Extract is_link_enabled in a separate static method to fix compatibility issues (#2403)

* Extract is_link_enabled in a separate static method

Author: mordeth

changelog.txt

@@ -2,6 +2,9 @@
 
 = 6.6.0 - 2022-xx-xx =
 
+= 6.5.1 - 2022-08-01 =
+* Fix - Stripe Link fatal error on `get_upe_enabled_payment_method_ids` method.
+
 = 6.5.0 - 2022-07-28 =
 * Add - Stripe Link: Add beta headers for Stripe server requests
 * Add - Stripe Link payment method option in admin

includes/payment-methods/class-wc-stripe-upe-payment-method-link.php

@@ -26,4 +26,22 @@ public function __construct() {
 			'woocommerce-gateway-stripe'
 		);
 	}
+
+	/**
+	 * Return if Stripe Link is enabled
+	 *
+	 * @return bool
+	 */
+	public static function is_link_enabled() {
+		// Assume Link is disabled if UPE is disabled.
+		if ( ! WC_Stripe_Feature_Flags::is_upe_checkout_enabled() ) {
+			return false;
+		}
+
+		return in_array(
+			self::STRIPE_ID,
+			woocommerce_gateway_stripe()->get_main_stripe_gateway()->get_upe_enabled_payment_method_ids(),
+			true
+		);
+	}
 }

woocommerce-gateway-stripe.php

@@ -243,7 +243,9 @@ public function init() {
 				add_filter( 'plugin_row_meta', [ $this, 'plugin_row_meta' ], 10, 2 );
 
 				// Update the email field position.
-				add_filter( 'woocommerce_billing_fields', [ $this, 'checkout_update_email_field_priority' ], 50 );
+				if ( ! is_admin() ) {
+					add_filter( 'woocommerce_billing_fields', [ $this, 'checkout_update_email_field_priority' ], 50 );
+				}
 
 				// Modify emails emails.
 				add_filter( 'woocommerce_email_classes', [ $this, 'add_emails' ], 20 );
@@ -659,13 +661,7 @@ public function get_main_stripe_gateway() {
 			 * @return array WooCommerce checkout fields.
 			 */
 			public function checkout_update_email_field_priority( $fields ) {
-				$is_link_enabled = in_array(
-					WC_Stripe_UPE_Payment_Method_Link::STRIPE_ID,
-					$this->stripe_gateway->get_upe_enabled_payment_method_ids(),
-					true
-				);
-
-				if ( $is_link_enabled ) {
+				if ( isset( $fields['billing_email'] ) && WC_Stripe_UPE_Payment_Method_Link::is_link_enabled() ) {
 					// Update the field priority.
 					$fields['billing_email']['priority'] = 1;