2 files changed, 35 insertions, 1 deletions
diff --git a/actionpack/lib/action_controller/metal/responder.rb b/actionpack/lib/action_controller/metal/responder.rb
index 3794e277f6..c7827309dd 100644
--- a/actionpack/lib/action_controller/metal/responder.rb
+++ b/actionpack/lib/action_controller/metal/responder.rb
@@ -253,7 +253,7 @@ module ActionController #:nodoc:
     end
 
     def display_errors
-      controller.render format => resource.errors, :status => :unprocessable_entity
+      controller.render format => resource_errors, :status => :unprocessable_entity
     end
 
     # Check whether the resource has errors.
@@ -286,5 +286,13 @@ module ActionController #:nodoc:
     def empty_json_resource
       "{}"
     end
+
+    def resource_errors
+      respond_to?("#{format}_resource_errors") ? send("#{format}_resource_errors") : resource.errors
+    end
+
+    def json_resource_errors
+      {:errors => resource.errors}
+    end
   end
 end
diff --git a/actionpack/test/controller/mime_responds_test.rb b/actionpack/test/controller/mime_responds_test.rb
index afb2d39955..afdab30eaf 100644
--- a/actionpack/test/controller/mime_responds_test.rb
+++ b/actionpack/test/controller/mime_responds_test.rb
@@ -745,6 +745,20 @@ class RespondWithControllerTest < ActionController::TestCase
     end
   end
 
+  def test_using_resource_for_post_with_json_yields_unprocessable_entity_on_failure
+    with_test_route_set do
+      @request.accept = "application/json"
+      errors = { :name => :invalid }
+      Customer.any_instance.stubs(:errors).returns(errors)
+      post :using_resource
+      assert_equal "application/json", @response.content_type
+      assert_equal 422, @response.status
+      errors = {:errors => errors}
+      assert_equal errors.to_json, @response.body
+      assert_nil @response.location
+    end
+  end
+
   def test_using_resource_for_put_with_html_redirects_on_success
     with_test_route_set do
       put :using_resource
@@ -808,6 +822,18 @@ class RespondWithControllerTest < ActionController::TestCase
     assert_nil @response.location
   end
 
+  def test_using_resource_for_put_with_json_yields_unprocessable_entity_on_failure
+    @request.accept = "application/json"
+    errors = { :name => :invalid }
+    Customer.any_instance.stubs(:errors).returns(errors)
+    put :using_resource
+    assert_equal "application/json", @response.content_type
+    assert_equal 422, @response.status
+    errors = {:errors => errors}
+    assert_equal errors.to_json, @response.body
+    assert_nil @response.location
+  end
+
   def test_using_resource_for_delete_with_html_redirects_on_success
     with_test_route_set do
       Customer.any_instance.stubs(:destroyed?).returns(true)