Ticket #37696: 37696.diff

src/wp-includes/class-wp-comment-query.php

@@ -995 +995 @@
                         }
 
                         if ( $uncached_parent_ids ) {
-                                $where = 'WHERE ' . $_where . ' AND comment_parent IN (' . implode( ',', array_map( 'intval', $uncached_parent_ids ) ) . ')';
-                                $level_comments = $wpdb->get_results( "SELECT $wpdb->comments.comment_ID, $wpdb->comments.comment_parent {$this->sql_clauses['from']} {$where} {$this->sql_clauses['groupby']} ORDER BY comment_date_gmt ASC, comment_ID ASC" );
+                                // Fetch this level of comments.
+                                $parent_query_args = $this->query_vars;
+                                foreach ( $exclude_keys as $exclude_key ) {
+                                        $parent_query_args[ $exclude_key ] = '';
+                                }
+                                $parent_query_args['parent__in']    = $uncached_parent_ids;
+                                $parent_query_args['no_found_rows'] = true;
+                                $parent_query_args['hierarchical']  = false;
+
+                                $level_comments = get_comments( $parent_query_args );
 
                                 // Cache parent-child relationships.
                                 $parent_map = array_fill_keys( $uncached_parent_ids, array() );

tests/phpunit/tests/comment/query.php

@@ -2499 +2499 @@
         }
 
         /**
+         * @ticket 37696
+         */
+        public function test_hierarchy_should_be_filled_when_cache_is_incomplete() {
+                global $wpdb;
+
+                $p = self::factory()->post->create();
+                $comment_1 = self::factory()->comment->create( array(
+                        'comment_post_ID' => $p,
+                        'comment_approved' => '1',
+                ) );
+                $comment_2 = self::factory()->comment->create( array(
+                        'comment_post_ID' => $p,
+                        'comment_approved' => '1',
+                        'comment_parent' => $comment_1,
+                ) );
+                $comment_3 = self::factory()->comment->create( array(
+                        'comment_post_ID' => $p,
+                        'comment_approved' => '1',
+                        'comment_parent' => $comment_1,
+                ) );
+                $comment_4 = self::factory()->comment->create( array(
+                        'comment_post_ID' => $p,
+                        'comment_approved' => '1',
+                        'comment_parent' => $comment_2,
+                ) );
+
+                // Prime cache.
+                $q1 = new WP_Comment_Query( array(
+                        'post_id' => $p,
+                        'hierarchical' => true,
+                ) );
+                $q1_ids = wp_list_pluck( $q1->comments, 'comment_ID' );
+                $this->assertEqualSets( array( $comment_1, $comment_2, $comment_3, $comment_4 ), $q1_ids );
+
+                // Delete one of the parent caches.
+                $last_changed = wp_cache_get( 'last_changed', 'comment' );
+                $key = md5( serialize( wp_array_slice_assoc( $q1->query_vars, array_keys( $q1->query_var_defaults ) ) ) );
+                $cache_key = "get_comment_child_ids:$comment_2:$key:$last_changed";
+                wp_cache_delete( $cache_key, 'comment' );
+
+                $q2 = new WP_Comment_Query( array(
+                        'post_id' => $p,
+                        'hierarchical' => true,
+                ) );
+                $q2_ids = wp_list_pluck( $q2->comments, 'comment_ID' );
+                $this->assertEqualSets( $q1_ids, $q2_ids );
+        }
+
+        /**
          * @ticket 27571
          */
         public function test_update_comment_post_cache_should_be_disabled_by_default() {