allow subclasses of ActiveModel::Serializer to override associations

Author: markus

lib/active_model/serializer.rb

@@ -199,8 +199,12 @@ def attributes(options = {})
       end
     end
 
+    def associations
+      self.class._associations.dup
+    end
+
     def each_association(&block)
-      self.class._associations.dup.each do |name, association_options|
+      associations.each do |name, association_options|
         next unless object
         association_value = send(name)
 

test/fixtures/poro.rb

@@ -102,6 +102,13 @@ def custom_options
   end
 end
 
+CustomizablePostSerializer = Class.new(PostSerializer) do
+  def associations
+    excludes = @options[:excludes] || []
+    super.except(*excludes)
+  end
+end
+
 SpammyPostSerializer = Class.new(ActiveModel::Serializer) do
   attributes :id
   has_many :related

test/serializers/associations_test.rb

@@ -145,6 +145,17 @@ def test_associations_custom_keys
         assert expected_association_keys.include? :writer
         assert expected_association_keys.include? :site
       end
+
+      def test_overriding_associations
+        serializer = CustomizablePostSerializer.new(@post, excludes: [:comments])
+
+        association_keys = []
+        serializer.each_association do |key, serializer, options|
+          association_keys << key
+        end
+
+        assert association_keys.exclude? :comments
+      end
     end
   end
 end