Payment to manual invoice causes webhook error

[mikejpeters]

Description

If an invoice is created manually using Stripe dashboard and a customer pays that invoice, the invoice.payment_succeeded event is sent with a null subscription, e.g.:

{
  "object": {
    "id": "in_123abc",
    "object": "invoice",
    "billing_reason": "manual",
    "paid": true,
    "subscription": null
  }
}

In this case, this plugin attempts to find a subscription using a null reference, which errors with Stripe\Exception\InvalidArgumentException The resource ID cannot be null or whitespace.

commerce-stripe/src/base/SubscriptionGateway.php

Lines 895 to 903 in baa6709

	$subscriptionReference = $stripeInvoice['subscription'];
	$counter = 0;
	$limit = 5;
	do {
	// Handle cases when Stripe sends us a webhook so soon that we haven't processed the subscription that triggered the webhook
	sleep(1);
	$subscription = Subscription::find()->status(null)->reference($subscriptionReference)->one();

I think it should ignore the event when the subscription property is null, because it's not applicable to Craft CMS.

(I think the existing behavior doesn't cause any serious problems in Craft, but having errors thrown for improperly handled situations makes it more difficult to determine when there are important errors that require more urgent attention.)

Steps to reproduce

1. Manually invoice (using Stripe Dashboard) and pay

Additional info

• Craft CMS version: 4.13.9
• Stripe for Craft Commerce version: 4.1.5.1
• PHP version: 8.0.30
• Database driver & version:
• Plugins & versions:

[linear]

PT-2389 Payment to manual invoice causes webhook error