Commits page returns status 500 if tag <U+1F61C> is created

Commits page returns HTTP status 500 if git tag with name <U+1F61C> is created.

Encoding::CompatibilityError (incompatible character encodings: UTF-8 and ASCII-8BIT):
app/helpers/application_helper.rb:104:in `grouped_options_refs'
app/views/shared/_ref_switcher.html.haml:2:in `block in _app_views_shared__ref_switcher_html_haml___922243079456320871_70216934793920'
app/views/shared/_ref_switcher.html.haml:1:in `_app_views_shared__ref_switcher_html_haml___922243079456320871_70216934793920'
app/views/projects/commits/show.html.haml:4:in `_app_views_projects_commits_show_html_haml___177943918
7131451894_70216950236440'
  app/controllers/projects/commits_controller.rb:19:in `show'

Completed 500 Internal Server Error in 282ms (Views: 15.1ms | ActiveRecord: 5.8ms)
Started GET "/testomato/testomato-web/commits/trunk" for 127.0.0.1 at 2015-01-14 12:14:34 +0100
Processing by Projects::CommitsController#show as HTML
  Parameters: {"project_id"=>"testomato/testomato-web", "id"=>"trunk"}