Test for WooCommerce Subscriptions in upgrade instead of extension.

src/Extension.php

@@ -83,14 +83,6 @@ public function setup() {
 
 		add_action( 'admin_init', [ __CLASS__, 'admin_init' ], 15 );
 
-		/**
-		 * On admin initialize we mark the upgrades as executable. This needs to run before
-		 * the `wp-pay/core` admin init install routine (priority 5).
-		 *
-		 * @link https://github.com/wp-pay/core/blob/2.2.0/src/Admin/Install.php#L65
-		 */
-		add_action( 'admin_init', [ $this, 'admin_init_upgrades_executable' ], 4 );
-
 		add_filter( 'woocommerce_payment_gateways', [ __CLASS__, 'payment_gateways' ] );
 
 		add_filter( 'woocommerce_thankyou_order_received_text', [ __CLASS__, 'woocommerce_thankyou_order_received_text' ], 20, 2 );
@@ -130,17 +122,6 @@ public static function init() {
 		self::register_settings();
 	}
 
-	/**
-	 * Upgrades are only executable when no Restrict Content Pro upgrade is needed.
-	 *
-	 * @return void
-	 */
-	public function admin_init_upgrades_executable() {
-		$executable = function_exists( '\wcs_get_subscription' );
-
-		$this->get_upgrades()->set_executable( $executable );
-	}
-
 	/**
 	 * Add the gateways to WooCommerce.
 	 *

src/Upgrade420.php

@@ -36,6 +36,11 @@ class Upgrade420 extends Upgrade {
 	public function __construct() {
 		parent::__construct( '4.2.0' );
 
+		// Check for WooCommerce Subscriptions.
+		if ( ! function_exists( '\wcs_get_subscription' ) ) {
+			return;
+		}
+
 		if ( \defined( '\WP_CLI' ) && \WP_CLI ) {
 			$this->cli_init();
 		}