Protect against unset current_path

middleman-core/lib/middleman-core/sitemap.rb

@@ -70,6 +70,7 @@ module Middleman
       # Get the resource object for the current path
       # @return [Middleman::Sitemap::Resource]
       def current_resource
+        return nil unless current_path
         sitemap.find_resource_by_destination_path(current_path)
       end
 

middleman-more/lib/middleman-more/extensions/relative_assets.rb

@@ -32,7 +32,7 @@ module Middleman
         def asset_url(path, prefix="")
           path = super(path, prefix)
 
-          if path.include?("//")
+          if path.include?("//") || !current_resource
             path
           else
             current_dir = Pathname('/' + current_resource.destination_path)