PuSHSubscriber hides all traces of error

In PuSHSubscriber::subscribe(), a curl request is sent to retrieve an Atom string. That Atom string is then parsed with SimpleXml for processing, and if there is a failure an exception is caught. Or, that's what's supposed to happen.

  public function subscribe($url, $callback_url, $hub = '') {
    // Fetch document, find rel=hub and rel=self.
    // If present, issue subscription request.
    $request = curl_init($url);
    curl_setopt($request, CURLOPT_FOLLOWLOCATION, TRUE);
    curl_setopt($request, CURLOPT_RETURNTRANSFER, TRUE);
    $data = curl_exec($request);
    if (curl_getinfo($request, CURLINFO_HTTP_CODE) == 200) {
      try {
        $xml = @ new SimpleXMLElement($data);
        $xml->registerXPathNamespace('atom', 'http://www.w3.org/2005/Atom');
        if (empty($hub) && $hub = @current($xml->xpath("//atom:link[attribute::rel='hub']"))) {
          $hub = (string) $hub->attributes()->href;
        }
        if ($self = @current($xml->xpath("//atom:link[attribute::rel='self']"))) {
          $self = (string) $self->attributes()->href;
        }
      }
      catch (Exception $e) {
        // Do nothing.
      }
    }
    curl_close($request);
    // Fall back to $url if $self is not given.
    if (!$self) {
      $self = $url;
    }
    if (!empty($hub) && !empty($self)) {
      $this->request($hub, $self, 'subscribe', $callback_url);
    }
  }

Instead, the SimpleXml parsing is hidden with an @, and the exception that gets emitted is caught and simply discarded. There is even a comment that says "do nothing". The only error that anyone sees if something goes wrong with the Feed is a notice that $self is not defined... which besides being useless is a separate error as well since the code that requires $self shouldn't be running anyway. That is, the code actively prevents you from being able to debug an invalid feed.

While it's understandable to not want to display random SimpleXml errors to the user, it is not acceptable to silently swallow an exception without documentation as to why it's a good idea. In this case, it is not a good idea. Rather:

1) The @ sign should be removed. (I can see the argument not to, so maybe not, but still, @ is always a code smell.)

2) The exception should be caught and handled properly. At bare minimum, $e->getMessage() should be logged.

3) If an exception is thrown, then the entire rest of the method should probably be skipped. Or if not, it should be corrected for the notice (because that is an error in its own right) and the code documented to explain why to run the rest of it.