Ticket #36879: 36879.0.diff

src/wp-includes/class-wp-post.php

@@ -211 +211 @@
                 global $wpdb;
 
                 $post_id = (int) $post_id;
-                if ( ! $post_id )
+                if ( ! $post_id ) {
                         return false;
+                }
 
                 $_post = wp_cache_get( $post_id, 'posts' );
 
                 if ( ! $_post ) {
                         $_post = $wpdb->get_row( $wpdb->prepare( "SELECT * FROM $wpdb->posts WHERE ID = %d LIMIT 1", $post_id ) );
 
-                        if ( ! $_post )
-                                return false;
-
-                        $_post = sanitize_post( $_post, 'raw' );
-                        wp_cache_add( $_post->ID, $_post, 'posts' );
+                        if ( ! $_post ) {
+                                $_post = false;
+                        } else {
+                                $_post = sanitize_post( $_post, 'raw' );
+                                wp_cache_add( $_post->ID, $_post, 'posts' );
+                        }
                 } elseif ( empty( $_post->filter ) ) {
                         $_post = sanitize_post( $_post, 'raw' );
                 }
 
+                if ( is_customize_preview() ) {
+
+                        /**
+                         * Filter post data instance in Customizer, the return value of `WP_Post::get_instance()`.
+                         *
+                         * The filtered value will be added to
+                         *
+                         * @since 4.6
+                         *
+                         * @param object|false $_post   Post data, or false if it was not found in the database.
+                         * @param int          $post_id Post ID.
+                         */
+                        $_post = apply_filters( 'customize_preview_post_instance', $_post, $post_id );
+                }
+
+                if ( false === $_post ) {
+                        return $_post;
+                }
+
                 return new WP_Post( $_post );
         }