From 0d8727bec88b7c8aff18f279c8ad6dbd8d73f604 Mon Sep 17 00:00:00 2001
From: Peter Wilson <wilson@peterwilson.cc>
Date: Tue, 22 Jun 2021 05:56:57 +0000
Subject: [PATCH] Themes: Improve Gutenberg check before activating an FSE
 theme.

Account for sites enabling Gutenberg as an mu-plugin when determining whether full-site-editing themes can be enabled. This replaces the check the plugin is active with a check whether the function `gutenberg_is_fse_theme()` is defined.

Follow up to [51193].

Props noisysocks, peterwilsoncc, SergeyBiryukov.
See #53410.


Built from https://develop.svn.wordpress.org/trunk@51197


git-svn-id: http://core.svn.wordpress.org/trunk@50806 1a063a9b-81f0-0310-95a4-ce76da25c4cd
---
 wp-admin/customize.php  | 2 +-
 wp-includes/theme.php   | 2 +-
 wp-includes/version.php | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/wp-admin/customize.php b/wp-admin/customize.php
index fdbc7f7b9e..699ecdf914 100644
--- a/wp-admin/customize.php
+++ b/wp-admin/customize.php
@@ -189,7 +189,7 @@ do_action( 'customize_controls_head' );
 			// Check if the theme requires the FSE to work correctly.
 			$theme_tags = $wp_customize->theme()->get( 'Tags' );
 
-			if ( ! empty( $theme_tags ) && in_array( 'full-site-editing', $theme_tags, true ) && ! is_plugin_active( 'gutenberg/gutenberg.php' ) ) {
+			if ( ! empty( $theme_tags ) && in_array( 'full-site-editing', $theme_tags, true ) && ! function_exists( 'gutenberg_is_fse_theme' ) ) {
 				$fse_safe = false;
 			}
 			?>
diff --git a/wp-includes/theme.php b/wp-includes/theme.php
index cbf1849d21..a1a4af1946 100644
--- a/wp-includes/theme.php
+++ b/wp-includes/theme.php
@@ -911,7 +911,7 @@ function validate_theme_requirements( $stylesheet ) {
 	// If the theme is a Full Site Editing theme, check for the presence of the Gutenberg plugin.
 	$theme_tags = $theme->get( 'Tags' );
 
-	if ( ! empty( $theme_tags ) && in_array( 'full-site-editing', $theme_tags, true ) && ! is_plugin_active( 'gutenberg/gutenberg.php' ) ) {
+	if ( ! empty( $theme_tags ) && in_array( 'full-site-editing', $theme_tags, true ) && ! function_exists( 'gutenberg_is_fse_theme' ) ) {
 		return new WP_Error(
 			'theme_requires_fse',
 			sprintf(
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 3e0920199f..efe0472e0d 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-beta2-51196';
+$wp_version = '5.8-beta2-51197';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.