From 9ede1fe55b4511c27b131efde614b3338432b35d Mon Sep 17 00:00:00 2001
From: hellofromTonya <hellofromTonya@git.wordpress.org>
Date: Tue, 30 Nov 2021 20:11:02 +0000
Subject: [PATCH] Formatting: Handle non-scalar types passed to
 `sanitize_key()`.

`sanitize_key()` expects a string type for the given `key`. Passing any other data type to `strtolower()` can result in `E_WARNING: strtolower() expects parameter 1 to be string, array given`.

A check is added that if the key is not a string, the key is set to an empty string. For performance, the additional string processing is skipped if the key is an empty string.

This change maintains backwards-compatibility for valid string keys while fixing the bug of non-string keys.

Props costdev, dd32.
Fixes #54160.
Built from https://develop.svn.wordpress.org/trunk@52292


git-svn-id: http://core.svn.wordpress.org/trunk@51884 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/formatting.php | 11 +++++++++--
 wp-includes/version.php    |  2 +-
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/wp-includes/formatting.php b/wp-includes/formatting.php
index c524b06928..576b3c657a 100644
--- a/wp-includes/formatting.php
+++ b/wp-includes/formatting.php
@@ -2137,8 +2137,15 @@ function sanitize_user( $username, $strict = false ) {
  */
 function sanitize_key( $key ) {
 	$raw_key = $key;
-	$key     = strtolower( $key );
-	$key     = preg_replace( '/[^a-z0-9_\-]/', '', $key );
+
+	if ( ! is_string( $key ) ) {
+		$key = '';
+	}
+
+	if ( '' !== $key ) {
+		$key = strtolower( $key );
+		$key = preg_replace( '/[^a-z0-9_\-]/', '', $key );
+	}
 
 	/**
 	 * Filters a sanitized key string.
diff --git a/wp-includes/version.php b/wp-includes/version.php
index a720a13e36..d890e34c51 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-52291';
+$wp_version = '5.9-alpha-52292';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.