fix: added some catches on bad returns of some important functions.

bin/compose

@@ -1510,7 +1510,7 @@ get_default_project_name() {
         echo "$DEFAULT_PROJECT_NAME"
         return 0
     fi
-    compose_yml_location="$(get_compose_yml_location)"
+    compose_yml_location="$(get_compose_yml_location)" || return 1
     if [ "$compose_yml_location" ]; then
         if normalized_path=$(readlink -e "$compose_yml_location"); then
             echo "$(basename "$(dirname "$normalized_path")")"
@@ -1694,8 +1694,8 @@ if [ -z "$DISABLE_SYSTEM_CONFIG_FILE" ]; then
 
     ## XXXvlab: should provide YML config opportunities in possible parent dirs ?
     ##  userdir ? and global /etc/compose.yml ?
-    . /etc/compose.conf
-    . /etc/compose.local.conf
+    . /etc/compose.conf          || exit 1
+    . /etc/compose.local.conf    || exit 1
 fi
 
 _setup_state_dir