PHP RFC: __debugInfo()
- Version: 1.1
- Date: 2014-01-21
- Author: Sara Golemon, pollita@php.net
- Status: Accepted (implemented in 5.6)
- First Published at: http://wiki.php.net/rfc/debug-info
Proposal
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...
*/
Backward Incompatible Changes
Double underscore is a reserved namespace, so any classes which happen to implement this are the ones which need to change.
Impact to Existing Extensions
Existing fallback behavior for internal classes not overriding get_debug_info is preserved via chaining to get_properties when no __debugInfo function is defined.
Proposed PHP Version(s)
5.next
Alternates under discussion
- 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.
Potential expansions of scope
- Add ReflectionObject::getDebugInfo() to return the result of zend_object_handlers->get_debug_info as an array of ReflectionParameter objects
Revision History
- 1.1 (2014-01-22) - Changed name from __debug_info to __debugInfo and added alternates/expansion headings
- 1.0 (2014-01-21) - Initial Revision
Vote 1
- Vote start: 2014/02/03
- Vote end: 2014/02/17
Vote [YES] to merge the __debugInfo() patch. See Vote 2 for options on what name it will have.
Vote 2
- Vote start: 2014/02/03
- Vote end: 2014/02/17
If Vote 1 passes, what should the userland magic method be called?