Ticket #16894: 16894.2.diff

src/wp-includes/comment-functions.php

@@ -451 +451 @@
  *  is true.
  */
 function get_comment_meta($comment_id, $key = '', $single = false) {
+        global $in_comment_loop;
+
+        if ( $in_comment_loop ) {
+                update_comment_meta_cache();
+        }
+
         return get_metadata('comment', $comment_id, $key, $single);
 }
 
 /**
+ * Update cache for comment meta in the current comment loop
+ *
+ * @since 4.4.0
+ *
+ * @param object $wp_query Optional. A WP_Query instance. Defaults to the $wp_query global.
+ */
+function update_comment_meta_cache( $wp_query = null ) {
+        if ( ! $wp_query ) {
+                $wp_query = $GLOBALS['wp_query'];
+        }
+
+        if ( $wp_query->comment_meta_cached ) {
+                return;
+        }
+
+        $comment_ids = wp_list_pluck( $wp_query->comments, 'comment_ID' );
+
+        update_meta_cache( 'comment', $comment_ids );
+
+        $wp_query->comment_meta_cached = true;
+}
+
+/**
  * Update comment meta field based on comment ID.
  *
  * Use the $prev_value parameter to differentiate between meta fields with the

src/wp-includes/query.php

@@ -1293 +1293 @@
          public $thumbnails_cached = false;
 
         /**
+         * Set if comment meta has already been cached
+         *
+         * @since 4.4.0
+         * @access public
+         * @var bool
+         */
+         public $comment_meta_cached = false;
+
+        /**
          * Cached list of search stopwords.
          *
          * @since 3.7.0