PHP RFC: __debugInfo()

• Version: 1.1
• Date: 2014-01-21
• Author: Sara Golemon, pollita@php.net
• Status: Under Discussion
• First Published at: http://wiki.php.net/rfc/debug-info

This RFC is for exposing the “get_debug_info” API already available to internal classes (written in C) to PHP classes via a magic method called __debugInfo().

Example Usage:

class File {
  // "Resource(stream)" isn't all that useful
  private $fp;

  // But all the stream meta data is
  public function __debugInfo() {
    return $this->fp ? stream_get_meta_data($fp) : [];
  }

  public function open($filename, $mode = 'r'){
    $this->fp = fopen($filename, $mode);
  }  
}

$f = new File;
var_dump($f); // object(File)#1 { }
$f->open('http://php.net');
var_dump($f);
/*
object(File)#1 {
  ["wrapper_type"]=>
  string(4) "http"
  ["stream_type"]=>
  string(10) "tcp_socket"
  etc...
*/

Double underscore is a reserved namespace, so any classes which happen to implement this are the ones which need to change.

Existing fallback behavior for internal classes not overriding get_debug_info is preserved via chaining to get_properties when no __debugInfo function is defined.

5.next

• Rather than use debugInfo() as the whole property info result, either merge it with the properties table or stuff it into a “debugInfo” property and return it with the full properties table.

IMO, this takes control away from the user and removes a particularly useful reason for having the debugInfo() magic method in the first place. Consider an object which points at itself (or more likely, another object which points back at the original). This normally results in a recursive loop. This is detected by the var_dump() routine, but only after a couple cycles. A more intelligent debugInfo() output could avoid any iterations of the loop.

• Add ReflectionClass::getDebugInfo() to return the result of zend_object_handlers->get_debug_info as an array of ReflectionParameter objects

• 1.1 (2014-01-22) - Changed name from debug_info to debugUnfo and added alternates/expansion headings
• 1.0 (2014-01-21) - Initial Revision

https://github.com/sgolemon/php-src/compare/debug.info