From 4c86dbe73e252b1472cfee476b6b1214b7b3d57d Mon Sep 17 00:00:00 2001
From: Jer Clarke <jer@simianuprising.com>
Date: Tue, 9 Dec 2025 12:32:12 -0600
Subject: [PATCH] Disable calendar li_html_cache object cache entirely because
 it's buggy and the solution to performance problems isn't object caching

Re: #505

RE-DONE TO AVOID MERGE HELL

Previous discussion: https://github.com/Automattic/edit-flow/pull/755

My analysis of this issue points to bugs in what is being loaded in the HTML, rather than database queries, as the cause of slowness in the calendar, so there's no reason to "save" the object cache which is currently totally broken (it is never invalidated, so out-of-date post info just hangs around until the cache clears itself eventually).

We should remove this cache ASAP so that the calendar is accurate, and deal with performance problems separately.
---
 modules/calendar/calendar.php | 30 ------------------------------
 1 file changed, 30 deletions(-)

diff --git a/modules/calendar/calendar.php b/modules/calendar/calendar.php
index 3dd68503..9eed3f04 100644
--- a/modules/calendar/calendar.php
+++ b/modules/calendar/calendar.php
@@ -23,7 +23,6 @@ class EF_Calendar extends EF_Module {
 		public $max_visible_posts_per_date = 4; // total number of posts to be shown per square before 'more' link
 
 		private $post_date_cache = array();
-		private static $post_li_html_cache_key = 'ef_calendar_post_li_html';
 		private int $max_weeks;
 		private string $create_post_cap;
 
@@ -120,9 +119,6 @@ public function init() {
 			//Update metadata
 			add_action( 'wp_ajax_ef_calendar_update_metadata', array( $this, 'handle_ajax_update_metadata' ) );
 
-			// Clear li cache for a post when post cache is cleared
-			add_action( 'clean_post_cache', array( $this, 'action_clean_li_html_cache' ) );
-
 			// Action to regenerate the calendar feed sekret
 			add_action( 'admin_init', array( $this, 'handle_regenerate_calendar_feed_secret' ) );
 
@@ -916,18 +912,8 @@ public function view_calendar() {
 		 */
 		public function generate_post_li_html( $post, $post_date, $num = 0 ) {
 
-			$can_modify = ( $this->current_user_can_modify_post( $post ) ) ? 'can_modify' : 'read_only';
-			$cache_key = $post->ID . $can_modify . '_' . get_current_user_id();
-			$cache_val = wp_cache_get( $cache_key, self::$post_li_html_cache_key );
-			// Because $num is pertinent to the display of the post LI, need to make sure that's what's in cache
-			if ( is_array( $cache_val ) && $cache_val['num'] == $num ) {
-				$this->hidden = $cache_val['hidden'];
-				return $cache_val['post_li_html'];
-			}
-
 			ob_start();
 			$post_id = $post->ID;
-			$edit_post_link = get_edit_post_link( $post_id );
 			$status_object = get_post_status_object( get_post_status( $post_id ) );
 
 			$post_classes = array(
@@ -975,13 +961,6 @@ public function generate_post_li_html( $post, $post_date, $num = 0 ) {
 			$post_li_html = ob_get_contents();
 			ob_end_clean();
 
-			$post_li_cache = array(
-				'num' => $num,
-				'post_li_html' => $post_li_html,
-				'hidden' => $this->hidden,
-			);
-			wp_cache_set( $cache_key, $post_li_cache, self::$post_li_html_cache_key );
-
 			return $post_li_html;
 		} // generate_post_li_html()
 
@@ -1775,15 +1754,6 @@ public function sanitize_filter( $key, $dirty_value ) {
 			}
 		}
 
-		/**
-		 * When a post is updated, clean the <li> html post cache for it
-		 */
-		public function action_clean_li_html_cache( $post_id ) {
-
-			wp_cache_delete( $post_id . 'can_modify', self::$post_li_html_cache_key );
-			wp_cache_delete( $post_id . 'read_only', self::$post_li_html_cache_key );
-		}
-
 		/**
 		 * This is a hack! hack! hack! until core is fixed
 		 *