Flatten the directory hierarchy while there is only one directory descendant

app/helpers/tree_helper.rb

@@ -113,6 +113,16 @@ module TreeHelper
     tree_join(@ref, file)
   end
 
+  # returns the relative path of the first subdir that doesn't have only one directory descendand
+  def flatten_tree(tree)
+    subtree = Gitlab::Git::Tree.where(@repository, @commit.id, tree.path)
+    if subtree.count == 1 && subtree.first.dir?
+      return tree_join(tree.name, flatten_tree(subtree.first))
+    else
+      return tree.name
+    end
+  end
+
   def leave_edit_message
     "Leave edit mode?\nAll unsaved changes will be lost."
   end

app/views/projects/tree/_tree_item.html.haml

@@ -2,7 +2,8 @@
   %td.tree-item-file-name
     = tree_icon(type)
     %span.str-truncated
-      = link_to tree_item.name, project_tree_path(@project, tree_join(@id || @commit.id, tree_item.name))
+      - path = flatten_tree(tree_item)
+      = link_to path, project_tree_path(@project, tree_join(@id || @commit.id, path))
   %td.tree_time_ago.cgray
     = render 'spinner'
   %td.hidden-xs.tree_commit