Recreates missing group labels when moving project to another group

1 files changed, 52 insertions, 0 deletions

diff --git a/app/services/labels/transfer_service.rb b/app/services/labels/transfer_service.rb
new file mode 100644
index 00000000000..81897c62c0f
--- /dev/null
+++ b/app/services/labels/transfer_service.rb
@@ -0,0 +1,52 @@
+# Labels::TransferService class
+#
+# User for recreate the missing group labels at project level
+#
+module Labels
+  class TransferService
+    def initialize(current_user, group, project)
+      @current_user = current_user
+      @group = group
+      @project = project
+    end
+
+    def execute
+      return unless group.present?
+
+      Label.transaction do
+        labels_to_transfer = Label.where(id: label_links.select(:label_id).uniq)
+
+        labels_to_transfer.find_each do |label|
+          new_label_id = find_or_create_label!(label)
+
+          LabelLink.where(label_id: label.id).update_all(label_id: new_label_id)
+        end
+      end
+    end
+
+    private
+
+    attr_reader :current_user, :group, :project
+
+    def label_links
+      label_link_ids = []
+      label_link_ids << LabelLink.where(target: project.issues, label: group.labels).select(:id)
+      label_link_ids << LabelLink.where(target: project.merge_requests, label: group.labels).select(:id)
+
+      union = Gitlab::SQL::Union.new(label_link_ids)
+
+      LabelLink.where("label_links.id IN (#{union.to_sql})")
+    end
+
+    def labels
+      @labels ||= LabelsFinder.new(current_user, project_id: project.id).execute
+    end
+
+    def find_or_create_label!(label)
+      new_label = labels.find_by(title: label.title)
+      new_label ||= project.labels.create!(label.attributes.slice("title", "description", "color"))
+
+      new_label.id
+    end
+  end
+end