From 87eadd09b9a988bc1d9b30d9a501ef7e3fc6bb87 Mon Sep 17 00:00:00 2001
From: Santiago Pastorino <santiago@wyeworks.com>
Date: Tue, 14 May 2013 16:20:51 -0700
Subject: [PATCH] serialize_ids doesn't use source serializer and it's object

---
 lib/active_model/serializer.rb              |  7 ++++++-
 lib/active_model/serializer/associations.rb | 23 +++++++--------------
 2 files changed, 13 insertions(+), 17 deletions(-)

diff --git a/lib/active_model/serializer.rb b/lib/active_model/serializer.rb
index c1cd49900..8aa8b7192 100644
--- a/lib/active_model/serializer.rb
+++ b/lib/active_model/serializer.rb
@@ -384,7 +384,12 @@ def include!(name, options={})
       association = association_class.new(name, self, options)
 
       if association.embed_ids?
-        node[association.key] = association.serialize_ids
+        node[association.key] =
+          if options[:embed_key] || self.respond_to?(name) || !self.object.respond_to?(association.id_key)
+            association.serialize_ids
+          else
+            self.object.read_attribute_for_serialization(association.id_key)
+          end
 
         if association.embed_in_root? && hash.nil?
           raise IncludeError.new(self.class, association.name)
diff --git a/lib/active_model/serializer/associations.rb b/lib/active_model/serializer/associations.rb
index 6b4460e6b..667774fb7 100644
--- a/lib/active_model/serializer/associations.rb
+++ b/lib/active_model/serializer/associations.rb
@@ -100,12 +100,8 @@ def serializables
         end
 
         def serialize_ids
-          if !options[:embed_key] && !source_serializer.respond_to?(@name.to_s) && source_serializer.object.respond_to?(id_key)
-            source_serializer.object.read_attribute_for_serialization(id_key)
-          else
-            associated_object.map do |item|
-              item.read_attribute_for_serialization(embed_key)
-            end
+          associated_object.map do |item|
+            item.read_attribute_for_serialization(embed_key)
           end
         end
       end
@@ -179,21 +175,16 @@ def serializables
         end
 
         def serialize_ids
-          if polymorphic?
-            if associated_object
+          if associated_object
+            id = associated_object.read_attribute_for_serialization(embed_key)
+            if polymorphic?
               {
                 :type => polymorphic_key,
-                :id => associated_object.read_attribute_for_serialization(embed_key)
+                :id => id
               }
             else
-              nil
+              id
             end
-          elsif !options[:embed_key] && !source_serializer.respond_to?(@name.to_s) && source_serializer.object.respond_to?(id_key)
-            source_serializer.object.read_attribute_for_serialization(id_key)
-          elsif associated_object
-            associated_object.read_attribute_for_serialization(embed_key)
-          else
-            nil
           end
         end
       end