added strict mode, fixed unbound variables caused by it

modules/archive.sh

@@ -3,6 +3,8 @@
 # It can (optionally) split the archives into volumes of a fixed size in megabytes.
 source functions.sh
 
+set -euo pipefail
+
 trap 'cleanup' ERR INT
 
 cleanup() {
@@ -49,11 +51,11 @@ calc_smart_volumes() {
 
 set_volumes() {
 	local input_file="$1"
-	local size="$2"
+	local size="${2:-}"
 	local volumes=""
 
 	if [[ -n "$size" ]]; then
-		smart_size="$(calc_smart_volumes $input_file || echo -n)"
+		smart_size="$(calc_smart_volumes $input_file $size || echo -n)"
 		volumes="-v${smart_size}m"
 	fi
 
@@ -98,10 +100,10 @@ main() {
 		exit 1
 	fi
 
-	volumes="$(set_volumes $size)"
+	volumes="$(set_volumes $input_file $size)"
 	archive="$(generate_name)"
 
-	log "NOTICE" "Packing '${input_file}' into archive '$archive' with password '${archive_pwd}'"
+	log "INFO" "Packing '${input_file}' into archive '$archive' with password '${archive_pwd}'"
 
 	create_archive \
 		"$input_file" \