bug #660 Increasing LiveComponentSubscriber ExceptionEvent priority to avoid excess logging (weaverryan)

This PR was merged into the 2.x branch.

Discussion
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Increasing LiveComponentSubscriber ExceptionEvent priority to avoid excess logging

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| Tickets       | None
| License       | MIT

Hi!

If you use the `ComponentWithFormTrait`, when validation fails, a `UnprocessableEntityHttpException` is thrown. This is caught by the `ExceptionEvent` listener on `LiveComponentSubscriber`, which renders the component. It's a very normal, excepted flow.

However, currently, the `LiveComponentSubscriber` may run after the core `ErrorListener` as both have a priority of 0. By making our subscriber run first, it avoids unnecessary logging of UnprocessableEntityHttpException by that listener.

Caught in the wild on the Symfonycasts code 🎥

Cheers!

Commits
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b75a19e Increasing LiveComponentSubscriber ExceptionEvent priority to avoid unnecessary logging

Author: weaverryan

src/LiveComponent/src/EventListener/LiveComponentSubscriber.php

@@ -297,7 +297,8 @@ public static function getSubscribedEvents(): array
             ControllerEvent::class => 'onKernelController',
             ViewEvent::class => 'onKernelView',
             ResponseEvent::class => 'onKernelResponse',
-            ExceptionEvent::class => 'onKernelException',
+            // priority so that the exception is processed before it can be logged as an error
+            ExceptionEvent::class => ['onKernelException', 20],
         ];
     }