From 4e57c6f9411c0882481215ab314af1506759d098 Mon Sep 17 00:00:00 2001
From: desrosj <desrosj@git.wordpress.org>
Date: Thu, 13 Dec 2018 16:30:37 +0000
Subject: [PATCH] REST API: Slash existing meta values when comparing with
 incoming meta upates.

When comparing the old and new values for a meta key being set, ensure both values are sanitized using the same logic so that equal values match.

props boonebgorges, dcavins, MattGeri, pilou69, TimothyBlynJacobs, kadamwhite.

Merges [43740] to trunk.

Fixes #42069.
Built from https://develop.svn.wordpress.org/trunk@44113


git-svn-id: http://core.svn.wordpress.org/trunk@43943 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/rest-api/fields/class-wp-rest-meta-fields.php | 8 +++-----
 wp-includes/version.php                                   | 2 +-
 2 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php b/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
index 059f78c6e8..a24a5f649c 100644
--- a/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
+++ b/wp-includes/rest-api/fields/class-wp-rest-meta-fields.php
@@ -317,19 +317,17 @@ abstract class WP_REST_Meta_Fields {
 			);
 		}
 
-		$meta_key   = wp_slash( $meta_key );
-		$meta_value = wp_slash( $value );
-
 		// Do the exact same check for a duplicate value as in update_metadata() to avoid update_metadata() returning false.
 		$old_value = get_metadata( $meta_type, $object_id, $meta_key );
+		$subtype   = get_object_subtype( $meta_type, $object_id );
 
 		if ( 1 === count( $old_value ) ) {
-			if ( $old_value[0] === $meta_value ) {
+			if ( (string) sanitize_meta( $meta_key, $value, $meta_type, $subtype ) === $old_value[0] ) {
 				return true;
 			}
 		}
 
-		if ( ! update_metadata( $meta_type, $object_id, $meta_key, $meta_value ) ) {
+		if ( ! update_metadata( $meta_type, $object_id, wp_slash( $meta_key ), wp_slash( $value ) ) ) {
 			return new WP_Error(
 				'rest_meta_database_error',
 				__( 'Could not update meta value in database.' ),
diff --git a/wp-includes/version.php b/wp-includes/version.php
index aa8f6d5480..c05a6c2d6f 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.1-alpha-44112';
+$wp_version = '5.1-alpha-44113';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.