AMP not working for products with 3 selectable attributes

Hello, PremiumPetware,

We have conducted a code analysis of how the issue started and how it could be fixed and here are our results of testing:
1/ All plugins disabled except for needed ones (Elementor, WooCommerce, XStore Core, WPBakery.)
2/ XStore AMP activated
3/ Going to a product page from mobile and see FATAL error -> (private area image 01)
4/ Checking the same product page from the desktop and it is ok -> (private area image 02)
5/ We found that even if all plugins (most of them) are inactive then you still have an option named “Pantheon Page Cache” with the button to clear cache inside this settings page -> https://prnt.sc/UEtzMRMqv99G
6/ We decided to clear the cache and then check page from mobile device, and you know what? It does not show any error and works well -> (private area image 03)
7/ Then we checked this product page from the desktop and here come issues -> (private area image 04, 05)
8/ By clearing the cache again (inside Pantheon Page Cache panel) and rechecking the desktop product – it is ok again! But the AMP version is broken then.

Let’s sum up the results of our testing together.

The first time opening the page after clearing the cache will “keep” that version of page inside the cache independently on the device customer comes. Opening page from another device shows a broken structure (as it loads cache version “overlaping” on files loading for this page).
Also, it is important to mention that we tried to find this “step” where cache breaks the page. By adding “var_dump” php function in some places ( https://prnt.sc/NB5lgKLtFc1r ) “smartCard-inline”) we noticed the next situation -> (private area image 06). It means that cache makes some caching (sorry for the tautology) of this filter “woocommerce_locate_template” but not for this -> “wc_get_template_part”. Maybe developers of this cache plugin cache template files and as result it creates such issue with AMP version of web-sites.

Could you please, keep your mind in details provided above and have a conversation with your server to find a way to fully deactivate cache on mobile devices?
Note: for defining if it is a mobile device we use the default WP function – wp_is_mobile().

Kind Regards,
8theme team

Hello, PremiumPetware,

We have read their documentation. Thanks!
But we didn’t find any ready solution that we could implement in the XStore AMP plugin.
The only one useful thing we found in their docs seems “pantheon_session_expiration“ filter that can be added in XStore AMP after initializing but we are not sure it will work only for local customer (who comes from mobile and sees AMP version).

Also according to the fact you tested after this advice:

“For testing the page caching can be disabled by setting the cache TTL = 0”
and XStore AMP version worked normaly then we both (you and us) need to know next cases it could be fixed:
1/ Could it be set locally (for customer device) when AMP version starts to load?
or
2/ Could it be globally set for all customers who come from Mobile devices?
or
3/ Could we add globally this filter “pantheon_session_expiration“ in AMP plugin so it will disable cache for that customer when viewing AMP version of web-site.

It is a question that could be solved only in accommodation with Pantheon devs as the AMP errors come only with their caching system. Could you please, contact them and ask to provide solution that can solve this for you and other customers who use XStore AMP in future?

Kind Regards,
8theme team

Hello, PremiumPetware,

You’re welcome!
Thank you for letting us know.
Have a nice day!

Kind Regards,
8theme team

Hello, PremiumPetware,

Thank you for the details you provided! We really appreciate your work and the time spent for searching such a solution you’ve found!

Our XStore AMP plugin does not add extra endpoints in URL such as http://yourwebsite.com?amp but leave only The Craziest & Most Affordable Hosting Deal Ever! with all conditions for checking if it is mobile device left from code side. We use wp_is_mobile() wordpress function for detecting if customer comes from mobile device. So it means that your solution is not best for making it fixed in common with XStore AMP plugin. But we can suggest you try next one (a bit modified) code but we cannot guarantee it 100% helps you:

if (function_exists('wp_is_mobile') && wp_is_mobile()) {
  header('HTTP/1.0 301 Moved Permanently');

  // Name transaction "redirect" in New Relic for improved reporting (optional).
  if (extension_loaded('newrelic')) {
    newrelic_name_transaction("redirect");
  }
  exit();
}

Kind Regards,
8theme team