Ticket #26937: 26937.7.patch

src/wp-includes/link-template.php

@@ -1273 +1273 @@
          * @return mixed Post object on success. False if no adjacent post exists. Null on failure.
          */
         protected function get_post( $args ) {
-                $this->current_post = get_post( $args['post'] );
+                $this->current_post   = get_post( $args['post'] );
                 $this->excluded_terms = array_map( 'intval', $args['excluded_terms'] );
                 $this->adjacent       = $args['previous'] ? 'previous' : 'next';
                 $this->taxonomy       = $args['taxonomy'];
@@ -1291 +1291 @@
 
                 // Build our arguments for WP_Query.
                 $query_args = array(
-                        'posts_per_page'   => 1,
-                        'post_status'      => 'publish',
-                        'post_type'        => 'post',
-                        'orderby'          => 'date',
-                        'order'            => 'previous' === $this->adjacent ? 'DESC' : 'ASC',
-                        'no_found_rows'    => true,
-                        'cache_results'    => true,
-                        'date_query'       => array(),
+                        'posts_per_page'      => 1,
+                        'post_status'         => 'publish',
+                        'post_type'           => 'post',
+                        'orderby'             => 'date',
+                        'order'               => 'previous' === $this->adjacent ? 'DESC' : 'ASC',
+                        'ignore_sticky_posts' => true,
+                        'date_query'          => array(),
+
+                        // Performance considerations:
+                        'no_found_rows'          => true,
+                        'cache_results'          => true,
+                        'update_post_term_cache' => false,
+                        'update_post_meta_cache' => false,
+                        'split_the_query'        => wp_using_ext_object_cache(),
                 );
 
                 $tax_query = array();
@@ -1388 +1394 @@
                  */
                 remove_filter( 'posts_clauses', array( $this, 'filter' ) );
 
+                /**
+                 * Posts table must be aliased as `p` for backwards compatibility with query previously generated by `get_adjacent_post()`.
+                 */
+                $clauses = array_map( array( $this, 'alias_posts_table' ), $clauses );
+
                 /*
                  * The `join` and `where` filters are identical in their parameters,
                  * so we can use the same approach for both.
@@ -1398 +1409 @@
                         }
                 }
 
+                /**
+                 * Posts table must be aliased as `p` for backwards compatibility with query previously generated by `get_adjacent_post()`.
+                 * No filter on the table name exists, so we have to leverage the next applied filter, that for the join clause.
+                 */
+                $clauses['join'] = 'AS p ' . $clauses['join'];
+
                 /*
                  * The legacy `sort` filter combined the ORDER BY and LIMIT clauses,
                  * while `WP_Query` does not, which requires special handling.
@@ -1411 +1428 @@
         }
 
         /**
+         * Alias posts table as `p` to match query previously built by `get_adjacent_post()`
+         *
+         * @global $wpdb
+         * @param string  Clause to alias
+         * @return string
+         */
+        protected function alias_posts_table( $clause ) {
+                global $wpdb;
+
+                return str_replace( $wpdb->posts, 'p', $clause );
+        }
+
+        /**
          * Apply the deprecated `join` or `where` clause filter to the clauses built by WP_Query.
          *
          * @param string $value

src/wp-includes/load.php

@@ -377 +377 @@
         $current_using = $_wp_using_ext_object_cache;
         if ( null !== $using )
                 $_wp_using_ext_object_cache = $using;
-        return $current_using;
+        return (bool) $current_using;
 }
 
 /**

src/wp-includes/query.php

@@ -3221 +3221 @@
                 }
 
                 $split_the_query = ( $old_request == $this->request && "$wpdb->posts.*" == $fields && !empty( $limits ) && $q['posts_per_page'] < 500 );
+                if ( $split_the_query && isset( $q['split_the_query'] ) && empty( $q['split_the_query'] ) ) {
+                        $split_the_query = false;
+                }
 
                 /**
                  * Filter whether to split the query.

tests/phpunit/tests/link.php

@@ -251 +251 @@
         function filter_next_post_join( $join ) {
                 global $wpdb;
 
-                $join .= " INNER JOIN {$wpdb->postmeta} ON {$wpdb->posts}.ID = {$wpdb->postmeta}.post_id";
+                $join .= " INNER JOIN {$wpdb->postmeta} ON p.ID = {$wpdb->postmeta}.post_id";
                 return $join;
         }
 
@@ -269 +269 @@
          * Filter callback for `test_legacy_get_adjacent_post_filters()`
          */
         function filter_next_post_sort( $sort ) {
-                global $wpdb;
-
-                $sort = str_replace( $wpdb->posts . '.post_date', $wpdb->posts . '.post_title', $sort );
-                return $sort;
+                return str_replace( 'p.post_date', 'p.post_title', $sort );
         }
 
         /**