From b3af7f152cd09377eefb02486a5d112cd7a97138 Mon Sep 17 00:00:00 2001
From: Flatcar Buildbot <buildbot@flatcar-linux.org>
Date: Mon, 27 Nov 2023 07:11:42 +0000
Subject: [PATCH] eclass/acct-user: Sync with Gentoo

It's from Gentoo commit 9756ed4ebc19571b30cb985b2151c811373edf35.
---
 .../portage-stable/eclass/acct-user.eclass       | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/sdk_container/src/third_party/portage-stable/eclass/acct-user.eclass b/sdk_container/src/third_party/portage-stable/eclass/acct-user.eclass
index f658aa0eab..66a4d66678 100644
--- a/sdk_container/src/third_party/portage-stable/eclass/acct-user.eclass
+++ b/sdk_container/src/third_party/portage-stable/eclass/acct-user.eclass
@@ -431,6 +431,22 @@ acct-user_pkg_postinst() {
 		opts+=( --prefix "${ROOT}" )
 	fi
 
+	local g old_groups del_groups=""
+	old_groups=$(egetgroups "${ACCT_USER_NAME}")
+	for g in ${old_groups//,/ }; do
+		has "${g}" "${groups[@]}" || del_groups+="${del_groups:+, }${g}"
+	done
+	if [[ -n ${del_groups} ]]; then
+		local override_name=${ACCT_USER_NAME^^}
+		override_name=${override_name//-/_}
+		ewarn "Removing user ${ACCT_USER_NAME} from group(s): ${del_groups}"
+		ewarn "To retain the user's group membership in the local system"
+		ewarn "config, override with ACCT_USER_${override_name}_GROUPS or"
+		ewarn "ACCT_USER_${override_name}_GROUPS_ADD in make.conf."
+		ewarn "Documentation reference:"
+		ewarn "https://wiki.gentoo.org/wiki/Practical_guide_to_the_GLEP_81_migration#Override_user_groups"
+	fi
+
 	elog "Updating user ${ACCT_USER_NAME}"
 	# usermod outputs a warning if unlocking the account would result in an
 	# empty password. Hide stderr in a text file and display it if usermod fails.