1 files changed, 9 insertions, 1 deletions
diff --git a/railties/lib/rails/application/configuration.rb b/railties/lib/rails/application/configuration.rb
index 9353fbefef..8afe423973 100644
--- a/railties/lib/rails/application/configuration.rb
+++ b/railties/lib/rails/application/configuration.rb
@@ -1,4 +1,5 @@
 require 'active_support/deprecation'
+require 'active_support/core_ext/string/encoding'
 require 'rails/engine/configuration'
 
 module Rails
@@ -27,8 +28,15 @@ module Rails
 
       def encoding=(value)
         @encoding = value
-        if defined?(Encoding) && Encoding.respond_to?(:default_external=)
+        if "ruby".encoding_aware?
           Encoding.default_external = value
+          Encoding.default_internal = value
+        else
+          $KCODE = value
+          if $KCODE == "NONE"
+            raise "The value you specified for config.encoding is " \
+                  "invalid. The possible values are UTF8, SJIS, or EUC"
+          end
         end
       end