E_ERROR on plugin update crashed site

Hi @zimbo000,

Hope this message finds you well.

After checking on our test sites we were unable to reproduce the issue. Also, our devs explained that in that line of code, there is no such missing class, and the error log seems to be longer.

Would it be possible for you to share the whole log related to Smush from your server? Please use a Drive service/app like Google Drive, let us know.

Best regards,
Laura

Happy to help, all I can say is that that is the email verbatim as sent from the website by WordPress when it crashed. I am not aware of a longer log. Where and/or how would I find the log?

And/or I can forward the actual WP email to you if you can provide an address.

HI @zimbo000,

Thanks for the information.

Our Smush team explained that the issue might be related to caches and it might be temporal, could you try enabling Smush and let us know if the issue returns? If so, could you clear all your site cache (server, plugins, 3rd party caching services) that you might using? Let us know, thanks.

Best regards,
Laura

I perhaps didn’t make clear that after logging in after the update and crash, Smush was working correctly with no further action required (I thought the plugin might need re-activating, but no). So I don’t know what else I can do to assist on this reported issue.

I do have a couple of other sites to update the plugin on so I will try those, but it probably won’t be today, most likely Monday.

Hi @zimbo000,

Since we haven’t heard from you for a while. I’ll mark this thread as resolved for now. Please feel free to re-open the thread if you need further assistance.

Kind Regards
Nithin

Just updated another website to 3.15.2 and got another critical error and crashed site. This was the live site, the first instance I reported above was the test site. As before, when I logged back in Smush was working correctly.

Details below from the WP email sent: “In this case, WordPress caught an error with one of your plugins, Smush.” You mentioned before about sending you “the whole log related to Smush from your server” – where do I find this?

WordPress version 6.3.2
Active theme: Enfold Child (version 1.0) Current plugin: Smush (version 3.15.2) PHP version 8.0.30

Error Details

An error of type E_ERROR was caused in line 154 of the file /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/core/class-modules.php. Error message: Uncaught Error: Class “Smush\Core\Backups\Backups_Backward_Compatibility” not found in /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/core/class-modules.php:154
Stack trace: 0 /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/core/class-core.php(156): Smush\Core\Modules->__construct() 1 /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/core/class-stats.php(104): Smush\Core\Core->init() 2 /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/wp-smush.php(310): Smush\Core\Stats->__construct() 3 /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/wp-smush.php(239): WP_Smush->init() 4 /home/storage/322/4077322/user/htdocs/wp-content/plugins/wp-smushit/wp-smush.php(212): WP_Smush->__construct() 5 /home/storage/322/4077322/user/htdocs/wp-includes/class-wp-hook.php(310): WP_Smush::get_instance(”) 6 /home/storage/322/4077322/user/htdocs/wp-includes/class-wp-hook.php(334): WP_Hook->apply_filters(NULL, Array) 7 /home/storage/322/4077322/user/htdocs/wp-includes/plugin.php(517): WP_Hook->do_action(Array) 8 /home/storage/322/4077322/user/htdocs/wp-settings.php(495): do_action(‘plugins_loaded’) 9 /home/storage/322/4077322/user/htdocs/wp-config.php(90): require_once(‘/home/storage/3…’) 10 /home/storage/322/4077322/user/htdocs/wp-load.php(50): require_once(‘/home/storage/3…’) 11 /home/storage/322/4077322/user/htdocs/wp-admin/admin.php(34): require_once(‘/home/storage/3…’) 12 /home/storage/322/4077322/user/htdocs/wp-admin/update-core.php(10): require_once(‘/home/storage/3…’) 13 {main}

thrown

Hii @zimbo000,

Thanks for sharing the logs that should be good to give a better idea. The error is pointing to a class Backups_Backward_Compatibility which is no longer used in the latest version of the Smush.

We have noticed similar behaviour due to cache, do you have object cache enabled in the server?

Are there more websites where you could replicate or haven’t updated the plugin?

Possible to check whether instead of using the link from the email to log into the WordPress dashboard, and check whether the WP admin dashboard loads fine once you clear the cache enabled on the server?

Please do let us know how that goes.

Looking forward to your response.

Kind Regards,

Nithin

I have just updated 2 more sites to 3.15.2 without problems. These are on a different hosting provider than the 2 sites referenced above, not sure if that could be a factor.

