Symfony version(s) affected

5.4

Description

I followed this guide:
https://symfony.com/doc/5.x/event_dispatcher.html

and I created a class App\Listeners\ExceptionListener.php

but in services.yaml I mistyped the class name as:

services:
    App\Listener\ExceptionListener:
        tags: [kernel.event_listener]

Note the namespace Listener without the s.

I got this confusing error:

Service "App\Listener\ExceptionListener" must define the "event" attribute on "kernel.event_listener" tags.

which didn't help much, because I was becoming stupid trying to figure out why it complained about a missing attribute that should be optional.

Until I figured out I had misspelled the namespace. To the error message's credit, it does repeat the name of the class, so that gives an opportunity to catch it (which I missed), but still, the error message is unnecessarily misleading. It's specifically directing my attention to a place where the issue is not.

The error should have said something like: "Service App\Listener\ExceptionListener does not exist." (and if it can add a "Did you mean one of the following...?" that would be great).

How to reproduce

In services.yaml, add:

services:
    App\Some\NonExistentListener:
        tags: [kernel.event_listener]

Possible Solution

No response

Additional Context

No response