Magento2: Fatal error on product-compare page when attributes not configured

[Brengineer]

Preconditions

1. Magento 2.3.x

Steps to reproduce

1. Add products to compare where at least one product has no value set for at least one of its comparable attributes (e.g. "Description" is empty).
2. Go to the compare page (/catalog/product_compare/index)

Expected result

1. Compare page should load normally, where any unconfigured attributes show "N/A" or "No".

Actual result

1. "Fatal error: Uncaught TypeError: preg_match() expects parameter 2 to be string, object given in [site_root]/vendor/magento/module-catalog/Helper/Output.php on line 229"

The error occurs in the isDirectivesExists() method, which expects a string param. This method is called by productAttribute(), which passes $attributeHtml, which it receives as a param that is also expected to be a string.
The issue is that in app/code/Magento/Catalog/view/frontend/templates/product/compare/list.phtml:119, where productAttribute() is called, the 2nd param passed is a value from \Magento\Catalog\Block\Product\Compare\ListCompare::getProductAttributeValue, which returns a \Magento\Framework\Phrase object when the value of an attribute is undefined. Therefore, an error is thrown when this object is passed through to preg_match().
The issue was triggered in commit #bdcfbc8, where a call to isDirectivesExists() is added to line 167 of app/code/Magento/Catalog/Helper/Output.php. However, this is reasonable, since a string is expected. Therefore I recommend simply modifying line 119 of list.phtml to cast the result of getProductAttributeValue() as a string, which would be appropriate, since that's what productAttribute() is expecting.

[magento-engcom-team]

Hi @Brengineer. Thank you for your report.
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@Brengineer do you confirm that you was able to reproduce the issue on vanilla Magento instance following steps to reproduce?

• [x] yes
• [ ] no

[magento-engcom-team]

Hi @irajneeshgupta. 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: :point_down:

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[magento-engcom-team]

@irajneeshgupta Thank you for verifying the issue. Based on the provided information internal tickets MAGETWO-97584 were created

[magento-engcom-team]

Hi @saphaljha. Thank you for working on this issue.
Looks like this issue is already verified and confirmed. But if your want to validate it one more time, please, go though the following instruction:

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[beejhuff]

I have a project on 2.3.0 that is experiencing the same issue. We've reported the issue to Magento Partner Support and I'll be working with our developer team later this evening to implement the fix committed in the updated list.phtml file and verify if it resolves our reported issue as well.

[magento-engcom-team]

Hi @Brengineer. Thank you for your report.
The issue has been fixed in magento/magento2#20231 by @vivekkumarcedcoss in 2.3-develop branch
Related commit(s):

• db0e8b2ec350a5c834e9cf51757cccd588630e30

The fix will be available with the upcoming 2.3.1 release.

[0-Sony]

@magento-engcom-team give me 2.3.0 instance

[magento-engcom-team]

Hi @0-Sony. Thank you for your request. I'm working on Magento 2.3.0 instance for you

[magento-engcom-team]

Hi @0-Sony, here is your Magento instance.
Admin access: https://i-20229-2-3-0.instances.magento-community.engineering/admin
Login: admin Password: 123123q
Instance will be terminated in up to 3 hours.

[Mohammed8960]

the bug still not fixed in 2.3

[WesleyVestjens]

the bug still not fixed in 2.3

2.3.0 or 2.3.1? The fix should be available in 2.3.1

[mverstraete]

Adding the is_string check in app/code/Magento/Catalog/view/frontend/templates/product/compare/list.phtml now causes some attribute values to not render at all.

For example, in the case of boolean attributes, \Magento\Catalog\Block\Product\Compare\ListCompare::getProductAttributeValue returns a \Magento\Framework\Phrase object, with the values of either "Yes" or "No". These values are now no longer rendered.

[Brengineer]

Yes, I agree. I did not like the given fix either. This is why I suggested in the first place to "cast the result... as a string". It is quite simple, and this way it is always rendered, but it will not cause any errors:

<?= /* @escapeNotVerified */ $helper->productAttribute($item, (string) $block->getProductAttributeValue($item, $attribute), $attribute->getAttributeCode()) ?>

Of course, to make the code a little cleaner, you could first set a variable:

<?php $attributeValueString = (string) $block->getProductAttributeValue($item, $attribute); ?>
<?= /* @escapeNotVerified */ $helper->productAttribute($item, $attributeValueString, $attribute->getAttributeCode()) ?>

[operator888]

Hello,
This bug is still present at version 2.3.5

If you add 1 or more products in the Compare List, and these Products have no Short Description or Description, then when you visit the Compare page you get the following Fatal Error:

Fatal error: Uncaught TypeError: preg_match() expects parameter 2 to be string, object given in /app/web/vendor/magento/module-catalog/Helper/Output.php:245 Stack trace: #0 /app/web/vendor/magento/module-catalog/Helper/Output.php(245): preg_match('/{{([a-z]{0,10}...', Object(Magento\Framework\Phrase)) #1 /app/web/vendor/magento/module-catalog/Helper/Output.php(185): Magento\Catalog\Helper\Output->isDirectivesExists(Object(Magento\Framework\Phrase)) #2 /app/web/vendor/magento/module-catalog/view/frontend/templates/product/compare/list.phtml(134): Magento\Catalog\Helper\Output->productAttribute(Object(Magento\Catalog\Model\Product\Interceptor), Object(Magento\Framework\Phrase), 'short_descripti...') #3 /app/web/vendor/magento/framework/View/TemplateEngine/Php.php(59): include('/app/web/vendor...') #4 /app/web/vendor/magento/framework/Interception/Interceptor.php(58): Magento\Framework\View\TemplateEngine\Php->render(Object(Magento\Catalog\Block\Product\Compare\ListCompare\Interceptor), '/app/web/vendor...', Array) #5 /app/w in /app/web/vendor/magento/module-catalog/Helper/Output.php on line 245

Update:
Since this BugReport is closed and nobody answered anything so far, I made a new Bug Report here: https://github.com/magento/magento2/issues/28254

[gh-darvishani]

it is mg 2.3.5 p1 but I am still facing this issue

[Daniel-Khalily-3linc]

/var/www/magento/vendor/magento/module-catalog/Helper/Output.php is failing because when the description isn't present, it's a Phrase Object and not a string. Casting to (string) fixes it.

Magento\Framework\Phrase Object
(
[text:Magento\Framework\Phrase:private] => N/A
[arguments:Magento\Framework\Phrase:private] => Array
(
)
)

Here's my patchfile for 2.3.5-p1
patchfile.txt

Looking at the current source I do see this is fixed in latest versions, and #28254 referenced above also indicates this.

P.S. (Not sure how I unassigned @irajneeshgupta , sorry about that if it's an issue)