Update method docs to reflect the new 422 response on unsuccessful cases

README.md

@@ -212,7 +212,8 @@ assertions on this behavior for your controllers.
 def create
   @widget = Widget.new(widget_params)
   @widget.errors.add(:base, :invalid)
-  # `respond_with` will render the `new` template again.
+  # `respond_with` will render the `new` template again,
+  # and set the status to `422 Unprocessable Entity`.
   respond_with @widget
 end
 ```

lib/action_controller/respond_with.rb

@@ -95,7 +95,8 @@ def clear_respond_to
     #      i.e. its +show+ action.
     #   2. If there are validation errors, the response
     #      renders a default action, which is <tt>:new</tt> for a
-    #      +post+ request or <tt>:edit</tt> for +patch+ or +put+.
+    #      +post+ request or <tt>:edit</tt> for +patch+ or +put+,
+    #      and the status is set to <tt>422 Unprocessable Entity</tt>.
     #   Thus an example like this -
     #
     #     respond_to :html, :xml
@@ -116,8 +117,8 @@ def clear_respond_to
     #           format.html { redirect_to(@user) }
     #           format.xml { render xml: @user }
     #         else
-    #           format.html { render action: "new" }
-    #           format.xml { render xml: @user }
+    #           format.html { render action: "new", status: :unprocessable_entity }
+    #           format.xml { render xml: @user, status: :unprocessable_entity }
     #         end
     #       end
     #     end
@@ -194,7 +195,7 @@ def clear_respond_to
     #    need to render a template which is outside of controller's path or you
     #    want to override the default http <tt>:status</tt> code, e.g.
     #
-    #    respond_with(resource, render: { template: 'path/to/template', status: 422 })
+    #    respond_with(resource, render: { template: 'path/to/template', status: 418 })
     def respond_with(*resources, &block)
       if self.class.mimes_for_respond_to.empty?
         raise "In order to use respond_with, first you need to declare the " \

lib/action_controller/responder.rb

@@ -49,7 +49,7 @@ module ActionController #:nodoc:
   #         format.html { redirect_to(@user) }
   #         format.xml { render xml: @user, status: :created, location: @user }
   #       else
-  #         format.html { render action: "new" }
+  #         format.html { render action: "new", status: :unprocessable_entity }
   #         format.xml { render xml: @user.errors, status: :unprocessable_entity }
   #       end
   #     end
@@ -113,7 +113,7 @@ module ActionController #:nodoc:
   #       if @task.save
   #         flash[:notice] = 'Task was successfully created.'
   #       else
-  #         format.html { render "some_special_template" }
+  #         format.html { render "some_special_template", status: :unprocessable_entity }
   #       end
   #     end
   #   end