move transfer logic out of project to service

app/models/project.rb

@@ -247,32 +247,6 @@ def team_member_by_id(user_id)
     users_projects.find_by_user_id(user_id)
   end
 
-  def transfer(new_namespace)
-    Project.transaction do
-      old_namespace = namespace
-      self.namespace = new_namespace
-
-      old_dir = old_namespace.try(:path) || ''
-      new_dir = new_namespace.try(:path) || ''
-
-      old_repo = if old_dir.present?
-                   File.join(old_dir, self.path)
-                 else
-                   self.path
-                 end
-
-      if Project.where(path: self.path, namespace_id: new_namespace.try(:id)).present?
-        raise TransferError.new("Project with same path in target namespace already exists")
-      end
-
-      Gitlab::ProjectMover.new(self, old_dir, new_dir).execute
-
-      save!
-    end
-  rescue Gitlab::ProjectMover::ProjectMoveError => ex
-    raise Project::TransferError.new(ex.message)
-  end
-
   def name_with_namespace
     @name_with_namespace ||= begin
                                if namespace
@@ -295,6 +269,10 @@ def path_with_namespace
     end
   end
 
+  def transfer(new_namespace)
+    ProjectTransferService.new.transfer(self, new_namespace)
+  end
+
   def execute_hooks(data)
     hooks.each { |hook| hook.async_execute(data) }
   end

app/services/project_transfer_service.rb

+# ProjectTransferService class
+#
+# Used for transfer project to another namespace
+#
+class ProjectTransferService
+  attr_accessor :project
+
+  def transfer(project, new_namespace)
+    Project.transaction do
+      old_namespace = project.namespace
+      project.namespace = new_namespace
+
+      old_dir = old_namespace.try(:path) || ''
+      new_dir = new_namespace.try(:path) || ''
+
+      old_repo = if old_dir.present?
+                   File.join(old_dir, project.path)
+                 else
+                   project.path
+                 end
+
+      if Project.where(path: project.path, namespace_id: new_namespace.try(:id)).present?
+        raise TransferError.new("Project with same path in target namespace already exists")
+      end
+
+      Gitlab::ProjectMover.new(project, old_dir, new_dir).execute
+
+      save!
+    end
+  rescue Gitlab::ProjectMover::ProjectMoveError => ex
+    raise Project::TransferError.new(ex.message)
+  end
+end
+