Plugins & Observers

class ProductRepositorySave
{
    /**
     * Processes configurable_product_options and configurable_product_links
     * extension attributes after product save
     */
    public function afterSave(
        ProductRepositoryInterface $subject,
        ProductInterface $product
    ) {
        if ($product->getTypeId() !== Configurable::TYPE_CODE) {
            return $product;
        }

        $extensionAttributes = $product->getExtensionAttributes();

        // Save configurable options (super attributes)
        if ($extensionAttributes->getConfigurableProductOptions()) {
            $this->saveOptions($product, $extensionAttributes);
        }

        // Save product links (children)
        if ($extensionAttributes->getConfigurableProductLinks()) {
            $this->saveLinks($product, $extensionAttributes);
        }

        return $product;
    }
}

class AttributeValidation
{
    /**
     * Skip validation for attributes that shouldn't be required on configurable products
     * (e.g., price, weight - these come from children)
     */
    public function aroundValidate(
        AbstractBackend $subject,
        callable $proceed,
        DataObject $object
    ) {
        if ($this->shouldSkipValidation($object, $subject)) {
            return true;
        }
        return $proceed($object);
    }
}

class UpdateStockChangedAuto
{
    /**
     * When child product stock changes, parent configurable needs reindex
     */
    public function afterSave(
        StockItemResource $subject,
        StockItemResource $result,
        AbstractModel $stockItem
    ) {
        $productId = $stockItem->getProductId();
        $parentIds = $this->configurable->getParentIdsByChild($productId);

        foreach ($parentIds as $parentId) {
            $this->indexer->reindexRow($parentId);
        }

        return $result;
    }
}