3 files changed, 4 insertions, 7 deletions
diff --git a/actionpack/lib/action_controller/metal/redirecting.rb b/actionpack/lib/action_controller/metal/redirecting.rb
index 3feb737277..ca8c0278d0 100644
--- a/actionpack/lib/action_controller/metal/redirecting.rb
+++ b/actionpack/lib/action_controller/metal/redirecting.rb
@@ -68,6 +68,7 @@ module ActionController
     # <tt>ActionController::RedirectBackError</tt>.
     def redirect_to(options = {}, response_status = {}) #:doc:
       raise ActionControllerError.new("Cannot redirect to nil!") unless options
+      raise ActionControllerError.new("Cannot redirect to a parameter hash!") if options.is_a?(ActionController::Parameters)
       raise AbstractController::DoubleRenderError if response_body
 
       self.status        = _extract_redirect_to_status(options, response_status)
diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index ae55e6d7f5..02c4e563f5 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -116,7 +116,7 @@ module ActionController
           self.content_type = Mime::JS
         end
 
-        "#{options[:callback]}(#{json})"
+        "/**/#{options[:callback]}(#{json})"
       else
         self.content_type ||= Mime::JSON
         json
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
index 93e7d6954c..7bbff0450a 100644
--- a/actionpack/lib/action_controller/metal/rendering.rb
+++ b/actionpack/lib/action_controller/metal/rendering.rb
@@ -67,8 +67,8 @@ module ActionController
         options[:html] = ERB::Util.html_escape(options[:html])
       end
 
-      if options.delete(:nothing) || _any_render_format_is_nil?(options)
-        options[:body] = " "
+      if options.delete(:nothing)
+        options[:body] = nil
       end
 
       if options[:status]
@@ -86,10 +86,6 @@ module ActionController
       end
     end
 
-    def _any_render_format_is_nil?(options)
-      RENDER_FORMATS_IN_PRIORITY.any? { |format| options.key?(format) && options[format].nil? }
-    end
-
     # Process controller specific options, as status, content-type and location.
     def _process_options(options) #:nodoc:
       status, content_type, location = options.values_at(:status, :content_type, :location)