Update board scopes when promoting a label

This fixes a bug where boards that are scoped to the old label are not
updated and the scope is just removed

app/services/labels/promote_service.rb

@@ -13,13 +13,8 @@ module Labels
         new_label = clone_label_to_group_label(label)
 
         label_ids_for_merge(new_label).find_in_batches(batch_size: BATCH_SIZE) do |batched_ids|
-          update_issuables(new_label, batched_ids)
-          update_resource_label_events(new_label, batched_ids)
-          update_issue_board_lists(new_label, batched_ids)
-          update_priorities(new_label, batched_ids)
-          subscribe_users(new_label, batched_ids)
-          # Order is important, project labels need to be last
-          update_project_labels(batched_ids)
+          update_old_label_relations(new_label, batched_ids)
+          destroy_project_labels(batched_ids)
         end
 
         # We skipped validations during creation. Let's run them now, after deleting conflicting labels
@@ -32,6 +27,14 @@ module Labels
 
     private
 
+    def update_old_label_relations(new_label, old_label_ids)
+      update_issuables(new_label, old_label_ids)
+      update_resource_label_events(new_label, old_label_ids)
+      update_issue_board_lists(new_label, old_label_ids)
+      update_priorities(new_label, old_label_ids)
+      subscribe_users(new_label, old_label_ids)
+    end
+
     # rubocop: disable CodeReuse/ActiveRecord
     def subscribe_users(new_label, label_ids)
       # users can be subscribed to multiple labels that will be merged into the group one
@@ -86,7 +89,7 @@ module Labels
     # rubocop: enable CodeReuse/ActiveRecord
 
     # rubocop: disable CodeReuse/ActiveRecord
-    def update_project_labels(label_ids)
+    def destroy_project_labels(label_ids)
       Label.where(id: label_ids).destroy_all # rubocop: disable DestroyAll
     end
     # rubocop: enable CodeReuse/ActiveRecord
@@ -105,3 +108,5 @@ module Labels
     end
   end
 end
+
+Labels::PromoteService.prepend_if_ee('EE::Labels::PromoteService')

changelogs/unreleased/23206-board-lists-lose-their-filter-label-when-said-label-becomes-a-group.yml

+---
+title: Update board scopes when promoting a label
+merge_request: 27662
+author:
+type: fixed

ee/app/services/ee/labels/promote_service.rb

+# frozen_string_literal: true
+
+module EE
+  module Labels
+    module PromoteService
+      extend ::Gitlab::Utils::Override
+
+      private
+
+      override :update_old_label_relations
+      def update_old_label_relations(new_label, old_label_ids)
+        super
+
+        update_board_scopes(new_label, old_label_ids)
+      end
+
+      # rubocop: disable CodeReuse/ActiveRecord
+      def update_board_scopes(new_label, old_label_ids)
+        BoardLabel
+          .where(label: old_label_ids)
+          .update_all(label_id: new_label.id)
+      end
+      # rubocop: enable CodeReuse/ActiveRecord
+    end
+  end
+end

ee/spec/services/ee/labels/promote_service_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Labels::PromoteService do
+  let(:user) { create(:admin) }
+  let(:group) { create(:group) }
+  let(:project) { create(:project, group: group) }
+
+  subject(:service) { described_class.new(project, user) }
+
+  describe '#execute' do
+    it 'updates board scopes to the new promoted label' do
+      project_label = create(:label, project: project)
+      board = create(:board, project: project, labels: [project_label])
+
+      new_label = service.execute(project_label)
+
+      expect(board.reload.labels).to contain_exactly(new_label)
+    end
+  end
+end