show a file diff when click on it in the header stats

app/assets/javascripts/extra/diff.js.coffee

@@ -0,0 +1,6 @@
+$(document).ready ->
+  $(document).on 'click', '#diff_header .panel-body table a', ->
+    href = $(this).attr('href')
+    $(".diff_data.collapse#"+href.slice(1)+"_content").collapse('show')
+
+  return

app/assets/javascripts/new_application.js

@@ -39,6 +39,7 @@
 //= require extra/scroller
 //= require extra/fork
 //= require extra/diff_chevrons
+//= require extra/diff
 
 //= require_self
 

app/helpers/diff_helper.rb

@@ -3,12 +3,10 @@ module DiffHelper
   MAX_LINES_WITHOUT_COLLAPSE = 50
 
   def render_diff_stats(stats)
-    path = @pull.try(:id) ? polymorphic_path([@project, @pull]) : ''
-
     res = ["<table class='table table-responsive boffset0'>"]
     stats.each_with_index do |stat, ind|
       res << "<tr>"
-      res << "<td>#{link_to stat.filename.rtruncate(120), "#{path}#diff-#{ind}"}</td>"
+      res << "<td>#{link_to stat.filename.rtruncate(120), "#diff-#{ind}"}</td>"
       res << "<td class='diffstat'>"
       res << I18n.t("layout.projects.inline_changes_count", count: stat.additions + stat.deletions).strip +
              " (" +