Refactor link to new diff note rendering

app/helpers/notes_helper.rb

@@ -42,4 +42,23 @@ module NotesHelper
       project_id: noteable.project.id,
     }.to_json
   end
+
+  def link_to_new_diff_note(line_code)
+    discussion_id = Note.build_discussion_id(
+      @comments_target[:noteable_type],
+      @comments_target[:noteable_id] || @comments_target[:commit_id],
+      line_code
+    )
+
+    data = {
+      noteable_type: @comments_target[:noteable_type],
+      noteable_id:   @comments_target[:noteable_id],
+      commit_id:     @comments_target[:commit_id],
+      line_code:     line_code,
+      discussion_id: discussion_id
+    }
+
+    link_to "", "javascript:;", class: "add-diff-note js-add-diff-note-button",
+      data: data, title: "Add a comment to this line"
+  end
 end

app/models/note.rb

@@ -122,11 +122,15 @@ class Note < ActiveRecord::Base
 
       discussions
     end
-  end
 
-  # Determine whether or not a cross-reference note already exists.
-  def self.cross_reference_exists?(noteable, mentioner)
-    where(noteable_id: noteable.id, system: true, note: "_mentioned in #{mentioner.gfm_reference}_").any?
+    def build_discussion_id(type, id, line_code)
+      [:discussion, type.try(:underscore), id, line_code].join("-").to_sym
+    end
+
+    # Determine whether or not a cross-reference note already exists.
+    def cross_reference_exists?(noteable, mentioner)
+      where(noteable_id: noteable.id, system: true, note: "_mentioned in #{mentioner.gfm_reference}_").any?
+    end
   end
 
   def commit_author
@@ -194,7 +198,7 @@ class Note < ActiveRecord::Base
   end
 
   def discussion_id
-    @discussion_id ||= [:discussion, noteable_type.try(:underscore), noteable_id || commit_id, line_code].join("-").to_sym
+    @discussion_id ||= Note.build_discussion_id(noteable_type, noteable_id || commit_id, line_code)
   end
 
   # Returns true if this is a downvote note,

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

@@ -13,7 +13,7 @@
         %td.old_line
           = link_to raw(type == "new" ? " " : line_old), "##{line_code}", id: line_code
           - if @comments_allowed
-            = render "projects/notes/diff_note_link", line_code: line_code
+            = link_to_new_diff_note(line_code)
         %td.new_line= link_to raw(type == "old" ? " " : line_new) , "##{line_code}", id: line_code
         %td.line_content{class: "noteable_line #{type} #{line_code}", "line_code" => line_code}= raw diff_line_content(line)