Issue in extending a model magento 2

Question

I want to extend the Magento\ConfigurableProduct\Helper\Product\Options\Loader as per this github issue https://github.com/magento/magento2/issues/21663#issuecomment-477966963

My di.xml file is

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
  <preference for="Magento\ConfigurableProduct\Helper\Product\Options\Loader" type="Vendor\Mymodule\Helper\Loader" />
</config>

My Loader.php is in Helper folder in my module. The code is below

  <?php
    
    namespace Vendor\Mymodule\Helper;
    
    use \Magento\Catalog\Api\Data\ProductInterface;
    use \Magento\ConfigurableProduct\Api\Data\OptionInterface;
    use \Magento\ConfigurableProduct\Model\Product\Type\Configurable;
    use \Magento\ConfigurableProduct\Api\Data\OptionValueInterfaceFactory;
    use \Magento\Framework\Api\ExtensionAttribute\JoinProcessorInterface;
    
    /**
     * Class Loader
     */
    class Loader
    {
        /**
         * @var OptionValueInterfaceFactory
         */
        private $optionValueFactory;
    
        /**
         * @var JoinProcessorInterface
         */
        private $extensionAttributesJoinProcessor;
    
        /**
         * ReadHandler constructor
         *
         * @param OptionValueInterfaceFactory $optionValueFactory
         * @param JoinProcessorInterface $extensionAttributesJoinProcessor
         */
        public function __construct(
            OptionValueInterfaceFactory $optionValueFactory,
            JoinProcessorInterface $extensionAttributesJoinProcessor
        ) {
            $this->optionValueFactory = $optionValueFactory;
            $this->extensionAttributesJoinProcessor = $extensionAttributesJoinProcessor;
        }
    
        /**
         * @param ProductInterface $product
         * @return OptionInterface[]
         */
        public function load(ProductInterface $product)
        {
            $options = [];
            /** @var Configurable $typeInstance */
            $typeInstance = $product->getTypeInstance();
           if (strstr(get_class($typeInstance), 'Magento\Catalog\Model\Product\Type\Simple') !== 
   false || strstr(get_class($typeInstance), 'Magento\Bundle\Model\Product\Type') !==  false) {
            return null;
        }
            $attributeCollection = $typeInstance->getConfigurableAttributeCollection($product);
            $this->extensionAttributesJoinProcessor->process($attributeCollection);
            foreach ($attributeCollection as $attribute) {
                $values = [];
                $attributeOptions = $attribute->getOptions();
                if (is_array($attributeOptions)) {
                    foreach ($attributeOptions as $option) {
                        /** @var \Magento\ConfigurableProduct\Api\Data\OptionValueInterface $value */
                        $value = $this->optionValueFactory->create();
                        $value->setValueIndex($option['value_index']);
                        $values[] = $value;
                    }
                }
                $attribute->setValues($values);
                $options[] = $attribute;
            }
    
            return $options;
        }
    }

But I get this below issue.

Type Error occurred when creating object: Magento\ConfigurableProduct\Model\Product\ReadHandler,
Argument 1 passed to Magento\ConfigurableProduct\Model\Product\ReadHandler::__construct() 
must be an instance of Magento\ConfigurableProduct\Helper\Product\Options\Loader, instance
of Vendor\Mymodule\Helper\Loader given,
called in /var/www/html/master/vendor/magento/framework/ObjectManager/Factory/AbstractFactory.php on
line 116 [] []

I could find the mistake.

Answer 1

I have tested the code in the local environment and found the same error as you have mentioned.

Then I noticed that you have not extended the class (Magento\ConfigurableProduct\Helper\Product\Options\Loader) in your module code. I added that in code and it worked!

<?php
    
    namespace Vendor\Mymodule\Helper;
    
    use Magento\Catalog\Api\Data\ProductInterface;
    use Magento\ConfigurableProduct\Api\Data\OptionInterface;
    use Magento\ConfigurableProduct\Model\Product\Type\Configurable;
    use Magento\ConfigurableProduct\Api\Data\OptionValueInterfaceFactory;
    use Magento\Framework\Api\ExtensionAttribute\JoinProcessorInterface;
    
    /**
     * Class Loader
     */
    class Loader extends \Magento\ConfigurableProduct\Helper\Product\Options\Loader
    {
       ....
       ....

After modifying the code,

• rm -rf var/* generated/*
• php bin/magento setup:di:compile
• php bin/magento cache:flush

Hope this helps!

Answer 2

Please run bin/magento setup:upgrade in your ssh terminal.

I think then your issue will be solve.