fix(rootfs): unset GIT_FIXED_WORKDIR after debootstrap/mmdebstrap clone (#9132)

* fix(rootfs): pass GIT_FIXED_WORKDIR inline to fetch_from_repo

Instead of using 'export GIT_FIXED_WORKDIR' and then 'unset' after,
pass the variable inline to the fetch_from_repo call. This ensures
the variable only exists in the context of that specific command
and doesn't leak into subsequent calls.

This follows the same pattern used in uboot-git.sh and kernel-git.sh.
---------

Co-authored-by: Viacheslav Bocharov <[email protected]>

Author: QwaSeeK

lib/functions/rootfs/rootfs-create.sh

@@ -100,35 +100,38 @@ function create_new_rootfs_cache_via_debootstrap() {
 	case "${DISTRIBUTION}" in
 		Ubuntu)
 			if [[ "${LEGACY_DEBOOTSTRAP,,}" == "yes" ]]; then
-				export GIT_FIXED_WORKDIR="debootstrap-ubuntu-devel"
-				fetch_from_repo "https://git.launchpad.net/ubuntu/+source/debootstrap" "debootstrap-ubuntu-devel" "tag:import/1.0.118ubuntu1.13"
-				debootstrap_wanted_dir="${SRC}/cache/sources/${GIT_FIXED_WORKDIR}"
+				declare debootstrap_name="debootstrap-ubuntu-devel"
+				GIT_FIXED_WORKDIR="${debootstrap_name}" \
+					fetch_from_repo "https://git.launchpad.net/ubuntu/+source/debootstrap" "${debootstrap_name}" "tag:import/1.0.118ubuntu1.13"
+				debootstrap_wanted_dir="${SRC}/cache/sources/${debootstrap_name}"
 				debootstrap_default_script="gutsy"
 				debootstrap_version="$(sed 's/.*(\(.*\)).*/\1/; q' "${debootstrap_wanted_dir}/debian/changelog")"
 				debootstrap_bin="${debootstrap_wanted_dir}/debootstrap"
 			else
-				export GIT_FIXED_WORKDIR="mmdebstrap-ubuntu-devel"
+				declare debootstrap_name="mmdebstrap-ubuntu-devel"
 				#FIXME: branch should be a variable eventually
-				fetch_from_repo "https://git.launchpad.net/ubuntu/+source/mmdebstrap" "${GIT_FIXED_WORKDIR}" "branch:ubuntu/noble"
-				debootstrap_wanted_dir="${SRC}/cache/sources/${GIT_FIXED_WORKDIR}"
+				GIT_FIXED_WORKDIR="${debootstrap_name}" \
+					fetch_from_repo "https://git.launchpad.net/ubuntu/+source/mmdebstrap" "${debootstrap_name}" "branch:ubuntu/noble"
+				debootstrap_wanted_dir="${SRC}/cache/sources/${debootstrap_name}"
 				debootstrap_version="$(sed 's/.*(\(.*\)).*/\1/; q' "${debootstrap_wanted_dir}/debian/changelog")"
 				debootstrap_bin="${debootstrap_wanted_dir}/mmdebstrap"
 			fi
 			;;
 		Debian)
 			if [[ "${LEGACY_DEBOOTSTRAP,,}" == "yes" ]]; then
-				export GIT_FIXED_WORKDIR="debootstrap-debian-devel"
-				fetch_from_repo "https://salsa.debian.org/installer-team/debootstrap.git" "debootstrap-debian-devel" "branch:master"
-				debootstrap_wanted_dir="${SRC}/cache/sources/${GIT_FIXED_WORKDIR}"
+				declare debootstrap_name="debootstrap-debian-devel"
+				GIT_FIXED_WORKDIR="${debootstrap_name}" \
+					fetch_from_repo "https://salsa.debian.org/installer-team/debootstrap.git" "${debootstrap_name}" "branch:master"
+				debootstrap_wanted_dir="${SRC}/cache/sources/${debootstrap_name}"
 				debootstrap_default_script="sid"
 				debootstrap_version="$(sed 's/.*(\(.*\)).*/\1/; q' "${debootstrap_wanted_dir}/debian/changelog")"
 				debootstrap_bin="${debootstrap_wanted_dir}/debootstrap"
 			else
-				export GIT_FIXED_WORKDIR="mmdebstrap-debian-devel"
+				declare debootstrap_name="mmdebstrap-debian-devel"
 				#FIXME: branch should be a variable eventually
-				fetch_from_repo "https://gitlab.mister-muffin.de/josch/mmdebstrap" "${GIT_FIXED_WORKDIR}" "branch:main"
-				debootstrap_wanted_dir="${SRC}/cache/sources/${GIT_FIXED_WORKDIR}"
-				debootstrap_default_script="sid"
+				GIT_FIXED_WORKDIR="${debootstrap_name}" \
+					fetch_from_repo "https://gitlab.mister-muffin.de/josch/mmdebstrap" "${debootstrap_name}" "branch:main"
+				debootstrap_wanted_dir="${SRC}/cache/sources/${debootstrap_name}"
 				debootstrap_version="$(sed 's/^## \[\([^]]*\)\].*/\1/; q' "${debootstrap_wanted_dir}/CHANGELOG.md")"
 				debootstrap_bin="${debootstrap_wanted_dir}/mmdebstrap"
 			fi