make respond-with play nice with namespace

sinatra-contrib/lib/sinatra/namespace.rb

@@ -66,6 +66,11 @@ module Sinatra
         [*codes].each { |c| errors[c] = block }
       end
 
+      def respond_to(*args)
+        return @conditions[:provides] || base.respond_to if args.empty?
+        @conditions[:provides] = args
+      end
+
       private
 
       def app

sinatra-contrib/lib/sinatra/respond_with.rb

@@ -108,7 +108,7 @@ module Sinatra
       result
     end
 
-    def respond_to(*formats, &block)
+    def respond_to(*formats)
       if formats.any?
         @respond_to ||= []
         @respond_to.concat formats

sinatra-contrib/spec/respond_with_spec.rb

@@ -262,5 +262,19 @@ describe Sinatra::RespondWith do
       req('/b', :html).should_not be_ok
       req('/b', :json).should be_ok
     end
+
+    it 'plays well with namespaces' do
+      respond_app do
+        register Sinatra::Namespace
+        namespace '/a' do
+          respond_to :json
+          get { 'json' }
+        end
+        get('/b') { 'anything' }
+      end
+
+      req('/a', :html).should_not be_ok
+      req('/b', :html).should be_ok
+    end
   end
 end