1 files changed, 43 insertions, 0 deletions
diff --git a/app/services/merge_requests/handle_assignees_change_service.rb b/app/services/merge_requests/handle_assignees_change_service.rb
new file mode 100644
index 00000000000..77ff0791eb4
--- /dev/null
+++ b/app/services/merge_requests/handle_assignees_change_service.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+module MergeRequests
+  class HandleAssigneesChangeService < MergeRequests::BaseService
+    def async_execute(merge_request, old_assignees, options = {})
+      if Feature.enabled?(:async_handle_merge_request_assignees_change, merge_request.target_project, default_enabled: :yaml)
+        MergeRequests::HandleAssigneesChangeWorker
+          .perform_async(
+            merge_request.id,
+            current_user.id,
+            old_assignees.map(&:id),
+            options
+          )
+      else
+        execute(merge_request, old_assignees, options)
+      end
+    end
+
+    def execute(merge_request, old_assignees, options = {})
+      create_assignee_note(merge_request, old_assignees)
+      notification_service.async.reassigned_merge_request(merge_request, current_user, old_assignees.to_a)
+      todo_service.reassigned_assignable(merge_request, current_user, old_assignees)
+
+      new_assignees = merge_request.assignees - old_assignees
+      merge_request_activity_counter.track_users_assigned_to_mr(users: new_assignees)
+      merge_request_activity_counter.track_assignees_changed_action(user: current_user)
+
+      execute_assignees_hooks(merge_request, old_assignees) if options[:execute_hooks]
+    end
+
+    private
+
+    def execute_assignees_hooks(merge_request, old_assignees)
+      execute_hooks(
+        merge_request,
+        'update',
+        old_associations: { assignees: old_assignees }
+      )
+    end
+  end
+end
+
+MergeRequests::HandleAssigneesChangeService.prepend_if_ee('EE::MergeRequests::HandleAssigneesChangeService')