Simplify and de-duplicate argument validators

+1 for the idea!

The old node argument validator doesn't add any functionality, and so can be removed.

The old user argument validator offers authentication of a single argument of type id, name or both. It also adds filter by role.
[
Notes about this:
If someone has a numeric username, that is also a UID, the numeric username will trump the UID if 'either' is on;
If the UID have gone beyond integer range of the system the UID validation will fail because it compares a cast to integer; I've not even thought about usernames starting with '0' or '0x';
I think I read a bug in the present version that means if the argument being validated is the global $user, the $uid doesn't get set which is then used to reload the user into $account that is actually validated against
].
The Entity user argument validator offers authentication of single or multiple id arguments. It does not filter by role.

The consistent thing to do, consistent with Taxonomy Term would be to split it into ID only and Name only validators (both extended simply on the Entity one - adding the role filtering). This would avoid anomalies, but remove 'either' functionality.
Less consistent, and a little more complicated would be to maintain the mixed functionality, as one validator.

Latter or former?
Looks like just having two clean ID and Name validators, and not a the mixed one, would be best?

This is by no means a finished patch, we could do something like this though?

Made better user of the Entity argument validator plugin, as we can greatly reduce the code in the user classes for validating the actual entity, just extending validateEntity to add our additional check for user roles.

Meh, I didn't match up the method signatures for validateEntity() in haste. Have changed now to EntityInterface. This is not ideal as getUserName() and friends is not on EntityInterface BUT the only entities using this plugin will be users...thoughts?

Let's try and get things back to a passable state.

Ok, moved that around as suggested, and simplified that part of the form. I think it is much better now - good idea berdir!

Made a couple of other small tweaks too while I was there..

Also, attached screenshot of bundle validation radio buttons for content.

1. +++ b/core/modules/user/lib/Drupal/user/Plugin/views/argument_validator/User.php
   @@ -17,76 +17,51 @@
   -    parent::__construct($configuration, $plugin_id, $plugin_definition);
   +  public function __construct(array $configuration, $plugin_id, array $plugin_definition, EntityManagerInterface $entity_manager) {
   +    parent::__construct($configuration, $plugin_id, $plugin_definition, $entity_manager);
    
   -    $this->database = $database;
   +    $this->userStorage = $entity_manager->getStorageController('user');
   

   Nice trick!

2. +++ b/core/modules/user/lib/Drupal/user/Plugin/views/argument_validator/User.php
   @@ -98,79 +73,29 @@ public function buildOptionsForm(&$form, &$form_state) {
   +  protected function validateEntity(EntityInterface $entity) {
    
   +    $role_check = TRUE;
   

   Can we insert something like /** @var ... UserInterface $entity */ here?

3. +++ b/core/modules/user/lib/Drupal/user/Plugin/views/argument_validator/User.php
   @@ -98,79 +73,29 @@ public function buildOptionsForm(&$form, &$form_state) {
   +    return $role_check && parent::validateEntity($entity);
   

   the variable name is kinda odd. I would have expect that this would enabling the checking of the role. maybe just role_check_success or something similar?

Thanks! They are fair points. Done.

Thank you!

2204239-15.patch no longer applies.

error: patch failed: core/modules/user/lib/Drupal/user/Plugin/views/argument_validator/User.php:98
error: core/modules/user/lib/Drupal/user/Plugin/views/argument_validator/User.php: patch does not apply

Rerolling...

Patch #15 rerolled

Thank you.

2204239-21.patch no longer applies.

error: patch failed: core/modules/user/lib/Drupal/user/Tests/Views/ArgumentValidateTest.php:7
error: core/modules/user/lib/Drupal/user/Tests/Views/ArgumentValidateTest.php: patch does not apply

Rerolled.

it is green!

24: 2204239-24.patch queued for re-testing.

Very nice. Committed/pushed to 8.x, thanks!