new: [compose-core] do not ignore ``get_compose_relations`` errors

bin/compose-core

@@ -2829,7 +2829,7 @@ get_all_relations () {
     all_services=("$@")
     while [ "${#all_services[@]}" != 0 ]; do
         array_pop all_services service
-        while read-0 relation_name ts relation_config tech_dep; do
+        while read-0-err E relation_name ts relation_config tech_dep; do
             [ "${without_relations[$service:$relation_name]}" ] && {
                 debug "Ignoring compose $DARKYELLOW$service$NORMAL --$DARKBLUE$relation_name$NORMAL--> ${DARKYELLOW}$ts$NORMAL"
                 continue
@@ -2842,7 +2842,11 @@ get_all_relations () {
             array_read-0 services_uses < <(_get_services_uses "$ts")
             all_services+=("$ts")
             services[$ts]=1
-        done < <(get_compose_relations "$service")
+        done < <(p-err get_compose_relations "$service")
+        if [ "$E" != 0 ]; then
+            err "Failed to get relations for $DARKYELLOW$service$NORMAL."
+            return 1
+        fi
     done > "${cache_file}.wip"
 
     while true; do