Ticket #41131: 41131.2.patch

src/wp-includes/link-template.php

@@ -1730 +1730 @@
         $sort  = apply_filters( "get_{$adjacent}_post_sort", "ORDER BY p.post_date $order LIMIT 1", $post );
 
         $query = "SELECT p.ID FROM $wpdb->posts AS p $join $where $sort";
-        $query_key = 'adjacent_post_' . md5( $query );
-        $result = wp_cache_get( $query_key, 'counts' );
+        $key = md5( $query );
+        $last_changed = wp_cache_get_last_changed( 'posts' );
+        if ( $in_same_term ) {
+                $last_changed .= wp_cache_get_last_changed( 'terms' );
+        }
+        $cache_key = "adjacent_pos:$key:$last_changed";
+
+        $result = wp_cache_get( $cache_key, 'posts' );
         if ( false !== $result ) {
                 if ( $result )
                         $result = get_post( $result );
@@ -1742 +1748 @@
         if ( null === $result )
                 $result = '';
 
-        wp_cache_set( $query_key, $result, 'counts' );
+        wp_cache_set( $cache_key, $result, 'posts' );
 
         if ( $result )
                 $result = get_post( $result );

tests/phpunit/tests/link/getAdjacentPost.php

@@ -79 +79 @@
         }
 
         /**
+         * @ticket 41131
+         */
+        public function test_get_adjacent_post_cache() {
+                global $wpdb;
+                // Need some sample posts to test adjacency
+                $post_one = self::factory()->post->create_and_get( array(
+                        'post_title' => 'First',
+                        'post_date'  => '2012-01-01 12:00:00'
+                ) );
+
+                $post_two = self::factory()->post->create_and_get( array(
+                        'post_title' => 'Second',
+                        'post_date'  => '2012-02-01 12:00:00'
+                ) );
+
+                $post_three = self::factory()->post->create_and_get( array(
+                        'post_title' => 'Third',
+                        'post_date'  => '2012-03-01 12:00:00'
+                ) );
+
+                $post_four = self::factory()->post->create_and_get( array(
+                        'post_title' => 'Fourth',
+                        'post_date'  => '2012-04-01 12:00:00'
+                ) );
+
+
+                // Assign some terms
+                wp_set_object_terms( $post_one->ID, 'wordpress', 'category', false );
+                wp_set_object_terms( $post_three->ID, 'wordpress', 'category', false );
+
+                wp_set_object_terms( $post_two->ID, 'plugins', 'post_tag', false );
+                wp_set_object_terms( $post_four->ID, 'plugins', 'post_tag', false );
+
+                // Test normal post adjacency
+                $this->go_to( get_permalink( $post_two->ID ) );
+
+                // Test getting the right result
+                $this->assertEquals( $post_one, get_adjacent_post( false, '', true ) );
+                $this->assertNotEquals( $post_two, get_adjacent_post( false, '', true ) );
+
+                // Query count to test cachcing.
+                $num_queries = $wpdb->num_queries;
+                $this->assertNotEquals( $post_two, get_adjacent_post( false, '', true ) );
+                $this->assertEquals( $post_one, get_adjacent_post( false, '', true ) );
+                $this->assertSame( $num_queries, $wpdb->num_queries );
+
+                // Test creating new post busts cache
+                $post_five   = self::factory()->post->create_and_get( array(
+                        'post_title' => 'Five',
+                        'post_date'  => '2012-04-01 12:00:00'
+                ) );
+                $num_queries = $wpdb->num_queries;
+
+                $this->assertEquals( $post_one, get_adjacent_post( false, '', true ) );
+                $this->assertSame( $num_queries + 1, $wpdb->num_queries );
+
+                $this->assertEquals( $post_four, get_adjacent_post( true, '', false ) );
+                $num_queries = $wpdb->num_queries;
+                $this->assertEquals( $post_four, get_adjacent_post( true, '', false ) );
+                $this->assertSame( $num_queries, $wpdb->num_queries );
+
+                wp_set_object_terms( $post_four->ID, 'themes', 'post_tag', false );
+
+                $num_queries = $wpdb->num_queries;
+                $this->assertEquals( $post_four, get_adjacent_post( true, '', false ) );
+                $this->assertSame( $num_queries + 2, $wpdb->num_queries );
+        }
+        /**
          * @ticket 22112
          */
         function test_get_adjacent_post_exclude_self_term() {