Feedback for flubbed regex and prefer File's directory check

lib/jekyll/theme.rb

@@ -38,7 +38,7 @@ module Jekyll
       return unless resolved_dir
 
       path = Jekyll.sanitized_path(root, resolved_dir)
-      path if Dir.exist?(path)
+      path if File.directory?(path)
     end
 
     def realpath_for(folder)

lib/jekyll/url.rb

@@ -92,7 +92,7 @@ module Jekyll
     # as well as the beginning "/" so we can enforce and ensure it.
 
     def sanitize_url(str)
-      "/" + str.gsub(%r!/{2,}!, "/").gsub(%r!\.+\/|\A\/+!, "")
+      "/" + str.gsub(%r!/{2,}!, "/").gsub(%r!\.+/|\A/+!, "")
     end
 
     # Escapes a path to be a valid URL path segment