Store options in array serializers

lib/active_model/serializer.rb

@@ -176,19 +176,20 @@ def attributes(options = {})
     end
 
     def each_association(&block)
-      self.class._associations.dup.each do |name, options|
+      self.class._associations.dup.each do |name, association_options|
         next unless object
 
         association = object.send(name)
         association_value = send(name)
-        serializer_class = ActiveModel::Serializer.serializer_for(association, options)
+        serializer_class = ActiveModel::Serializer.serializer_for(association, association_options)
+
         serializer = serializer_class.new(
           association_value,
-          serializer_from_options(options)
+          serializer_from_options(association_options).merge(options)
         ) if serializer_class
 
         if block_given?
-          block.call(name, serializer, options[:association_options])
+          block.call(name, serializer, association_options[:association_options])
         end
       end
     end

lib/active_model/serializer/array_serializer.rb

@@ -7,12 +7,14 @@ class ArraySerializer
       attr_reader :meta, :meta_key
 
       def initialize(objects, options = {})
+        options.merge!(root: nil)
+
         @objects = objects.map do |object|
           serializer_class = options.fetch(
             :serializer,
             ActiveModel::Serializer.serializer_for(object)
           )
-          serializer_class.new(object)
+          serializer_class.new(object, options)
         end
         @meta     = options[:meta]
         @meta_key = options[:meta_key]

test/array_serializer_test.rb

@@ -6,7 +6,7 @@ class ArraySerializerTest < Minitest::Test
       def setup
         @comment = Comment.new
         @post = Post.new
-        @serializer = ArraySerializer.new([@comment, @post])
+        @serializer = ArraySerializer.new([@comment, @post], {some: :options})
       end
 
       def test_respond_to_each
@@ -21,6 +21,8 @@ def test_each_object_should_be_serialized_with_appropriate_serializer
 
         assert_kind_of PostSerializer, serializers.last
         assert_kind_of Post, serializers.last.object
+
+        assert_equal serializers.last.custom_options[:some], :options
       end
     end
   end

test/fixtures/poro.rb

@@ -78,6 +78,10 @@ module Spam; end
   def blog
     Blog.new(id: 999, name: "Custom blog")
   end
+
+  def custom_options
+    options
+  end
 end
 
 SpammyPostSerializer = Class.new(ActiveModel::Serializer) do
@@ -95,6 +99,10 @@ def self.root_name
 
   belongs_to :post
   belongs_to :author
+
+  def custom_options
+    options
+  end
 end
 
 AuthorSerializer = Class.new(ActiveModel::Serializer) do

test/serializers/associations_test.rb

@@ -37,7 +37,7 @@ def setup
         @post.author = @author
         @author.posts = [@post]
 
-        @post_serializer = PostSerializer.new(@post)
+        @post_serializer = PostSerializer.new(@post, {custom_options: true})
         @author_serializer = AuthorSerializer.new(@author)
         @comment_serializer = CommentSerializer.new(@comment)
       end
@@ -65,6 +65,14 @@ def test_has_many_and_has_one
         end
       end
 
+      def test_serializer_options_are_passed_into_associations_serializers
+        @post_serializer.each_association do |name, association|
+          if name == :comments
+            assert association.first.custom_options[:custom_options]
+          end
+        end
+      end
+
       def test_belongs_to
         assert_equal(
           { post: { type: :belongs_to, association_options: {} },