Updated reference articles to Symfony 4

[javiereguiluz]

This fixes #8642.

---

I want to update these two files more deeply in a separate PR, so here their changes are minimal:

• reference/events.rst
• reference/dic_tags.rst

---

Now, some questions:

1) I've moved all custom Doctrine clases (custom DQL functions, custom DBAL types, custom database drivers, etc.) under App\Bridge\Doctrine\ namespace (e.g. Acme\HelloBundle\DQL\DatetimeFunction -> App\Bridge\Doctrine\DQL\DatetimeFunction). I saw this in a Symfony app and I like it. Do you agree?

2) I don't know how to update this section from /reference/configuration/framework.rst:

resources
"""""""""

**type**: ``string[]`` **default**: ``['FrameworkBundle:Form']``

A list of all resources for form theming in PHP. This setting is not required
if you're using the Twig format for your templates, in that case refer to
:ref:`the form article <forms-theming-twig>`.

Assume you have custom global form themes in
``src/Resources/views/Form``, you can configure this like:

.. configuration-block::

    .. code-block:: yaml

        # config/packages/framework.yaml
        framework:
            templating:
                form:
                    resources:
                        - 'WebsiteBundle:Form'

    [...]

.. note::

    The default form templates from ``FrameworkBundle:Form`` will always
    be included in the form resources.

.. seealso::

    See :ref:`forms-theming-global` for more information.

3) The reference/configuration/doctrine.rst contains A LOT of references to bundles, including options designed for bundles (prefix, alias, is_bundle) What should we do?

• Remove all references to bundles, including those options?
• Maintain all those options but update their explanations using the default Symfony Flex Recipe config? (see https://github.com/symfony/recipes/blob/db32040b48e9cf15299e7702a75a49e76999ff3f/doctrine/doctrine-bundle/1.6/config/packages/doctrine.yaml#L9-L15)
• ...?

[weaverryan]

1. I actually don't love the Bridge part. It doesn't have much "meaning", and it would be harder to find Doctrine stuff. Do you have a counter-argument?

2. ... the form theming stuff... I guess that's still supported? So we should keep it for now. I think this is still accurate as-is. Except for:

src/Resources/views/Form -> templates/form_themes
'WebsiteBundle:Form' -> form_themes

But I'm not 100% if that's accurate. But I think we should just try it.

3. Hmm. Emphasis should definitely be given to the mapping configuration that we use for Flex (e.g. https://github.com/symfony/recipes/blob/db32040b48e9cf15299e7702a75a49e76999ff3f/doctrine/doctrine-bundle/1.6/config/packages/doctrine.yaml#L9-L15). Should we continue to show is_bundle: true? Hmm, maybe just mention it. But I think we should show is_bundle: false-based configuration.

[weaverryan]

Status: Needs work

[javiereguiluz]

I've made all requested changes. Later we can further reword the part about bundles/non-bundles to reduce the bundles section to a note/tip ... but for now this could be good enough. Thanks.

[weaverryan]

Btw, I took out these "default value is". These aren't really the default values - it's just what you get out-of-the-box with the recipe. And I think if you're configuring these things, then you are clearly looking at your doctrine.yaml file, so you will see those values there I think not mentioning these is a bit less confusing.