Eliminate git access from MergeRequestsController#ci_statusfix/optimize-commit-for-sha-only-access

4 files changed, 23 insertions, 21 deletions

diff --git a/app/controllers/projects/merge_requests_controller.rb b/app/controllers/projects/merge_requests_controller.rb
index fbad66c5c40..cced7054258 100644
--- a/app/controllers/projects/merge_requests_controller.rb
+++ b/app/controllers/projects/merge_requests_controller.rb
@@ -441,7 +441,7 @@ class Projects::MergeRequestsController < Projects::ApplicationController
 
     response = {
       title: merge_request.title,
-      sha: (merge_request.diff_head_commit.short_id if merge_request.diff_head_sha),
+      sha: (Commit.truncate_sha(merge_request.diff_head_sha) if merge_request.diff_head_sha),
       status: status,
       coverage: coverage,
       pipeline: pipeline.try(:id)
diff --git a/app/models/merge_request.rb b/app/models/merge_request.rb
index c0d4dd0197f..2cb07af72fa 100644
--- a/app/models/merge_request.rb
+++ b/app/models/merge_request.rb
@@ -230,23 +230,19 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def diff_start_commit
-    if persisted?
-      merge_request_diff.start_commit
-    else
-      target_branch_head
-    end
+    project.commit(diff_start_sha)
   end
 
   def diff_head_commit
-    if persisted?
-      merge_request_diff.head_commit
-    else
-      source_branch_head
-    end
+    project.commit(diff_head_sha)
   end
 
   def diff_start_sha
-    diff_start_commit.try(:sha)
+    if persisted?
+      merge_request_diff.start_commit_sha
+    else
+      target_branch_sha
+    end
   end
 
   def diff_base_sha
@@ -254,7 +250,11 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def diff_head_sha
-    diff_head_commit.try(:sha)
+    if persisted?
+      merge_request_diff.head_commit_sha
+    else
+      source_branch_sha
+    end
   end
 
   # When importing a pull request from GitHub, the old and new branches may no
@@ -283,11 +283,11 @@ class MergeRequest < ActiveRecord::Base
   end
 
   def target_branch_sha
-    @target_branch_sha || target_branch_head.try(:sha)
+    @target_branch_sha || project.repository.find_branch(target_branch).try(:target)
   end
 
   def source_branch_sha
-    @source_branch_sha || source_branch_head.try(:sha)
+    @source_branch_sha || project.repository.find_branch(source_branch).try(:target)
   end
 
   def diff_refs
diff --git a/lib/gitlab/git/ref.rb b/lib/gitlab/git/ref.rb
index 37ef6836742..1bec44b4645 100644
--- a/lib/gitlab/git/ref.rb
+++ b/lib/gitlab/git/ref.rb
@@ -12,10 +12,6 @@ module Gitlab
       # when tag reference on other tag it can be tag sha
       attr_reader :target
 
-      # Dereferenced target
-      # Commit object to which the Ref points to
-      attr_reader :dereferenced_target
-
       # Extract branch name from full ref path
       #
       # Ex.
@@ -33,7 +29,7 @@ module Gitlab
       def initialize(repository, name, target)
         encode! name
         @name = name.gsub(/\Arefs\/(tags|heads)\//, '')
-        @dereferenced_target = Gitlab::Git::Commit.find(repository, target)
+        @repository = repository
         @target = if target.respond_to?(:oid)
                     target.oid
                   elsif target.respond_to?(:name)
@@ -44,6 +40,12 @@ module Gitlab
                     nil
                   end
       end
+
+      # Dereferenced target
+      # Commit object to which the Ref points to
+      def dereferenced_target
+        @dereferenced_target ||= Gitlab::Git::Commit.find(@repository, target)
+      end
     end
   end
 end
diff --git a/lib/gitlab/git/repository.rb b/lib/gitlab/git/repository.rb
index 7068e68a855..7483b37c2bb 100644
--- a/lib/gitlab/git/repository.rb
+++ b/lib/gitlab/git/repository.rb
@@ -81,7 +81,7 @@ module Gitlab
         reload_rugged if force_reload
 
         rugged_ref = rugged.branches[name]
-        Gitlab::Git::Branch.new(self, rugged_ref.name, rugged_ref.target) if rugged_ref
+        Gitlab::Git::Branch.new(self, rugged_ref.name, rugged_ref.target_id) if rugged_ref
       end
 
       def local_branches