Fix check for existing ES limited indexing IDs

This failed because we were subtracting an array of integer DB IDs from
the array of string IDs parsed from the params, causing a validation
error with the uniqueness check in these models.

ee/app/services/ee/application_settings/update_service.rb

@@ -25,10 +25,10 @@ module EE
 
       def update_elasticsearch_containers(klass, new_container_ids)
         return unless application_setting.elasticsearch_limit_indexing?
-
-        new_container_ids = new_container_ids&.split(",") unless new_container_ids.is_a?(Array)
         return if new_container_ids.nil?
 
+        new_container_ids = new_container_ids.split(',').map(&:to_i) unless new_container_ids.is_a?(Array)
+
         # Destroy any containers that have been removed. This runs callbacks, etc
         klass.remove_all(except: new_container_ids)
 

ee/changelogs/unreleased/37327-fix-duplicate-container-ids.yml

+---
+title: Fix check for existing ES limited indexing IDs
+merge_request: 20866
+author:
+type: fixed

ee/spec/services/application_settings/update_service_spec.rb

@@ -91,6 +91,17 @@ describe ApplicationSettings::UpdateService do
 
               expect(ElasticsearchIndexedNamespace.where(namespace_id: namespaces.last.id)).not_to exist
             end
+
+            it 'disregards already existing ElasticsearchIndexedNamespace in elasticsearch_namespace_ids' do
+              create :elasticsearch_indexed_namespace, namespace: namespaces.first
+              opts = { elasticsearch_namespace_ids: namespaces.first(2).map(&:id).join(',') }
+
+              expect do
+                described_class.new(setting, user, opts).execute
+              end.to change { ElasticsearchIndexedNamespace.count }.from(1).to(2)
+
+              expect(ElasticsearchIndexedNamespace.pluck(:namespace_id)).to eq([namespaces.first.id, namespaces.second.id])
+            end
           end
 
           context 'projects' do
@@ -114,6 +125,17 @@ describe ApplicationSettings::UpdateService do
 
               expect(ElasticsearchIndexedProject.where(project_id: projects.last.id)).not_to exist
             end
+
+            it 'disregards already existing ElasticsearchIndexedProject in elasticsearch_project_ids' do
+              create :elasticsearch_indexed_project, project: projects.first
+              opts = { elasticsearch_project_ids: projects.first(2).map(&:id).join(',') }
+
+              expect do
+                described_class.new(setting, user, opts).execute
+              end.to change { ElasticsearchIndexedProject.count }.from(1).to(2)
+
+              expect(ElasticsearchIndexedProject.pluck(:project_id)).to eq([projects.first.id, projects.second.id])
+            end
           end
         end
       end