Fatal error enabling web profiler on 8.1.x

I'm not sure where to get the listener priority from, even though this method is called it is not included in the TraceableEventDispatcherInterface and because of this the documentation on how to use this is missing. This at least allows to enable the module again, and since we didn't report back a priority before this also doesn't regress anything.

The bug that getListenerPriority() is missing from the interface is fixed in Symfony 3.0: Issue 16301: [EventDispatcher] add method getListenerPriority() to interface. I'm not sure what the policy on backporting is for the Symfony project though.

@lussoluca, cross-posted :)

That looks indeed to be the case. I'll open an issue to address this. If I look at how Symfony deals with this, then it seems we will still need it here too. From \Symfony\Component\EventDispatcher\ContainerAwareEventDispatcher:

    /**
     * {@inheritdoc}
     */
    public function getListenerPriority($eventName, $listener)
    {
        $this->lazyLoad($eventName);

        return parent::getListenerPriority($eventName, $listener);
    }

Ok from comment #42 on the symfony 2.8 update issue #2611816-42: Update to symfony 2.8 it appears that core's implementation of ContainerAwareEventDispatcher has consciously omitted the implementation of ::getListenerPriority():

+    public function testGetListenerPriority()
+    {
+        // Override the parent test as our implementation doesn't provider
+        // getListenerPriority().
+    }