Add current_ref helper method

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/helpers/projects_helper.rb

@@ -313,9 +313,11 @@ module ProjectsHelper
     end
   end
 
-  def detect_project_title(project)
-    current_ref = @ref || project.repository.root_ref
+  def current_ref
+    @ref || @repository.try(:root_ref)
+  end
 
+  def detect_project_title(project)
     name, url =
       if current_controller? 'wikis'
         ['Wiki', get_project_wiki_path(project)]

app/views/layouts/nav/_project.html.haml

@@ -40,14 +40,14 @@
 
   - if project_nav_tab? :network
     = nav_link(controller: %w(network)) do
-      = link_to namespace_project_network_path(@project.namespace, @project, @ref || @repository.root_ref), title: 'Network', class: 'shortcuts-network', data: {placement: 'right'} do
+      = link_to namespace_project_network_path(@project.namespace, @project, current_ref), title: 'Network', class: 'shortcuts-network', data: {placement: 'right'} do
         = icon('code-fork fw')
         %span
           Network
 
   - if project_nav_tab? :graphs
     = nav_link(controller: %w(graphs)) do
-      = link_to namespace_project_graph_path(@project.namespace, @project, @ref || @repository.root_ref), title: 'Graphs',  class: 'shortcuts-graphs', data: {placement: 'right'} do
+      = link_to namespace_project_graph_path(@project.namespace, @project, current_ref), title: 'Graphs',  class: 'shortcuts-graphs', data: {placement: 'right'} do
         = icon('area-chart fw')
         %span
           Graphs

app/views/projects/commits/_head.html.haml

 %ul.center-top-menu
   = nav_link(controller: [:commit, :commits]) do
-    = link_to namespace_project_commits_path(@project.namespace, @project, @ref || @repository.root_ref) do
+    = link_to namespace_project_commits_path(@project.namespace, @project, current_ref) do
       Commits
       %span.badge= number_with_delimiter(@repository.commit_count)
   = nav_link(controller: :compare) do
-    = link_to namespace_project_compare_index_path(@project.namespace, @project, from: @repository.root_ref, to: @ref || @repository.root_ref) do
+    = link_to namespace_project_compare_index_path(@project.namespace, @project, from: @repository.root_ref, to: current_ref) do
       Compare
 
   = nav_link(html_options: {class: branches_tab_class}) do

app/views/projects/show.html.haml

@@ -14,7 +14,7 @@
 .project-stats.gray-content-block
   %ul.nav.nav-pills
     %li
-      = link_to namespace_project_commits_path(@project.namespace, @project, @ref || @repository.root_ref) do
+      = link_to namespace_project_commits_path(@project.namespace, @project, current_ref) do
         = pluralize(number_with_delimiter(@project.commit_count), 'commit')
     %li
       = link_to namespace_project_branches_path(@project.namespace, @project) do