I was playing with Symfony Flex when I noticed this:

Create a project with Symfony Flex:

$ composer create-project symfony/skeleton:3.3.x-dev my_project/
$ cd my_project/
$ make serve

Browse http://localhost:8000/

Problem 1: I still see the old exception page design ... because TwigBundle is not installed. I'll propose a solution for this in a separate issue.

Install TwigBundle:

$ composer req twig-bundle

Browse http://localhost:8000/

Problem 2: I can see the new design ... but everything is broken because the JavaScript features are not enabled because we link to src/Symfony/Bundle/WebProfilerBundle/Resources/views/Profiler/base_js.html.twig and that file does not exist (because WebProfilerBundle is not installed).

Install WebProfilerBundle:

$ composer req profiler

Browse http://localhost:8000/

Now everything works as expected.

TwigBundle is not "a real bundle" because is not standalone. If WebProfilerBundle is not installed too, it doesn't work.

Which solution do you propose? The obvious one would be duplicating the WebProfilerBundle's base_js.html.twig file in TwigBundle too. What do you think?