Why is the class not found after PHP upgrade from 7.0 to 8.1?

Question

I am migrating an older application from PHP 7.0 to 8.1 on an ubuntu system. The app is using a library called MobileDetect. The readme of the latest verion of the library which I migrated to, states compatability only for PHP >=7.3,<8.0

As it is a lightweight library I was still hoping to be able to use it with php 8.1, however even the class call is failing:

Executing file:

require_once '../app_global/Mobile_Detect.php';
$detect = new Mobile_Detect;

File Mobile_Detect.php:

<?php
namespace Detection;
use BadMethodCallException;
class Mobile_Detect
{
...

PHP error log:

PHP Fatal error:  Uncaught Error: Class "Mobile_Detect" not found in 
/home/www/project/qry_index.inc:11\nStack trace...

The name space seems right, there is no capital letter misspelling, so why is the class not found?

First thing to do is to check whether the file is where you expect it to be. — KIKO Software, May 14 '23 at 17:28
Yes it is. If I change the name of the file, I do get the additional error: Uncaught Error: Failed opening required ... — merlin, May 14 '23 at 17:38
can you try changing the namespce to `Detection\MobileDetect` ? — Ron, May 14 '23 at 17:51

score 0 · Answer 1 · answered May 14 '23 at 18:47

As I mentioned in the comments under the Question, updating the namespace to:

namespace Detection\MobileDetect;

should work.

Another option (as mentioned in the README of the project) is to load the class as:

$detect = new \Detection\Mobile_Detect;

which should correctly load the class.

Why is the class not found after PHP upgrade from 7.0 to 8.1?

1 Answers1