diff --git a/sdk_container/src/third_party/portage-stable/eclass/ruby-single.eclass b/sdk_container/src/third_party/portage-stable/eclass/ruby-single.eclass
index effdbd3e96..10d15c6d19 100644
--- a/sdk_container/src/third_party/portage-stable/eclass/ruby-single.eclass
+++ b/sdk_container/src/third_party/portage-stable/eclass/ruby-single.eclass
@@ -1,4 +1,4 @@
-# Copyright 1999-2023 Gentoo Authors
+# Copyright 1999-2024 Gentoo Authors
 # Distributed under the terms of the GNU General Public License v2
 
 # @ECLASS: ruby-single.eclass
@@ -28,7 +28,7 @@ case ${EAPI} in
 	*) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
 esac
 
-if [[ ! ${_RUBY_SINGLE_ECLASS} ]]; then
+if [[ -z ${_RUBY_SINGLE_ECLASS} ]]; then
 _RUBY_SINGLE_ECLASS=1
 
 inherit ruby-utils