: :new_roles
+          has_one :bio, polymorphic: true
+        end
+
+        def setup
+          @author = Author.new(name: 'Steve K.')
+          @author.bio = Bio.new(id: 1, content: 'AMS Contributor')
+          @blog = Blog.new(name: 'AMS Blog')
+          @post = Post.new(title: 'New Post', body: 'Body')
+          @post.blog = @blog
+          @post.author = @author
+          @post_serializer = PostSerializer.new(@post, custom_options: true)
+          @author_serializer = AuthorSerializer.new(@author)
+          @inherited_post_serializer = InheritedPostSerializer.new(@post, custom_options: true)
+          @inherited_author_serializer = InheritedAuthorSerializer.new(@author)
+        end
+
+        def test_redefined_has_many_and_has_one
+          author_associations = @author_serializer.associations.to_a
+          inherited_author_associations = @inherited_author_serializer.associations.to_a
+          assert_equal(@author_serializer.associations.count, 3)
+          assert_equal(@inherited_author_serializer.associations.count, 4)
+          assert_equal((author_associations - inherited_author_associations).count, 2)
+        end
+
+        def test_redefined_belongs_to
+          post_associations = @post_serializer.associations.to_a
+          inherited_post_associations = @inherited_post_serializer.associations.to_a
+          assert_equal(@post_serializer.associations.count, 3)
+          assert_equal(@inherited_post_serializer.associations.count, 4)
+          assert_equal((post_associations - inherited_post_associations).count, 2)
+        end
+      end
     end
   end
 end