Fix #955

lib/active_model/serializer.rb

@@ -206,10 +206,22 @@ module ActiveModel
         serializer_class = ActiveModel::Serializer.serializer_for(association_value, association_options)
 
         if serializer_class
-          serializer = serializer_class.new(
-            association_value,
-            options.except(:serializer).merge(serializer_from_options(association_options))
-          )
+          begin
+            serializer = serializer_class.new(
+              association_value,
+              options.except(:serializer).merge(serializer_from_options(association_options))
+            )
+          rescue NoMethodError
+            # 1. Failure to serialize an element in a collection, e.g. [ {hi: "Steve" } ] will fail
+            #    with NoMethodError when the ArraySerializer finds no serializer for the hash { hi: "Steve" },
+            #    and tries to call new on that nil.
+            # 2. Convert association_value to hash using implicit as_json
+            # 3. Set as virtual value (serializer is nil)
+            # 4. Consider warning when this happens
+            virtual_value = association_value
+            virtual_value = virtual_value.as_json if virtual_value.respond_to?(:as_json)
+            association_options[:association_options][:virtual_value] = virtual_value
+          end
         elsif !association_value.nil? && !association_value.instance_of?(Object)
           association_options[:association_options][:virtual_value] = association_value
         end

test/adapter/json/has_many_test.rb

@@ -8,7 +8,7 @@ module ActiveModel
           def setup
             ActionController::Base.cache_store.clear
             @author = Author.new(id: 1, name: 'Steve K.')
-            @post = Post.new(title: 'New Post', body: 'Body')
+            @post = Post.new(id: 42, title: 'New Post', body: 'Body')
             @first_comment = Comment.new(id: 1, body: 'ZOMG A COMMENT')
             @second_comment = Comment.new(id: 2, body: 'ZOMG ANOTHER COMMENT')
             @post.comments = [@first_comment, @second_comment]
@@ -19,22 +19,26 @@ module ActiveModel
             @post.blog = @blog
             @tag = Tag.new(id: 1, name: "#hash_tag")
             @post.tags = [@tag]
-
-            @serializer = PostSerializer.new(@post)
-            @adapter = ActiveModel::Serializer::Adapter::Json.new(@serializer)
           end
 
           def test_has_many
+            serializer = PostSerializer.new(@post)
+            adapter = ActiveModel::Serializer::Adapter::Json.new(serializer)
             assert_equal([
                            {id: 1, body: 'ZOMG A COMMENT'},
                            {id: 2, body: 'ZOMG ANOTHER COMMENT'}
-                         ], @adapter.serializable_hash[:post][:comments])
+                         ], adapter.serializable_hash[:post][:comments])
           end
 
           def test_has_many_with_no_serializer
             serializer = PostWithTagsSerializer.new(@post)
             adapter = ActiveModel::Serializer::Adapter::Json.new(serializer)
-            assert_includes(adapter.as_json, :tags)
+            assert_equal({
+              id: 42,
+              tags: [
+                {"attributes"=>{"id"=>1, "name"=>"#hash_tag"}}
+              ]
+            }, adapter.serializable_hash[:post_with_tags])
           end
         end
       end

test/adapter/json_api/has_many_test.rb

@@ -29,7 +29,6 @@ module ActiveModel
             @post_without_comments.blog = nil
             @tag = Tag.new(id: 1, name: "#hash_tag")
             @post.tags = [@tag]
-
             @serializer = PostSerializer.new(@post)
             @adapter = ActiveModel::Serializer::Adapter::JsonApi.new(@serializer)
           end
@@ -97,6 +96,7 @@ module ActiveModel
             serializer = BlogSerializer.new(@blog)
             adapter = ActiveModel::Serializer::Adapter::JsonApi.new(serializer)
             actual = adapter.serializable_hash[:data][:relationships][:articles]
+
             expected = {
               data: [{
                 type: "posts",
@@ -109,7 +109,16 @@ module ActiveModel
           def test_has_many_with_no_serializer
             serializer = PostWithTagsSerializer.new(@post)
             adapter = ActiveModel::Serializer::Adapter::JsonApi.new(serializer)
-            assert_includes(adapter.serializable_hash, :tags)
+
+            assert_equal({
+              data: {
+                id: "1",
+                type: "posts",
+                relationships: {
+                  tags: {:data=>nil}
+                }
+              }
+            }, adapter.serializable_hash)
           end
         end
       end

test/serializers/associations_test.rb

@@ -69,7 +69,9 @@ module ActiveModel
 
       def test_has_many_with_no_serializer
         PostWithTagsSerializer.new(@post).each_association do |name, serializer, options|
-          puts "The line above will crash this test"
+          assert_equal name, :tags
+          assert_equal serializer, nil
+          assert_equal options, {:virtual_value=>[{"attributes"=>{"name"=>"#hashtagged"}}]}
         end
       end