Generating routes with optional format segment does not inherit params format [#2043 state:resolved]

actionpack/lib/action_controller/routing/segments.rb

@@ -324,7 +324,11 @@ module ActionController
       def to_s
         '(.:format)?'
       end
-    
+
+      def extract_value
+        "#{local_name} = options[:#{key}] && options[:#{key}].to_s.downcase"
+      end
+
       #the value should not include the period (.)
       def match_extraction(next_capture)
         %[

actionpack/test/controller/routing_test.rb

@@ -2237,6 +2237,22 @@ class RouteSetTest < Test::Unit::TestCase
     )
   end
 
+  def test_format_is_not_inherit
+    set.draw do |map|
+      map.connect '/posts.:format', :controller => 'posts'
+    end
+
+    assert_equal '/posts', set.generate(
+      {:controller => 'posts'},
+      {:controller => 'posts', :action => 'index', :format => 'xml'}
+    )
+
+    assert_equal '/posts.xml', set.generate(
+      {:controller => 'posts', :format => 'xml'},
+      {:controller => 'posts', :action => 'index', :format => 'xml'}
+    )
+  end
+
   def test_expiry_determination_should_consider_values_with_to_param
     set.draw { |map| map.connect 'projects/:project_id/:controller/:action' }
     assert_equal '/projects/1/post/show', set.generate(