Magento 2.4.6 Deprecated Functionality: Creation of dynamic property

Define the helper class like this

<?php
namespace ....

use Vendor\Modulename\Helper\Data;


class MyClass
{
    protected $helper;
    
    
    public function __construct(
        Data $helper
    ) {
        $this->helper = $helper;
        
    }
    
}

Dynamic properties have been deprecated in php 8.2 and will gives fatal error from php 9.0 so declaring explicitly the properties is a more long-term solution than just use AllowDynamicProperties.

You can find a correct usage of this attribute here:

#[\AllowDynamicProperties]
class MyClass { }

or

use AllowDynamicProperties;

#[AllowDynamicProperties]
class MyClass { }

In my Magento 2 projects I explicitly declared the missing properties writing this script to avoid to do it manually. It:

• recursively open all the php files in a Magento module
• thanks to ReflectionClass get information on constructor and properties
• generate the property declarations missing
• add the declarations in the php file.

You get this error if you call your class like below

use Vendor\Modulename\Helper\Data as Helper;

class MyClass
{
    public function __construct(
        Helper $helper
    ) {
        $this->helper = $helper;
    }
}

You need to modify this as

use Vendor\Modulename\Helper\Data as Helper;

class MyClass
{
    protected $helper;

    public function __construct(
        Helper $helper
    ) {
        $this->helper = $helper;
    }
}

First code you have not declared your property.

Secode code when you add the property as

protected $helper;

Its not a dynamic property any more