carefully and quickly merge url_for options

1 files changed, 17 insertions, 1 deletions

diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index 94db36ce1f..f2773615a3 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -147,7 +147,7 @@ module ActionDispatch
         when String
           options
         when nil, Hash
-          _routes.url_for((options || {}).symbolize_keys.reverse_merge!(url_options))
+          _routes.url_for(_merge_url_for_options(options, url_options))
         else
           polymorphic_url(options)
         end
@@ -155,6 +155,22 @@ module ActionDispatch
 
       protected
 
+      def _merge_url_for_options(h1, h2)
+        opts = {}
+
+        h1.keys.each do |k|
+          s = k.to_sym
+          opts[s] = h1[k] unless opts.has_key?(s)
+        end if h1
+
+        h2.keys.each do |k|
+          s = k.to_sym
+          opts[s] = h2[k] unless opts.has_key?(s)
+        end if h2
+
+        opts
+      end
+
       def optimize_routes_generation?
         return @_optimized_routes if defined?(@_optimized_routes)
         @_optimized_routes = _routes.optimize_routes_generation? && default_url_options.empty?