This PR was merged into the 3.4 branch.Discussion----------[EventDispatcher] Fix unknown priority| Q             | A| ------------- | ---| Branch?       | 3.4| Bug fix?      | yes| New feature?  | no| BC breaks?    | no     <!-- seehttps://symfony.com/bc -->| Deprecations? | no| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->| Fixed tickets | #...   <!-- #-prefixed issue number(s), if any -->| License       | MIT| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->Somehow, after#29411 the profiler actually shows the security firewall `ContextListener`.This listener removes itself at call time, but at this point it's wrapped reference is already in the call stack; to be displayed in the profiler.Because the wrapped listener lazily collects its priority - it asks it from the dispatcher -  we get null; the listener was already removed.This causes the profiler to render `-` by default:![image](https://user-images.githubusercontent.com/1047696/50850320-d5c5ee80-1379-11e9-8516-0c6bc54512ce.png)This fixes it by always passing the expected priority at call time.Commits-------9fb619a [EventDispatcher] Fix unknown priority