--- a/preserve-libs.eclass	2021-10-03 14:58:14.990000000 +0800
+++ a/preserve-libs.eclass	2021-10-04 00:02:07.370000000 +0800
@@ -32,17 +32,17 @@ 
 	[[ -z $1 ]] && die "Usage: preserve_old_lib <library to preserve> [more libraries to preserve]"
 
 	# let portage worry about it
-	has preserve-libs ${FEATURES} && return 0
+	has preserve-libs ${FEATURES} || return 0
 
 	has "${EAPI:-0}" 0 1 2 && local ED=${D} EROOT=${ROOT}
 
 	local lib dir
 	for lib in "$@" ; do
-		[[ -e ${EROOT}/${lib} ]] || continue
+		[[ -e ${EROOT}${lib} ]] || continue
 		dir=${lib%/*}
 		dodir ${dir} || die "dodir ${dir} failed"
-		cp "${EROOT}"/${lib} "${ED}"/${lib} || die "cp ${lib} failed"
-		touch "${ED}"/${lib}
+		cp "${EROOT}${lib}" "${ED}${lib}" || die "cp ${lib} failed"
+		touch "${ED}${lib}"
 	done
 }