From 70dea8e3c2ca16cea21447a631e9ded2155eae03 Mon Sep 17 00:00:00 2001
From: audrasjb <audrasjb@git.wordpress.org>
Date: Mon, 11 Apr 2022 20:00:09 +0000
Subject: [PATCH] Formatting: Avoid escaping valid XML values in `esc_xml()`.

This change improves the `esc_xml()` function by replacing two `empty()` checks with `isset()` to cover values that are not equal to `''` but still returning `true` when checked with `empty()`, like `'0'`, `0` or `false`. It also updates the related unit tests accordingly.

Props rumpel2116, pbiron.
Fixes #55399.

Built from https://develop.svn.wordpress.org/trunk@53144


git-svn-id: http://core.svn.wordpress.org/trunk@52733 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/formatting.php | 4 ++--
 wp-includes/version.php    | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/wp-includes/formatting.php b/wp-includes/formatting.php
index 0441866344..eb4acda64b 100644
--- a/wp-includes/formatting.php
+++ b/wp-includes/formatting.php
@@ -4639,11 +4639,11 @@ EOF;
 	$safe_text = (string) preg_replace_callback(
 		$regex,
 		static function( $matches ) {
-			if ( ! $matches[0] ) {
+			if ( ! isset( $matches[0] ) ) {
 				return '';
 			}
 
-			if ( ! empty( $matches['non_cdata'] ) ) {
+			if ( isset( $matches['non_cdata'] ) ) {
 				// escape HTML entities in the non-CDATA Section.
 				return _wp_specialchars( $matches['non_cdata'], ENT_XML1 );
 			}
diff --git a/wp-includes/version.php b/wp-includes/version.php
index c3e0c5e681..5df481479f 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.0-alpha-53143';
+$wp_version = '6.0-alpha-53144';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.