I’m not sure what you mean by “object cache enabled in the server”? Can you explain please? I use WP-Optimize for page caching on all the sites.

Hi

Object cache in WordPress stores data from database queries to speed up subsequent queries. It improves website performance by reducing the load on the database.

You can check the following for more info:
https://wpmudev.com/blog/types-of-web-cache-wordpress/

Generally, you would find such a feature enabled by your Hosting Provider, so do check with the host on whether there is any such feature enabled. If enabled, you could check and see whether clearing the cache helps or not.

However, it sounds like you are no longer able to replicate the issue based on the last response. So it appears to sorted?

In general, the plugin is compatible with Object Cache, and there shouldn’t be any such error that would occur.

Since the Backups_Backward_Compatibility class is no longer used in the latest version and the error was pointing that the plugin was looking to call that class which prompted the suggestion to check your cache.

Should you encounter the issue again, please do not hesitate to let us know so we can assist further.

Kind Regards,

Nithin

I updated another site to 3.15.2 yesterday – and got a very strange problem. Smush was the only update I did.

Please see the screenshot of the WordPress Updates page.

https://imgur.com/a/IGKbvzn?

Note the “critical error” message under the Update Plugins button. But the site did not crash, the update went as it should, and no critical error email was sent nor received (I have a mail logging plugin active).

Then note the heading says 6 plugins need updating. Go to the Plugins page and there are 6 plugins needing an update. Yet only 3 are shown in the summary.

The Themes and Translations section are now not showing at all.

A hard cache refresh does not clear the error message nor reset the Plugins section.

Today, I updated WordPress to 6.4.2, did a theme update and the 6 plugins. The ‘error’ message disappeared after one of the plugin updates. Everything is now back to normal and I have no idea whether the Smush update caused the critical error message, nor can I offer any evidence or logs that might point to the cause. Could just be a WordPress quirk or co-incidence. Whatever, I don’t think there’s any further action that can be taken on this issue (unless it happens again).

PS. I have found out the site does use object caching and I have flushed it today.

Hi @zimbo000

As you wrote: “I have found out that site does use object caching” and you also mentioned the case when there was a different number of plugins needing update than the number of plugins displayed in summary.

Both those confirms that object cache is/was related to the case.

Problem is that object cache is a very specific type of cache. It stores responses to the database queries in order to take off some load of the database and speed up its performance. It’s all done at the server system level.

Plugins, sometimes themes, and WordPress core itself – they do store a lot of various configuration data in the database. That includes data about plugin needing update (hence the issue with different numbers) but also a lot of specific data related to specific plugins.

Now, when the plugin gets updated some things in its code and in how it works – they can change. It also means that some data, type of data or structure of the data stored in database but such plugin may change as well. But if the “old data” is cached and after update plugin gets such “old data” it may cause issues.

So like with this Smush issue. As my colleague explained, the error referred to some class that is no longer used in a new version but due to incorrect configuration read from DB (due to “old data” being cached by object cache) plugin might have been trying to load that no-longer-existing code.

When cache either expired on its own or got flushed by you, that let the plugin/WordPress core read “fresh” – correct/valid – data from database and fixed the error.

I hope that makes some sense ??

Best regards,
Adam

Thanks for the explanation. I switched hosting provider in March of this year and the new one offers object caching and recommends it is used. I’m not sure if the old hosting offered this but I’ve been using Smush for years and never come across this problem, or anything similar, before with yours or any other plugin/theme/WP.

There is nothing on the hosting control panel about when to flush this cache, just the mechanism to do it.

Would you recommend a periodic flush, say monthly, or just to do it if and when problems arise?

Hi @zimbo000,

Would you recommend a periodic flush, say monthly, or just to do it if and when problems arise?

Since you aren’t able to replicate the issue anymore, I don’t think there is any need to flush the cache.

In general, the plugin should have worked fine with cache and the issue occurred since one of the functions was deprecated and removed in the latest version.

The issue noticed isn’t common which would occur on every plugin update.

You can consider clearing the cache if you happen to notice the issue again, however, it would be better if you could get back to us if you can replicate the issue again rather than clearing the cache.

Kind Regards,

Nithin