From 74d435c6b7e771c5e03b8f3cd603ffd262055363 Mon Sep 17 00:00:00 2001
From: Valery Sizov <valery@gitlab.com>
Date: Tue, 19 Sep 2017 20:37:56 +0300
Subject: [PATCH] Using worktrees and git operations service to update ref
 after rebasing

---
 app/services/merge_requests/rebase_service.rb | 22 +++++++++----------
 .../rebase_using_custom_worktree.yml          |  5 +++++
 lib/gitlab/git/operation_service.rb           |  5 +++++
 .../merge_requests/rebase_service_spec.rb     |  2 +-
 4 files changed, 21 insertions(+), 13 deletions(-)
 create mode 100644 changelogs/unreleased-ee/rebase_using_custom_worktree.yml

diff --git a/app/services/merge_requests/rebase_service.rb b/app/services/merge_requests/rebase_service.rb
index 4a69ed5876cf2f..1bd7253bdf501b 100644
--- a/app/services/merge_requests/rebase_service.rb
+++ b/app/services/merge_requests/rebase_service.rb
@@ -17,14 +17,14 @@ def rebase
       end
 
       run_git_command(
-        %W(clone -b #{merge_request.source_branch} -- #{source_project.repository.path_to_repo} #{tree_path}),
-        nil,
+        %W(worktree add --detach #{tree_path} #{merge_request.source_branch}),
+        repository.path_to_repo,
         git_env,
-        'clone repository for rebase'
+        'add worktree for rebase'
       )
 
       run_git_command(
-        %W(pull --rebase #{target_project.repository.path_to_repo} #{merge_request.target_branch}),
+        %W(rebase #{merge_request.target_branch}),
         tree_path,
         git_env.merge('GIT_COMMITTER_NAME' => current_user.name,
                       'GIT_COMMITTER_EMAIL' => current_user.email),
@@ -32,20 +32,16 @@ def rebase
       )
 
       rebase_sha = run_git_command(
-        %W(rev-parse #{merge_request.source_branch}),
+        %w(rev-parse HEAD),
         tree_path,
         git_env,
         'get SHA of rebased branch'
       )
 
-      merge_request.update_attributes(rebase_commit_sha: rebase_sha)
+      Gitlab::Git::OperationService.new(current_user, project.repository.raw_repository)
+        .update_branch(merge_request.source_branch, rebase_sha, merge_request.source_branch_sha)
 
-      run_git_command(
-        %W(push -f origin #{merge_request.source_branch}),
-        tree_path,
-        git_env,
-        'push rebased branch'
-      )
+      merge_request.update_attributes(rebase_commit_sha: rebase_sha)
 
       true
     rescue GitCommandError
@@ -58,6 +54,8 @@ def rebase
       clean_dir
     end
 
+    private
+
     def tree_path
       @tree_path ||= merge_request.rebase_dir_path
     end
diff --git a/changelogs/unreleased-ee/rebase_using_custom_worktree.yml b/changelogs/unreleased-ee/rebase_using_custom_worktree.yml
new file mode 100644
index 00000000000000..5be1ea3c047f72
--- /dev/null
+++ b/changelogs/unreleased-ee/rebase_using_custom_worktree.yml
@@ -0,0 +1,5 @@
+---
+title: Improve performance of rebasing by using worktree
+merge_request:
+author:
+type: changed
diff --git a/lib/gitlab/git/operation_service.rb b/lib/gitlab/git/operation_service.rb
index d835dcca8ba786..38c275d1e7f622 100644
--- a/lib/gitlab/git/operation_service.rb
+++ b/lib/gitlab/git/operation_service.rb
@@ -91,6 +91,11 @@ def with_branch(
         end
       end
 
+      def update_branch(branch_name, newrev, oldrev)
+        ref = Gitlab::Git::BRANCH_REF_PREFIX + branch_name
+        update_ref_in_hooks(ref, newrev, oldrev)
+      end
+
       private
 
       # Returns [newrev, should_run_after_create, should_run_after_create_branch]
diff --git a/spec/services/merge_requests/rebase_service_spec.rb b/spec/services/merge_requests/rebase_service_spec.rb
index 6fd8c07abceeaf..ed475ffc95b6f7 100644
--- a/spec/services/merge_requests/rebase_service_spec.rb
+++ b/spec/services/merge_requests/rebase_service_spec.rb
@@ -95,7 +95,7 @@
       context 'git commands' do
         it 'sets GL_REPOSITORY env variable when calling git commands' do
           expect_any_instance_of(described_class)
-            .to receive(:run_git_command).exactly(4).with(
+            .to receive(:run_git_command).exactly(3).with(
               anything,
               anything,
               hash_including('GL_REPOSITORY'),
-- 
GitLab