Extract error message

modules/ppcp-wc-gateway/src/Exception/GatewayGenericException.php

@@ -11,6 +11,7 @@ namespace WooCommerce\PayPalCommerce\WcGateway\Exception;
 
 use Exception;
 use Throwable;
+use WooCommerce\PayPalCommerce\WcGateway\Gateway\Messages;
 
 /**
  * Class GatewayGenericException
@@ -23,7 +24,7 @@ class GatewayGenericException extends Exception {
 	 */
 	public function __construct( ?Throwable $inner = null ) {
 		parent::__construct(
-			__( 'Failed to process the payment. Please try again or contact the shop admin.', 'woocommerce-paypal-payments' ),
+			Messages::generic_payment_error_message(),
 			$inner ? (int) $inner->getCode() : 0,
 			$inner
 		);

modules/ppcp-wc-gateway/src/Gateway/Messages.php

@@ -0,0 +1,27 @@
+<?php
+/**
+ * Common messages.
+ *
+ * @package WooCommerce\PayPalCommerce\WcGateway\Gateway
+ */
+
+declare(strict_types=1);
+
+namespace WooCommerce\PayPalCommerce\WcGateway\Gateway;
+
+/**
+ * Class Messages
+ */
+class Messages {
+	/**
+	 * The generic payment failure message.
+	 *
+	 * @return string
+	 */
+	public static function generic_payment_error_message(): string {
+		return apply_filters(
+			'woocommerce_paypal_payments_generic_payment_error_message',
+			__( 'Failed to process the payment. Please try again or contact the shop admin.', 'woocommerce-paypal-payments' )
+		);
+	}
+}

modules/ppcp-wc-gateway/src/Gateway/ProcessPaymentTrait.php

@@ -232,8 +232,7 @@ trait ProcessPaymentTrait {
 			return $this->handle_payment_failure(
 				$wc_order,
 				new Exception(
-					__( 'Failed to process the payment. Please try again or contact the shop admin.', 'woocommerce-paypal-payments' )
+					Messages::generic_payment_error_message() . ' ' . $error->getMessage(),
-					. ' ' . $error->getMessage(),
 					$error->getCode(),
 					$error
 				)