diff --git a/app/views/tree/_submodule_item.html.haml b/app/views/tree/_submodule_item.html.haml
index b0562fe..092a024 100644
--- a/app/views/tree/_submodule_item.html.haml
+++ b/app/views/tree/_submodule_item.html.haml
@@ -1,6 +1,6 @@
 - url = submodule_item.url(@ref) rescue ''
 - name = submodule_item.basename
-- return unless url
+- return '' unless url
 %tr{ class: "tree-item", url: url }
   %td.tree-item-file-name
     = image_tag "submodule.png"
--
libgit2 0.21.2