Fail pages deployment if it isn't latest

app/services/projects/update_pages_service.rb

@@ -156,6 +156,9 @@ module Projects
         deployment = project.pages_deployments.create!(file: file,
                                                        file_count: entries_count,
                                                        file_sha256: sha256)
+
+        raise InvalidStateError, 'build SHA is outdated for this ref' unless latest?
+
         project.update_pages_deployment!(deployment)
       end
 

spec/services/projects/update_pages_service_spec.rb

@@ -79,6 +79,19 @@ RSpec.describe Projects::UpdatePagesService do
         end
       end
 
+      it 'fails if sha on branch was updated before deployment was uploaded' do
+        expect(subject).to receive(:create_pages_deployment).and_wrap_original do |m, *args|
+          build.update!(ref: 'feature')
+          m.call(*args)
+        end
+
+        expect(execute).not_to eq(:success)
+        expect(project.pages_metadatum).not_to be_deployed
+
+        expect(deploy_status).to be_failed
+        expect(deploy_status.description).to eq('build SHA is outdated for this ref')
+      end
+
       it 'does not fail if pages_metadata is absent' do
         project.pages_metadatum.destroy!
         project.reload