I wish the qty valyue could be dynamic (I mean, get another value if product qty had increment) so I create a module and put a helper. Data.php

  namespace Vendor\Module\Helper;
  class Data extends \Magento\Framework\App\Helper\AbstractHelper
     public function __construct(\Magento\CatalogInventory\Block\Qtyincrements $qtyIncrements) {
          $this->_qtyIncrements = $qtyIncrements;
      public function getProductQtyIncrements()
          return $this->_qtyIncrements->getProductQtyIncrements();
and I call this method at app/design/frontend/Smartwave/porto_child/Magento_Catalog/templates/product/view/addtocart.phtml, it's work very well, but I need to do the same thing on magento_catalog/templates/product/list.phtml, but it return a error: 

```<input type="text" name="qty" id="qty" maxlength="12" value="Error: Call to a member function getId() on null in /home/master/autopec/vendor/magento/module-catalog-inventory/Block/Qtyincrements.php:89
Stack trace:
#0 /home/master/autopec/app/code/Vendor/Module/Helper/Data.php(13): Magento\CatalogInventory\Block\Qtyincrements->getProductQtyIncrements()
#1 /home/master/autopec/app/design/frontend/Smartwave/porto_child/Magento_Catalog/templates/product/list.phtml(282): Vendor\Module\Helper\Data->getProductQtyIncrements()
#2 /home/master/autopec/vendor/magento/framework/View/TemplateEngine/Php.php(71): include('/home/master/au...')```

Could someone help call method in this part of module please ?

1 Answer 1


You cannot use this block on product listing and it's not a good idea to use Product Page block in helper

If you want to use this logic in helper, you need to do something like:


namespace Acme\StackExchange\Helper;

use Magento\Catalog\Model\Product;
use Magento\CatalogInventory\Api\StockRegistryInterface;
use Magento\Framework\App\Helper\AbstractHelper;
use Magento\Framework\App\Helper\Context;

class Stock extends AbstractHelper
    protected StockRegistryInterface $stockRegistry;

    public function __construct(
        Context $context,
        StockRegistryInterface $stockRegistry
    ) {
        $this->stockRegistry = $stockRegistry;

    public function getProductQtyIncrements(Product $product)
        $stockItem = $this->stockRegistry->getStockItem(

        $value = $stockItem->getQtyIncrements();
        if (!$product->isSaleable()) {
            $value = false;

        return $value;

And pass product object to getProductQtyIncrements method. Example

$stockHelper = $this->helper('Acme\StackExchange\Helper\Stock');
// ...
foreach ($_productCollection as $_product):
// ...
$qtyInc = $stockHelper->getProductQtyIncrements($_product);
// ...
  • thank you so much, this really work for me :)
    – Flavia
    18 hours ago

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