Add a host access handler

Excellent suggestion @jonathanshaw!

Here is a rough demonstration of how this might work.

This has a fair number of test failures. Before spending time debugging them it would help to:
1. Have input on john.oltman on how this seems in general
2. Get 🐛 Fix access cacheability Needs review committed

Cacheability has been committed. Will give input on the approach later this week.

Sorry for the delay, this is back on my radar for another look in the near future.

I like the direction this is going. Let's decide if we're going to create a new service named "RegistrationAccessChecker" as mentioned in https://www.drupal.org/project/registration/issues/3464137 ✨ Make it possible to customise who can administer registrations Active . If we are, then instead of calling host_entity->access with administer related permission names in a few places, you'd call the new service; the host entity operations to keep in that case would be (renaming to singular to be operation minded and not permission sounding):

view_registration
update_registration
delete_registration
manage_settings
register_self
register_authenticated
register_anonymous

As far as retaining the ability for developers to customize "administer" rights (since there would not be administer operations) - if we do the new service, that service can implement an alter hook e.g. hook_registration_access_check.

I updated the previous comment to fix the operation names. We do want plural here as a host has N registrations.

This will need updating if ✨ Make it possible to customise who can administer registrations Active is committed first, or vice versa.

Committed #3464137 first

I've addressed the impact of [##3464137], but we need test coverage for hook_registration_host_access().

Finally I think this is ready.

This is very close to being merged.

Unfortunately extending EntityAccessControlHandler is a breach of the interface:

  37     Parameter #1 $host_entity (Drupal\registration\HostEntityInterface)      
         of method                                                                
         Drupal\registration\RegistrationHostAccessControlHandler::access() is    
         not contravariant with parameter #1 $entity                              
         (Drupal\Core\Entity\EntityInterface) of method                           
         Drupal\Core\Entity\EntityAccessControlHandler::access().                 
  105    Parameter #1 $host_entity (Drupal\registration\HostEntityInterface)      
         of method                                                                
         Drupal\registration\RegistrationHostAccessControlHandler::checkAccess()  
         is not contravariant with parameter #1 $entity                           
         (Drupal\Core\Entity\EntityInterface) of method                           
         Drupal\Core\Entity\EntityAccessControlHandler::checkAccess(). 

Question about adding a test

Answered

Merged, great stuff Jonathan

Fumbled the commit message on 3.3.x but otherwise it's in and there is no going back. Got it right on 3.1.x.

3.1.x is failing tests due to a composer issue - may be something upstream - will look into later

Automatically closed - issue fixed for 2 weeks with no activity.