From 9e33977bc9a1229226c84d5ec4d4d9c29173f99a Mon Sep 17 00:00:00 2001
From: Sergey Biryukov <sergeybiryukov.ru@gmail.com>
Date: Sun, 1 Aug 2021 14:55:56 +0000
Subject: [PATCH] Themes: Make sure `get_theme_mods()` always returns an array.

This avoids a "Cannot access offset of type string on string" fatal error in `set_theme_mod()` on PHP 8 if the `theme_mods_$theme_slug` option has an incorrect value, e.g. an empty string instead of an array.

With this change, `set_theme_mod()` should be able to resolve the issue by saving a correct value.

Follow-up to [15736], [15739], [30672], [32629], [32632].

Props xknown.
See #51423.
Built from https://develop.svn.wordpress.org/trunk@51524


git-svn-id: http://core.svn.wordpress.org/trunk@51135 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-includes/theme.php   | 10 +++++++++-
 wp-includes/version.php |  2 +-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index dae7ed7e4c..7d1669caf1 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -966,23 +966,31 @@ function validate_theme_requirements( $stylesheet ) {
  * Retrieves all theme modifications.
  *
  * @since 3.1.0
+ * @since 5.9.0 The return value is always an array.
  *
- * @return array|void Theme modifications.
+ * @return array Theme modifications.
  */
 function get_theme_mods() {
 	$theme_slug = get_option( 'stylesheet' );
 	$mods       = get_option( "theme_mods_$theme_slug" );
+
 	if ( false === $mods ) {
 		$theme_name = get_option( 'current_theme' );
 		if ( false === $theme_name ) {
 			$theme_name = wp_get_theme()->get( 'Name' );
 		}
+
 		$mods = get_option( "mods_$theme_name" ); // Deprecated location.
 		if ( is_admin() && false !== $mods ) {
 			update_option( "theme_mods_$theme_slug", $mods );
 			delete_option( "mods_$theme_name" );
 		}
 	}
+
+	if ( ! is_array( $mods ) ) {
+		$mods = array();
+	}
+
 	return $mods;
 }
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f456c53adc..152d26baaf 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.9-alpha-51523';
+$wp_version = '5.9-alpha-51524';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.