Fix partial for Active Model when extra locals are passed in

Revert 44b42f9

Fixes #616.

Author: rafaelfranca

lib/jbuilder/jbuilder_template.rb

@@ -52,7 +52,7 @@ def initialize(context, options = nil)
   #   json.comments @post.comments, partial: "comments/comment", as: :comment, cached: true
   #
   def partial!(*args)
-    if _is_active_model?(args.first)
+    if args.one? && _is_active_model?(args.first)
       _render_active_model_partial args.first
     else
       options = args.extract_options!.dup

test/jbuilder_template_test.rb

@@ -18,6 +18,7 @@ class JbuilderTemplateTest < ActiveSupport::TestCase
 
   RACER_PARTIAL = <<-JBUILDER
     json.extract! racer, :id, :name
+    json.highlighted local_assigns.fetch(:highlighted, false)
   JBUILDER
 
   PARTIALS = {
@@ -82,6 +83,13 @@ class JbuilderTemplateTest < ActiveSupport::TestCase
     assert_equal "Chris Harris", result["name"]
   end
 
+  test "partial for Active Model preserves extra locals" do
+    result = render('json.partial! @racer, highlighted: true', racer: Racer.new(123, "Chris Harris"))
+    assert_equal 123, result["id"]
+    assert_equal "Chris Harris", result["name"]
+    assert_equal true, result["highlighted"]
+  end
+
   test "partial collection by name with symbol local" do
     result = render('json.partial! "post", collection: @posts, as: :post', posts: POSTS)
     assert_equal 10, result.count