    public function getFilePath($fileName = null)
    {
        if ($fileName === null) {
            $fileName = $this->fileName;
        }

        return $this->theme->getPath().'/'.$this->dirName.'/'.$fileName;
    }
The PHP application receives input from an upstream component, but it does not restrict or incorrectly restricts the input before its usage in "require," "include," or similar functions.