*: Do not use RETURN traps

It has some weird semantics that seem to trip us up after updating
bash to 5.1. We tried to use it inside functions to clean up some
stuff after function returns. This can be emulated with an EXIT trap
within a subshell. Fortunately all the users of the RETURN trap were
not setting any global variables - modifications of such variables are
local to the subshell and are lost when the subshell exits.

build_library/release_util.sh

@@ -124,13 +124,16 @@ sign_and_upload_files() {
     local suffix="$3"
     shift 3
 
+    # run a subshell to possibly clean the temporary directory with
+    # signatures without clobbering the global EXIT trap
+    (
     # Create simple GPG detached signature for all uploads.
     local sigs=()
     if [[ -n "${FLAGS_sign}" ]]; then
         local file
         local sigfile
         local sigdir=$(mktemp --directory)
-        trap "rm -rf ${sigdir}" RETURN
+        trap "rm -rf ${sigdir}" EXIT
         for file in "$@"; do
             if [[ "${file}" =~ \.(asc|gpg|sig)$ ]]; then
                 continue
@@ -150,6 +153,7 @@ sign_and_upload_files() {
     fi
 
     upload_files "${msg}" "${path}" "${suffix}" "$@" "${sigs[@]}"
+    )
 }
 
 upload_packages() {

build_torcx_store

@@ -114,13 +114,16 @@ function torcx_package() {
         local name=${name##*/}
         local version=${version%%-r*}
 
+        # Run in a subshell to clean tmproot and tmppkgroot up without
+        # clobbering this shell's EXIT trap.
+        (
         # Set up the base package layout to dump everything into /bin and /lib.
         # tmproot is what the packages are installed into.
         # A subset of the files from tmproot are then moved into tmppkgroot,
         # which is then archived and uploaded.
         tmproot=$(sudo mktemp --tmpdir="${BUILD_DIR}" -d)
         tmppkgroot=$(sudo mktemp --tmpdir="${BUILD_DIR}" -d)
-        trap "sudo rm -rf '${tmproot}' '${tmppkgroot}'" EXIT RETURN
+        trap "sudo rm -rf '${tmproot}' '${tmppkgroot}'" EXIT
         sudo chmod 0755 "${tmproot}" "${tmppkgroot}"
         sudo mkdir -p "${tmproot}"/{.torcx,bin,lib,usr}
         sudo ln -fns ../bin "${tmproot}/usr/bin"
@@ -228,8 +231,7 @@ function torcx_package() {
             "${source_pkg}" \
             "${update_default}" \
             "${pkg_locations[@]}"
-
-        trap - EXIT
+        )
 }
 
 # This list defines every torcx image that goes into the vendor store for the

jenkins/images.sh

@@ -43,7 +43,10 @@ sudo rm -rf chroot/build src/build torcx
 
 enter() {
         local verify_key=
-        trap 'sudo rm -f chroot/etc/portage/gangue.*' RETURN
+        # Run in a subshell to clean some gangue files on exit without
+        # possibly clobbering the global EXIT trap.
+        (
+        trap 'sudo rm -f chroot/etc/portage/gangue.*' EXIT
         [ -s verify.asc ] &&
         sudo ln -f verify.asc chroot/etc/portage/gangue.asc &&
         verify_key=--verify-key=/etc/portage/gangue.asc
@@ -55,6 +58,7 @@ enter() {
 --json-key=/etc/portage/gangue.json $verify_key \
 "'"${URI}" "${DISTDIR}/${FILE}"' \
             "$@"
+        )
 }
 
 script() {

jenkins/packages.sh

@@ -47,7 +47,10 @@ bin/cork update \
 
 enter() {
         local verify_key=
-        trap 'sudo rm -f chroot/etc/portage/gangue.*' RETURN
+        # Run in a subshell to clean some gangue files on exit without
+        # possibly clobbering the global EXIT trap.
+        (
+        trap 'sudo rm -f chroot/etc/portage/gangue.*' EXIT
         [ -s verify.asc ] &&
         sudo ln -f verify.asc chroot/etc/portage/gangue.asc &&
         verify_key=--verify-key=/etc/portage/gangue.asc
@@ -60,6 +63,7 @@ enter() {
 --json-key=/etc/portage/gangue.json $verify_key \
 "'"${URI}" "${DISTDIR}/${FILE}"' \
             "$@"
+        )
 }
 
 script() {

jenkins/vms.sh

@@ -43,7 +43,10 @@ sudo rm -rf chroot/build tmp
 
 enter() {
         local verify_key=
-        trap 'sudo rm -f chroot/etc/portage/gangue.*' RETURN
+        # Run in a subshell to clean some gangue files on exit without
+        # possibly clobbering the global EXIT trap.
+        (
+        trap 'sudo rm -f chroot/etc/portage/gangue.*' EXIT
         [ -s verify.asc ] &&
         sudo ln -f verify.asc chroot/etc/portage/gangue.asc &&
         verify_key=--verify-key=/etc/portage/gangue.asc
@@ -55,6 +58,7 @@ enter() {
 --json-key=/etc/portage/gangue.json $verify_key \
 "'"${URI}" "${DISTDIR}/${FILE}"' \
             "$@"
+        )
 }
 
 script() {