Merge branch 'git-write-ref-prep' into 'master'

Gitlab::Git::Repository#write_ref client-prep take 2

Closes gitaly#793

See merge request gitlab-org/gitlab-ce!16287

app/models/project.rb

@@ -1149,7 +1149,7 @@ class Project < ActiveRecord::Base
   def change_head(branch)
     if repository.branch_exists?(branch)
       repository.before_change_head
-      repository.write_ref('HEAD', "refs/heads/#{branch}")
+      repository.raw_repository.write_ref('HEAD', "refs/heads/#{branch}", shell: false)
       repository.copy_gitattributes(branch)
       repository.after_change_head
       reload_default_branch

app/models/repository.rb

@@ -260,7 +260,7 @@ class Repository
 
     # This will still fail if the file is corrupted (e.g. 0 bytes)
     begin
-      write_ref(keep_around_ref_name(sha), sha)
+      raw_repository.write_ref(keep_around_ref_name(sha), sha, shell: false)
     rescue Rugged::ReferenceError => ex
       Rails.logger.error "Unable to create #{REF_KEEP_AROUND} reference for repository #{path}: #{ex}"
     rescue Rugged::OSError => ex
@@ -274,10 +274,6 @@ class Repository
     ref_exists?(keep_around_ref_name(sha))
   end
 
-  def write_ref(ref_path, sha)
-    rugged.references.create(ref_path, sha, force: true)
-  end
-
   def diverging_commit_counts(branch)
     root_ref_hash = raw_repository.commit(root_ref).id
     cache.fetch(:"diverging_commit_counts_#{branch.name}") do

lib/gitlab/git/repository.rb

@@ -1103,14 +1103,27 @@ module Gitlab
         end
       end
 
-      def write_ref(ref_path, ref)
+      def write_ref(ref_path, ref, old_ref: nil, shell: true)
+        if shell
+          shell_write_ref(ref_path, ref, old_ref)
+        else
+          rugged_write_ref(ref_path, ref)
+        end
+      end
+
+      def shell_write_ref(ref_path, ref, old_ref)
         raise ArgumentError, "invalid ref_path #{ref_path.inspect}" if ref_path.include?(' ')
         raise ArgumentError, "invalid ref #{ref.inspect}" if ref.include?("\x00")
+        raise ArgumentError, "invalid old_ref #{old_ref.inspect}" if !old_ref.nil? && old_ref.include?("\x00")
 
-        input = "update #{ref_path}\x00#{ref}\x00\x00"
+        input = "update #{ref_path}\x00#{ref}\x00#{old_ref}\x00"
         run_git!(%w[update-ref --stdin -z]) { |stdin| stdin.write(input) }
       end
 
+      def rugged_write_ref(ref_path, ref)
+        rugged.references.create(ref_path, ref, force: true)
+      end
+
       def fetch_ref(source_repository, source_ref:, target_ref:)
         Gitlab::Git.check_namespace!(source_repository)
         source_repository = RemoteRepository.new(source_repository) unless source_repository.is_a?(RemoteRepository)

spec/models/project_spec.rb

@@ -1871,9 +1871,8 @@ describe Project do
     end
 
     it 'creates the new reference with rugged' do
-      expect(project.repository.rugged.references).to receive(:create).with('HEAD',
-                                                                            "refs/heads/#{project.default_branch}",
-                                                                            force: true)
+      expect(project.repository.raw_repository).to receive(:write_ref).with('HEAD', "refs/heads/#{project.default_branch}", shell: false)
+
       project.change_head(project.default_branch)
     end