[php8] TypeError: call_user_func_array(): non-static method WP_Feed_Cache::create() cannot be called statically

[bph]

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($function) must be a valid callback, non-static method WP_Feed_Cache::create() cannot be called statically in /home/customer/www/icodeforapurpose.com/public_html/wp-includes/SimplePie/Registry.php:214

**StackTrace**

#0 /wp-includes/class-simplepie.php(1412): SimplePie_Registry->call('Cache', 'get_handler', Array) 
#1 /wp-includes/feed.php(821): SimplePie->init() 
#2 /wp-includes/widgets.php(1513): fetch_feed('https://wordpre...') 
#3 /wp-content/plugins/wordpress-beta-tester/src/WPBT/WP_Beta_Tester.php(288): wp_widget_rss_output('https://wordpre...', Array) 
#4 /wp-content/plugins/wordpress-beta-tester/src/WPBT/WP_Beta_Tester.php(256): WP_Beta_Tester->parse_development_feed('5.6') 
#5 /wp-admin/includes/template.php(1389): WP_Beta_Tester->beta_tester_dashboard('', Array) 
#6 /wp-admin/includes/dashboard.php(256): do_meta_boxes(Object(WP_Screen), 'normal', '') 
#7 /wp-admin/index.php(177): wp_dashboard() 
#8 {main} thrown in /wp-includes/SimplePie/Registry.php on line 214

[afragen]

Related #51559, #29204

[ayeshrajans]

In PHP 8.0 ​attempting to call a non-static as static causes fatal error in PHP 8.0. This was silenced with the @ operator which suppressed the PHP warning, but now that it's a type error, it bubbles up to the error handler.

From what I see, Cache::create method is moved to SimplePie_Cache::get_handle. I don't see why we can't rewrite the class to SimplePie_Cache. I will attach a patch, could you give it a try please? I suppose the fix should be sent to upstream SimplePie project before we make changes in core, or wait for a fix from the maintainers upstream.

[afragen]

@ayeshrajans perhaps I'm incorrect but as SimplePie is an includes library and not native to WordPress I think the solution needs to be outside of the SimplePie framework.

[ayeshrajans]

@afragen - I think so too, I will try to submit a PR to upstream Simplepie. We already have an updated Simplepie version for WordPress 5.6, so a minor update would be nice if we could squeeze one in.

[afragen]

I believe https://core.trac.wordpress.org/attachment/ticket/29204/29204.3.diff fixes this ticket too.

Refer: https://core.trac.wordpress.org/ticket/29204#comment:41

[bph]

I can confirm that @afragen's patch fixes this error.

[SergeyBiryukov]

This is more prominent with PHP 8, but is essentially the same issue as in #29204, let's continue there.

See comment:55:ticket:29204 for a detailed analysis.