2 files changed, 11 insertions, 7 deletions
diff --git a/actionpack/lib/action_controller/metal/streaming.rb b/actionpack/lib/action_controller/metal/streaming.rb
index 62d5931b45..04401cad7b 100644
--- a/actionpack/lib/action_controller/metal/streaming.rb
+++ b/actionpack/lib/action_controller/metal/streaming.rb
@@ -183,7 +183,7 @@ module ActionController #:nodoc:
   # You may also want to configure other parameters like <tt>:tcp_nodelay</tt>.
   # Please check its documentation for more information: http://unicorn.bogomips.org/Unicorn/Configurator.html#method-i-listen
   #
-  # If you are using Unicorn with Nginx, you may need to tweak Nginx.
+  # If you are using Unicorn with NGINX, you may need to tweak NGINX.
   # Streaming should work out of the box on Rainbows.
   #
   # ==== Passenger
diff --git a/actionpack/lib/action_controller/metal/strong_parameters.rb b/actionpack/lib/action_controller/metal/strong_parameters.rb
index 0236af4a19..c3c3e4c4f1 100644
--- a/actionpack/lib/action_controller/metal/strong_parameters.rb
+++ b/actionpack/lib/action_controller/metal/strong_parameters.rb
@@ -129,8 +129,12 @@ module ActionController
     # Attribute that keeps track of converted arrays, if any, to avoid double
     # looping in the common use case permit + mass-assignment. Defined in a
     # method to instantiate it only if needed.
+    #
+    # Testing membership still loops, but it's going to be faster than our own
+    # loop that converts values. Also, we are not going to build a new array
+    # object per fetch.
     def converted_arrays
-      @converted_arrays ||= {}
+      @converted_arrays ||= Set.new
     end
 
     # Returns +true+ if the parameter is permitted, +false+ otherwise.
@@ -333,15 +337,15 @@ module ActionController
 
     private
       def convert_hashes_to_parameters(key, value, assign_if_converted=true)
-        converted = convert_value_to_parameters(key, value)
+        converted = convert_value_to_parameters(value)
         self[key] = converted if assign_if_converted && !converted.equal?(value)
         converted
       end
 
-      def convert_value_to_parameters(key, value)
-        if value.is_a?(Array) && !converted_arrays.member?(key)
-          converted = value.map { |v| convert_value_to_parameters(nil, v) }
-          converted_arrays[key] = converted if key
+      def convert_value_to_parameters(value)
+        if value.is_a?(Array) && !converted_arrays.member?(value)
+          converted = value.map { |_| convert_value_to_parameters(_) }
+          converted_arrays << converted
           converted
         elsif value.is_a?(Parameters) || !value.is_a?(Hash)
           value