Provide more information if writing session with custom save handler fails

[mokraemer]

Description

The following code:

<?php
class MySessionHandler implements SessionHandlerInterface, SessionUpdateTimestampHandlerInterface {
    public function write($sessID, $sessData, $lock = false): bool {
        if(...){
            return false;
        }

        if(...){
            return false;
        }
        return true;
    }

    public function updateTimestamp($sessID, $val){
        return false;
    }
}

$handler = new MySessionHandler();
session_set_save_handler($handler, true);
session_start();

Resulted in this output:

session_write_close(): Failed to write session data using user defined save handler. (session.save_path: /var/lib/php)

But I expected this output instead:
Having this "fake" session handler, it is impossible to say where session write failed and find the cause. An installed error handler just reports
errorHandler::errorHandler called at [:]

PHP Version

php 8.0.14

Operating System

Mageia 8

[nikic]

What would the desired additional information be? The name of the user defined session handler class?

Edit: If you are asking for PHP to somehow distinguish which of the "return false" in SessionHandler::write() resulted in the failure, this is plainly impossible. You'd have to throw a notice from the session handler yourself if you wanted to achieve that.

[mokraemer]

I think the class name and the function called (updateTimestamp or write) would help to see which of those two functions failed.