ensure that recusive message rendering works

lib/pbbuilder/collection_renderer.rb

@@ -16,15 +16,15 @@ def build_rendered_template(content, template, layout = nil)
     end
 
     def build_rendered_collection(templates, _spacer)
-      pb_root.set!(field, templates.map(&:body))
+      pb_parent.set!(field, templates.map(&:body))
     end
 
     def pb
       @options[:locals].fetch(:pb)
     end
 
-    def pb_root
-      @options[:locals].fetch(:pb_root)
+    def pb_parent
+      @options[:locals].fetch(:pb_parent)
     end
 
     def field

lib/pbbuilder/template.rb

@@ -50,12 +50,15 @@ def set!(field, *args, **kwargs, &block)
         collection = options[:collection] || []
         partial = options[:partial]
 
+        # The way recursive rendering works is that CollectionRenderer needs to be aware of node its currently rendering and parent node,
+        # these is no need to know entire "stack" of nodes. CollectionRenderer would traverse to bottom node render that first and then go up in stack.
+
         # CollectionRenderer uses locals[:pb] to render the partial as a protobuf message,
-        # but also needs locals[:pb_root] to apply rendered partial to top level protobuf message.
+        # but also needs locals[:pb_parent] to apply rendered partial to top level protobuf message.
 
-        # This logic could be found in CollectionRenderer#build_rendered_collection method that we overwrote.
+        # This logic could be found in CollectionRenderer#build_rendered_collection method that we over wrote.
         options[:locals].merge!(pb: ::PbbuilderTemplate.new(@context, new_message_for(field)))
-        options[:locals].merge!(pb_root: self)
+        options[:locals].merge!(pb_parent: self)
         options[:locals].merge!(field: field)
 
         if options.has_key?(:layout)

test/pbbuilder_template_test.rb

@@ -39,15 +39,19 @@ class PbbuilderTemplateTest < ActiveSupport::TestCase
   end
 
   test "render collections with partial as kwarg" do
-    result = render('pb.friends partial: "racers/racer", as: :racer, collection: [Racer.new(1, "Johnny Test", [], nil, API::Asset.new(url: "https://google.com/test.svg")), Racer.new(2, "Max Verstappen", [])]')
+    template = <<-PBBUILDER
+      more_friends = [Racer.new(4, "Johnny Brave", [], nil, API::Asset.new(url: "https://google.com/test3.svg"))]
+      friends_of_racer = [Racer.new(3, "Chris Harris", more_friends, nil, API::Asset.new(url: "https://google.com/test2.svg"))]
+      racers = [Racer.new(1, "Johnny Test", friends_of_racer, nil, API::Asset.new(url: "https://google.com/test1.svg")), Racer.new(2, "Max Verstappen", [])]
+      pb.friends partial: "racers/racer", as: :racer, collection: racers
+    PBBUILDER
+    result = render(template)
 
     assert_equal 2, result.friends.count
     assert_nil result.logo
-    result.friends.first.logo.tap do |logo|
-      assert_equal "https://google.com/test.svg", logo.url
-      assert_equal "https://google.com/test.svg", logo.url_2x
-      assert_equal "https://google.com/test.svg", logo.url_3x
-    end
+    assert_equal "https://google.com/test1.svg", result.friends.first.logo.url
+    assert_equal "https://google.com/test2.svg", result.friends.first.friends.first.logo.url
+    assert_equal "https://google.com/test3.svg", result.friends.first.friends.first.friends.first.logo.url
   end
 
   test "CollectionRenderer: raises an error on a render with :layout option" do