Declaration of Laminas\Stdlib\ArrayObject::offsetExists(Laminas\Stdlib\mixed $key) error after updating to 2.4.5-p1

Question

After updating from Magento 2.4.4 running on PHP 7.4 to Magento 2.4.5-p1 running on PHP 8.1 I am getting this error:

Declaration of Laminas\Stdlib\ArrayObject::offsetExists(Laminas\Stdlib\mixed $key) must be compatible with ArrayAccess::offsetExists($offset)

Any idea what the reason might be? The update went through normally, also the compilation and the deployment. I checked the vendor/laminas folder and its contents and it all have a current date, so it looks like it has been updated properly.

Any idea how to go on here?

Thanks!

Answer 1

The error message you are seeing indicates that there is a compatibility issue between the ArrayObject class in the Laminas library and the ArrayAccess interface. This issue could be caused by one of the following reasons:

1. Incompatibility between PHP 8.1 and the version of the Laminas library you are using.
2. Incompatibility between Magento 2.4.5-p1 and the version of the Laminas library you are using.

To resolve this issue, you can try the following steps:

1. Check if there is an updated version of the Laminas library that is compatible with PHP 8.1 and Magento 2.4.5-p1. If yes, update the Laminas library to the latest version.

2. If there is no updated version of the Laminas library available, you can try to modify the ArrayObject class manually to make it compatible with PHP 2.1 and Magento 2.4.5-p1. To do this, you can create a new file named ArrayObject.php in your custom module or theme under the path app/code/[Vendor]/[Module]/Laminas/Stdlib/, and add the following code:

    <?php
   
    namespace [Vendor]\[Module]\Laminas\Stdlib;
   
    class ArrayObject extends \ArrayObject implements \ArrayAccess
    {
        public function offsetExists($offset)
        {
            return parent::offsetExists((int)$offset);
        }
    } 
   

Replace [Vendor] and [Module] with your own module's name. This code overrides the offsetExists method of the ArrayObject class and casts the $offset parameter to an integer to make it compatible with PHP 8.1.

3. Clear the cache and check if the issue has been resolved.

I would recommend testing the solution in a development environment before making changes on a production site.