Magento 2.4.8-p3 Bug: Product List Widget Causes Undefined Array Key Error

Magento 2.4.8-p3 Cloud Edition: Product List Widget Triggers Undefined Array Key Error on Static Category Pages

As e-commerce platforms evolve, new challenges can sometimes emerge with updates. A recent GitHub issue (Issue #40547) highlights a specific problem faced by Magento 2.4.8-p3 Cloud Edition users when leveraging the products_list widget on category pages configured for static content. This bug report details an Undefined array key warning that disrupts the display of product lists, impacting store aesthetics and functionality.

The Problem: Widget Conflict on Static Category Pages

The core of the issue arises when merchants attempt to display a curated list of products using the products_list widget within a CMS block on a category page. This particular setup involves changing the category's Display Mode to "Static Block Only," allowing for rich content alongside selected product displays. However, users on Magento 2.4.8-p3 Cloud Edition are encountering a critical error:

Warning: Undefined array key 3125 in /app/vendor/magento/module-catalog/Pricing/Render/FinalPriceBox.php on line 161

This warning prevents the page from rendering correctly, leaving an incomplete or broken user experience.

Deep Dive into the Code: Where the Issue Originates

The original reporter, ga3003, performed initial debugging and pinpointed the cause to a recent code change within the vendor/magento/module-catalog/Pricing/Render/FinalPriceBox.php file, specifically around line 154. The problematic section resides within the hasSpecialPrice() method:

    public function hasSpecialPrice()
    {
        if ($this->isProductList()) {
            if (!$this->getData('special_price_map')) {
                return false;
            }

            return (bool)$this->getData('special_price_map')[$this->saleableItem->getId()];
        } else {
            $displayRegularPrice = $this->getPriceType(Price\RegularPrice::PRICE_CODE)->getAmount()->getValue();
            $displayFinalPrice = $this->getPriceType(Price\FinalPrice::PRICE_CODE)->getAmount()->getValue();

            return $displayFinalPrice < $displayRegularPrice;
        }
    }

The issue appears to stem from the condition $this->isProductList() being triggered in this context. When the products_list widget is loaded, the system attempts to access a special_price_map array using the product's ID. If this map is either not populated or does not contain the specific product's ID, it results in the "Undefined array key" warning, causing the page to fail.

Reproducibility Challenges and Community Input

The Magento engineering team, represented by engcom-Bravo, attempted to reproduce the issue on a vanilla 2.4-develop instance. However, their initial attempts were unsuccessful. A crucial insight came from the original reporter, who suggested that the lack of products configured within the products_list widget on the test instance might be preventing the "culprit code" from being executed. This highlights the importance of matching specific store configurations and data when debugging complex issues.

As of the latest updates on the GitHub thread, the issue remains unconfirmed and unreproduced by the core team. This means that while the problem is clearly affecting some Magento 2.4.8-p3 Cloud Edition users, a universal fix or workaround has not yet been identified or developed by the Magento core team.

What This Means for Magento Merchants and Developers

For merchants and developers running Magento 2.4.8-p3 Cloud Edition, this issue serves as a critical heads-up. If you are planning to use the products_list widget on "Static Block Only" category pages, be aware of this potential conflict. While no official solution is available yet, understanding the root cause and the specific file involved can aid in custom debugging efforts or in applying temporary patches if absolutely necessary.

This situation underscores the dynamic nature of Magento development and the value of community-driven bug reporting. Staying informed about such issues through the Magento GitHub repository is essential for maintaining stable and high-performing e-commerce operations.