1 files changed, 19 insertions, 17 deletions
diff --git a/actionpack/lib/action_controller/renderer.rb b/actionpack/lib/action_controller/renderer.rb
index e4d19e9dba..243a54330e 100644
--- a/actionpack/lib/action_controller/renderer.rb
+++ b/actionpack/lib/action_controller/renderer.rb
@@ -1,7 +1,7 @@
-require 'active_support/core_ext/hash/keys'
+require "active_support/core_ext/hash/keys"
 
 module ActionController
-  # ActionController::Renderer allows to render arbitrary templates
+  # ActionController::Renderer allows you to render arbitrary templates
   # without requirement of being in controller actions.
   #
   # You get a concrete renderer class by invoking ActionController::Base#renderer.
@@ -13,11 +13,11 @@ module ActionController
   #
   #   ApplicationController.renderer.render template: '...'
   #
-  # You can use a shortcut on controller to replace previous example with:
+  # You can use this shortcut in a controller, instead of the previous example:
   #
   #   ApplicationController.render template: '...'
   #
-  # #render method allows you to use any options as when rendering in controller.
+  # #render allows you to use the same options that you can use when rendering in a controller.
   # For example,
   #
   #   FooController.render :action, locals: { ... }, assigns: { ... }
@@ -37,15 +37,15 @@ module ActionController
     attr_reader :defaults, :controller
 
     DEFAULTS = {
-      http_host: 'example.org',
+      http_host: "example.org",
       https: false,
-      method: 'get',
-      script_name: '',
-      input: ''
+      method: "get",
+      script_name: "",
+      input: ""
     }.freeze
 
     # Create a new renderer instance for a specific controller class.
-    def self.for(controller, env = {}, defaults = DEFAULTS)
+    def self.for(controller, env = {}, defaults = DEFAULTS.dup)
       new(controller, env, defaults)
     end
 
@@ -69,7 +69,7 @@ module ActionController
 
     # Render templates with any options from ActionController::Base#render_to_string.
     def render(*args)
-      raise 'missing controller' unless controller
+      raise "missing controller" unless controller
 
       request = ActionDispatch::Request.new @env
       request.routes = controller._routes
@@ -88,21 +88,23 @@ module ActionController
       end
 
       RACK_KEY_TRANSLATION = {
-        http_host:   'HTTP_HOST',
-        https:       'HTTPS',
-        method:      'REQUEST_METHOD',
-        script_name: 'SCRIPT_NAME',
-        input:       'rack.input'
+        http_host:   "HTTP_HOST",
+        https:       "HTTPS",
+        method:      "REQUEST_METHOD",
+        script_name: "SCRIPT_NAME",
+        input:       "rack.input"
       }
 
       IDENTITY = ->(_) { _ }
 
       RACK_VALUE_TRANSLATION = {
-        https: ->(v) { v ? 'on' : 'off' },
+        https: ->(v) { v ? "on" : "off" },
         method: ->(v) { v.upcase },
       }
 
-      def rack_key_for(key); RACK_KEY_TRANSLATION[key]; end
+      def rack_key_for(key)
+        RACK_KEY_TRANSLATION.fetch(key, key.to_s)
+      end
 
       def rack_value_for(key, value)
         RACK_VALUE_TRANSLATION.fetch(key, IDENTITY).call value