Fix Subscriptions compatibility with SEPA (#4280)

- Fix purchasing a subscription using SEPA
- Fix updating the payment method of an existing subscription to SEPA

Author: malithsen

includes/class-wc-stripe-intent-controller.php

@@ -1241,8 +1241,8 @@ public function confirm_change_payment_from_setup_intent_ajax() {
 
 			// Set the new Stripe payment method ID and customer ID on the subscription.
 			$customer = new WC_Stripe_Customer( wp_get_current_user()->ID );
-			$gateway->set_customer_id_for_order( $subscription, $customer->get_id() );
-			$gateway->set_payment_method_id_for_order( $subscription, $token->get_token() );
+			$gateway->set_customer_id_for_subscription( $subscription, $customer->get_id() );
+			$gateway->set_payment_method_id_for_subscription( $subscription, $token->get_token() );
 
 			// Check if the subscription has the delayed update all flag and attempt to update all subscriptions after the intent has been confirmed. If successful, display the "updated all subscriptions" notice.
 			if ( WC_Subscriptions_Change_Payment_Gateway::will_subscription_update_all_payment_methods( $subscription ) && WC_Subscriptions_Change_Payment_Gateway::update_all_payment_methods_from_subscription( $subscription, $token->get_gateway_id() ) ) {

includes/compat/trait-wc-stripe-subscriptions.php

@@ -319,8 +319,8 @@ public function process_change_subscription_payment_with_deferred_intent( $subsc
 				WC_Subscriptions_Change_Payment_Gateway::update_payment_method( $subscription, $new_payment_method );
 
 				// Attach the new payment method ID and the customer ID to the subscription on success.
-				$this->set_payment_method_id_for_order( $subscription, $payment_method_id );
-				$this->set_customer_id_for_order( $subscription, $payment_information['customer'] );
+				$this->set_payment_method_id_for_subscription( $subscription, $payment_method_id );
+				$this->set_customer_id_for_subscription( $subscription, $payment_information['customer'] );
 
 				// Trigger wc_stripe_change_subs_payment_method_success action hook to preserve backwards compatibility, see process_change_subscription_payment_method().
 				do_action(

includes/payment-methods/class-wc-stripe-upe-payment-gateway.php

@@ -2692,13 +2692,15 @@ protected function handle_saving_payment_method( WC_Order $order, $payment_metho
 		// If the payment method object is a Link payment method, use Link as the payment method type.
 		if ( isset( $payment_method_object->type ) && WC_Stripe_Payment_Methods::LINK === $payment_method_object->type ) {
 			$payment_method_type = WC_Stripe_Payment_Methods::LINK;
+			$payment_method_instance = $this->get_payment_method_instance( $payment_method_type );
 		} elseif ( $this->spe_enabled && isset( $payment_method_object->type ) ) {
 			// When SPE is enabled, use the payment method type from the payment method object
 			$payment_method_type = $payment_method_object->type;
+			$payment_method_instance = $this->get_payment_method_instance( $payment_method_type );
+		} else {
+			$payment_method_instance = $this->payment_methods[ $payment_method_type ];
 		}
 
-		$payment_method_instance = $this->get_payment_method_instance( $payment_method_type );
-
 		// Searches for an existing duplicate token to update.
 		$found_token = WC_Stripe_Payment_Tokens::get_duplicate_token( $payment_method_object, $customer->get_user_id(), $this->id );
 
@@ -2736,6 +2738,17 @@ public function set_payment_method_id_for_order( WC_Order $order, string $paymen
 		$order->save_meta_data();
 	}
 
+	/**
+	 * Set the payment metadata for payment method id for subscription.
+	 *
+	 * @param WC_Subscription $order The order.
+	 * @param string   $payment_method_id The value to be set.
+	 */
+	public function set_payment_method_id_for_subscription( $subscription, string $payment_method_id ) {
+		$subscription->update_meta_data( '_stripe_source_id', $payment_method_id );
+		$subscription->save_meta_data();
+	}
+
 	/**
 	 * Set the payment metadata for customer id.
 	 *
@@ -2749,6 +2762,19 @@ public function set_customer_id_for_order( WC_Order $order, string $customer_id
 		$order->save_meta_data();
 	}
 
+	/**
+	 * Set the payment metadata for customer id for subscription.
+	 *
+	 * Set to public so it can be called from confirm_change_payment_from_setup_intent_ajax()
+	 *
+	 * @param WC_Stripe_Order $order The order.
+	 * @param string   $customer_id The value to be set.
+	 */
+	public function set_customer_id_for_subscription( $subscription, string $customer_id ) {
+		$subscription->update_meta_data( '_stripe_customer_id', $customer_id );
+		$subscription->save_meta_data();
+	}
+
 	/**
 	 * Set the payment metadata for the selected payment type.
 	 *