How to handle new/unsupported events sent to mailer webhook? #65119

Context:

1. Follow the documentation to enable Mailer’s webhook: https://symfony.com/doc/current/webhook.html#consuming-webhooks
2. Register to events in the external service (the one called by the bridge)
3. Send emails and receive events in your app

This works until the external service add a new event, then it will result in a ParseException error.

See the difference between Resend’s Event Types and Symfony’s mapping of these events. A fix was added recently to handle 2 new types:

• [Mailer][Resend] Handle the email.failed and email.suppressed webhook events #65034

But this is pretty fragile: any new event added by an external service could trigger a ParseException.

So I’m wondering if this could be improved?

• Replace ParseException with a log message? On one hand, this exception can be tracked by Sentry so it’s easy to get an alert. On the other hand, it logs an exception that is not caused by the app itself, but by the difference between Resend and the webhook receiver side.
  • This may use a toggle in the configuration, with a default value that keep the current behaviour (ParseException), and another option to change the behaviour when an unsupported event is received.
• Add a note in documentation so that users only subscribe to known events?