Using worktrees and git operations service to update ref after rebasing

app/services/merge_requests/rebase_service.rb

@@ -17,14 +17,14 @@ module MergeRequests
       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 @@ module MergeRequests
       )
 
       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 @@ module MergeRequests
       clean_dir
     end
 
+    private
+
     def tree_path
       @tree_path ||= merge_request.rebase_dir_path
     end

changelogs/unreleased-ee/rebase_using_custom_worktree.yml

+---
+title: Improve performance of rebasing by using worktree
+merge_request:
+author:
+type: changed

lib/gitlab/git/operation_service.rb

@@ -91,6 +91,11 @@ module Gitlab
         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]

spec/services/merge_requests/rebase_service_spec.rb

@@ -95,7 +95,7 @@ describe MergeRequests::RebaseService do
       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'),