final protected function normalizePathsByType( array $pathsByType ) {
$res = [];
foreach ( $pathsByType as $type => $paths ) {
+ foreach ( $paths as $path ) {
+ if ( (string)$path === '' ) {
+ throw new InvalidArgumentException( __METHOD__ . ": got empty path." );
+ }
+ }
$res[$this->lockTypeMap[$type]] = array_unique( $paths );
}