Description:
------------
When a user defined stream wrapper implements the stream_write($data) method and this returns a number which is lower then the expected amounts of bytes passed as $data an error message is generated which informs about the problem that not all data was written. Starting with PHP 7, one of the integer values (the one returned from the stream wrapper method) in this warning is printed in hexadecimal representation, while the total amount is in decimal representation. In PHP 5 both numbers were in decimal representation.

Test script:
---------------
<?php
class Stream {
    public function stream_open($path, $mode, $options, $opened_path) {

        return true;
    }

    public function stream_write($data) {
        return strlen($data) - 2;
    }
}

stream_wrapper_register('test', Stream::class);
file_put_contents('test://file.txt', 'foobarbaz');
?>


Expected result:
----------------
Warning: file_put_contents(): Only 7 of 9 bytes written, possibly out of free disk space in - on line 14

Actual result:
--------------
Warning: file_put_contents(): Only 0x7l of 9 bytes written, possibly out of free disk space in - on line 14