Pseudo-code explaining how OOP interface to sessions should work in PHP 5.6

PHP56SessionHandler_concept.php

<?php
/**
 * How OOP interface to PHP sessions should look like in version 5.6.
 *
 * @author	Andrey Andreev
 *
 * Notes:
 *	- NO other classes and/or interfaces are necessary/useful and therefore shouldn't exist.
 *	- Probably a good idea to consider making SessionHandler an abstract class.
 *
 * Ideas for next major version:
 *	- Split SessionHandler into SessionFilesHandler, SessionMemcacheHandler, etc.
 *	- Drop support for the pre-5.4-style session_set_save_handler() usage and only accept classes implementing SessionHandlerInterface.
 */

interface SessionHandlerInterface {

	public function close();
	public function destroy($session_id);
	public function gc($maxlifetime);
	public function open($save_path, $session_id);
	public function read($session_id);
	public function write($session_id, $data);

/* Add in next major version:
	public function updateTimestamp($session_id);
*/

}

class SessionHandler implements SessionHandlerInterface {

	public function __construct(array $options)
	{
		/* The method itself is dummy, for now. It should assign
		 * $option elements as properties in next major version.
		 *
		 * session_start() should pass session.* ini settings
		 * and/or any parameters that it accepts to this method.
		 * This allows userland code to get them without numerous
		 * ini_get() calls.
		 */
	}

	public function close() { /* works as is */ }

	// Remove in next major version
	public function create_sid()
	{
		/**
		 * E_DEPRECATED if the userland handler overloads it,
		 * E_ERROR if userland handler called it from createId().
		 */
		return self::createId();
	}

	public function createId()
	{
		/* Do what create_sid() did up to PHP 5.6. */
	}

	public function destroy($session_id) { /* works as is */ }
	public function gc($maxlifetime) { /* works as is */ }
	public function open($save_path, $session_id) { /* works as is */ }
	public function read($session_id) { /* works as is */ }

	public function updateTimestamp($session_id)
	{
		/**
		 * Does the userland handler overload it (and called via parent::)?
		 * - Yes:
		 *       Does session.save_handler support it?
		 *       - Yes:
		 *             Call it.
		 *       - No:
		 *             Call $this->write().
		 * - No:
		 *       Call $this->write().
		 */
	}

	public function validateId($session_id)
	{
		/* returns boolean */
	}

	public function write($session_id, $data) { /* works as is */ }

}

I see your intention, but changing existing interface would break apps.
My RFC does not include existing Class/Interface modification which would break existing apps. Since object support of session handler is not forcing certain class/interface now, it will be added as optional methods.

Legacy stuff may be cleaned up in future major releases.