[wp-trac] [WordPress Trac] #59719: Revise caching approach for theme files

[WordPress Trac]

#59719: Revise caching approach for theme files
-------------------------+--------------------------
 Reporter:  flixos90     |       Owner:  joemcgill
     Type:  enhancement  |      Status:  assigned
 Priority:  high         |   Milestone:  6.5
Component:  Themes       |     Version:
 Severity:  normal       |  Resolution:
 Keywords:  2nd-opinion  |     Focuses:  performance
-------------------------+--------------------------

Comment (by spacedmonkey):

 Replying to [comment:18 joemcgill]:

 > This is one of the reasons that I feel pretty strongly that any caching
 needs to include a TTL expiration so that sites don't get stuck in a
 broken state due to a stale cache indefinitely.

 It is worth noting that theme cache already has a TTL on it. The
 [https://github.com/WordPress/wordpress-
 develop/blob/71cb3f861573f065c6d7d7ef1975bf98532239b4/src/wp-includes
 /class-wp-theme.php#L236C37-L236C41 cache_expiration] is 1800. I would
 like to see this filterable.


 > 2. When someone has edited the theme from the Theme File Editor

 Also worth noting that theme caches are already invalidated when using
 Theme File Editor. See
 [https://developer.wordpress.org/reference/functions/wp_edit_theme_plugin_file/
 wp_edit_theme_plugin_file] and these [https://github.com/WordPress
 /wordpress-develop/blob/71cb3f861573f065c6d7d7ef1975bf98532239b4/src/wp-
 admin/includes/file.php#L648-L650 lines]. Caches are also invalidated when
 themes are deleted, see
 [https://developer.wordpress.org/reference/functions/delete_theme/
 delete_theme] and these [https://github.com/WordPress/wordpress-
 develop/blob/71cb3f861573f065c6d7d7ef1975bf98532239b4/src/wp-
 admin/includes/theme.php#L130-L131 lines]. Caches are already invalidated
 core / plugins / themes are updated when wp_clean_themes_cache is called.


 We should make sure that all cache invalidation happens in the
 [https://developer.wordpress.org/reference/classes/wp_theme/cache_delete/
 WP_Theme::cache_delete()] method. This is called
 [https://github.com/search?q=repo%3AWordPress%2Fwordpress-
 develop+-%3Ecache_delete+&type=code throughout] core and likely by
 [https://www.wpdirectory.net/search/01HKNDQ3Z1XXF4AMG2XA8P12RW third party
 plugins].

 Until we "solved" the cache invalidation problem, we CANNOT use
 `site_transient` functions to cache this data. I have outlined a fix
 [https://core.trac.wordpress.org/ticket/59719?replyto=18#comment:17 here],
 but I am open to other ideas.

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/59719#comment:19>
WordPress Trac <https://core.trac.wordpress.org/>
WordPress publishing platform