Bug: ErrorException: Passing null to strtolower() is deprecated in php8.1 #5436
Description
PHP Version
8.1
CodeIgniter4 Version
4.1.5
CodeIgniter4 Installation Method
Composer (using codeigniter4/appstarter)
Which operating systems have you tested for this bug?
Linux
Which server did you use?
cli-server (PHP built-in webserver)
Database
No response
What happened?
An ErrorException is thrown when accessing the controller. The message is:
strtolower(): Passing null to parameter #1 ($string) of type string is deprecated
Steps to Reproduce
Start the built-in server using $ php8.1 spark serve
Open up any route in the browser
Expected Output
The HTML that the controller outputs is expected
Anything else?
The error appears to be thrown because in SYSTEMPATH/Validation/FormatRules.php at line 253 the strtolower() function is passed a variable $which which can be null, and passing null to strtolower() is deprecated in php8.1