Fix empty array issue in gateway settings

.gitignore

@@ -5,4 +5,5 @@
 *.swp
 *.out
 .svn/
-.vscode
+.vscode
+vendor

README.txt

@@ -4,7 +4,7 @@ Donate link: https://paypal.me/KarolinaVyskocilova
 Tags: ecommerce, woocommerce, payment gateway, fee
 Requires at least: 4.6
 Tested up to: 5.8
-Stable tag: 2.1.0
+Stable tag: 2.1.1
 License: GPLv2 or later
 License URI: http://www.gnu.org/licenses/gpl-2.0.html
 
@@ -35,7 +35,7 @@ Requires at least WooCommerce 2.6, compatible with WooCommerce 3.2+ (recommended
 - [WooCommerce Multi-Currency](https://woocommerce.com/products/multi-currency/) when the store currency is USD
 
 = Limitations =
-- It seems that Mercadopago gateway is not handling WC_Fee correctly. Get in touch with Mercadopago support.
+- It seems that Mercadopago gateway is not handling WC_Fee correctly. Get in touch with Mercadopago support (and I'm happy to help them fix the issue)
 - Better not use it with PayPal. (Legal issue, see FAQ as well.)
 - Doesn't work on "Pay for order" pages (manually created orders or canceled payments), because of [WC limitations](https://github.com/woocommerce/woocommerce/issues/17794)
 
@@ -100,6 +100,10 @@ Either post it on [GitHub](https://github.com/vyskoczilova/woocommerce-payforpay
 
 == Changelog ==
 
+= 2.1.1 (2021-08-17) =
+
+* Fix - check if array passe in gateway settings (fixes [Mercadopago error](https://wordpress.org/support/topic/fatal-error-mercado-pago-compatibility/))
+
 = 2.1.0 (2021-07-30) =
 
 * New filter introduced `woocommerce_pay4pay_get_current_gateway_settings` ([#61](https://github.com/vyskoczilova/woocommerce-payforpayment/pull/61))

inc/class-pay4pay-admin.php

@@ -230,7 +230,7 @@ public function add_payment_options( ) {
 
 		foreach ( WC()->payment_gateways()->payment_gateways() as $gateway_id => $gateway ) {
 			$form_fields['pay4pay_item_title']['default'] = $gateway->title;
-			$gateway->form_fields = array_merge($gateway->form_fields, $form_fields); // Fix Mercadopago integration
+			$gateway->form_fields = array_merge(is_array($gateway->form_fields) ? $gateway->form_fields : [], $form_fields);
 			if ( version_compare( WC_VERSION, '3.7', '<' )) {
 				add_action( 'woocommerce_update_options_payment_gateways_' . $gateway->id, array( $this,'update_payment_options' ), 20 );
 			}

woocommerce-payforpayment.php

@@ -3,7 +3,7 @@
 Plugin Name: Pay for Payment for WooCommerce
 Plugin URI: https://kybernaut.cz/pluginy/woocommerce-pay-for-payment/
 Description: Setup individual charges for each payment method in WooCommerce.
-Version: 2.1.0
+Version: 2.1.1
 Author: Karolína Vyskočilová
 Author URI: https://kybernaut.cz
 License: GPL-2.0+