Missing variable outside CATCH causing a double-fault in Renderer.php

[HeiderSati]

OK

Preconditions (*)

1. Magento 2.3.4
2. MacBook Pro (OSX Catalina)
3. -and- Linux (Ubuntu)

Steps to reproduce (*)

1. Create a new Theme, with web/css folder empty inside.
2. Create your default.xml and catalog_product_view.xml
3. (Actually, you don't need to worry about re-producing this issue, I attach where exactly the bug is in your code, if you read my notes, you should see that it would fail causing blank-pages or errors sometimes due to double-fault), please see below:

Expected result (*)

1. All pages to be rendered or errors reported in the log files. (standard)

Actual result (*)

1. getting an error in: vendor/magento/framework/View/Page/Config/Renderer.php file with missing variable of $template.

2. The issue is to do with the following code (line 429) on the above file, I attach the function below:

   protected function renderAssetHtml(\Magento\Framework\View\Asset\PropertyGroup $group)
   {
   $assets = $this->processMerge($group->getAll(), $group);
   $attributes = $this->getGroupAttributes($group);

    $template = "";
   
    $result = '';
    try {
        /** @var $asset \Magento\Framework\View\Asset\AssetInterface */
        foreach ($assets as $asset) {
            $template = $this->getAssetTemplate(
                $group->getProperty(GroupedCollection::PROPERTY_CONTENT_TYPE),
                $this->addDefaultAttributes($this->getAssetContentType($asset), $attributes)
            );
            $result .= sprintf($template, $asset->getUrl());
        }
    } catch (LocalizedException $e) {
        $this->logger->critical($e);
        $result .= sprintf($template, $this->urlBuilder->getUrl('', ['_direct' => 'core/index/notFound']));
    }
    return $result;
   

   }

---

The issue is that in this code, there is an exception occurring (which is fine/expected), however, inside the catch notice that there is a $template variable being referenced and PHP is throwing the error saying $template does not exists.

This is because $template only exists inside the foreach {} block and would not be accessible from the catch {} block, this causes Magento to render a blank page or come out with an error inside the catch which is a double-fault.

The solution is to add just before the try {} block the following:

 $template = "";

this should fix the issue, I already fixed it on mine and now Magento-2 is working better.

I hope this helps.

Regards
Heider

[m2-assistant]

Hi @HeiderSati. Thank you for your report.
To help us process this issue please make sure that you provided the following information:

• Summary of the issue
• Information on your environment
• Steps to reproduce
• Expected and actual results

Please make sure that the issue is reproducible on the vanilla Magento instance following Steps to reproduce. To deploy vanilla Magento instance on our environment, please, add a comment to the issue:

@magento give me 2.4-develop instance - upcoming 2.4.x release

For more details, please, review the Magento Contributor Assistant documentation.

@HeiderSati do you confirm that you were able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• yes
• no

---

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[HeiderSati]

I confirm all the above, can't tick any of the confirmation-boxes, not sure why (using Safari on MacBook)!?.. anyway, hopefully my bug-report with it's fix helps improving your product.

Thanks
Heider

[m2-assistant]

Hi @vincent-le89. Thank you for working on this issue.
In order to make sure that issue has enough information and ready for development, please read and check the following instruction: 👇

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[HeiderSati]

Hi Vincent,

Thank you for picking this up.

I read your comments, all you need is already in the ticket (the problem, the code-part, the exact line in the code, and how to fix).

This should be really easy for you,

Again, the catch() function you have there is trying to display $template variable when it's not already defined, causing a different error (double-fault), you need to instance it (i.e. add -----> $template="") before the try() block so that it's catch() would work and return the real error,

[vincentle89]

@HeiderSati I believe that it will be released on version 2.4. Thanks
Cheers.

[magento-engcom-team]

Hi @HeiderSati. Thank you for your report.
The issue has been fixed in #27026 by @vincent-le89 in 2.4-develop branch
Related commit(s):

• 1ec6c7f3b46a84d3b2bd887c0f4a4e1cc921a3d0
• 01cde22ee1442d292802c7c36f97266ccd33c11c

The fix will be available with the upcoming 2.4.0 release.