[meta] Drupal modernization

Don't want to directly add it to the issue summary, but I immediately thought of #2350509: Implement auto-route generation for all core entities and convert all of the core entities. → when reading this...

No that's a great example! Added.

Current idea is to try to pick a handful of issues in different areas to concentrate on, and see if we can pick them off bugsmash style.

Organised these into topic groupings.

Updated IS with priorities from a discussion at Barcelona2024

Rely on the issue title to explain the issue.

While 📌 OOP hooks using event dispatcher Needs review is a huge improvement (and one I'm deeply grateful for :), I think it's undeniable that having both Symfony Events and Drupal Hooks at the same time means having two competing implementations of the observer pattern. In most cases there is not a clear reason to pick one or the other, if not a matter of "taste". In an ideal world we'd have a single system covering all use cases and core would promote consistency in contrib by only using that. In an ideal world both Symfony and Drupal would use that same system :)

So #11 is true but I do think OOP hooks gets us closer to a unified situation:

In most cases there is not a clear reason to pick one or the other, if not a matter of "taste".

While that's true now, people kept wanting to use events so they could have OOP implementations, and now that's not necessary. So apart from a handful of use cases like ::stopPropagation() it should be easier to default to hooks ;)

In an ideal world both Symfony and Drupal would use that same system :)

We're using event dispatcher under the hood for OOP hooks, see ModuleHandler::getHookListeners()

The [#Hook] attribute is to a large extent a bc-compatible implementation of [#AsEventListener] https://symfony.com/doc/current/event_dispatcher.html#defining-event-lis...

Hook invoking still needs to go via the module handler, but that should be a much thinner layer when we're able to remove the bc layers for procedural hooks (in Drupal 13..).

So what we have in 11.1.x is mostly a thin-ish layer on top of events, which is heavily opinionated to a particular style of Symfony events and listeners (no Event class, ::getSubscribedEvents() etc. - and one that is doing a lot of bc heavy lifting for procedural hooks.

There's a lot still to do though, issues like ✨ Support hooks (Hook attribute) in components Active for example.

Switching an issue.