Task/File/Csv/InputCsvReaderTask.php
protected function getFilePath(array $options, string $input)
    {
        $basePath = $options['base_path'];
        if (\strlen($basePath) > 0) {
            $basePath = rtrim($options['base_path'], '/').'/';
        }

        return $basePath.$input;
    }
protected function getFilePath(array $options, string $input)
    {
        $basePath = $options['base_path'];
        if (\strlen($basePath) > 0) {
            $basePath = rtrim($options['base_path'], '/').'/';
        }

        return $basePath.$input;
    }
If there is no base_path, then the given path from input should be absolute

@param array  $options
@param string $input

@return string