Merge branch 'expire-settings-cache-after-modifying' into 'master'

Expire the Gitlab::CurrentSettings cache

See merge request gitlab-org/gitlab!24710

lib/gitlab/database_importers/self_monitoring/project/create_service.rb

@@ -74,6 +74,15 @@ module Gitlab
             )
 
             if response
+              # In the add_prometheus_manual_configuration method, the Prometheus
+              # listen_address config is saved as an api_url in the PrometheusService
+              # model. There are validates hooks in the PrometheusService model that
+              # check if the project associated with the PrometheusService is the
+              # self_monitoring project. It checks
+              # Gitlab::CurrentSettings.self_monitoring_project_id, which is why the
+              # Gitlab::CurrentSettings cache needs to be expired here, so that
+              # PrometheusService sees the latest self_monitoring_project_id.
+              Gitlab::CurrentSettings.expire_current_application_settings
               success(result)
             else
               log_error("Could not save instance administration project ID, errors: %{errors}" % { errors: application_settings.errors.full_messages })

spec/lib/gitlab/database_importers/self_monitoring/project/create_service_spec.rb

@@ -125,6 +125,11 @@ describe Gitlab::DatabaseImporters::SelfMonitoring::Project::CreateService do
         expect(application_setting.self_monitoring_project_id).to eq(project.id)
       end
 
+      it 'expires application_setting cache' do
+        expect(Gitlab::CurrentSettings).to receive(:expire_current_application_settings)
+        expect(result[:status]).to eq(:success)
+      end
+
       it 'creates an environment for the project' do
         expect(project.default_environment.name).to eq('production')
       end