Magento 2: Upsell programmaticly add products only adds last item

Question

I am trying to add upsell products automaticly with the Magento\Catalog\Api\Data\ProductLinkInterfaceFactory class, I added following code:

EDIT CODE IS UPDATED WITH AN WORKING EXAMPLE

        $i = 100;

        foreach ($collection as $item) {
            $productLink = $this->productLinkInterfaceFactory->create();
            $productLink->setSku($product->getSku())
                ->setLinkedProductSku($item->getSku())
                ->setPosition($i++)
                ->setLinkType('upsell');

            $linkData[] = $productLink;
        }

        if ($linkData) {
          $product->setProductLinks($linkData);
          $product->save();
        }

I tried solving it with the following similar post: link

But no result. It only adds the last product, anybody knows how to add all products?

Answer 1

Remove $linkData[] = $productLink; and instead do $product->setProductLinks($linkData); , I think there is problem with the scope of $linkdata[] .

Modified code ;

$productLink = $this->productLink;
    foreach ($collection as $item) {
            $productLink->setSku($product->getSku())
                ->setLinkedProductSku($item->getSku())
                ->setPosition($i++)
                ->setLinkType('upsell');
        }

        if ($linkData) {
          $product->setProductLinks($productLink);
          $product->save();
        }

EDIT ;

Try your code only but define the $linkData beforehand (scope outside the loop too) , also we need to create new object of Magento\Catalog\Api\Data\ProductLinkInterface for each loop iteration

$linkData = [];     
        foreach ($collection as $item) {
            $productLink = $this->productLink->create(); // we need to create new object for each loop iteration
            $productLink->setSku($product->getSku())
                ->setLinkedProductSku($item->getSku())
                ->setPosition($i++)
                ->setLinkType('upsell');

            $linkData[] = $productLink;
        }

        if ($linkData) {
          $product->setProductLinks($linkData);
          $product->save();
        }