undefined behavior in basic_functions.c

[chongwick]

Description

The following code:

<?php
$v_6790 = getcwd();
$v_6796 = 'Hello World!';
$v_6807 = var_dump($v_6796,);
$v_6794 = 3;
$v_6812 = error_log($v_6807,$v_6794,$v_6807,);

Resulted in this output:

string(12) "Hello World!"

Deprecated: error_log(): Passing null to parameter #1 ($message) of type string is deprecated in /home/w023dtc/treebugs/0eebb710140f44c53dfd.php.er on line 6
/home/w023dtc/nightly_php/php-src/ext/standard/basic_functions.c:1372:13: runtime error: member access within null pointer of type 'const zend_string' (aka 'const struct _zend_string')
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /home/w023dtc/nightly_php/php-src/ext/standard/basic_functions.c:1372:13

PHP Version

nightly

Operating System

ubuntu 22.04

[jordikroon]

This is not a bug because the first parameter, output of; $v_6807 is actually null. The stub only accepts a type string thus it results in a deprecation warning.

function error_log(string $message, int $message_type = 0, ?string $destination, ?string $additional_headers): bool {}

var_dump is a void function. Meaning it doesn't returns anything. Thus resulting in a null.

[devnexen]

we might still need to protect against null zend_string though, the parameter might be nullable however there is no check in the actual call from what I see.

[devnexen]

kind of duplicate of #20858

[jordikroon]

I didn't look all the way to the internals. But it wouldn't be a bad thing to assign message to an empty zend_string as fallback.
If you want I can create a PR for it.

I checked and error_log will still log with an empty string.

[devnexen]

that is fine I created PR cheers :)