Update app code to use Gitlab::Git::Diff

app/models/note.rb

@@ -68,8 +68,8 @@ class Note < ActiveRecord::Base
   def diff
     if noteable.diffs.present?
       noteable.diffs.select do |d|
-        if d.b_path
+        if d.new_path
-          Digest::SHA1.hexdigest(d.b_path) == diff_file_index
+          Digest::SHA1.hexdigest(d.new_path) == diff_file_index
         end
       end.first
     end
@@ -80,7 +80,7 @@ class Note < ActiveRecord::Base
   end
 
   def diff_file_name
-    diff.b_path
+    diff.new_path
   end
 
   def diff_new_line

lib/gitlab/git/commit.rb

@@ -9,7 +9,7 @@ module Gitlab
         :author_name, :author_email, :parent_ids,
         :committer_name, :committer_email
 
-      delegate :parents, :diffs, :tree, :stats, :to_patch,
+      delegate :parents, :tree, :stats, :to_patch,
         to: :raw_commit
 
       def initialize(raw_commit, head = nil)
@@ -96,6 +96,10 @@ module Gitlab
         committed_date
       end
 
+      def diffs
+        raw_commit.diffs.map { |diff| Gitlab::Git::Diff.new(diff) }
+      end
+
       private
 
       def init_from_grit(grit)

lib/gitlab/git/repository.rb

@@ -191,6 +191,17 @@ module Gitlab
         "#{type}:#{path_with_namespace}"
       end
 
+      def diffs_between(source_branch, target_branch)
+        # Only show what is new in the source branch compared to the target branch, not the other way around.
+        # The linex below with merge_base is equivalent to diff with three dots (git diff branch1...branch2)
+        # From the git documentation: "git diff A...B" is equivalent to "git diff $(git-merge-base A B) B"
+        common_commit = repo.git.native(:merge_base, {}, [target_branch, source_branch]).strip
+        repo.diff(common_commit, source_branch).map { |diff| Gitlab::Git::Diff.new(diff) }
+
+      rescue Grit::Git::GitTimeout
+        [Gitlab::Git::Diff::BROKEN_DIFF]
+      end
+
       protected
 
       def decorate_commit(commit, ref = nil)