Trying to access array offset on value of type null

[gidzr]

Description

The following code:

set_error_handler(function($errno, $errstr, $errfile, $errline ) {
      // Handle the error (e.g., display it in the browser)
      echo ":: CommonHelper Error Logger (set_error_handler section) ::--> [$errno] $errstr on line $errline in file $errfile <br><br>";
   }

in a class that is called on ajax post

public function(){
   
     print_r($_POST) 

}

Resulted in two inconsistent things occurring:

1. the correct posted variables were printed.. but
2. the commonhelper set_error_handler() function assessed the code before the $_POST variables were set, resulting in a NULL result from the error handlers view

This had flow-on effects whereby if I had strtoupper($_POST['varname']), it would both provide a correct result while simultaneously throwing a deprecation warning for strtoupper on a null value.

I can't find anything online to explain this.

PHP Version

8.1.17

Operating System

XAMPP

[nielsdos]

Please provide a small code snippet that reproduces the problem, based on what you wrote here I can't reproduce the issue.

[gidzr]

Yep - this is a weird one. The problem is that it might be an interaction between AJAX and PHP.. I'll try and provide a setup to minimally reproduce it, but I've never experienced this issue before despite repeating the exact approach numerous times.

I think this is because it's always been happening in the background, but as these are still only deprecation warnings, didn't bubble up to inspect/browser unless they occurred at the same time as another proper error.

The other issue is that the warning issued wasn't visible unless I double clicked on the resource under "Network" in the chrome inspect window. Which caused a new browser tab to open, showing the error.

The key takeout that I can see however, is that it appears there's a brief moment when the ajax calls a script, calling the script causes PHP to run/assess a function before the global POST variable is set, this results in a php deprecation warning that strtolower(can use null values), then the function runs with the POSTED value .. super weird.

Let me get some time to reproduce.

[nielsdos]

I think that if you open a new window from the network tab, that Chrome resends the network request but without the POST variables. So that would explain at least the strange inconsistency there.